Combo with "BIO 2160-Test Mastering A&P Ch. 11" and 25 others
Nerve impulses
A brief reversal of membrane potential with a total amplitude of 100 mV They do not decrease in strength over distance They are the principal means of neural communication Occur only in the axon of a neuron Nerve Impulse Once initiated it has the same physiology as an Action Potential in a muscle cell. Initiation is by voltage gated Na channels on the membrane of the axon hillock and results from the summation of graded potentials. Threshold - a critical level of depolarization (-55 to -50 mV) At threshold, depolarization becomes self-generating
Of what do we think an engram consists?
A permanent change in the synapses of a specific circuit of neurons that facilitates impulse transmission at those synapses.
What happens wheen the limbic system operates without the influence of other parts of the cerebral cortex?
Normal emotional expression is impaired. (ex: abnormal, uncontrollable fits of rage)
lumbar puncture
A procedure used to remove cerebrospinal fluid from the spinal canal & it's done between L3 & L4 or L4 & L
Describe Depolarization
A reduction in membrane potential (toward zero) Inside of the membrane becomes less negative than the resting potential Increases the probability of producing a nerve impulse
A reflex arc always includes a(n) __________. efferent axon sensory receptor afferent axon A reflex arc always includes all of these structures.
A reflex arc always includes all of these structures.
temporal lobe
A region of the cerebral cortex responsible for hearing and language. Purple area
Motor output
A response to integrated stimuli that activates muscles or glands
Summation of potentials
A single potential cannot induce a nerve impulse at the axon hillock Potentials must summate temporally or spatially to induce an action potential Temporal summation - all potentials are received from the same terminal Spatial summation - postsynaptic neuron is stimulated by a large number of terminals at the same time Both inhibitory (-) and excitatory (+) potentials sum
Which of the following will occur when an excitatory postsynaptic potential (EPSP) is being generated on the dendritic membrane?
A single type of channel will open, permitting simultaneous flow of sodium and potassium.
Which of the following will occur when an excitatory postsynaptic potential (EPSP) is being generated on the dendritic membrane? A single type of channel will open, permitting simultaneous flow of sodium and potassium. Sodium gates will open first, then close as potassium gates open. Specific potassium gates will open. Specific sodium gates will open.
A single type of channel will open, permitting simultaneous flow of sodium and potassium.
midbrain
A small part of the brain above the pons; it contains grey matter, nerve fibers & reflex centers that move the eyes & head (11)
infundibulum
A stalk that attaches the pituitary gland to the hypothalamus.
Relative Refractory Period
A stronger-than-threshold stimulus can initiate another action potential
What are engrams?
A structural traces, or specific part of the brain, where a long term memory is stored.
Types of plasma ion channels
Passive channels - always open Chemically gated channels - open with binding of a specific neurotransmitter Voltage-gated channels - open and close in response to membrane potential Mechanically gated channels - open and close in response to physical deformation of receptors
trigeminal neuralgia
AKA Tic Douloreux. Lightning-like pain. Electric shocks caused by compression of trigeminal nerve
Describe information transfer in a chemical synapse
AP arrives at axon terminal of the presynaptic neuron and opens voltage-gated Ca2+ channels Synaptotagmin protein binds Ca2+ and promotes fusion of synaptic vesicles with axon membrane Exocytosis of neurotransmitter occurs Neurotransmitter diffuses and binds to receptors (often chemically gated ion channels) on the postsynaptic neuron Ion channels are opened, causing an excitatory or inhibitory event (graded potential) See p. 409 in textbook
transmitter
AS A RESULT OF PRESYNAPTIC FACILITATION: An action potential in the presynaptic terminal leads to a greater amount of Ca2+ influx, and therefore more ______ is released
transmitter
AS A RESULT OF PRESYNAPTIC INHIBITION: Fewer Ca2+ channels are opened with a subsequent action potential in Presynaptic cell and therefore the Ca2+ influx will be reduced. Less Ca2+ influx leads to less _______ release and a smaller EPSP.
The neuromuscular junction is a well-studied example of a chemical synapse. Which of the following statements describes a critical event that occurs at the neuromuscular junction?
Acetylcholine is released by axon terminals of the motor neuron.
What enzyme rapidly decomposes the acetylcholine that cholinergic fibers release
Acetylcholinesterase
What is the stimulus in the withdrawal reflex
Activated skin receptors
Neurotransmitters: Novel Messengers Nitric oxide (NO)
Activates the intracellular receptor guanylyl cyclase Is involved in learning and memory Carbon monoxide (CO) is a main regulator of cGMP in the brain May explain narcotic effects of Nitrogen under pressure and CO excess
What is the response in the withdrawal reflex
Activation of muscles
Much of the norepinephrine released from adrenergic fibers is released from the synapse by what
Active transport
The axoplasm of the axon contains which of the following? neurofibrils vesicles neurotubules mitochondria All of the answers are correct.
All of the answers are correct.
The effect that a neurotransmitter has on the postsynaptic membrane depends on the characteristics of the receptors. the nature of the neurotransmitter. the quantity of neurotransmitters released. the frequency of neurotransmitter release. All of the answers are correct.
All of the answers are correct.
The efferent division of the peripheral nervous system innervates: heart muscle cells skeletal muscle cells smooth muscle cells glandular cells All of the answers are correct.
All of the answers are correct.
The function of the astrocytes in the CNS includes which of the following? adjusting the composition of the interstitial fluid guiding neuron development maintaining the blood-brain barrier repairing damaged neural tissue All of the answers are correct.
All of the answers are correct.
Which of the following is a recognized class of opioid neuromodulators? dynorphins endomorphins enkephalins endorphins All of the answers are correct.
All of the answers are correct.
Which of the following is true regarding an epidural block? It can provide sensory and motor anesthesia, depending on the anesthetic selected. It affects only the spinal nerves in the immediate area of the injection. It can provide mainly sensory anesthesia, depending on the anesthetic selected. It is commonly used as a method of pain control during labor and delivery. All of the answers are correct.
All of the answers are correct.
A synaptic cleft, or synaptic gap, can be found between a neuron and ______. another neuron. a gland. a muscle cell.
All of them
Ridges or convolutions, separated by grooves that mark the cerebrums surface
Gyri
at once
During spatial summation many presynaptic cells are sending signals. Postsynaptic cell has to sum all the info ___ ___.
cancel
During spatial summation of EPSPs and IPSPs changes in membrane potential can _____ each other out.
depolarizing
During stimulatory effect neurotransmitters act on receptors on postsynaptic cell and have the effect of ______ the postsynaptic cell.
last
During temporal summation the action potentials fire close together, the _____ action potential fired is what causes the depolarization.
open
During the depolarizing phase, Na+ channels ____.
inactivating, k+
During the repolarizing phase, the Na+ channels are _____, and the ___ channels open.
leakage
During the resting state, ALL gated Na+ and K+ channels are closed. Only the ____ channels are opened, maintaining resting membrane potential.
no
During the resting state, ___ ions move through voltage gated channels.
An example of the brain modifying reflex patterns is _________. postponing emptying a full urinary bladder holding your breath deliberately walking on hot coals All of these are examples of the brain modifying reflex patterns.
All of these are examples of the brain modifying reflex patterns.
wernicke's area
An area of the brain's left hemisphere that is involved in language comprehension.
Muktiple Sclerosis
An autoimmune disease that mainly affects young adults Symptoms: visual disturbances, weakness, loss of muscular control, and urinary incontinence Immune cells attack and damage the neurilemma and myelin sheath Shunting and short-circuiting of nerve impulses occurs
cardio
An example of electrical synapse is between ______-myocytes.
What conditions will increase the diffusion of molecules, such as neurotransmitters?
An increase in the amount of neurotransmitter exocytized by the presynaptic axon.
List types of neuroglia and in what systems they are found
Astrocytes (CNS) Microglia (CNS) Ependymal cells (CNS) Oligodendrocytes (CNS) Satellite cells (PNS) Schwann cells (PNS)
receptor proteins; postsynaptic
At a chemical synapse, ____________ are found only in the plasma membrane of the ____________ cell. A) neurotransmitters; postsynaptic B) receptor proteins; postsynaptic C) neurotransmitters; presynaptic D) receptor proteins; presynaptic
What two parts typically make up a chemical synapse?
Axon terminal of the presynaptic neuron, which contains synaptic vesicles Receptor region on the postsynaptic neuron Gap between the two is the SYNAPTIC CLEFT
Synaptic cleft
Axonal terminals are separated from the next neuron by a gap called the ______
neurotransmitters
Axonal terminals contain vesicles with ______
Which of the following is not a chemical class of neurotransmitters? A) acetycholine B) amino acid C) biogenic amine D) ATP and other purines E) nucleic acid
E
Which of the following is not a function of astrocytes? A) support and brace neurons B) anchor neurons to blood vessels C) guide the migration of young neurons, synapse formation, and helping to determine capillary permeability D) control the chemical environment around neurons E) provide the defense for the CNS
E
Which of the following correctly describes a graded potential? A) long distance signaling B) amplitude of various sizes C) voltage stimulus to initiate D) voltage regulated repolarization
B
Which of the following describes the excitatory postsynaptic potential? A) short distance hyperpolarization B) short distance depolarization C) opens K+ or Cl- channels D) moves membrane potential away from threshold
B
Which of the following describes the nervous system integrative function? A) senses changes in the environment B) analyzes sensory information, stores information, makes decisions C) responds to stimuli by gland secretion or muscle contraction
B
Which of the following is false or incorrect? A) An excitatory postsynaptic potential occurs if the excitatory effect is greater than the inhibitory effect but less than threshold. B) A nerve impulse occurs if the excitatory and inhibitory effects are equal. C) An inhibitory postsynaptic potential occurs if the inhibitory effect is greater than the excitatory, causing hyperpolarization of the membrane.
B
Which of the following neurotransmitters inhibits pain and is mimicked by morphine, heroin, and methadone? A) acetylcholine B) endorphin C) serotonin D) nitric oxide
B
putamen *** not on test #11
Basal ganglia associated with sensorimotor and movement *** not on test #11
Often called the basal ganglia..masses of gray matter deep within the cerebral hemispheres
Basal nuclei
The two main function so the spinal card are
Center for spinal reflexes & a conduit for impulses to and from the brain
The gray commissure surrounds the
Central canal
Thin layer of gray matter on the surface of the white matter in the cerebellum is known as the
Cerebellar cortex
The cerebellum communicates with other parts of the CNS by means of 3 pairs of nerve tracts called
Cerebellar peduncles
Large mass of tissue inferior to the occipital loves of the cerebrum & posterior to the pons & the medulla oblongata is the
Cerebellum
Narrow canal that passes lengthwise through the brainstem and connects the 4th ventricle to the 3rd is called
Cerebral aqueduct
Spaces and brain regions produced by the mesencephalon
Cerebral aqueduct; midbrain
Outermost portion of the cerebrum is covered by a thin layer of gray matter which houses abt 75% of all the neuron cell bodies in the nervous system is called the
Cerebral cortex
2 prominent bundles of nerve fibers on the underside of the midbrain comprise the..which include the corticospinal tracts & are the main motor pathways btwn the cerebrum & the lower parts of the nervous system
Cerebral peduncles
Largest part of the mature brain & has 2 hemispheres
Cerebrum
occipital lobe
Cerebrum Lobe responsible for vision (yellow area)
Thickening of the spinal cord in the neck region that supplies nerves to the upper limbs is called what
Cervical enlargement
Plexus of nerves to the muscles & skin of the neck formed btwn C1-C4
Cervical plexus
Neurotransmitters
Chemicals used for neuronal communication with the body and the brain 50 different neurotransmitters have been identified Classified chemically and functionall
Preganglionic neurons of the sympathetic & parasympathetic division all secrete acetylcholine & are called
Cholinergic
__________ receptors on skeletal muscle cells are of the __________ type.
Cholinergic; nicotinic
Tiny, reddish cauliflower-like masses of specialized capillaries from the pia mater that secrete CSF are called
Choroid plexuses
Chemical transmitters
Classified into chemical families Acetylcholine (ACh) Biogenic amines Amino acids Peptides Novel messengers: ATP and dissolved gases NO and CO
5) Bipolar neurons are commonly ________. A) motor neurons B) called neuroglial cells C) found in ganglia D) found in the retina of the eye
D
Strong stimuli cause the amplitude of action potentials generated to increase.
False
Strong stimuli cause the amplitude of action potentials generated to increase. T or F
False
The ANS stimulates smooth muscles, skeletal muscles and glands, whereas the somatic nervous system innervates skeletal muscles only T/F
False
The all-or-none phenomenon as applied to nerve conduction states that the whoel nerve cell must be stimulated for conduction to take place. T/F
False
The all-or-none phenomenon as applied to nerve conduction states that the whole nerve cell must be stimulated for conduction to take place.
False
The all-or-none phenomenon as applied to nerve conduction states that the whole nerve cell must be stimulated for conduction to take place. T or F
False
The autonomic nervous system is under voluntary control; whereas, the somatic nervous system is involuntary.
False
The autonomic nervous system is under voluntary control; whereas, the somatic nervous system is involuntary. T or F
False
The nodes of Ranvier are found only on myelinated, peripheral neuron processes.
False
The nodes of Ranvier are found only on myelinated, peripheral neuron processes. T or F
False
The sodium-potassium pump ejects two Na+ from the cell and then transports three K+ back into the cell in order to maintain the concentration gradients for sodium and potassium.
False
The sympathetic and parasympathetic divisions of the ANS have the same effect on most body organ systems. T/F
False
Unmyelinated fibers conduct impulses faster than myelinated fibers.
False
The sodium-potassium pump ejects two Na from the cell and then transports three K back into the cell in order to stabilize the resting membrane potential.
False The sodium-potassium pump ejects three Na from the cell and then transports two K back into the cell in order to stabilize the resting membrane potential
Separates the R&L cerebellar hemispheres
Falx cerebelli
Extends down into the longitudinal fissure & separates the R&L cerebral hemispheres
Falx cerebri
Layer of dura matter that separates the hemispheres of the cerebrum
Falx cerebri
The 3 major ascending tracts which conduct sensory impulses to the brain are
Fasciculus gracilis & cuneatus, lateral & anterior spinothalmic tract, posterior & anterior spinocerebellar tracts
Supply's motor impulses to muscles of the anterior thighs & receives sensory impulses from the skin of the thighs & legs
Femoral nerves
Thin cord of connective tissue that originates from the conus medullaris, descending to the upper surface of the coccyx is called what
Filum terminale
Deep grooves are called
Fissures
Interneurons (association neurons)
Found in the neural pathways in the central nervous system Connect sensory and motor neurons
corpora quadrigemina *** not on test #13
Four rounded elevations; centers for visual & auditory reflexes *** not on test #13
Neural Integration: Neuronal Pools
Functional groups of neurons that: Integrate incoming information Forward the processed information to its appropriate destination
Ependymal cells ________.
Help to circulate the cerebrospinal fluid
How do action potential propagation speeds compare in myelinated and unmyelinated axons?
Propagation is faster in myelinated axons.
ow do action potential propagation speeds in myelinated and unmyelinated axons compare?
Propagation is faster in myelinated axons.
3 major cavities of embryonic brain development..(forebrain, midbrain & hindbrain)
Prosencephalon, mesencephalon & rhombensephalon
General functions of Neuroglia
Provide a supportive scaffolding for neurons Segregate and insulate neurons Guide young neurons to the proper connections Promote health and growth
withdrawal reflex
Pulling body part away from source of stimulation, Usually initiated by pain; a protective response reflex
Which of the following is NOT a difference between graded potentials and action potentials?
Spatial summation is used to increase the amplitude of a graded potential; temporal summation is used to increase the amplitude of an action potential.
Chemical synapses
Specialized for the release and reception of neurotransmitters Typically composed of two parts: Axonal terminal of the presynaptic neuron, which contains synaptic vesicles filled with neurotransmitters Receptor region on the postsynaptic neuron
The preganglionic fibers lead outward on cranial & sacral nerves to ganglia near or in various organs known as
Terminal ganglia
voltage na+
The TYPES OF CHANNELS for an action potential are restricted to the _______ channel specifically.
ions
The exchange of _____ initiates an action potential in the neuron
In a myelinated axon, how do the nodes of Ranvier differ from other segments of the same axon? The nodes are longer segments of the axon. The nodes are wrapped in myelin. The nodes are less numerous. The nodes are more permeable to ions.
The nodes are more permeable to ions.
What occurred in the presence of tetrodotoxin?
The number of action potentials decreased, and an action potential was always seen at R1
What is the function of the myelin sheath?
The myelin sheath increases the speed of action potential conduction from the initial segment to the axon terminals.
Which of the following best describes the concept of integration?
The nervous system processes and interprets sensory input and decides what should be done at each moment.
common
The neurotransmitter acetycholine is the most _____ in the body.
hich of the following occurred in the presence of tetrodotoxin?
The number of action potentials decreased.
Neuroglia
Support and protect neurons
Describe the structure and function of Satellite cells
Surround (wrap around) neuron cell BODIES in the PNS Similar to astrocytes in CNA - serve communication function
Describe the structure and function of Schwann cells (neurolemmocytes)
Surround peripheral nerve fibers and form myelin sheaths (whole cell, not just processes) Cytoplasm squeezed out is called neurilemma Vital to regeneration of damaged peripheral nerve fibers
Fight or flight is what division of the autonomic NS
Sympathetic
2 divisions of the autonomic NS
Sympathetic & parasympathetic
Ganglia located in chains along the sides of the vertebral column are known as
Sympathetic chain ganglia
The sympathetic chain ganglia and their fibers compose the
Sympathetic trunks
Two functional subdivisions of Autonomic (involuntary) nervous system (ANS)
Sympathetic: FIGHT/FLIGHT Parasympathetic: REST/DIGEST
What are chemical synapses?
Synapses specialized for the release and reception of neurotransmitters
Calcium entry into the axon terminal triggers which of the following events?
Synaptic vesicles fuse to the plasma membrane of the axon terminal and release acetylcholine.
ligand gated sodium channels open and sodium diffuses in
THE SYNAPSE: Acetylcholine has which effect on the post-synaptic neuron? A) Ligand gated calcium channels open and calcium diffuses in. B) Ligand gated sodium channels open and sodium diffuses in. C) Terminal vessels migrate to the plasma membrane. D) Voltage gated calcium ion channels open and calcium diffuses in. E) Voltage gated sodium ion channels open and sodium diffuses in.
false
THE SYNAPSE: Acetylcholine is actively transported from the pre-synaptic membrane to the post - synaptic membrane. A) True B) False
calcium ions to diffuse into the cell
THE SYNAPSE: An action potential arriving at the presynaptic terminal causes... A) sodium ions to diffuse into the cell. B) sodium ions to diffuse out of the cell. C) calcium ions to diffuse into the cell. D) acetylcholine to diffuse into the cell. E) ligand-gated sodium channels to open.
synaptic vesicles migrate to the plasma membrane and release acetylcholine
THE SYNAPSE: As a result of calcium ions diffusing into the presynaptic cell... A) synaptic vesicles migrate to the plasma membrane and release acetylcholine. B) acetylcholine is actively transported from the pre-synaptic neuron. C) acetylcholine is actively transported to the post synaptic neuron. D) ligand-gated sodium channels open. E) sodium ions diffuse into the cell.
true
THE SYNAPSE: If the post-synaptic membrane potential reaches threshold level, an action potential will be produced. A) True B) False
filum terminale
Tapering end of spinal cord, distal to the conus medullaris
Anterior portion of the prosencephalon
Telencephalon
What is another name for the terminal branches of an Axon?
Telodendria
When one or more presynaptic neurons fire in rapid order it produces a much greater depolarization of the postsynaptic membrane than would result from a single EPSP; this event is called ________ summation.
Temp-oral
What is the response in the patellar tendon reflex
Tension in the quadriceps femoris muscle group
Separates the occipital lobes of the cerebellum and the cerebrum
Tentorium cerebelli
analgesia
The relief of pain without loss of consciousness.
What effect did increasing the extracellular potassium have on the resting membrane potential?
The resting membrane potential became less negative.
In their resting state, all body cells exhibit a resting membrane potential ranging from -50 to about +50 millivolts.
The resting membrane potential is maintained by solely by passive transport processes.
Hypothetically, what would be the most immediate effect of doubling the number of Na+ leakage channels in the plasma membrane?
The resting membrane potential would become less negative (more positive).
Suppose a drug is developed that blocks K+ leakage channels. The drug prevents ions from passing through those channels. If this drug was applied to a neuron, what would be the most immediate effect on that neuron?
The resting membrane potential would become less negative (more positive).
endorphins
The sensory neuron for pain accepts presynaptic inhibition from enkephalins, more commonly called ______.
In myelinated axons the voltage-regulated sodium channels are concentrated at the nodes of Ranvier. T or F
True
Large-diameter nerve fibers conduct impulses much faster than small-diameter fibers.
True
Large-diameter nerve fibers conduct impulses much faster than small-diameter fibers. T or F
True
Myelination of the nerve fibers in the central nervous system is the job of the oligodendrocyte.
True
Myelination of the nerve fibers in the central nervous system is the job of the oligodendrocyte. T or F
True
Neurons and nerve cells are different names for the same thing.
True
Neurons are also called nerve cells.
True
Neurons in the CNS are organized into functional groups.
True
Neurons in the CNS are organized into functional groups. T or F
True
Opening K+ or Cl- channels in a postsynaptic membrane would produce an inhibitory postsynaptic potential (IPSP).
True
Reflexes are rapid, automatic responses to stimuli.
True
Reflexes are rapid, automatic responses to stimuli. T or F
True
Some neurotransmitters can be either excitatory or inhibitory depending upon the receptor.
True
Some neurotransmitters can be either excitatory or inhibitory depending upon the receptor. T or F
True
The action potential is caused by permeability changes in the plasma membrane.
True
The action potential is caused by permeability changes in the plasma membrane. T/F
True
The action potential is caused by permeability changes in the plasma membrane. T or F
True
The oligodendrocytes can myelinate serveral axons T/F
True
The oligodendrocytes can myelinate several axons.
True
The overlapping functions of the nervous system are sensory input, integration, and motor output T/F
True
The overlapping functions of the nervous system are sensory input, integration, and motor output.
True
The overlapping functions of the nervous system are sensory input, integration, and motor output. T or F
True
The sympathetic division is also called the "thoracolumbar division" of the autonomic nervous system T/F
True
Through direct neural stimulation, the sympathetic division promotes many metabolic effects via hormone release. T/F
True
Unipolar neurons have axons structurally divided into peripheral and central processes.
True
Unipolar neurons have axons structurally divided into peripheral and central processes. T or F
True
Temporal Summation
Two action potentials arrive in close succession at the presynaptic membrane
Functional Classification of Neurotransmitters
Two classifications: excitatory and inhibitory Excitatory neurotransmitters cause depolarizations Inhibitory cause hyperpolarizations Some have both excitatory and inhibitory effects Determined by the receptor type of the postsynaptic neuron Example: acetylcholine Excitatory at neuromuscular junctions Inhibitory in cardiac muscle
temporal summation
Two excitatory stimuli close in time cause EPSPs that add together.
spatial summation
Two simultaneous stimuli at different locations cause ESPSs that add together.
no summation
Two stimuli seperated in time cause EPSPs that do not add together.
Which of these axons will conduct an action potential most quickly? Type A fiber Type B fiber Type C fiber All fibers have the same propagation speed.
Type A fiber
Compared to type A axons, type C axons are __________. slower propagating unmyelinated smaller diameter Type C axons have all of these characteristics.
Type C axons have all of these characteristics.
The plasma membrane is much more permeable to K+ than to Na+. Why?
There are many more K+ leak channels than Na+ leak channels in the plasma membrane.
presynaptic, cleft, postsynaptic
There are three critical components for a chemical synapse: -_____ axon terminal that releases neurotransmitters -synaptic _____ -________ membrane receptors
Which of the following is NOT a characteristic of peroxisomes?
They contain powerful enzymes called acid hydrolases.
Which of the following is not true of graded potentials?
They increase amplitude as they move away from the stimulus point
Which of the following is not true of graded potentials?
They increase amplitude as they move away from the stimulus point.
Which of the following is not true of graded potentials? They can form on receptor endings. They increase amplitude as they move away from the stimulus point. They can be called postsynaptic potentials. They are short-lived.
They increase amplitude as they move away from the stimulus point.
Which of the following is NOT true of chemical synapses?
They transmit nerve impulses directly from one neuron to another.
Describe Unmyelinated Axons
Thin nerve fibers are unmyelinated One Schwann cell may incompletely enclose 15 or more unmyelinated axons
dentate nucleus *** not on test #16
This is the largest and most lateral of the deep cerebellar nucleus; associated with hand control, maintain posture & coordination; *** not on test #16
During the hyperpolarization phase of the action potential, voltage eventually returns to the resting membrane potential. What processes are primarily responsible for this return to the resting membrane potential?
Voltage-gated K+ channels close. K+ and Na+ diffuse through leakage channels.
What opens first in response to a threshold stimulus?
Voltage-gated Na+ channels
What is the first change to occur in response to a threshold stimulus?
Voltage-gated Na+ channels change shape, and their activation gates open.
Following repolarization, the neuron may become slightly hyperpolarized before it re-establishes its resting membrane potential. Hyperpolarization is due to a difference between how the voltage-gated Na+ and K+ channels work. What is this difference? Voltage-gated Na+ channels stop the flow of Na+ relatively quickly, while voltage-gated K+ channels are slow to close, resulting in the overshoot. Voltage-gated K+ channels possess an inactivation gate that keeps them closed until repolarization is almost complete. Voltage-gated Na+ channels are responsible for depolarization, while voltage-gated K+ channels return K+ to their original location. Voltage-gated Na+ channels can open much faster than voltage-gated K+ channels.
Voltage-gated Na+ channels stop the flow of Na+ relatively quickly, while voltage-gated K+ channels are slow to close, resulting in the overshoot.
During an action potential, after the membrane potential reaches +30 mV, which event(s) primarily affect(s) the membrane potential?
Voltage-gated sodium channels begin to inactivate (close) and voltage-gated potassium channels begin to open.
Deteriorating changes in the distal segment of an axon as a result of a break between it and the soma is called ________ degeneration. Wallerian central neural conduction peripheral
Wallerian
presynaptic, postsynaptic, vesicle
What is A? What is B? What is C? (NOTE-- there are lots of C's, which tells you that A is, infact, A.)
chemical
What is the most common synapse to occur in the body?
enkephalins, endorphins
What two neuropeptides are common in use of analgesia?
larger
What type of diameter makes an action potential faster?
electrical
What type of synapse: Neurotransmission is mediated via conduction of action potentials directly between adjacent cells that are in contact with each other (no synaptic cleft).
depolarization
What us the ONLY phase of generation of action potential that the voltage sensitive, or activation gate is opened?
going in
When BOTH gates are open--- Na+ is ___ ___to the cell.
open, open
When a threshold depolarization occurs; The activation gate will be ____ , and the inactivation gate will be ____.
activation, inactivation
When at rest; The ____ gate is closed, and the ____ is opened.
refractory
When the insensitive gate is closed, but the sensitive gate is opened; it is said that the cell is in a ____ period.
na+
When we say "All or none", we are refering to the fact that the same number of ____ ions will enter a cell due to the activity of both the activation and inactivation gates.
microglia
Which glial cells behave much like certain leukocytes? A) microglia B) ependymal cells C) oligodendrocytes D) satellite cells
neurolemmocytes
Which glial cells participate in the repair of damaged nerves? A) satellite and ependymal cells B) neurolemmocytes C) oligodendrocytes D) astrocytes and microglia
ans and sns
Which nervous system divisions or components contain no afferent neurons? A) somatic and visceral sensory B) CNS and PNS C) PNS and ANS D) ANS and SNS
Types Of glial cells
Glial cells of the CNS are of 4 types Astrocytes - most numerous, involved in care and feeding of neurons Microglia - specialized phagocytes Ependymal cells - ciliated cells lining CNS cavities that secrete CSF Oligodendrocytes - produce myelin sheaths in the CNS Glial cells of the PNS are of 2 types Satellite cells - surround PNS neuron cell bodies, function unknown Schwann cells - produce myelin sheaths in the PNS
Cranial nerves IX..muscles in pharynx..blood pressure in carotid sinus..1/3 of tongue..mixed
Glossopharyngeal
excitatory
Glutamate is _____ in the CNS.
inhibitory
Glycine is ______ in the CNS.
k+
Hyperpolarization is caused by _____ continuing to leave the cell.
Cranial nerves XII..muscles of the tongue..primarily motor
Hypoglossal
Region within the diencephalon that includes many nuclei and forms the lower walls & floor of the 3rd ventricle..regulates a variety of visceral activities important in homeostasis & also regulates some of the endocrine system
Hypothalamus
What is the difference between white and gray matter?
White matter: Dense collections of myelinated fibers Gray matter: Mostly neuron cell bodies and unmyelinated fibers
Preganglionic fibers leave the spinal nerves through branches called
White rami
Myelin sheath
Whitish, fatty (protein-lipoid), segmented sheath around most long axons It functions to: Protect the axon Electrically insulate fibers from one another Increase the speed of nerve impulse transmission
What are the differences in ionic makeup between ICF and ECF in a "resting" neuron?
ICF has lower concentration of Na+ and Cl- than ECF ICF has higher concentration of K+ and negatively charged proteins (A-) than ECF
The third ventricle communicates with the 2 lateral ventricles through openings called
Interventricular foramina
Passageway btwn vertebrae to & from the spinal cord is known as the
Intervertebral foramen
Neurotransmitters: Novel Messengers ATP
Is found in both the CNS and PNS Produces excitatory or inhibitory responses depending on receptor type Induces Ca2+ wave propagation in astrocytes Provokes pain sensation
Nerve cell body(soma)
Is the major biosynthetic center hence has well-developed Nissl bodies (rough ER) and Golgi Is the focal point for the outgrowth of neuronal processes Contains an axon hillock - cone-shaped area from which axons arise
How would the absolute refractory period be affected if voltage-regulated sodium channels failed to inactivate? It would be much briefer. It would last indefinitely. It would be basically unaffected.
It would last indefinitely.
What type of reflex occur when you touch something painful or potentially damaging
Withdrawal reflex
The electrochemical gradient for potassium ions when the transmembrane potential is at the resting potential (-70 mV) is caused by what?
a chemical gradient going out of the cell and an electrical gradient going into the cell
What type of channel on the postsynaptic membrane binds neurotransmitter?
a chemically gated channel
What is the posterior median sulcus?
a deep groove on the posterior (back) side of the spinal cord.
What is the anterior median fissure?
a deep, wide groove on the anterior (front) side of the spinal cord.
Cardiovascular effects of the sympathetic division include all except _________. a) dilation of the blood vessels serving the skin and digestive viscera b) construction of most blood vessels c) increase of heart rate and force d) dilation of the vessels serving the skeletal muscles
a) dilation of the blood vessels serving the skin and digestive viscera
Which of the following is NOT associated with the parasympathetic division of the autonomic nervous system (ANS)? a) emergency action b) resting c) digesting d) energy conservation
a) emergency action
Which of the following is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle? a) acetylcholine b) norepinephrine c) gamma aminobutyric acid d)bcholinesterase
a) acetylcholine
Which neuroglia are the most abundant and versatile of the glial cells? a) astrocytes b) ependymal cells c) oligodendrocytes d) Schwann cells
a) astrocytes
The part of a neuron that conducts impulses away from its cell body is called a(n) ________. a) axon b) dendrite c) Schwann cell d) neurolemma
a) axon
Which of the following is the conducting region of the neuron? a) axon b) dendrites c) terminal boutons d) soma
a) axon
The term central nervous system refers to the ________. a) brain and spinal cord b) brain, spinal cord, and peripheral nerves c) spinal cord and spinal nerves d) autonomic nervous system
a) brain and spinal cord
the term central nervous system refers to the ___________. a) brain and spinal cord b) spinal cord and spinal nerves c) peripheral and spinal nerves d) brain, spinal cord, and peripheral nerves
a) brain and spinal cord
What are ciliated CNS neuroglia that play an active role in moving the cerebrospinal fluid called? a) ependymal cells b) Schwann cells c) oligodendrocytes d) astrocytes
a) ependymal cells
Emotions influence autonomic reactions primarily through integration in the __________ a) hypothalamus b) inferior colliculus c) lateral horn of the spinal cord d) lateral geniculate of the thalamus
a) hypothalamus
Which of the following is responsible for the overall integration of the autonomic nervous system (ANS)? a) hypothalamus b) reticular formation c) frontal lobe of the cerebral cortex d) brain stem
a) hypothalmus
Which of the following types of neurons carries impulses away from the CNS? a) motor b) association c) afferent d) sensory
a) motor
List some characteristics of Neurons (Nerve Cells)
Long-lived (100 years or more) Amitotic (with few exceptions) High metabolic rate: depend on continuous supply of O2 / glucose Plasma membrane functions in: - Electrical signaling - Cell-to-cell interactions during development
Fissure that separates the R&L cerebral hemispheres
Longitudinal fissure
If a drug that inhibits __________ is used, it will cause more acetylcholine to remain in the synaptic cleft to bind to the remaining nicotinic receptors on skeletal muscle cells.
acetylcholinesterase
Which of the following describes the nervous system integrative function?
analyzes sensory information, stores information, makes decisions
reticular formation *** not on test #14
Loosely organized nuclei that extend throughout the brainstem and filter sensory information; arouses the cerebral cortex to new stimulation and keeps the brain alert (even during sleep).**** not on test #14
________ channels open or close in response to physical distortion of the membrane surface. Mechanically-gated Active Voltage-gated Chemically-gated Leak
Mechanically-gated
Describe the threshold stage of action potential
Membrane is depolarized by 15 to 20 mV Na+ permeability increases Na influx exceeds K+ efflux The positive feedback cycle begins
Which statement best describes exocytosis?
Membrane organelles fuse with the membrane and release contents out of the cell.
Define Meninges:
Membranes covering the brain and spinal cord.
Located btwn the bone & soft tissue on the NS, this membrane protects the brain and spinal cord
Meninges
Contains the cerebral aqueduct that connects the 3rd & 4th ventricles
Mesencephalon (midbrain)
Short section of the brainstem between the diencephalon & the pons
Mesencephalon (midbrain)
Anterior portion of the rhombencephalon
Metencephalon
types of glial cells monitor the health of neurons, and can transform into a special type of macrophage to protect endangered neurons?
Microglia
Presynaptic neuron
- conducts impulses toward the synapse
What structural classification describes this neuron?
Multipolar
________ neurons are the most common class in the CNS. Multipolar Unipolar Sensory Anaxonic Bipolar
Multipolar
What are the dentate nuclei and what is their function?
- clusters of neuron cell bodies (one in each cerebellar hemisphere) which are connected by tracts to: the thalamus and motor areas in the cerebrum. - They influence the brain's motor areas and directly affect muscle tone andd movement coordination.
Where are gray and white matter generally found in the cerebellum?
- gray matter found in cortex (outer portion) - white matter predominated interior
What is the function of the Basal Ganglia?
- help regulate voluntary motor functions. - ex: most muscle contractions involved in posture, walking, and other gross or repetitive movements are begun or modified in the basal ganglia.
Describe the Epidural space:
- space between boney coverings and the dura mater. - contains supporting cushion of fat and other connective tissues.
Describe the Subdural space:
- space between dura mater and arachnoid membrane. - contains a little lubricating serous fluid.
Describe the Subarachnoid space:
- space between the arachnoid and pia mater. - contains cerebrospinal fluid (CSF).
What 2 structures does the medulla connect? Of what is the medulla composed?
- spinal cord and the pons. - composed of white matter (tracts) and the reticular formation.
A chemical messenger that does not directly cause ESPSs or IPSPs but does affect the strength of synaptic transmission is a ________.
Neuro-mod-ulator
________ account for roughly half of the volume of the nervous system. Dendrites Efferent fibers Neuroglia Synapses Axons
Neuroglia
cerebral aqueduct
Passageway for CSF between 3rd and 4th ventricle ( 4 )
What is the role of neurotransmitter at a chemical synapse?
Neurotransmitter binds to receptors on the postsynaptic cell membrane and allows ions to diffuse across the membrane.
synaptic delay
Neurotransmitter must be released, diffuse across the synapse, and bind to receptors Synaptic delay - time needed to do this (0.3-5.0 ms) Synaptic delay is the rate-limiting step of neural transmission
Post synaptic potentials
Neurotransmitter receptors mediate changes in membrane potential according to: The amount of neurotransmitter released The amount of time the neurotransmitter is bound to receptors The two types of postsynaptic potentials are: Excitatory postsynaptic potentials Inhibitory postsynaptic potentials
The afferent division of the PNS _____________. controls smooth muscle carries sensory information carries motor commands controls skeletal muscle
carries sensory information
describe motor or efferent neurons
carry impulses away from the CNS to the effector organs (muscles and glands) of the body periphery, multipolar, mostly cell bodies located in CNS
Ions are unequally distributed across the plasma membrane of all cells. This ion distribution creates an electrical potential difference across the membrane. What is the name given to this potential difference?
resting membrane potential
The brain area that regulates activities that control the state of wakefulness or alertness of the cerebral cortex is the ________. limbic system pyramids reticular formation thalamus
reticular formation
The rabies virus travels to the CNS via retrograde axoplasmic transport. subcutaneous connective tissue. blood vessels. cerebrospinal fluid. anterograde axoplasmic transport.
retrograde axoplasmic transport.
what is movement away from the axon terminals called
retrograde movement
Which pattern of neural processing works in a predictable, all-or-nothing manner, where reflexes are rapid and automatic responses to stimuli in which a particular stimulus always causes the same response?
serial processing
Which pattern of neural processing works in a predictable, all-or-nothing manner, where reflexes are rapid and automatic responses to stimuli in which a particular stimulus always causes the same response? oscillative processing parallel processing serial processing reflexive processing
serial processing
Spinocerebellar tracts ________. terminate in the spinal cord give rise to conscious experience of perception carry proprioceptive inputs to the cerebellum are found in the dorsal columns of the spinal cord
carry proprioceptive inputs to the cerebellum
All of the following are structures of the limbic system except the ________. amygdaloid nucleus hippocampus cingulate gyrus caudate nucleus
caudate nucleus
what happens when the impulse reaches the axon terminal
causes neurotransmitters, signalling chemicals stored in vesicles there to be released into the extracellular space
What happens to the spinal cord between L1 and L2 vertebrae?
ceases to be a solid body. Individual nerves continue into Lumbar. Sacral & Coccygeal parts of spine hang loose and look like a horse's tail called the Caudum Equinum.
The dorsal root ganglia mainly contain synapses. cell bodies of motor neurons. axons of motor neurons. cell bodies of sensory neurons. axons of sensory neurons.
cell bodies of sensory neurons.
The dorsal root ganglia consist mainly of __________. axons of multipolar neurons axons of unipolar neurons cell bodies of multipolar neurons cell bodies of unipolar neurons
cell bodies of unipolar neurons
why is the protective role of microglia important
cells of the immune system are denied access to the CNS
The ________ nervous system is composed of the brain and spinal cord. central efferent afferent peripheral autonomic
central
What part of the nervous system performs information processing and integration?
central nervous system
What part of the nervous system performs information processing and integration? somatic nervous system central nervous system parasympathetic nervous system sympathetic nervous system
central nervous system
what are the two parts of the nervous system
central nervous system and peripheral nervous system
The spinal cord is part of the autonomic nervous system. central nervous system. peripheral nervous system. somatic nervous system. afferent nervous system.
central nervous system.
Subdivisions of nervous system
central: spinal cord and brain peripheral: sensory receptors and nerves
Which of these components is usually absent from a neuron? centrioles cell body dendrites axons
centrioles
The arbor vitae refers to ________. the pleatlike convolutions of the cerebellum cerebellar white matter cerebellar gray matter flocculonodular nodes
cerebellar white matter
Which of the following regions of the brain provides the precise timing and appropriate patterns of skeletal muscle contraction for the smooth, coordinated movements and agility that are needed for our daily living? cerebellum medulla oblongata pons midbrain
cerebellum
Which part of the brain processes inputs received from the cerebral motor cortex, brain stem nuclei, and various sensory receptors, and then uses this information to coordinate somatic motor output so that smooth, well-timed movements occur? cerebellum thalamus pons diencephalon
cerebellum
Which parts of the brain constitute the "emotional brain" known as the limbic system? diencephalic and brain stem structures cerebral and brain stem structures cerebral and diencephalic structures diencephalic and mesencephalic structures
cerebral and diencephalic structures
Which part of the brain is the "executive suite" for all brain activity? diencephalon brain stem cerebellum cerebral cortex
cerebral cortex
White matter (myelinated fibers) is found in all of the following locations except the ________. outer portion of the spinal cord cerebral cortex corpus callosum corticospinal tracts
cerebral cortex
Muscles of the neck and shoulder are innervated by spinal nerves from the ________ region. cervical coccygeal lumbar sacral thoracic
cervical
Which of the following is not a possible drug effect on synaptic function? interfere with neurotransmitter reuptake interfere with neurotransmitter synthesis change the type of receptor found in the postsynaptic membrane prevent neurotransmitter inactivation block neurotransmitter binding to receptors
change the type of receptor found in the
stimuli
changes
Leak channels allow the movement of potassium and sodium ions by what type of membrane transport?
channel-mediated diffusion
Which of the following is NOT a functional classification of neurotransmitters?
chemical
Which type of synapse is most common in the nervous system? electrical processing chemical radiative mechanical
chemical
The electrochemical gradient for sodium ions in a neuron when the transmembrane potential is at the resting potential is caused by what?
chemical and electrical gradients both going into the cell
Which component has a role in the postsynaptic cell during synaptic activity?
chemically gated channels
Binding of a neurotransmitter to its receptors opens __________ channels on the __________ membrane.
chemically gated; postsynaptic
A postsynaptic neuron will have an Excitatory Postsynaptic Potential (EPSP) when more calcium ions than usual diffuse into the neuron. the neuron is hyperpolarized. chemically-regulated potassium channels are open and potassium is diffusing out of the cell. chemically-regulated sodium channels are open and sodium is diffusing into the cell. more potassium ions than usual diffuse out of the neuron.
chemically-regulated sodium channels are open and sodium is diffusing into the cell.
Which of the following is NOT one of the chemical classes into which neurotransmitters fall?
chlorides
Which of the following is NOT one of the chemical classes into which neurotransmitters fall? amino acids gases and lipids chlorides peptides
chlorides
The receptors on effectors for parasympathetic postganglinic axons are categorized as __________, while the receptors on effectors for sympathetic postganglionic axons are __________.
cholinergic; adrenergic
Which type of white matter fiber tract connects the two cerebral hemispheres? internal capsules commissures association fibers projection fibers
commissures
Which of the following is the mildest consequence of traumatic brain injury? concussion swelling hemorrhage contusion
concussion
Axon
conduct impulses away from the cell body
Dendrites
conduct impulses toward the cell body
Functions of astrocytes include all of the following, except guiding neuron development. maintaining the blood-brain barrier. responding to neural tissue damage. conducting action potentials. forming a three-dimensional framework for the CNS.
conducting action potentials.
what does the axon do
conducting region, generates nerve impulses and transmits them, typically away from the cell body along the plasma membrane or axolemma
We describe the regeneration of the action potential down the membrane of the axon of the neuron as _______.
conduction or propagation
massa intermedia
connects the two halves of the thalamus together
Integral membrane proteins that connect electrical synapses are called desmosomes. synapsins. sodium channels. receptors. connexons.
connexons.
what does the afferent division do
consists of nerve fibres (axons) that convey impulses to the central nervous system from sensory receptors
What type of conduction takes place in unmyelinated axons?
continuous conduction
Which of the following is a characteristic of a coma but is NOT a characteristic of sleep? absence of brain waves ("flat EEG") irreversible brain damage continuously reduced mitochondrial activity in brain neurons All of the listed responses are correct.
continuously reduced mitochondrial activity in brain neurons
What is the function of the Accessory nerve?
control muscles of back & neck.
What is the function of the Abductens nerve?
control muscles that abduct the eyes.
What is the function of the Hypoglossal nerve?
control muscles that move the tongue.
What is the function of the Oculomotor nerve?
control muscles that: control eye movement, opening of iris, and focus the lenses.
What is the function of the Trochlear nerve?
control some eye movement.
pons
controls the rate and depth of breathing; relays nerve impulses between medulla oblongata & cerebellum
medulla oblongata
controls vital & nonvital reflexes: breathing, heart rate, vomiting, salivations, coughing, and sneezing; located at lowest portion of brainstem
K out of cell
depolarization, less gradient
An action potential is self-regenerating because __________.
depolarizing currents established by the influx of Na+ flow down the axon and trigger an action potential at the next segment
The region of the body surface monitored by a pair of spinal nerves is known as a(n) __________. segment input domain dermatome dermal band
dermatome
What is the role of acetylcholinesterase?
destroy ACh a brief period after its release by the axon endings
What type of membrane transport causes the depolarization phase of the action potential in neurons?
diffusion
Which of the following is not a function of the nervous system? integrate sensory information control peripheral effectors direct long-term functions, such as growth sense the internal and external environments coordinate voluntary and involuntary activities
direct long-term functions, such as growth
The synapse more common in embryonic nervous tissue than in adults is the ________.
electrical synapse
Where are muscarinic cholinergic receptors found?
effector organs of the parasympathetic nervous system
Binding of the neurotransmitter to its receptor causes the membrane to __________.
either depolarize or hyperpolarize
Myasthenia gravis directly causes a decrease in the __________ in skeletal muscle cells.
end-plate potential
The reason that the skeletal muscle __________ get smaller after repetitive stimulation is due to acetylcholine being ineffectively used as the somatic motor neuron continues to fire action potentials.
end-plate potentials
Sensory receptors
endings of neurons or cells that detect senses
The outermost connective-tissue covering of nerves is the perineurium. endomysium. epineurium. endoneurium. epimysium.
epineurium.
Cold sores on the skin of the mouth occur when herpes simplex viruses that are dormant in neural ganglia become active and travel to the skin of the mouth. Which of the following is the mechanism by which these viruses travel from the ganglia (located within the head) to the skin of the mouth?
retrograde transport
what are characteristic of neurons
extreme longevity, amitotic, high metabolic rate
Some transport processes use transport proteins in the plasma membrane, but do not require ATP. This type of transport is known as _____.
facilitated diffusion
The majority of water molecules moving across plasma membranes by osmosis do so via a process that is most similar to ____.
facilitated diffusion
A flat EEG is a good indication of deep sleep. True False
false
Commissural fibers connect the cerebrum to the diencephalon. True False
false
Meningitis is the most accurate term for inflammation of neurons. True False
false
Nondeclarative memories preserve the circumstances in which they are learned. True False
false
Projection fibers in the brain mainly connect the right and left hemispheres. True False
false
Sorting of sensory information and relaying it to the appropriate cerebral sensory area occurs in the hypothalamus. True False
false
Strong stimuli cause the amplitude of action potentials generated to increase. True False
false
The RAS is comprised of specific pathways primarily in the limbic system. True False
false
The all-or-none phenomenon as applied to nerve conduction states that the whole nerve cell must be stimulated for conduction to take place. True False
false
The autonomic nervous system is under voluntary control; whereas, the somatic nervous system is involuntary. True False
false
The canal connecting the third and fourth ventricles and running through the midbrain is the foramen of Monro. True False
false
The hypothalamus is the area where afferent impulses from all senses and all parts of the body are sorted out and then relayed to the appropriate area of the sensory cortex. True False
false
The nodes of Ranvier are found only on myelinated, peripheral neuron processes. True False
false
The three basic regions of the cerebrum are the cerebral cortical gray matter, internal white matter, and the superior and inferior colliculi. True False
false
In addition to diffusion, what are two other mechanisms that terminate neurotransmitter activity?
reuptake and degragation
Which neuron circuit pattern is involved in the control of rhythmic activities such as breathing?
reverberating circuit
Which neuron circuit pattern is involved in the control of rhythmic activities such as breathing? diverging circuit parallel after-discharge circuit reverberating circuit converging circuit
reverberating circuit
Which of the following circuit types is involved in the control of rhythmic activities such as the sleep-wake cycle, breathing, and certain motor activities (such as arm swinging when walking)?
reverberating circuits
Compared to nerve action potentials, muscle action potentials do not have __________. greater resting potentials slower propagation faster propagation longer duration
faster propagation
Which of these would you not find in the cerebral cortex? dendrites unmyelinated axons fiber tracts cell bodies
fiber tracts
Processes
fibers that extend from the cell body
The ________ is a strand of fibrous tissue that provides longitudinal support as a component of the coccygeal ligament. filum terminale ventral root conus medullaris dorsal root cauda equina
filum terminale
cerebral ventricles
four interconnected cavities that lie in the cerebral hemispheres & brainstem; they are continuous with the central canal of the spinal cord & filled with CSF
What does the central nervous system use to determine the strength of a stimulus?
frequency of action potentials
What does the central nervous system use to determine the strength of a stimulus? type of stimulus receptor frequency of action potentials size of action potentials origin of the stimulus
frequency of action potentials
Which of the following areas of the brain controls voluntary movement of the eyes? primary visual cortex gustatory cortex frontal eye field visual association area
frontal eye field
The central sulcus separates which lobes? frontal from parietal temporal from parietal frontal from temporal parietal from occipital
frontal from parietal
Collections of nerve cell bodies outside the central nervous system are called ________.
ganglia
Collections of nerve cell bodies outside the central nervous system are called ________. nuclei nerves ganglia tracts
ganglia
how are astrocytes connected together
gap junctions
Nodes of Ranvier
gaps in myelin sheath along the axon
what are nodes of ranvier or myelin sheath gaps
gaps in the sheath because the schwann cells along an axon do not touch one another
Sensory input
gathering information, to monitor the changes inside/outside of the body
If EPSPs summate to a sustained value above threshold, then the initial segment will __________. generate both large and frequent action potentials inactivate generate a string of action potentials generate larger than normal action potentials
generate a string of action potentials
When a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n) ________.
generator potential
When a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n) ________. postsynaptic potential generator potential excitatory potential action potential
generator potential
what do sacral nerves control and how many?
genitals lower digestive tract 5
what do astrocytes do for the blood brain barrier?
gives rise to blood-brain barrier to... 1. limits permeability of number of blood-borne substances 2. define what blood-borne components can enter CNS
Bipolar neurons
have 2 projections coming off of the cells body (1 axon, 1 dendrite) Least common- Found in eye and nose
describe multipolar neurons
have 3 or more processes- one axon and rest dendrites, most common neuron, major neuron type in CNS
Unipolar neurons
have a short single process leaving the cell body
describe unipolar neurons
have a single short process that emerges from the cell body and divides T like into proximal and distal branches, found mainly in PNS, common only in dorsal root ganglia of the spinal cord and sensory ganglia of cranial nerves
In contrast to the internodes of a myelinated axon, the nodes __________.
have lower membrane resistance to ion movement
Myasthenia gravis most commonly affects skeletal muscles of the __________.
head
The six projections from the gray matter seen in cross-sections of the spinal cord are called __________. pyramids flares tracts horns
horns
The outward projections from the central gray matter of the spinal cord are called fibers. wings. tracts. pyramids. horns.
horns.
An inhibitory postsynaptic potential (IPSP) is associated with ________.
hyperpolarization
less K in extracellular
hyperpolarization, steeper gradient
An axon that is more negative than the resting membrane potential is said to be
hyperpolarized
An axon that is more negative than the resting membrane potential is said to be _______.
hyperpolarized
The most promising current therapy for myasthenia gravis is __________.
immune type therapy
Describe the impulse pathway of the Reticular Activating System:
impulses from spinal cord --> reticular formations in brain stem --> thalamus --> all parts of the cerebral cortex (without continual impulses from the reticular formations to cortex, you will be unconscious and cannot be aroused)
where are most neuron cell bodies located
in the CNS, protected by bones of skull and vertebral column
Voltage-gated channels are present on the surface of dendrites. on the soma of neurons. at the motor end plate. along the perikaryon of neurons. in the membrane that covers axons.
in the membrane that covers axons.
Compared to the electrical gradient for sodium at rest, the electrical gradient for potassium at rest is __________.
in the same direction and of the same magnitude.
what do dendrites convey
incoming messages toward cell body usually graded potentials
Which of the following does not occur during a narcoleptic sleep episode? increased heart rate REM sleep increased oxygen use increased gastrointestinal activity
increased gastrointestinal activity
Increase in stimulus intensity
increases the frequency of action potentials
Action potential propagation begins (is first generated at) what region of a neuron?
initial segment
Where do most action potentials originate?
initial segment
In what part of the neuron does the action potential typically initiate?
initial segment of the axon
Which of the following is not a role of the basal nuclei? regulating attention and cognition controlling starting and stopping movements initiating protective reflex actions inhibiting unnecessary or antagonistic movements
initiating protective reflex actions
Which of the following is not a function of the CSF? reduction of brain weight protection from blows initiation of some nerve impulses nourishment of the brain
initiation of some nerve impulses
Reflexes based on synapses formed during development are ________ reflexes. visceral innate somatic vegetative acquired
innate
Which of the following is not a function of the autonomic nervous system?
innervation of skeletal muscle
Which of the following is not a function of the autonomic nervous system? innervation of glands innervation of skeletal muscle innervation of cardiac muscle innervation of smooth muscle of the digestive tract
innervation of skeletal muscle
What component of the reflex arc determines the response to a stimulus?
integration center
What component of the reflex arc determines the response to a stimulus? integration center sensory neuron receptor effecto
integration center
what is meant by integration and does it occur mainly in the CNS or PNS
integration involves processing and interpreting sensory information, making a decision about motor output. primarily occurs in CNS
The most abundant category of neurons is __________. somatic afferents somatic motor interneurons visceral motor
interneurons
which neurons make up over 99% of the neurons of the body
interneurons
functions of the brain
interpret sensation, determine perception, stores memory, reasoning, makes decisions, coordinates muscular movements, regulates visceral activities, determines personality
The time interval between the action potential is called the
interspike interval
Autonomic nervous system
involuntary
what is the ANS also called
involuntary nervous system
When neurotransmitter molecules bind to receptors in the plasma membrane of the receiving neuron,
ion channels in the plasma membrane of the receiving neuron open.
The rate with which an action potential travels along an axon _______.
is called the conduction velocity and is measured in meters/sec
Broca's area ________. is usually found in the right hemisphere serves the recognition of complex objects is considered a motor speech area corresponds to Brodmann's area 8
is considered a motor speech area
Declarative memory ________. is hard to unlearn when learned once usually involves motor skills is best remembered in the doing is the ability to learn specific information
is the ability to learn specific information
why is the somatic nervous system called the voluntary nervous system
it allows us to consciously control our skeletal muscles
Spinal nerves from the sacral region of the cord innervate the ________ muscles. abdominal leg facial intercostal shoulder
leg
Which of the following is used to block pain?
lidocaine
In the presence of lidocaine, the action potential was NOT affected at R1 because
lidocaine was applied downstream of R1
In the presence of lidocaine, the action potential was NOT affected at R1 because _______.
lidocaine was applied downstream of R1
describe interneurons/ association neurons
lie between motor and sensory neurons in neural pathways and shuttle signals through CNS pathways where integration occurs, most confined within CNS, almost all are multipolar
where are ependymal cells found
line central cavities of brain, spinal cord form a permeable barrier between cerebrospinal fluid and tissue fluid
where are oligodendrocytes found
line up along thicker neuron fibres in CNS
diencephalon
located between cerebral hemispheres, superior to the brainstem; surrounds 3rd ventricle & consists of the thalamus, hypothalamus, optic chiasm, and pineal body
hypothalamus
located in diencephalon; helps maintain homeostasis by regulating visceral activities and links nervous to the endocrine system
frontal eye field
located in the motor cortex just above the broca's area that controls voluntary movement of eyes & eye lids
post central gyrus
located in the parietal lobe it interprets sensations on skin
The nodes of Ranvier are _______.
locations on the axon where the myelin sheath is absent
Which fissure separates the cerebral hemispheres? central fissure parieto-occipital fissure lateral fissure longitudinal fissure
longitudinal fissure
what does amitotic mean
lose ability to divide, cannot be replaced if destroyed
Injury to the hypothalamus may result in all of the following except ________. loss of body temperature control pathologic sleep loss of proprioception production of excessive quantities of urine
loss of proprioception
Extensive damage to oligodendrocytes in the CNS could result in loss of sensation and motor control. decreased production of cerebrospinal fluid. a breakdown of the blood-brain barrier. loss of the structural framework of the brain. inability to produce scar tissue a the site of an injury.
loss of sensation and motor control.
Type B nerve fiber
medium-diameter, lightly myelinated. Conduct at 3-15 m/s. Part of ANS
The vital centers for the control of heart rate, respiration, and blood pressure are located in the ________. cerebrum midbrain medulla pons
medulla
Which of the following structures is probably not directly involved in memory? thalamus medulla prefrontal cortex hippocampus
medulla
Which part of the brain stem houses the reflex centers for respiration and cardiovascular functioning? reticular formation pons medulla oblongata midbrain
medulla oblongata
Which of the following is NOT a functional region of a neuron?
medullary region
gyri
rounded ridges located on the surface of the cerebral hemispheres of the brain
Parasympathetic preganglionic cell bodies are located in the brainstem and _____ region of the spinal cord.
sacral
The node-to-node "jumping" regeneration of an action potential along a myelinated axon is called __________.
salatory conduction
what substances are moved in the anterograde direction
mitochondria, cytoskeletal elements, membrane components used to renew the axon plasma membrane and enzymes needed for the synthesis of certain neurotransmitters
What are some examples of molecules and organelles moved along an axon toward its TERMINAL end?
mitochondria, membrane components, enzymes
facial nerve ( VII )
mixed nerve; sensory from taste receptors; motor to muscles of facial expressions, salivary & tear ducts ( J )
A primary active transport process is one in which __________.
molecules move through transport proteins that have been activated by ATP
Which of the following would increase the membrane permeability to K+?
more K+ leakage channels
Which of the following would increase the membrane permeability to K+? more K+ leakage channels more negative membrane potential more Na+ leakage channels a greater concentration gradient for K+
more K+ leakage channels
A suprathreshold stimulus results in _______.
more action potentials
what is the peripheral process
more distal process in unipolar neurons often associated with a sensory receptor
The input for the stretch reflex comes from the __________. gamma motor neuron extrafusal fibers muscle spindle efferent fibers
muscle spindle
Myasthenia gravis is an automimmune disease in which antibodies are produced against nicotinic cholinergic receptors. What would be a direct symptom of this?
muscle weakness and/or dysfunction
what are the effector organs
muscles and glands
The white matter of the spinal cord is mainly unmyelinated axons. Schwann cells. myelinated and unmyelinated axons. neuroglia. nodes of Ranvier.
myelinated and unmyelinated axons.
The white matter of the spinal cord contains ________. myelinated and unmyelinated nerve fibers unmyelinated nerve fibers only soma that have both myelinated and unmyelinated nerve fibers myelinated nerve fibers only
myelinated and unmyelinated nerve fibers
Which of these is absent in the gray matter of the spinal cord? neuroglia unmyelinated axons neuron cell bodies myelinated axons
myelinated axons
White matter
myelinated axons. Nerve tracts propagate actin potentials from one area in the CNS to another
do myelinated or unmyelinated fibres conduct quicker nerve impulses
myelinated conduct rapidly
White matter
myelinated fibers (mainly axons)
The node-to-node "jumping" regeneration of an action potential along a myelinated axon is called __________.
saltatory propagation
what is motor output
nervous system causes a response by activating effector organs- muscles and glands
what is in the PNS
nervous system outside CNS, mainly nerves- spinal nerves, cranial nerves
what is integration
nervous system processes and interprets sensory input and decides what to do at each moment
what is sensory input
nervous system uses millions of sensory receptor to monitor changes occurring both inside and outside body, gathered information is sensory input
The sheath of Schwann is also called the ________.
neurilemma
Which of the following are bundles of neurofilaments that are important in maintaining the shape and integrity of neurons?
neurofibrils
Which of the following are bundles of neurofilaments that are important in maintaining the shape and integrity of neurons? perikaryon axolemma chromatophilic substance neurofibrils
neurofibrils
what is the difference between communcation of neurons and communication of neuroglia?
neuroglia can communicate with many other cells at one time, where neurons has a flow of information or communication along chains of neurons
The basic functional unit of the nervous system is the ________.
neuron
How would a chemical that prevents the opening of voltage-regulated Na+ channels affect the function of a neuron? neuron will only be able to hyperpolarize action potentials will lack a repolarization phase neuron will only be capable of producing graded potentials neuron will depolarize more rapidly neuron will automatically and repeatedly produce graded potentials
neuron will only be capable of producing graded potentials
When pressure is applied to neural tissue, all these effects are possible, except a decrease in blood flow. action potentials are generated spontaneously. a decrease in available oxygen. neurons are triggered to divide. glial cells degenerate.
neurons are triggered to divide.
A molecule that carries information across a synaptic cleft is a
neurotransmitter
The substance released at axon terminals to propagate a nervous impulse is called a(n) ________.
neurotransmitter
The substance released at axon terminals to propagate a nervous impulse is called a(n) ________. cholinesterase neurotransmitter ion biogenic amine
neurotransmitter
The same ________ can have different effects depending on the properties of the ________. substrate; receptor receptor; neurotransmitter hormone; neurotransmitter propagation; neurotransmitter neurotransmitter; receptor
neurotransmitter; receptor
are dendrites myelinated
never
Which of these neurotransmitters does not bind to a plasma membrane receptor? GABA nitric oxide serotonin norepinephrine
nitric oxide
Increasing the voltage resulted in
no change to the action potential
Increasing the voltage resulted in which of the following?
no change to the action potential
A single action potential is described as _______.
no graded
When the calcium was removed from the extracellular solution
no neurotransmitter was released
When the calcium was removed from the extracellular solution, _______.
no neurotransmitter was released
what organelles are in the axon
same as in dendrites and cell body but without nissl bodies and a golgi apparatus (Structures involved with protein synthesis and packaging)
Which of the following is a type of glial cell found in the peripheral nervous system? satellite cells oligodendrocytes ependymal cells astrocytes microglia
satellite cells
Which of these types of neuroglia are abundant in peripheral ganglia? microglia oligodendrocytes astrocytes satellite cells
satellite cells
Glial cells that surround the neurons in ganglia are oligodendrocytes. satellite cells. ependymal cells. astrocytes. microglia.
satellite cells.
Neuroglia of PNS
schwann and satellite
how do oligodendrocytes differ from schwann cells
schwann cells only form one segment of a myelin sheath but oligodendrocytes have multiple flat processes that can coil around as many as 60 axons at the same time
myelin sheaths in the PNS are formed by what
schwann cells which indent to receive an axon and then wrap themselves around it in a jelly role fashion, initially lose but gradually cytoplasm is squeezed from between membrane layers
which 2 neuroglia form myelin sheaths
schwann cells, oligodendrocytes
As the ________ nerve approaches the knee, it divides into two branches, the fibular nerve and the tibial nerve. perineal femoral pudendal brachial sciatic
sciatic
Each of the following nerves originates in the lumbar plexus, except the ________ nerve. femoral obturator genitofemoral saphenous sciatic
sciatic
Which of the following is NOT a function of the hypothalamus? emotional responses regulation of body temperature secretion of the hormone melatonin regulation of food intake
secretion of the hormone melatonin
Explain one of the funtions of the Pineal body:
seems to regulate the body's biological clock. A big part of this is regulated by the hormone melatonin, which is produced in the Pineal gland.
What is the function of the Vestibulocochlear nerve?
sense of hearing and equilibrium.
What is the function of the Olfactory nerve?
sense of smell
What is the function of the Facial nerve?
sense of taste. Motor impulses to facial muscles, tear, & salivary glands.
What is the function of the Optic nerve?
sense of vision
Which of the following is NOT a structural classification of neurons?
sensory
division of PNS
sensory (afferent) and motor (efferent)
which subdivision of the PNS is involved in relaying the feeling of a full stomach after a meal
sensory (afferent) division of PNS
what are somatic afferent fibres
sensory fibres conveying impulses from skin, skeletal muscles and joints
If the dorsal root of a spinal nerve is severed, the spinal cord would not be able to process information at that level. output to skeletal muscles would be blocked. output to visceral organs would be blocked. sensory input would be blocked. the brain would not be able to communicate with that level of the spinal cord
sensory input would be blocked.
what are three functions of the nervous system
sensory input, integration, motor output
What is the function of the Trigeminal nerve?
sensory inputs from face, teeth, and mouth. Control muscles in mouth.
optic nerve ( II )
sensory nerve that carries visual impulses from the eye to the brain ( E )
olfactory nerve
sensory nerve: functioning in the sense of smell ( C )
The posterior horns of the spinal cord contain mainly somatic motor nuclei. nerve tracts. sensory nuclei. autonomic motor nuclei. sympathetic nuclei.
sensory nuclei
The stimulus for graded potentials includes _______.
sensory stimuli and neurotransmitter
what are the subdivision of the PNS
sensory/afferent division, motor/efferent division
Which of the following describes the excitatory postsynaptic potential?
short distance depolarization
Which of the following describes the excitatory postsynaptic potential? moves membrane potential away from threshold short distance hyperpolarization short distance depolarization opens K+ or Cl- channels
short distance hyperpolarization
what are dendrites
short tapering diffusely branching extensions
what do thoracic nerves control and how many?
shoulders chest upper abdomen 12
Which of the following activities or sensations is not monitored by interoceptors? activities of the digestive system urinary activities cardiovascular activities taste sight
sight
The effects of lidocaine and tetrodotoxin were
similar, but tetrodotoxin had a greater effect
The effects of lidocaine and tetrodotoxin were _______.
similar, but tetrodotoxin had a greater effect
Hyperpolarization results from __________.
slow closing of voltage-gated K+ channels
Which of the following is least likely to increase the rate of diffusion?
small concentration gradient
Which of the following best characterizes depolarization?
small consecutive steps of Na+ penetration into the axon along its length
Which of the following best characterizes depolarization? small consecutive steps of Na+ penetration into the axon along its length small consecutive steps of Na+ exit from cytoplasm into extracellular fluid small consecutive steps of K+ entering the cytoplasm mass movement of Na+ into the axon cytoplasm from the cell body to the terminal
small consecutive steps of Na+ penetration into the axon along its length
what are microglia
small ovoid cells with relatively long thorny processes
microglia
small, ovoid cells with spiny processes Phagocytes that monitor the health of neurons
Type C nerve fiber
small-diameter, unmyelinated. Conduct at 2 m/s or less. Part of ANS
what are neuroglia
smaller cells that surround and wrap the more delicate neurons
how can neuroglia be distinguised
smaller size and darker staining nuclei
The movement of what ion is responsible for the local currents that depolarize other regions of the axon to threshold?
sodium (Na+)
Which of the following is true about the movement of ions across excitable living membranes?
sodium gates in the membrane can open in response to electrical potential changes
When cholinergic receptors are stimulated, chloride ions enter the postsynaptic neuron. sodium ions leave the postsynaptic neuron. sodium ions enter the postsynaptic neuron. norepinephrine deactivates acetylcholine. chloride ions leave the postsynaptic neuron.
sodium ions enter the postsynaptic neuron.
Establishing the resting membrane potential requires energy through the use of the _______.
sodium-potassium pump
That part of the nervous system that is voluntary and conducts impulses from the CNS to the skeletal muscles is the ________ nervous system.
somatic
The ________ nervous system controls the skeletal muscles. sympathetic autonomic afferent somatic parasympathetic
somatic
The anterior horns of the spinal cord contain mainly autonomic motor nuclei. sympathetic nuclei. nerve tracts. sensory nuclei. somatic motor nuclei.
somatic motor nuclei.
what is the somatic nervous system composed of
somatic nerve fibres that conduct impulses from CNS to skeletal muscles
what are the 2 parts of the motor division
somatic nervous system, autonomic nervous system
which subdivision of the PNS is involved in contracting the muscles to lift your arm
somatic nervous system, motor (efferent) division of PNS
Summation that results from the cumulative effect of multiple synapses at multiple places on the neuron is designated temporal summation. spatial summation. inhibition of the impulse. impulse transmission. hyperpolarization.
spatial summation.
what does the neuron cell body consist of
spherical nucleus with conspicuous nucleolus surrounded by cytoplasm
Which of these is not part of the peripheral nervous system (PNS)? afferent nerve fibers cranial nerves spinal nerves spinal cord
spinal cord
If the caudal portion of the neural tube failed to develop properly the ________. spinal cord may be affected telencephalon would cease development cranial nerves would not form hindbrain would not be present
spinal cord may be affected
Components of the Nervous System
spinal cord, brain, sensory receptors, nerves
The __________ is part of the CNS and the __________ is part of the PNS. spinal cord; spinal nerve cranial nerve; spinal nerve spinal nerve; spinal cord brain; spinal cord
spinal cord; spinal nerve
The specialized membranes that surround the spinal cord are termed the spinal mater. cranial mater. spinal meninges. epidural membranes. cranial meninges.
spinal meninges
A dorsal and ventral root of each spinal segment unite to form a cervical enlargement. lumbar enlargement. spinal ganglion. spinal meninx. spinal nerve.
spinal nerve.
Select the correct statement about serial processing
spinal reflexes are an example
what are neurons
structural units of nervous system, highly specialised cells that conduct messages in the form of nerve impulses from one part of the body to another
thalamus
structure in the diencephalon that processes all sensory information for except smell, and relays it to the cerebral cortex ( j )
The cerebrospinal fluid (CSF) circulates within the __________. subarachnoid space pia mater subdural space dura mater
subarachnoid space
Cerebrospinal fluid flows within the pia mater. subarachnoid space. arachnoid mater. filum terminale. dura mater.
subarachnoid space.
Samples of CSF for diagnostic purposes are normally obtained by placing the tip of a needle in the dura mater. cerebral ventricles. arachnoid mater. subarachnoid space. epidural space.
subarachnoid space.
Opioids relieve pain by blocking the release of substance Q. substance P. substance X. substance O. None of the answers are correct.
substance P.
increasing the strength of the stimulus applied to the sensory receptor increased _______.
the frequency of action potentials in the sensory neuron, the amount of neurotransmitter released at the axon terminal of the sensory neuron and the frequency of action potentials in the interneuron
lateral fissure
the gap that divides the temporal from the frontal and parietal lobes
An action potential in one segment of axon causes adjacent sections of axon membrane to reach threshold through what mechanism?
the generation of local currents
An action potential in one segment of axon causes adjacent sections of axon membrane to reach threshold through what mechanism? the generation of local currents Na+ ions diffusing across the membrane through leakage channels K+ ions diffusing through voltage-gated channels neurotransmitters causing chemically gated channels to open
the generation of local currents
All EXCEPT which of the following organs receives its innervation from fibers that synapse with preganglionic neurons in collateral ganglia?
the heart
The small space between the sending neuron and the receiving neuron is the
synaptic cleft
If the chemically-gated sodium channels in the postsynaptic membrane were completely blocked, smaller action potentials would result. the presynaptic neuron would release a different neurotransmitter. the presynaptic membrane would be unable to reach threshold. synaptic transmission would fail. release of neurotransmitter would stop.
synaptic transmission would fail.
Proteins in cell
synthesized there, don't dissolve in phospholipids of membrane
Axons terminate in a series of fine extensions known as dendrites. terminals. collaterals. telodendria. synapses.
telodendria.
The primary auditory cortex is located in the ________. frontal lobe prefrontal lobe parietal lobe temporal lobe
temporal lobe
When a second EPSP arrives at a single synapse before the effects of the first have disappeared, what occurs? decrease in speed of impulse transmission spatial summation temporal summation inhibition of the impulse hyperpolarization
temporal summation
REM sleep is associated with ________. decreased vital signs, such as heart rate and blood pressure decreased activity of the brain, especially the cerebral cortex decreased oxygen use, especially in the cerebral cortex temporary skeletal muscle inhibition except for ocular muscles and diaphragm
temporary skeletal muscle inhibition except for ocular muscles and diaphragm
The reflex that limits muscle tension is the __________ reflex. tendon reciprocal flexor stretch
tendon
The reflex that prevents a muscle from exerting too much tension is the ________ reflex. flexor stretch tendon reciprocal crossed extensor
tendon
the branches at the end of an axon are called what
terminal branches or telodendria
what is the end of an axon called
terminus
occipital lobe association area
the association area that is in charge of visual images w/ other sensory experiences
frontal lobe association areas
the association areas of concentrating, planning, problem solving, & judging are located?
parietal lobe association areas
the association areas of understanding speech and using words to express thought are located?
temporal lobe association areas
the association areas to remember music, visual scenes, complex patterns, & auditory are located?
non-dominant hemisphere controls *** not on test #7
the hemisphere of the brain that controls intuitive thought processes, nonverbal, motor tasks, interpreting musical, & visual patterns, emotions *** not on test #7
Many medications introduced into the bloodstream cannot directly affect the neurons of the CNS because the neurolemma is impermeable to most molecules. oligodendrocytes form a continuous myelin sheath around the axons. astrocytes form a capsule around neurons. ependymal cells restrict the flow of interstitial fluid between the capillaries and the neurons. the endothelium of CNS capillaries forms a blood-brain barrier.
the endothelium of CNS capillaries forms a blood-brain barrier.
what are neurons
the excitable nerve cells that transmit electrical signals
On what does consciousness depend?
the excitation of cortical neurons by impulses conducted to them by a network of neurons known as the Reticular Activiating System.
transverse fissure
the fissure that separates the cerebrum from the cerebellum
dominant hemisphere controls *** not on test #6
the hemisphere of the brain that controls speech, writing, reading, verbal skills, analytical skills, computational skills *** not on test #6
If a motor neuron in the body were stimulated by an electrode placed about midpoint along the length of the axon ________.
the impulse would spread bidirectionally
If a motor neuron in the body were stimulated by an electrode placed about midpoint along the length of the axon ________. the impulse would move to the axon terminal only muscle contraction would occur the impulse would spread bidirectionally the impulse would move to the axon terminal only, and the muscle contraction would occur
the impulse would spread bidirectionally
pia mater
the innermost meninge that tightly surrounds the brain & spinal cord ( 12 )
What is the infundibulum?
the part of the hypothalamus that forms a "stalk" between the hypothalamus and the pituitary gland.
Which of the following are gaps found along a myelin sheath?
nodes of Ranvier
what is are the gaps between the schwann cells on an axon in the PNS?
nodes of ranvier
Which of these neurotransmitters do adrenergic synapses use? nitric oxide GABA acetylcholine norepinephrine
norepinephrine
Which of these neurotransmitters is released at CNS adrenergic synapses? norepinephrine GABA serotonin adrenaline
norepinephrine
Adrenergic synapses release the neurotransmitter acetylcholine. serotonin. dopamine. GABA. norepinephrine.
norepinephrine.
The ventral rami form four major plexuses, including all of the following, except the ________ plexus. lumbar nuchal sacral brachial cervical
nuchal
Which of the following is not a chemical class of neurotransmitters?
nucleic acid
Which of the following is not a chemical class of neurotransmitters? acetycholine biogenic amine nucleic acid ATP and other purines amino acid
nucleic acid
Cell body
nucleus and metabolic center of the cell YES Nucleus NO centrioles
What are varicosities?
numerous swellings located at intervals along the axons of postganglionic neurons
what are axon collateral's
occasional branches along an axon, extend at right angles
Nuclei of cranial nerves V, VI, and VII are found in the ________. medulla midbrain cerebrum pon
pons
what is the neurilemma
portion of the Schwann cell that includes the exposed part of its plasma membrane- nucleus and cytoplasm of S cell end up as bulge external to myelin sheath
Immediately after an action potential has peaked, which cellular gates open?
potassium
The movement of which ion through leakage channels establishes the negative membrane potential?
potassium
What causes repolarization of the membrane potential during the action potential of a neuron?
potassium efflux (leaving the cell)
The most abundant intracellular cation is __________ while the most abundant extracellular anion is __________. sodium; chloride potassium; chloride potassium; protein anions sodium; protein anions
potassium; chloride
Which of the following is NOT a type of circuit?
pre-discharge circuits
Which of the following is NOT a type of circuit? reverberating circuits pre-discharge circuits converging circuits diverging circuits
pre-discharge circuits
Which part of the cerebral cortex is involved in intellect, cognition, recall, and personality? prefrontal cortex posterior association area limbic association area combined primary somatosensory cortex and somatosensory association cortex
prefrontal cortex
Loss of ability to perform skilled motor activities such as piano playing, with no paralysis or weakness in specific muscles, might suggest damage to the ________. spinal cord rubrospinal tracts primary motor cortex premotor cortex
premotor cortex
Which best represents synaptic transmission?
presynaptic axon to synapse to dendrite or postsynaptic cell body
Which best represents synaptic transmission? presynaptic axon to synapse to dendrite or postsynaptic cell body presynaptic axon to synapse to postsynaptic axon presynaptic axon to presynaptic cell body to dendrite presynaptic cell body to dendrite to synapse
presynaptic axon to synapse to dendrite or postsynaptic cell body
The neurotransmitter GABA blocks presynaptic voltage-gated calcium channels. Consequently, GABA produces __________. EPSPs presynaptic facilitation presynaptic inhibition IPSPs
presynaptic inhibition
In a synapse, neurotransmitters are stored in vesicles located in the __________.
presynaptic neuron
trochlear nerve ( IV )
primarily a motor nerve it carries motor impulses to oblique muscles of eye ( G )
hypoglossal nerve ( XII )
primarily a motor nerve: motor to move muscles of the tongue ( O )
accessory nerve ( XI )
primarily a motor nerve; to muscles of soft palate, pharynx, neck & back ( N )
The sodium-potassium pump uses ATP to move sodium and potassium ions across the plasma membrane. This statement describes _____.
primary active transport
Which of the following are motor areas of the cerebral cortex that lie in the posterior part of the frontal lobes and control voluntary movement? primary somatosensory cortex; somatosensory association cortex; visual areas Broca's area; posterior association area; auditory areas; visual areas primary motor cortex; premotor cortex; prefrontal cortex; gustatory cortex primary motor cortex; premotor cortex; Broca's area; frontal eye field
primary motor cortex; premotor cortex; Broca's area; frontal eye field
Which of the following areas of the brain is responsible for spatial discrimination? primary somatosensory cortex vestibular cortex Broca's area gustatory cortex
primary somatosensory cortex
Which category of memory is involved when playing the piano? declarative motor emotional procedural
procedural
what is the central process
process entering the CNS
what is the function of microglia
processes touch nearby neurons to monitor health and when they sense injured neurons migrate towards them.
Oligodendrocytes
produce myelin sheath around nerve fibers in the central nervous system
Which of the following is not a recognized structural classification for neurons? multipolar pseudopolar anaxonic unipolar bipolar
pseudopolar
Which of these is not a neuron structural category? multipolar pseudopolar unipolar bipolar
pseudopolar
Two terms for the massive motor tracts serving voluntary movement are ________. segmental and nigrostriatal pyramidal and corticospinal extrapyramidal and rubrospinal supplementary and cerebellar-pontine
pyramidal and corticospinal
what do ependymal cells look like
range in shape form squamous to columnar and many are ciliated
ependymal cells
range in shape from squamous to columnar, many are ciliated They produce CSF, line the central cavities of the brain and spinal column, and create CSF flow
After acetylcholinesterase acts, the synaptic terminal reabsorbs axoplasm. reabsorbs the acetate. reabsorbs the acetylcholine. reabsorbs the choline. pinches off and a new terminal grows
reabsorbs the choline.
Neuron & parts
receive stimuli and transmit action potentials -cell body:soma -dendrites: input -axons: output
The receptor potential is generated at the
receiving region
Which of the following processes allows cells to concentrate material that is present only in very small amounts in the extracellular fluid?
receptor-mediated endocytosis
Spinal interneurons inhibit antagonist motor neurons in a process called a crossed extensor reflex. a stretch reflex. reciprocal inhibition. reverberating circuits. a tendon reflex.
reciprocal inhibition.
Which of the following would you not find in normal cerebrospinal fluid? red blood cells protein glucose potassium
red blood cells
Which of the following is (are) involved with motor activity (either initiation or coordination)? Wernicke's area postcentral gyrus red nuclei gustatory cortex
red nuclei
Which of the following is NOT an adaptation that occurs at the neuromuscular junction in response to exercise?
reduced degradation of acetylcholine in the neuromuscular junction
Which of the following is NOT one of the basic functions of the nervous system?
regulation of neurogenesis
Which of the following is NOT one of the basic functions of the nervous system? integration of sensory input monitor changes occurring both inside and outside the body control the activity of muscles and glands regulation of neurogenesis
regulation of neurogenesis
Clenching the fists often enhances the knee jerk reflex. This is an example of __________. stimulus response enhancement reinforcement nerve injury
reinforcement
Neuroglia perform all of these functions except __________. secrete CSF provide supportive framework release neurotransmitters regulate extracellular fluid composition
release neurotransmitters
If the __________ muscles are affected, then the person may have to be placed __________.
respiratory; respirator
Which of the following describes the nervous system integrative function? analyzes sensory information, stores information, makes decisions responds to stimuli by gland secretion or muscle contraction senses changes in the environment
analyzes sensory information, stores information, makes decisions
Neurons that are rare, small, and lack features that distinguish dendrites from axons are called anaxonic. bipolar. multipolar. unipolar. tripolar.
anaxonic.
During the relative refractory period,
another action potential can be generated provided the stimulus is large enough
knee-jerk reflex
another name for patellar reflex; this is a monosynaptic reflex (no interneuron); helps maintain an upright posture
Which of the following is a factor that determines the rate of impulse propagation, or conduction velocity, along an axon? a) the number of axon collaterals extending from a truncated axon b) degree of myelination of the axon c) whether the axon is located in the central nervous system or in the peripheral nervous system d) length of the axon
b) degree of myelination of the axon
Collections of nerve cell bodies outside the central nervous system are called _________. a) nuclei b) ganglia c) tracts d) nerves
b) ganglia
The two types of receptors that bind acetylcholine are __________ and _______ receptors. a) alpha; beta b) nicotinic; muscarinic c) caffeinic; muscarinic d) nicotinic; caffeinic
b) nicotinic; muscarinic
Mary is in an automobile accident and suffers a spinal cord injury. She has lost feeling in her lower body. Her doctor tells her that swelling is compressing a portion of her spinal cord. Which part of her cord is likely to be compressed? descending tracts the anterior gray commissures the anterior gray horns ascending tracts the anterior white commissures
ascending tracts
A neuron that has as its primary function the job of connecting other neurons is called a(n) ________.
association neuron
A neuron that has as its primary function the job of connecting other neurons is called a(n) ________. association neuron glial cell efferent neuron afferent neuron
association neuron
Neuroglia that control the chemical environment around neurons by buffering potassium and recapturing neurotransmitters are ________.
astrocytes
Neuroglia that control the chemical environment around neurons by buffering potassium and recapturing neurotransmitters are ________. microglia oligodendrocytes Schwann cells astrocytes
astrocytes
Which is the largest and most abundant type of neuroglia? astrocytes ependymal cells satellite cells oligodendrocytes
astrocytes
Which neuroglia are the most abundant and versatile of the glial cells?
astrocytes
Which neuroglia are the most abundant and versatile of the glial cells? ependymal cells Schwann cells oligodendrocytes astrocytes
astrocytes
Which of the following types of glial cells are the most abundant and versatile, and aid in making exchanges between capillaries and neurons?
astrocytes
what is the most abundant and versatile glial cell
astrocytes
Neuroglia of CNS
astrocytes, epydymal, oligondendryte, microglia
The largest and most numerous of the glial cells in the central nervous system are the microglia. ependymal cells. satellite cells. oligodendrocytes. astrocytes.
astrocytes.
The neuroglial cells that participate in maintaining the blood-brain barrier are the oligodendrocytes. microglia. Schwann cells. ependymal cells. astrocytes.
astrocytes.
Where are action potentials regenerated as they propagate along an unmyelinated axon?
at every segment of the axon
The release of neurotransmitter occurs _______.
at the axon terminal
During what part of the action potential do voltage-gated Na+ channels begin to inactivate (their inactivation gates close)?
at the end of the depolarization phase, as the membrane potential approaches its peak value
Where are action potentials regenerated as they propagate along a myelinated axon?
at the nodes
Where are action potentials regenerated as they propagate along a myelinated axon?
at the nodes of Ranvier
Where are action potentials regenerated as they propagate along a myelinated axon? at the nodes of Ranvier at every segment of the axon at the axon hillock at the myelinated segments
at the nodes of Ranvier
An excitatory postsynaptic potential occurs _______.
at the receiving end of the interneuron
Myasthenia gravis is a medical condition of __________ etiology that results in __________ muscle weakening.
autoimmune; skeletal muscle
reflexes
automatic, subconcious response to a stimuli
which subdivision of the PNS is involved in increasing your heart rate
autonomic nervous system, motor (efferent) division of PNS
The conducting region of the neuron is the
axon
The conducting region of the neuron is the _______
axon
The part of a neuron that conducts impulses away from its cell body is called a(n) ________.
axon
Which of the following is the conducting region of the neuron?
axon
Which of the following is the conducting region of the neuron? terminal boutons axon soma dendrites
axon
Which part of the neuron is responsible for generating a nerve impulse?
axon
Which part of the neuron is responsible for generating a nerve impulse? soma axon dendrite chromatophilic substance
axon
what is the conduction region of the neuron
axon
what can emerge from the nodes of ranvier
axon collaterals
EPSPs and IPSPs summate at the __________. synaptic knob postsynaptic receptors axon hillock electrical synapse
axon hillock
The simplest level of information processing takes place at the __________. axon terminals axon hillock soma dendrites
axon hillock
Where in the neuron is an action potential initially generated?
axon hillock
The axon is connected to the soma at the collaterals. synaptic terminal. telodendria. synapse. axon hillock.
axon hillock.
The site in the neuron where EPSPs and IPSPs are integrated is the synaptic terminal. electrical synapse. chemical synapse. axon hillock. dendritic membrane
axon hillock.
what is the secretory region of the neuron
axon terminals
what are the knoblike distal ending of the terminal branches called
axon terminals, synaptic knobs, boutons
The part of a neuron that conducts impulses away from its cell body is called a(n) ________. axon Schwann cell neurolemma dendrite
axon\
The ventral root of a spinal nerve contains axons of sensory neurons. axons of motor neurons. cell bodies of motor neurons. cell bodies of sensory neurons. interneurons.
axons of motor neurons.
The dorsal root of a spinal nerve contains cell bodies of motor neurons. axons of sensory neurons. cell bodies of sensory neurons. axons of motor neurons. interneurons.
axons of sensory neurons.
what are visceral afferent fibres
axons transmitting impulses from the visceral organs- organs within the ventral body cavity
Which of the following are gaps found along a myelin sheath? a) Neurilemma b) Nodes of Ranvier c) Telodendria d) Axolemma
b) Nodes of Ranvier
Preparing the body for the "fight-or-flight" response is the role of the _______. a) somatic nervous system b) sympathetic nervous system c) cerebrum d) parasympathetic nervous system
b) sympathetic nervous system
what is the purpose of the ependymal cells cillia
beating cilia helps to circulate cerebrospinal fluid that cushions the brain and spinal cord
inhibition
because cell M1 regulates the ability of the presynaptic cell to release transmitter, it is called PRESYNAPTIC _____.
why do CNS myelin sheaths lack neurilemma
because cell extensions are doing the coiling and the squeezed out cytoplasm is forced not peripherally but back towards the centrally located nucleus
Which of the following is not true of graded potentials? a) They can be called postsynaptic potentials. b) They increase amplitude as they move away from the stimulus point. c) They are short-lived. d) They can form on receptor endings.
b) They increase amplitude as they move away from the stimulus point.
The part of a neuron that conducts impulses away from its cell body is called a(n) ________. a) Schwann cell b) axon c) dendrite d) neurolemma
b) axon
Spinal nerves are purely motor. purely sensory. involuntary. both sensory and motor. interneuronal.
both sensory and motor
During depolarization, which gradient(s) move(s) Na+ into the cell?
both the electrical and chemical gradients
In which plexus does the ulnar nerve arise? lumbar cranial cervical brachial sacral
brachial
The ventral rami of spinal nerves C5 to T1 contribute fibers to the ________ plexus. lumbar sacral cervical brachial thoracic
brachial
The term central nervous system refers to the ________.
brain and spinal cord
The term central nervous system refers to the ________. brain and spinal cord brain, spinal cord, and peripheral nerves spinal cord and spinal nerves peripheral and spinal nerves
brain and spinal cord
what is in the CNS
brain and spinal cord, integrating and command centre
A nerve is _______.
bundle of axons
nerve
bundle of axons and their sheaths that connects CNS to sensory receptors, muscles, and glands (cranial and spinal)
What is the ventral nerve root?
bundle of nerve fibers carrying motor information out of the cord.
The white matter of the spinal cord contains both axons and dendrites. sensory and motor nuclei. interneurons. bundles of axons with common origins, destinations, and functions. bundles of dendrites with common origins, destinations, and functions.
bundles of axons with common origins, destinations, and functions.
what are neurofibrils
bundles of intermediate filaments
describe sensory/afferent neurons
transmit impulses from sensory receptors in the skin or internal organs toward or into the CNS, mostly all are unipolar and cell bodies located in sensory ganglia outside CNS, peripheral processes long
The region on the neuron where action potentials are generated is called the ______.
trigger zone
A disturbance of posture, muscle tremors at rest, and uncontrolled muscle contraction are all symptoms of damage to the basal nuclei. True False
true
A postsynaptic potential is a graded potential that is the result of a neurotransmitter released into the synapse between two neurons. True False
true
A stimulus traveling toward a synapse appears to open calcium ion channels at the presynaptic end, which in turn promotes fusion of synaptic vesicles to the axonal membrane
true
A stimulus traveling toward a synapse appears to open calcium ion channels at the presynaptic end, which in turn promotes fusion of synaptic vesicles to the axonal membrane. True False
true
Cell bodies of sensory neurons may be located in ganglia lying outside the central nervous system. True False
true
Cell bodies of the somatic motor neurons of the spinal nerves are located in the ventral horn of the spinal cord. True False
true
Cerebrospinal fluid circulates within the ventricles of the brain and in the subarachnoid space outside the brain. True False
true
During depolarization, the inside of the neuron's membrane becomes less negative. True False
true
Efferent nerve fibers may be described as motor nerve fibers. True False
true
Embryonic damage to the mesencephalon could result in improper formation of the midbrain. True False
true
If bacteria invaded the CNS tissue, microglia would migrate to the area to engulf and destroy them. True False
true
In general, information flows from sensory receptors to the appropriate primary sensory cortex. True Fals
true
In myelinated axons the voltage-regulated sodium channels are concentrated at the nodes of Ranvier. True False
true
Most of the ascending and descending pathways to and from the brain cross over from one side of the body to the other. True False
true
Myelination of the nerve fibers in the central nervous system is the job of the oligodendrocyte. True False
true
NREM sleep normally exhibits four distinct stages, which appear to alternate. True False
true
Neurons in the CNS are organized into functional groups. True False
true
Nuclei relating to the startle reflex are located in the corpora quadrigemina of the midbrain. True False
true
One functional center found within the medulla oblongata is a respiratory center involved in the control of the rate and depth of breathing. True False
true
Opening K+ or Cl- channels in a postsynaptic membrane would produce an inhibitory postsynaptic potential (IPSP). True False
true
Reflexes are rapid, automatic responses to stimuli.
true
Reflexes are rapid, automatic responses to stimuli. True False
true
Some neurotransmitters can be either excitatory or inhibitory depending upon the receptor. True False
true
Specific motor and sensory functions are localized in specific areas called domains, whereas memory and language have overlapping domains. True False
true
The adult spinal cord ends between L1 and L2. True False
true
The first obvious sign that the nervous system is forming in the embryo is the thickening of the surface ectoderm to form the neural plate. True False
true
The left cerebral hemisphere is usually dominant. True False
true
The limbic system acts as our emotional, or affective, brain. True False
true
The oligodendrocytes can myelinate several axons. True False
true
The overlapping functions of the nervous system are sensory input, integration, and motor output. True False
true
The primary visual cortex contains a map of visual space. True False
true
The term cerebral dominance designates the hemisphere that is dominant for language. True False
true
The terms fainting and syncope describe the same thing. True False
true
Unipolar neurons have axons structurally divided into peripheral and central processes. True False
true
Neurotransmitters ready for release are stored in synaptic terminals. vesicles. mitochondria. neurosomes. telodendria.
vesicles
Important nuclei of the indirect (multineural) system that receive impulses from the equilibrium apparatus of the inner ear and help to maintain balance by varying muscle tone of postural muscles are the ________. reticular nuclei vestibular nuclei red nuclei superior colliculi
vestibular nuclei
A reflex that leads to secretion of saliva is a(n) __________ reflex. acquired motor somatic visceral
visceral
Which of the following best describes the hypothalamus? somatic motor control center gateway to the cerebellum visceral control center of the body relay station for the special senses
visceral control center of the body
what does the ANS consist of
visceral motor nerve fibres that regulate the activity of smooth muscles, cardiac muscles and glands
The area of the cortex that is responsible for sensations of the full bladder and the feeling that your lungs will burst when you hold your breath too long is the ________. gustatory cortex vestibular cortex olfactory cortex visceral sensory area
visceral sensory area
Which of the following is NOT one of the three types of functional areas within the cerebral cortex? sensory areas motor areas association areas visual areas
visual areas
An individual who could trace a picture of a bicycle with his or her finger but could not recognize it as a bicycle is most likely to have sustained damage to the ________. primary visual area visual association area lateral geniculate body calcarine cortex
visual association area
In this simulation, ___________________ will be used to stimulate the axon.
voltage
Which ion channel opens in response to a change in membrane potential and participates in the generation and conduction of action potentials?
voltage- gated channels
An action potential releases neurotransmitter from a neuron by opening which of the following channels?
voltage-gated Ca2+ channels
The depolarization phase of an action potential results from the opening of which channels?
voltage-gated Na+ channels
In response to an action potential, what type of channels open in the motor neuron terminal buttons at the neuromuscular junction to cause neurotransmitter release?
voltage-gated calcium channel
Which ion channel opens in response to a change in membrane potential and participates in the generation and conduction of action potentials?
voltage-gated channel
Which of the following membrane ion channels open and close in response to changes in the membrane potential?
voltage-gated channels
When an action potential arrives at the end of the axon terminal, a series of events take place that result in the release of neurotransmitter from the presynaptic axon. Select the answer that correctly describes the primary stimulus for vesicles to move towards the cell membrane and eventually release their contents.
voltage-gated membrane channels open, and Ca+2 enters the cytoplasm, increasing intracellular calcium
What is primarily responsible for the brief hyperpolarization near the end of the action potential?
voltage-gated potassium channels taking some time to close in response to the negative membrane potential
An action potential requires _______.
voltage-gated sodium channels to open and sodium to flow with its electrochemical gradient
Somatic nervous system
voluntary
axoaxonic
what type of synapse? Axon of presynaptic neuron synapses with presynaptic terminal of another neuron (e.g. many synapses of CNS).
short term memory *** not on test #8
when a closed circuit of neurons is stimulated over & over in order to maintain memory; when stimulation ceases so does the memory *** not on test #8
describe unmyelintated cells
when schwann cells surround peripheral nerve fibres but the coiling process does not occur. typically thin fibres
axon terminals
where axons end
what is the axon hillock
where the axon rises from
Which of the following does not influence the time necessary for a nerve impulse to be transmitted? diameter of the axon presence or absence of nodes length of the axon whether or not the impulse begins in the CNS presence or absence of a myelin sheath
whether or not the impulse begins in the CNS
Reflexes can be classified according to all of the following, except the motor response. where information processing occurs. their development. the complexity of the neural circuit. whether they are sensory or motor.
whether they are sensory or motor.
Autonomic motor nuerons
GVE
Classified as sympathetic or parasympathetic
GVE
Efferent motor flow to cardiac muscle, smooth muscle of visceral organs and blood vessels, and glads
GVE
Involuntary motor
GVE
Neurons of the autonomic nervous system
GVE
cell body, processies
Major regions of neurons
What is the peripheral bulge of the Schwann cell cytoplasm called?
Neurilemma [where the jelly roll bulges out]
What is the stimulus in the patellar tendon reflex
Striking the patellar tendon
How is Cerebrospinal Fluid formed?
Structures called choroid plexus separate some fluid from the blood. That fluid is CSF.
Upper masses of the corpora quadrigemina which contain the centers for certain visual reflexes
Superior colliculi
How much CSF do humans secrete daily
500 ml
Which areas of this neuron would be classified as receptive regions?
Cell body
Amitotic
Cells do not replace themselves.
Norepinephrine-releasing fibers are called cholinergic fibers T/F
False
Cannot convey distinctions between hot vs. cold, fine vs. course pressure
GVA
Mainly subconscious (exception: visceral pain, nausea, sensation of fullness)
GVA
Sensory nuerons with cell bodies loacated in the dorsal/posterior root ganglion (ass. with GVE)
GVA
Sensory receptors located in visceral organs, blood vessels, and glands
GVA
Transmit info from visceral organs to CNS
GVA
Anterior branches of the spinal cord form complex networks called
Plexuses
Appears as a rounded bulge on the underside of the brainstem where it separates the midbrain from the medulla oblongata
Pons
Relays information from spinal nerves to higher brain centers and the cerebrum & the cerebellum..also the center for the rhythm of breathing
Pons
Define Thalamus:
Portion of the Diencephalon; mass of gray matter involved in relay of sensory information, emotion, arousal and complex reflexes.
Define Brain Stem:
Portion of the brain made up of the midbrain, pons, and medulla oblongata.
What functional area of the cerebral cortex serves as the primary area for the general somatic senses?
Postcentral Gyrus
The posterior and anterior wings of the gray matter are called the
Posterior & anterior horns
Location of the fasciculus
Posterior funiculi
Spinal nerves branch into 3 different branches called
Posterior, anterior & visceral
Fibers that leave the ganglion to synapse on the visceral effector are
Postganglionic fibers
Define POSTsynaptic neuron
Postsynaptic neuron: transmits impulses away from the synapse
Fibers that leave the CNS to synapse at the ganglion are
Preganglionic fibers
Sympathetic
Prepares body for physical activity.
________ neurons form the afferent division of the PNS. Sensory Neural sensory Somatic sensory Visceral sensory Motor
Sensory
Neuron Classification Functional
Sensory (afferent) — transmit impulses toward the CNS Motor (efferent) — carry impulses away from the CNS Interneurons — shuttle signals through CNS pathways and perform integration
__________ needs neural stimulation/excitation before it can contract; the other forms of muscle can also be stimulated by hormones and/or other chemicals.
Skeletal muscle
Describe the structure and function of Microglial cells
Small, ovoid cells with thorny processes Migrate toward injured neurons Phagocytize microorganisms and neuronal debris M = M: microglia macrophage
Saltatory conduction is made possible by ________.
The myelin sheath
Fissure that separates the cerebrum from the cerebellum
Transverse fissure
The cytoplasm that surrounds the nucleus of a neuron is called the protoplasm. neuroplasm. perikaryon. nucleoplasm. sarcoplasm.
perikaryon.
The layer of connective tissue that surrounds a fascicle within a peripheral nerve is the endosteum. endoneurium. epimysium. epineurium. perineurium.
perineurium.
The nervous tissue outside of the central nervous system composes the ________ nervous system.
peripheral
The ________ nerve, which arises in the cervical plexus, innervates the diaphragm. sciatic radial phrenic lesser occipital ansa cervicalis
phrenic
The brachial plexus gives rise to all of the following nerves, except the median. radial. musculocutaneous. ulnar. phrenic
phrenic
The layer of the meninges in direct contact with the spinal cord is the dura mater. subarachnoid space. arachnoid. pia mater. choroid plexus.
pia mater
Blood vessels that supply the spinal cord run along the surface of the epidural space. pia mater. subarachnoid space. dura mater. subdural space.
pia mater.
The CSF is confined between the __________ and the __________. pia mater; dura mater epidural space; subdural space dura mater; arachnoid mater pia mater; arachnoid mater
pia mater; arachnoid mater
what is the site of electrical signalling in a neuron
plasma membrane
The complex, interwoven network formed by contributions from the ventral rami of neighboring spinal nerves is termed a(n) plexus. lateral nerve. autonomic nerve. dermatome. tract.
plexus.
Enteric
plexuses within the wall of the digestive tract
corpus callosum
the thick flat bundle of axons that connects the two cerebral hemispheres
ascending tract
the tract in the white matter of the spinal cord that carries sensory information towards the brain
lateral spinothalamic
the tracts in the lateral funiculi of the spinal cord that carry afferent nerve fibers to the thalamus
fasciculus cuneatus
the tracts in the posterior funiculi of spinal cord; transmits fine touch, and proprioception information from sensory nerves
During an action potential of a neuron, what directly causes the different channels to open and close?
the transmembrane potential (voltage)
three parts of the brainstem
these three parts (midbrain / pons / medulla oblongata) A, B, C, D
Which of the following is not characteristic of neurons?
they are mitotic
What are the somatic senses?
they are the general (not specialized) senses. They do not require complex sensory organs.
When calcium ions enter the synaptic terminal,
they cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the sending neuron.
why are unipolar neurons more accurately called pseudo unipolar neurons
they originate as bipolar neurons then during early embryonic development the two process converge and partially fuse to form short single process that issues from the cell body
What are descending tracts?
tracts conduct impulses down the cord away from the brain
what are bundles of neuron processes called
tracts in the CNS, nerves in the PNS
What are ascending tracts?
tracts that conduct impulses to the brain
oligodendrocytes function
1. cells that produce myelin in the CNS 2. produce grow-inhibitory proteins that inhibit the growth of injured neuons
Define Synapse
A junction that mediates information transfer from one neuron: - To another neuron, or - To an effector cell
Synapse
A junction that mediates information transfer from one neuron: To another neuron To an effector cell
Saltatory conduction
"jumping" of impulse from node to node
Which of the following occurred in the presence of tetrodotoxin?
An action potential was always seen at R1.
Describe the structure and function of Astrocyte cells
*SUPPORT / COMMUNICATION* Most abundant, versatile, and highly branched glial cells Cling to neurons, synaptic endings, and capillaries Support and brace neurons Help determine capillary permeability Guide migration of young neurons Control the chemical environment Participate in information processing in the brain Communication between capillary & neurons A = A: astrocytes attach to arteries
In a typical neuron, what is the equilibrium potential for sodium?
+66mV
How many segments does the spinal cord have? What arises from each segment?
- 31 - a pair of spinal nerves arises from each segment.
Where does the midbrain lie? Of what is it composed?
- Above the pons and below the cerebellum. - Composed of white matter (tracts) and reticular formation.
Where does the spinal cord begin and end? How long is the average spinal cord?
- Begins at the Foramen Magnum and ends at the lower border of the 1st lumbar vertebra. - 18 inches
What is the difference between Cholinergic and Adrenergic Fibers?
- Cholinergic fibers are nerve fibers which secrete Acetylcholine. Mostly parasympathetic nerve fibers. - Adrenergic Fibers secrete norepinephrine (noradrenaline). Mostly sympathetic fibers.
Describe the cause and treatment of epilepsy:
- Epilespy is a seizure disorder - Cause: chemical imbalance, tumors, sometimes idiopathic. (Often diagnosed and specifically located by using EEG.) - Treatment: anti-convulsive drugs such as phenobarbital that block neurotransmitters in the affected area of the brain.
What is Internal Hydrocephalus and how is it treated in infants?
- Excess of CSF in lateral and 3rd ventricles beacuse drainage is blocked. - Increased pressure leads to coma and/or death. - Treat by catheterize the ventricle(s) and clear the obstruction.
What are arachnoid villi and what do they do?
- Finger-like projections of the arachnoid membrane. - They absorb CSF and pass it into veins in the arachnoid membrane.
Where do cranial nerves arise, and where do they terminate?
Arise from underside of brain. Terminate in the head, neck, and trunk.
Describe the Pia Mater:
- Innermost layer - Adheres to the outer layer of the brain and spinal cord and contains blood vessels.
What happens to sensory info sent to the primary sensory areas in the cortex?
- It is relayed to various sensory association areas (and other parts of the brain) where it is "compared and evaluated". - The cortext intergrates these separate bits of information into the whole perception.
Describe the Arachnoid Membrane:
- Middle layer - Delicate - Cobweb-like layer
What are medullary nuclei and where are they?
- Nuclei (clusters of neuron cell bodies), some of which control the cardiac, respiratory, and vasomotor activities. - Others control non-vital reflex centers associated with coughing, sneezing, swallowing, and vomiting.
Describe the Dura Mater:
- Outermost layer - Strong - White fibrous connective tissue
What is the dorsal nerve root?
- bundle of nerve fibers carrying sensory information into the spinal cord. - located on the dorsal side of cord
What is the function of axon terminals?
- Secretory regions of neuron - Release neurotransmitters to excite or inhibit other cells
Why are tracts both structural and functional organizations of nerve fibers?
- Structural because all axons in a tract originate from cell bodies in the same structure and all axons terminate in the same structure. - Functional because all axons in one tract serve one general function (ex: spinothalamic tracts are sensory. All transmit impulses that produce sensation of crude touch, pain, and temperature.)
What are Sulci and Gyri?
- Sulci are grooves. - Gyri are raised areas.
What is a CVA?
- a cerebrovascular acccident. Also known as a stroke. - is caused by bleeding or blockage of cerebral blood vessels. - causes loss of oxygen to brain.
Where does the pons lie?
- between the medulla and the midbrain. - composed of white matter (tracts) and reticular formation.
Describe the basic structure and function of the white matter in the spinal cord:
- each side of the cord has 3 columns (or Funiculi) of white matter: Anterior, Lateral,& Posterior. - each column is subdivided into tracts. - the tracts carry signals from the brain to the spinal cord and from the spinal cord to the brain. - Tract's name tells you 3 things: 1) where it is (anterior, lateral, or posterior side of cord) 2) where it originates 3) where it terminates Ex: Anterior Spinocerebellar -- front side of cord, starts in spinal cord, ends in cerebellum
What are the lumbar and cervical enlargements and what structures arise form them?
- places where the spinal cord thickens in the cervical and lumbar vertebrae. - the cervical enlargement gives rise to the major nerves going to the arms and neck. - the lumbar enlargement gives rise to major nerves in the legs and feet. Divide the cord into left and right halves.
Define Hypothalamus:
- portion of the diencephalon. - vital neuroendocrine and autonomic control center.
Describe the basic structure and function of the core of grey matter in the spinal cord:
- shaped like the letter H. - limbs of the H are called the Anterior, Lateral, and Posterior horms of grey matter or grey columns. - consist primarily of the cell bodies of interneurons and motor nuerons. - Primary job is to function a reflex arcs.
Neuroglia found in the CNS that bind axons and blood vessels to each other are called ________.
Astro-cytes
Define Language functions: In which lobes are the speech centers foound?
- the ability to speak and write words and the ability to understand spoken and written word.
function of blood-brain barrier
1. protects cerebrospinal fluid (CSF) from blood-born toxins and drugs 2. allows exchange of gases and nutrients 3. removes wastes
What is the cerebral cortex and how deep is it?
- the surface of the cerebrum, which is made up of gray matter. - 2-4mm (1/12 to 1/6 of an inch)
Postsynaptic neuron
- transmits impulses away from the synapse
Around what transmembrane potential does threshold commonly occur?
-60 mV
Assume you have a membrane with only potassium leak channels. The RMP is -90mV. Predict the RMP if we add leak channels. The most likely RMP value of is __________.
-70 mV
What is the value for the resting membrane potential for most neurons?
-70 mV
In a typical neuron, what is the equilibrium potential for potassium?
-90mV
Propagation of action potential in unmyelinated
-Action potential in one site causes action potential at the next location (domino affect)
Absolute Refractory Period
-Complete insensitivity exists to another stimulus -No matter how large the stimulus, a second action potential cannot be produced
vermis
-connects the two hemispheres of the cerebellar cortex (grey matter)
Astrocytes
-cover the surfaces of neurons and blood vessels and the pia mater -Blood-brain barrier: protects neurons from toxic substances, allows the exchange of nutrients and waste between neurons and blood, prevents fluctuations in the composition of the blood from affecting the functions of the brain
Excitatory postsynaptic potential
-depolarization occurs
autonomic nervous system
-from CNS to cardiac and smooth muscle & glands -2 neuron system CNS->ganglion->effector -divisions are paroxysm, sym, and enteric
somatic nervous system
-from CNS to skeletal -voluntary -single neuron system
In brain: In spinal cord:
-gray is outer, white is inner -white is outer, gray is inner
Inhibitory postsynaptic potential
-hyperpolarization
ependymal
-line the cavities of the brain a& central canal of spinal cord -form the choroid plexus
Neurotransmitter Removal
-method depends of neurotransmitter -ACh: acetylcholinesterase splits ACh into acetic acid and choline. Choline recycled within presynaptic neuron.
microglia
-phagocytize foreign substances
Myelinated axons
-protects and insults axons -speeds transmission -not continuous (nodes of ravine)
Satellite cells
-surround neuron cell bodies in sensory ganglia, provide support and nutrients
oliogodendrocytes
-wrap around axons -can form myelin sheaths and wrap around multiple axons
Schwann cells
-wrap around portion of only one axon to form myelin sheath
Approximately how fast do action potentials propagate in unmyelinated axons in humans?
1 meter per second
The spinal cord tapers to a point and terminates near the intervertebral disc that separates btwn what 2 vertebrae
1&2 lumbar
List the 3 general functions of the cerebellum:
1) Acts with motor areas in cerebrum to produce skilled movements by coordinating the activities of groups of muscles. 2) Helps control posture. 3) Controls skeletal muscles to maintain equilibrium.
How much CSF is in the nervous system at any given time
140 ml
Describe the cause and progress of Alzheimer's disease and Huntington's disease:
1) Alzheimer's disease - lesions develop in the cortex during middle to late adulthood. Leads to dementia. Cause is unknown and there is no cure. 2) Huntington's disease - deterioration of the cerebral cortex. Begins age 30-40. Death usually by age 55. Caused by a dominant gene on non-sex chromosome. No cure yet.
List the 4 types of brain waves in order from fastest to slowest: When is each type generally seen?
1) Beta - seen when the brain is engaged in mental activities. 2) Alpha - awake. eyes closed. relaxed state. cerebrum is "idling". 3) Theta - drowsiness. 4) Delta - deep sleep.
Describe the path of CSF from its formation by a choroid plexus to its reabsorption into the blood:
1) CSF formed in 1st & 2nd ventricles passes into a tube called the interventricular foramen. 2) Interventricular foramen --> 3rd ventricle. 3) 3rd ventricle --> a tube called the cerebral aqueduct. 4) cerebral aqueduct --> 4th ventricle 5) 4th ventricle --> Central canal of spinal cord; Left lateral, right lateral, & median foramen. 6) Left lateral, right lateral, & median foramen --> Cisterna Magna 7) Cisternal Magna --> subarachnoid space and arachnoid villi. 8) arachnoid villi --> venous blood
List the 4 major brain divisions:
1) Cerebrum 2) Cerebellum 3) Diencephalon 4) Brain Stem
What are the subdivisions of the Cerebrum?
1) Cortex 2) Corpus Callosum
List the 3 layers of meninges in order from the outermost layer to the innermost layer:
1) Dura Mater 2) Arachnoid Membrane 3) Pia Mater
List 3 important spaces between and around the meninges:
1) Epidural space 2) Subdural space 3) Subarachnoid space
List the 3 important inward extensions of the dura mater and identify the structures that each separates:
1) Falx Cerebri: separates the left and right halves of the cerebrum. 2) Falx Cerebelli: seperates the left and right halves of the cerebellum. 3) Tentorium Cerebelli: Separates the cerebellum from the cerebrum.
List the 5 major cerebral lobes andd their locations:
1) Frontal Lobes - under the frontal bone. 2) Parietal Lobes - under the parietal bones. 3) Temporal Lobes - under the temporal bones. 4) Occipital Lobes - under the occipital bone. 5) Insula - under the lateral fissures.
How does the thalamus relay sensory impulses on their way to the cerebral cortex?
1) Impulses from spinal cord, brain stem, cerebellum, basal ganglia, and various parts of the cerebrum 2) go to the thalamic nuclei 3) then to all areas of the cerebral cortex
List the major descending tracts and their functions:
1) Lateral & Anterior Corticospinal Tracts - voluntary muscle. 2) Lateral, Anterior, & Medial Reticulospinal Tracts - conducts impulses controlling muscle tone and sweat gland activity. 3) Rubrospinal Tracts - transmits impulses that coordinate body movements and maintenance of posture.
List the major ascending tracts and their functions:
1) Lateral & Anterior Spinothalamic - touch, temp, pain, and pressure. 2) Fasiculi Gracilis & Cuneatus - discriminating touch, pressure, & conscious sensation of position and movement of body parts (Kinesthesia). 3) Spinocerebellar Tracts - sensory inputs from muscles of lower limbs and trunk to cerebellum for muscle movement coordination.
List the 4 major cerebral fissures and the structures they divide:
1) Longitudinal Fissure - deepest groove in the cerebrum. Divides the cerebrum into 2 hemispheres. 2) Central Sulcus (Fissure of Rolando) - groove between the frontal and parietal lobes. 3) Lateral Fissure (Fissure of Sylvius) - A deep groove between the temporal lobe below and the frontal and parietal lobes above. Insula lies deep in this fissure. 4) Parietooccipital Fissure - Groove that separates occipital lobe from two parietal lobes.
What are the subdivisions of the Brain Stem?
1) Midbrain 2) Pons 3) Medulla Oblongata
List the 12 cranial nerve pairs:
1) Olfactory 2) Optic 3) Oculomotor 4) Trochlear 5) Trigeminal 6) Abductens 7) Facial 8) Vestibulocochlear 9) Glossopharyngeal 10) Vagus 11) Accesory 12) Hypoglossal
What are the two protective coverings of the brain and spinal cord?
1) Outer covering: Cranial bones which protect the brain and Vertebrae which protect the spinal cord. 2) Inner covering: the Meninges
List the 3 major cerebral tracts and explain what each does:
1) Projection Tracts - extensions of ascending and descending tracts from the spinal cord. 2) Association Tracts - extend from one convolution (gyrus) to another. 3) Commissural Tracts - extend from one convolution to the corresponding convolution in the other hemisphere.
List and describe the subdivisions of the PNS:
1) Somatic Nevous System - the cranial and spinal nerves that connect the CNS to the skin & skeletal muscles. Controls conscious activities. 2) Autonomic Nervous System - fibers connecting CNS to viscera. Controls unconscious activies.
Name the 4 parts of the diencephalon:
1) Thalamus 2) Hypothalamus 3) Pineal Body 4) Optic Chiasma
What are the subdivisions of the Diencephalon?
1) Thalamus 2) Pineal Body 3) Hypothalamus
Name 4 intergrative cerebral function:
1) consciousness 2) Language 3) emotions 4) memory
What 2 characteristics are used to classify brain waves?
1) frequency of waves (cycles/sec.) 2) amplitude. height of brain wave. voltage of the impulses.
List the 7 functions of the hypothalamus:
1) helps control and integrate autonomic activities. 2) the major relay station between the cerebral cortex and lower autonomic centers (parts of the brain stem and spinal cord). 3) some neurons make the hormones released by the posterior pituitary gland (ADH/water balance). 4) other neurons make other hormones which cause the anterior pituitary gland to release its hormones. 5) plays essential tole in maintaining the waking state. 6) helps regulate appetite. 7) has crucial role in maintaining normal body temperature.
List 2 current concepts about the role of the reticular activating system in consciousness:
1) it functions as the arousal or alerting system for the cerebral cortex 2) its functioning is crucial for maintaining consciousness.
List the primary functions of the thalamus:
1) plays 2 parts in mechanism responsible for sensations: - Produces conscious recognition of crude pain, temp. and touch. - Relays all kinds of seonsory impulses, except olfactory, to the cerebrum. 2) Associates sensory impulses with feelings of pleasantness and unpleasantness. 3) Plays a part in arousal or alerting mechanism 4) Plays a part in production of complex movements
What are the 2 general functions of the spinal cord?
1) provides routes for nerve impulses to travel to the brain or away from the brain. 2) serves as the reflex center for all spinal reflexes
List 4 of the Somatic senses:
1) touch 2) pressure 3) temperature 4) body position (proprioception)
function of autonomic motor system
1. "involuntary" nervous system 2. innervates cardiac muscle, smooth muscle, and glands from the CNS
function of somatic motor system
1. "voluntary" nervous system 2. innervates skeletal muscle From the CNS
Two main divisions of Nervous System
1. Central nervous system (CNS): - Brain and spinal cord - Integration and command center 2. Peripheral nervous system (PNS) - Paired spinal and cranial nerves carry messages to and from the CNS
What are the three types of gated membrane ion channels in a neuron?
1. Chemically gated (ligand-gated) channels—open with binding of a specific neurotransmitter 2. Voltage-gated channels—open and close in response to changes in membrane potential 3. Mechanically gated channels—open and close in response to physical deformation of receptors
What are the two main types of membrane ion channels in a neuron?
1. Leakage (nongated) channels—always open 2. Gated channels (three types)
Functions of Nervous system
1. Maintain homeostasis 2. Receiving sensory input 3. Integrating Info 4. Controlling muscles and glands 5. Est. & maintaining mental acitivity
What are the three structural classifications of Neurons?
1. Multipolar—1 axon and several dendrites (most abundant; found in both motor neurons and interneurons) 2. Bipolar—1 axon and 1 dendrite (rare, e.g., retinal neurons) 3. Unipolar (pseudounipolar)—single, short process that has two branches
Two principal cell types of Nervous Tissue
1. Neurons—excitable cells that transmit electrical signals 2. Neuroglia (glial cells): supporting cells
What are the two branches of unipolar neurons?
1. Peripheral process—more distal branch, often associated with a sensory receptor 2. Central process—branch entering the CNS
what is the difference between schwann cells and oligodendrocytes?
1. Schwann cells are in PNS, oligo are in CNS 2. one Scwann cell only produce myelin to cover a small portion of axons, one oligodendrocyte produce myelin to cover multiple axons
Two functional divisions of Peripheral Nervous System (PNS)
1. Sensory (afferent) division: - Somatic afferent fibers—convey impulses from skin, skeletal muscles, and joints - Visceral afferent fibers—convey impulses from visceral organs 2. Motor (efferent) division - Transmits impulses from the CNS to effector organs
What are the three functional classifications of Neurons?
1. Sensory (afferent): transmit impulses from sensory receptors toward the CNS 2. Motor (efferent): carry impulses from the CNS to effectors 3. Interneurons (association neurons): shuttle signals through CNS pathways; most are entirely within the CNS
Three main functions of the Nervous System
1. Sensory input: Information gathered by sensory receptors about internal and external changes [afferent] 2. Integration: Interpretation of sensory input 3. Motor output: Activation of effector organs (muscles and glands) produces a response [efferent]
Two divisions of PNS
1. Somatic (voluntary) nervous system: conscious control of skeletal muscles 2. Autonomic (involuntary) nervous system (ANS): - Visceral motor nerve fibers - Regulates smooth muscle, cardiac muscle, and glands
what are the 4 groups of spinal nerves?
1. cervical nerves 2. thoracic nerves 3. lumbar nerves 4. sacral nerves
sensory nervous system
1. contains receptors 2. transmits info from receptors to the CNS
information flow down a neuron steps
1. dendrites, cell body receive incoming signals 2. perikaryon: soma (cell body) 3. axon hillock 4. initial segment of axon (AP originates here) 5. axon 6. synaptic terminals 7. synapse 8. postsynaptic cell
function and location of microglia
1. found in CNS 2. specialized macrophages 3. respond to inflammation 4. move through tissue to phagocytize necrotic tissue, microorganisms, and foreign substances in the CNS 5. kind of like WBC's 6. maintain homeostasis of CSF and nervous tissue by repsonding to signals from other cells and remove material that affect homeostasis 7. derived from blood cells
function and location of shwann cells
1. found in PNS 2. produce myelin sheaths 3. help electrical currents flow along axons 4. help peripheral nerves regenerate 5. produce extracellular matrix around nerves 6. total axonal length covered by several of Schwann cells, and the gap between is nodes of ranvier
what is the purpose of myelin in the CNS what makes it?
1. insulator 2. increases action potential conduction velocity 3. oligodendrocytes make myelin in CNS
how is neuroglia able to communicate with multiple cells at a time?
1. intracellular waves of Ca2+ 2. intercellular diffusion of chemical messengers (like ATP)
what are the types of signals between neurons and neuroglia?
1. ion fluxes 2. neurotransmitters 3. cell adhesion molecules 4. specialized signaling molecules release from synaptic and nonsynaptic regions of neuron
ependymal cells location and function
1. line the brain 2. line the spinal cord central canal ventricles (cavities) 3. combine w/ blood vessels to form choroid plexus 4. contain cilia that beat to move CSF throughout brain, increasing efficiency of diffusion 5. their basal cell surfaces extend deep into brain and spinal cord that play similar role as astrocytes
what are the 6 types of neuroglial cells?
1. oligodendrocytes 2. astrocyes 3. ependymal cells 4. microglia 5. schwann cells 6. satellite cells
astrocytes function
1. provide supportive framework for blood vessels, neurons, and pia mater 2. limit normal permeability of capillary endothelium by secreting chemicals 3. induce blood brain barrier 4. surround synapses to regulate extracellular concentration of K+ 5. uptakes neurotransmitters 6. regulate CSF composition by regulating the levels of ions and gases
function of somatic sensory system
1. receives sensory info from skin, fascia,joints, skeletal muscle, and special senses and brings it to CNS
function of visceral sensory system
1. receives sensory info from viscera (organs) and brings it to CNS
how can neuroglia affect neuronal excitability, synaptic transmission, or coordinate activity across networks of neurons?
1. releasing neurotransmitters 2. releasing other extracellular signaling molecules
.choroid plexus
1. secretes CSF that circulate in brain and spinal cord 2. essential part in blood brain barrier because it limits the flow of solutes into the brain 3. made by combination of epithelial cells in blood vessels and ependymal cells in ventricles
What are the names of the two nervous systems in the PNS?
1. sensory nervous system 2. motor nervous system
what are the two parts of the motor nervous system in the PNS?
1. somatic motor 2. autonomic motor
what are the two parts of the sensory nervous system in the PNS?
1. somatic sensory 2. visceral sensory
function and location of satellite cells
1. surround neuronal cell bodies in ganglia OUTSIDE THE CNS 2. provide support to cell bodies 3. provide nutrients to cell bodies 4. produce blood-ganglia barrier 5. highly sensitive to injury and inflammation, important role in chronic pain
motor nervous system
1. transmits info from CNS to the rest of the body 2. sends motor information to its effectors
What is the magnitude (amplitude) of an action potential?
100 mV
Which of the following associations is incorrect? 5 sacral spinal nerves 8 cervical spinal nerves 1 coccygeal spinal nerve 11 thoracic spinal nerves 5 lumbar spinal nerves
11 thoracic spinal nerves
# of pairs of cranial nerves
12
cranial nerves & their functions
12 pair of nerves fibers; somatic fibers to skin & skeletal muscles; autonomic fibers connecting to viscera, exit at lateral edges of brainstem
# of thoracic nerves
12, spinal nerves
The two largest ventricles which begin in the L&R cerebral hemispheres & extend anteriorly & down into the cerebral hemispheres
2 lateral ventricles
What is the typical duration of a nerve action potential?
2 ms
describe bipolar neurons
2 processes- axon and dendrite, extend from opposite dies of the cell body, rare found in some special sense organs
Somatic nervous system, Autonomic nervous system
2 types of motor division
how many types of glial cells in the PNS
2- satellite cells, Schwann cells
# of pairs of spinal nerves
31
The spinal cord consists of __________ segments, each associated with two pairs of nerve roots. 12 29 to 31 5 31
31
The spinal cord consists of five regions and ________ segments. 31 25 12 5 The number varies widely among individuals.
31
The spinal cord consists of how many arguments & bilateral pairs of spinal nerves
31
spinal nerves & their functions
31 pairs of nerves; somatic fibers connecting to skin & skeletal muscle; autonomic fibers connecting to viscera
Narrow space in the midline of the brain beneath the corpus callosum, which is a bridge of axons that link the 2 cerebral hemispheres is what ventricle
3rd ventricle
Spaces and brain regions produced by the diencephalon
3rd ventricle; thalamus, hypothalamus, posterior pituitary gland & pineal gland
After age ________ the vertebral column continues to elongate, but the spinal cord itself does not. 8 18 1 12 4
4
The spinal cord stops elongating at about __________ years of age. 4 10 15 2
4
The following are the steps involved in transmission at a cholinergic synapse. 1. Chemically-gated sodium channels on the postsynaptic membrane are activated. 2. Calcium ions enter the synaptic terminal. 3. Acetylcholinesterase hydrolyzes acetylcholine. 4. An action potential depolarizes the synaptic terminal at the presynaptic membrane. 5. The synaptic terminal reabsorbs choline. 6. Acetylcholine is released from storage vesicles by exocytosis. 7. Acetylcholine binds to receptors on the postsynaptic membrane. 8. Calcium ions are removed from the cytoplasm of the synaptic terminal. The correct sequence for these events is 2, 5, 4, 6, 7, 1, 8, 3. 4, 2, 6, 7, 8, 5, 3, 1. 4, 2, 6, 7, 1, 8, 3, 5. 2, 4, 6, 7, 1, 8, 3, 5. 6, 4, 2, 7, 1, 8, 3, 5.
4, 2, 6, 7, 1, 8, 3, 5
The following are the main steps in the generation of an action potential. 1. Sodium channels are inactivated. 2. Voltage-gated potassium channels open and potassium moves out of the cell, initiating repolarization. 3. Sodium channels regain their normal properties. 4. A graded depolarization brings an area of an excitable membrane to threshold. 5. A temporary hyperpolarization occurs. 6. Sodium channel activation occurs. 7. Sodium ions enter the cell and depolarization occurs. The proper sequence of these events is 4, 6, 7, 3, 2, 5, 1. 2, 4, 6, 7, 1, 3, 5. 4, 2, 5, 6, 7, 3, 1. 6, 7, 4, 1, 2, 3, 5. 4, 6, 7, 1, 2, 3, 5.
4, 6, 7, 1, 2, 3, 5
how many types of glial cells in the CNS
4- astrocytes, microglia, ependymal, oligodendrocytes
Located in the brainstem, just anterior to the cerebellum and has openings in its roof that lead to the subarachnoid space is what ventricle
4th ventricle
Spaces and brain regions produced by the metencephalon
4th ventricle; cerebellum & pons
Spaces and brain regions produced by the myelencephalon
4th ventricle; medulla oblongata
# of lumbar nerves
5, spinal nerves
# of sacral nerves
5, spinal nerves
31 pairs of spinal nerves
8 cervical, 12 thoracic, 5 lumbar, 5 sacral & 1 coccygeal
# of cervical nerves
8, spinal nerves
A second nerve impulse cannot be generated until ________. A) the membrane potential has been reestablished B) the Na ions have been pumped back into the cell C) proteins have been resynthesized D) all sodium gates are closed
A
Neuroglia that control the chemical environment around neurons by buffering potassium and recapturing neurotransmitters are ________. A) astrocytes B) oligodendrocytes C) microglia D) Schwann cells
A
Saltatory conduction is made possible by ________. A) the myelin sheath B) large nerve fibers C) diphasic impulses D) erratic transmission of nerve impulses
A
The part of a neuron that conducts impulses away from its cell body is called a(n) ________. A) axon B) dendrite C) neurolemma D) Schwann cell
A
What are ciliated CNS neuroglia that play an active role in moving the cerebrospinal fluid called? A) ependymal cells B) Schwann cells C) oligodendrocytes D) astrocytes
A
Which of the choices below describes the ANS? A) motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands B) motor fibers that conduct nerve impulses from the CNS to skeletal muscles C) sensory neurons that convey information from somatic receptors in the head, body wall, and limbs and from receptors from the special senses of vision, hearing, taste, and smell to the CNS D) sensory and motor neurons that supply the digestive tract
A
unmyenlienated axons of the pns
A Schwann cell surrounds nerve fibers but coiling does not take place Schwann cells partially enclose 15 or more axons
graded, action
A ___ potential will cause EITHER hyperpolarization or depolarization, while a ______ potential will cause a depolarization only.
sodium
A depolarized membrane allows ______ to flow inside the membrane
limbic system
A group of neural structures at the base of the cerebral hemispheres & structures in the diencephalon that is associated with ( emotion and motivation !!!)
Define Limbic System:
A group of structures surrounding the corpus callosum which produces various emotional feelings: fear, anger, sorrow, etc.
choroid plexus
A highly vascular tissue in the lining of the ventricles that secretes CSF (blue area)
Cl− is a common negatively charged extracellular ion. Predict the effect on the RMP if many Cl− gated channels are suddenly opened. A more negative RMP would result. There would be no change in the RMP. The membrane would become hypopolarized or have less charge separation across the membrane. The RMP would become more positive.
A more negative RMP would result.
a visceral motor neuron
A multipolar neuron that synapses on a gland cell is functionally classified as A) a visceral motor neuron B) a somatic motor neuron C) a sensory neuron D) an interneuron
node of ranvier
A myelinated axon will allow an action potential to jump from one ___ ___ ___ to another.
both a and b
A nerve impulse involves ____________ across a neuron's plasma membrane. A) changes in voltage B) movement of ions C) both a and b D) neither a nor b
Which of the following is false or incorrect?
A nerve impulse occurs if the excitatory and inhibitory effects are equal.
Define Reticular Formation:
A network of gray and white matter fibers within the brain stem that: 1) connect the superior spinal cord to all major brain parts. 2) arouse the cerebrum. 3) filter inbound sensory impulses for importance.
Which of the following is true of axons?
A neuron can have only one axon, but the axon may have occasional branches along its length.
Which of the following is true of axons? Axons use chemically gated ion channels to generate graded potentials. Neurons can have multiple axons but only one dendrite. Smaller (thinner) axons are more likely to bear myelin sheaths than larger (thicker) axons. A neuron can have only one axon, but the axon may have occasional branches along its length.
A neuron can have only one axon, but the axon may have occasional branches along its length.
voltage
A neuron generates an action potential at the trigger zone, where there is a high density of _____ gated channels.
Cranial nerves VI..primarily motor
Abducens
Are there more neurons or neuroglia cells in the CNS?
Abundantly more neuroglia than neurons in CNS
Cranial nerves XI..muscles of soft palate..trapezius & sternocleidomastoid..primarily motor
Accessory
excitatory, either
Acetycholine is ______ in the neuromuscular junction and can be ______ elsewhere in the body.
Preganglionic neurons in the sympathetic division release what
Acetylcholine
Action potential propagation in a skeletal muscle fiber ceases when acetylcholine is removed from the synaptic cleft. Which of the following mechanisms ensures a rapid and efficient removal of acetylcholine?
Acetylcholine is degraded by acetylcholinesterase.
Most sympathetic postganglionic neurons secrete norepinephrine & are called
Adrenergic
sodium potassium pump
After hyperpolarization, what brings the RMP back to -70?
Active neurons need ATP to support which of the following? the movement of materials from the soma by axoplasmic transport the synthesis of neurotransmitter molecules the recovery from action potentials the movement of materials to the soma by axoplasmic transport All of the answers are correct.
All of the answers are correct.
Any stimulus that opens ________ ion channel will produce a graded potential. a voltage-gated a sodium a mechanically-gated a chemically-gated All of the answers are correct.
All of the answers are correct.
In meningitis, viruses can be the cause. bacteria can be the cause. inflammation of the meninges occurs. CSF flow can be disrupted. All of the answers are correct.
All of the answers are correct.
During propagation of the action potential, __________. local currents depolarize a spot adjacent to the active zone after threshold is reached, sodium channels open rapidly the axon hillock depolarizes the initial segment All of these events occur during propagation of the action potential.
All of these events occur during propagation of the action potential.
The effect of a nerve impulse on a postsynaptic neuron depends on the __________. kind of neurotransmitter released by the presynaptic neuron quantity of neurotransmitter released characteristics of the receptor on the postsynaptic neuron All of these factors affect what happens at the postsynaptic neuron.
All of these factors affect what happens at the postsynaptic neuron.
Which processes are always part of a reflex arc? receptor activation afferent action potential efferent action potential All of these processes are part of every reflex arc.
All of these processes are part of every reflex arc.
The two major types of adrenergic receptors are
Alpha & beta
ependymal cells; epithelial cells
Although classified as glial cells, ____________ are also ____________ that line the cavities in the brain and spinal cord and help form the choroid plexus. A) astrocytes; phagocytes B) microglia; phagocytes C) ependymal cells; epithelial cells D) oligodendrocytes; epithelial cells
neurons; glial cells
Although they outnumber ____________ by as much as ten to one, ____________ account for only about half of the total volume of the nervous system. A) neuroglia; neurons B) neurons; glial cells C) interneurons; sensory neurons D) astrocytes; oligodendrocytes
glutamate, gaba, glycine
Amino acid neurotransmitters include what three main types?
Which of the following occurs first? An action potential arrives at the axon terminal. Synaptic vesicles exit by exocytosis. Voltage-gated calcium channels are opened. Extracellular calcium enters the axon terminal.
An action potential arrives at the axon terminal.
What conditions will increase the diffusion of molecules, such as neurotransmitters? An increase in the distance between the neurons. An increased viscosity of the fluid between neurons. An increase in number of postsynaptic receptors. An increase in the amount of neurotransmitter exocytized by the presynaptic axon.
An increase in the amount of neurotransmitter exocytized by the presynaptic axon.
How is an action potential propagated along an axon? Stimuli from the graded (local) potentials from the soma and dendrites depolarize the entire axon. An efflux of potassium from the current action potential depolarizes the adjacent area. An influx of sodium ions from the current action potential depolarizes the adjacent area
An influx of sodium ions from the current action potential depolarizes the adjacent area
How is an action potential propagated along an axon?
An influx of sodium ions from the current action potential depolarizes the adjacent area.
________ neurons are small and have no anatomical features that distinguish dendrites from axons. Sensory Bipolar Unipolar Multipolar Anaxonic
Anaxonic
thirst center
Angiotensin II stimulates the ____ _____.
What are some places an axon terminal can connect?
Another nerve cell (dendrites) A muscle or gland
The gray matter of the spinal cord divides the white matter of the spinal cord into 3 regions on each side called the
Anterior, lateral & posterior funiculi
CSF is continuously reabsorbed into the blood through tiny, finger-like projections called
Arachnoid granulations
Thin weblike membrane that does not have blood vessels and is located btwn the dura and pia mater
Arachnoid mater
Removal of neurotransmitters occurs when they:
Are degraded by enzymes Are reabsorbed by astrocytes or the presynaptic terminals Diffuse from the synaptic cleft
Nerve fibers
Arm-like extensions from the soma There are two types: axons (carry impulses away from the soma) and dendrites (carry impulses toward the soma) Bundles of fibers are called tracts in the CNS and nerves in the PNS
The process of linking new facts with old facts already stored in the memory bank is called ________. long-term memory automatic memory Association rehearsal
Association
Unconscious activity is what division of the PNS
Autonomic NS
Supply's muscles & skin of the anterior, lateral & posterior regions of the arm
Axillary nerves
List and describe different types of synapses
Axodendritic—between the axon of one neuron and the dendrite of another Axosomatic—between the axon of one neuron and the soma of another Less common types: - Axoaxonic (axon to axon) - Dendrodendritic (dendrite to dendrite) - Dendrosomatic (dendrite to soma)
axodendritic synapse
Axon terminal of presynaptic neuron terminates on dendrites or cell body of postsynaptic neuron (e.g. many synapses of PNS).
An impulse from one nerve cell is communicated to another nerve cell via the ________. A) cell body B) synapse C) receptor D) effector
B
An inhibitory postsynaptic potential (IPSP) is associated with ________. A) a change in sodium ion permeability B) hyperpolarization C) opening of voltage-regulated channels D) lowering the threshold for an action potential to occur
B
In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment? The interior is ________. A) positively charged and contains less sodium B) negatively charged and contains less sodium C) negatively charged and contains more sodium D) positively charged and contains more sodium
B
Which ion channel opens in response to a change in membrane potential and participates in the generation and conduction of action potentials? A) mechanically gated channel B) voltage-gated channel C) leakage channel D) ligand-gated channel
B
An example of the brain affecting spinal reflexes is the replacement of the __________ by the __________. Babinski sign; plantar reflex plantar reflex; Babinski sign Babinski sign; flexor reflex flexor reflex; plantar reflex
Babinski sign; plantar reflex
Where is the Hypothalamus located?
Beneath the thalamus. It forms the floor of the 3rd ventricle.
catecholamines, indolamines
Biogenetic Amines are neurotransmitters that contain which two main groups?
Describe a Neuron Cell Body
Biosynthetic center of a neuron Spherical nucleus with nucleolus Well-developed Golgi apparatus Rough ER = Nissl bodies (chromatophilic substance) Network of neurofibrils (neurofilaments) Axon hillock—cone-shaped area from which axon arises
________ neurons are short, with a cell body between dendrite and axon, and occur in special sense organs. Multipolar Unipolar Motor Bipolar Anaxonic
Bipolar
What is the difference between a suclus and a fissure?
Both are grooves. Fissures are deep. Sulci are shallow.
Which of the following is true of adrenergic receptors?
Both epinephrine and norepinephrine are coupled to a G protein
axons of the cns
Both myelinated and unmyelinated fibers are present Myelin sheaths are formed by oligodendrocytes Nodes of Ranvier are widely spaced There is no neurilemma
The structures labeled "1" are dendrites. Their membranes contain numerous chemically-gated ion channels. The first statement is false but the second statement is true. Both statements are true. The first statement is true but the second statement is false. Both statements are false. Both statements are true and relate to synaptic transmission.
Both statements are true and relate to synaptic transmission.
What is another name for the synaptic knobs of axon terminals?
Boutons
Plexus of nerves to the muscles & skin of the upper limbs formed btwn C5-T1
Brachial plexus
Central Nervous System
Brain and spinal cord Integration and command center
Centers for control of the SANS & PANS are primarily located where
Brain stem
Connects the brain to the spinal cord & consists of the midbrain, pons & the medulla oblongata
Brainstem
The preganglionic fibers of the parasympathetic division arise from neurons in the
Brainstem & S2-4 region of the spinal cord
Describe the structure and function of Oligodendrocytes
Branched cells Processes wrap CNS nerve fibers [jelly roll], forming insulating myelin sheaths (once wrapped) Function: insulation
What is the difference between nerves and tracts?
Bundles of neuron processes are called tracts in the CNS and nerves in the PNS.
What are bundles of neural processes called in the CNS? In the PNS?
Bundles of processes are called: Tracts in the CNS Nerves in the PNS
A neuron that has as its primary function the job of connecting other neurons is called a(n) ________. A) efferent neuron B) afferent neuron C) association neuron D) glial cell
C
Collections of nerve cell bodies outside the central nervous system are called ________. A) nuclei B) nerves C) ganglia D) tracts
C
If a motor neuron in the body were stimulated by an electrode placed about midpoint along the length of the axon ________. A) the impulse would move to the axon terminal only B) muscle contraction would occur C) the impulse would spread bidirectionally D) the impulse would move to the axon terminal only, and the muscle contraction would occur
C
Schwann cells are functionally similar to ________. A) ependymal cells B) microglia C) oligodendrocytes D) astrocytes
C
The substance released at axon terminals to propagate a nervous impulse is called a(n) ________. A) ion B) cholinesterase C) neurotransmitter D) biogenic amine
C
The term central nervous system refers to the ________. A) peripheral and spinal nerves B) brain, spinal cord, and peripheral nerves C) brain and spinal cord D) spinal cord and spinal nerves
C
What does the central nervous system use to determine the strength of a stimulus? A) origin of the stimulus B) type of stimulus receptor C) frequency of action potentials D) size of action potentials
C
What is the role of acetylcholinesterase? A) act as a transmitting agent B) amplify or enhance the effect of ACh C) destroy ACh a brief period after its release by the axon endings D) stimulate the production of acetylcholine
C
Which of the following is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle? A) cholinesterase B) norepinephrine C) acetylcholine D) gamma aminobutyric acid
C
Which of the following is not characteristic of neurons? A) They conduct impulses. B) They have extreme longevity. C) They are mitotic. D) They have an exceptionally high metabolic rate.
C
Which of the following is not true of graded potentials? A) They are short-lived. B) They can form on receptor endings. C) They increase amplitude as they move away from the stimulus point. D) They can be called postsynaptic potentials.
C
Which of the following is true about the movement of ions across excitable living membranes? A) Ions always move actively across membranes through leakage channels. B) Ions always move passively across membranes. C) Sodium gates in the membrane can open in response to electrical potential changes. D) Ions always move from an area of higher concentration to an area of lower concentration
C
Which fibers generate the smallest value for conduction velocity?
C Fibers
Which fibers generate the smallest value for conduction velocity?
C fibers
Central Nervous System
CNS
The neural tube of the embryonic brain gave rise to the
CNS
Functions as nutritive & protective..helps maintain a stable ionic concentration in the CNS..provides a pathway to the blood for waste
CSF
Ventricles are continuous with the central canal of the spinal cord and contain what fluid
CSF
What is the role of calcium in synaptic activity?
Calcium influx into the synaptic terminal causes vesicle fusion.
Based on your knowledge of action potentials in neurons, what can you conclude about how they occur in cardiac muscle fibers?
Cardiac muscle fibers depolarize more quickly and spend more time depolarized than neurons do.
Motor (efferent ) neurons
Carry impulse from the central system to the PMS
Sensory (afferent) neurons
Carry impulses from the sensory receptors to the CNS (found in Cutaneous Sense Organs)
ne, epinephrine, da
Catecholamines contains which three neurotransmitters?
Nerves that descend from the bottom of the spinal cord are called
Cauda equina
The filum terminale and the spinal nerves below the conus medullaris form a structure that resembles a horses' tail is called what
Cauda equina
3 basal ganglia's
Caudate nucleus, putamen & globus pallidus
What is a Perikaryon or Soma?
Cell Body of a Neuron
What are clusters of cell bodies called in the CNS? In the PNS?
Clusters of cell bodies are called: 1. Nuclei in the CNS (not to be confused with organelle) 2. Ganglia in the PNS
cauda equina
Collection of spinal nerves below the end of the spinal cord
Which statement about coma is true? Coma may be caused by widespread cerebral or brain stem trauma. Coma is neurologically identical to syncope. During coma, brain oxygen consumption resembles that of a waking state. Coma is a form of deep sleep.
Coma may be caused by widespread cerebral or brain stem trauma.
Combined Summation
Combined spatial and temporal summation
What causes membrane potential changes?
Concentrations of ions across the membrane change Permeability of membrane to ions changes
What is the general function of an axon?
Conducting region of a neuron Generates and transmits nerve impulses (action potentials) away from the cell body [efferent] Molecules and organelles are moved along axon by motor molecules both toward the axon terminal and toward the cell body
Conduction velocities of axons
Conduction velocities vary widely among neurons Rate of impulse propagation is determined by: Axon diameter - the larger the diameter, the faster the impulse Presence of a myelin sheath - myelination dramatically increases impulse speed Presence and frequency of nodes of Ranvier which result in saltatory conduction
conus medullaris
Cone-shaped ending of the spinal cord. in the lumbar area
cerebellum
Controls posture, balance and coordinates complex movements ( o )
Structure that is inferior to the lumbar enlargement where the spinal cord tapers off and becomes the nerves of the remaining lumbar and sacral levels is called what
Conus medullaris
2 pair of rounded knobs on the superior surface of the midbrain mark the location of 4 nuclei known collectively as
Corpora quadrigemina
Broad, flat bundles of axons that connect the hemispheres of the cerebrum
Corpus callosum
PNS include what two types of nerves
Cranial & spinal
When flexor muscles on the the affected side contract the flexor muscles of the limb in the other side are inhibited is called what type of reflex
Crossed extensor reflex
decussation
Crossing-over of some nerve tracts in the CNS; occurs with ascending & descending nerve tracts
Salatory conduction
Current passes through a myelinated axon only at the nodes of Ranvier Voltage-gated Na+ channels are concentrated at these nodes Action potentials are triggered only at the nodes and jump from one node to the next Much faster than conduction along unmyelinated axons
14) Which of the following is not a function of the autonomic nervous system? A) innervation of smooth muscle of the digestive tract B) innervation of cardiac muscle C) innervation of glands D) innervation of skeletal muscle
D
Immediately after an action potential has peaked, which cellular gates open? A) sodium B) chloride C) calcium D) potassium
D
Nerve cell adhesion molecules (N-CAMs) ________. A) release nerve growth factor B) are found on "pathfinder" neurons C) are crucial in the production of neurotransmitters D) are crucial for the development of neural connections
D
Select the correct statement regarding synapses. A) Cells with gap junctions use chemical synapses. B) The release of neurotransmitter molecules gives cells the property of being electrically coupled. C) Neurotransmitter receptors are located on the axons terminals of cells. D) The synaptic cleft prevents an impulse from being transmitted directly from one neuron to another.
D
The period after an initial stimulus when a neuron is not sensitive to another stimulus is the ________. A) resting period B) repolarization C) depolarization D) absolute refractory period
D
When a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n) ________. A) postsynaptic potential B) excitatory potential C) action potential D) generator potential
D
Which of the following will occur when an excitatory postsynaptic potential (EPSP) is being generated on the dendritic membrane? A) Specific sodium gates will open. B) Specific potassium gates will open. C) Sodium gates will open first, then close as potassium gates open. D) A single type of channel will open, permitting simultaneous flow of sodium and potassium.
D
dopamine
DA AKA
Which of the following statements is a false or incorrect statement? Damage to the primary motor cortex results only in the loss of both voluntary muscle control and reflexes. Damage to the premotor cortex results in loss of motor skills programmed in that area but movement is still possible. Damage to the primary auditory cortex results in the inability to interpret pitch, loudness, and location. Damage to the primary visual cortex results in functional blindness.
Damage to the primary motor cortex results only in the loss of both voluntary muscle control and reflexes.
Way of mapping the sensory information of the different spinal nerves
Dermatomes
Two grooves that extend the length of the spinal cord, dividing it into R&L halves are the
Deep anterior median fissure & shallow posterior median sulcus
What are three ways to terminate a neurostransmitter effect?
Degradation by enzymes Reuptake by astrocytes or axon terminal Diffusion away from the synaptic cleft
What are the two kinds of processes found in a neuron?
Dendrites and axons
na+
Density of voltage-gated ____ channels is greater at the trigger zone during summation.
Largest & most important deep nuclei within he cerebellum is the
Dentate nucleus
Develops from the posterior forebrain & is located btwn the cerebral hemispheres & superior to the brainstem.. Surrounds the 3rd ventricle & is largely composed of gray matter
Diencephalon
Optic tracts, optic chiasma, infundibulum, posterior pituitary gland, mammillary bodies & pineal gland are located within the
Diencephalon
Posterior portion of the prosencephalon
Diencephalon
reflex arc
Direct route from a stimulated sensory neuron, to an interneuron, to a motor neuron, (only a couple of neurons are involved)
Neurotransmitter Receptor Mechanisms
Direct: neurotransmitters that open ion channels Promote rapid responses Examples: ACh and amino acids Indirect: neurotransmitters that act through second messengers Promote long-lasting effects Examples: biogenic amines, peptides, and dissolved gases
Types of Circuits in Neuronal Pools
Divergent - one incoming fiber stimulates ever increasing number of fibers, often amplifying circuits Convergent - opposite of divergent circuits, resulting in either strong stimulation or inhibition Reverberating - chain of neurons containing collateral synapses with previous neurons in the chain Parallel after-discharge - incoming neurons stimulate several neurons in parallel arrays
yes
Does the action potential have a refractory period?
yes
Does the action potential propagate?
no
Does the graded potential have a refractory period?
no
Does the graded potential propagate?
Neurotransmitter used by the basal ganglia's
Dopamine
Nerve fibers enter & exit the spinal cord via 3 roots
Dorsal(sensory), dorsal ganglion(cell bodies) & ventral(motor)
some, reset
During hyperpolarization, ___ K+ channels remain open and Na+ channels ____.
Falx cerebelli, falx cerebri & tentorium cerebelli are the three partitions of what layer of meninges
Dura mater
Forms strong tubular sheath to protect the spinal cord and ends at the 2 sacral vertebra..it is separated from the vertebrae by epidural space
Dura mater
Forms the internal periosteum of the skull..splits into 2 layers forming channels called dural & venous sinuses
Dura mater
Outermost layer of meninges composed of tough, white, dense connective tissue and contains many blood vessels
Dura mater
3 layers of meninges
Dura, arachnoid & pia mater
falx cerebri
Dural Septa separating the cerebral hemispheres
crosses over
During an electrical synapse there is a continuous flow among the membrane of electrical stimulus. This ____ ____ to the other cell.
hyperpolarizing
During an inhibitory effect the neurotransmitter released by presynaptic cell binds to the postsynaptic cell receptors and has a _________ effect.
neuron
During both presynaptic facilitation and presynaptic inhibition another ______ steps in and helps regulate the activity of the presynaptic cell.
gap , propagates
ELECTRICAL SYNAPSE STEP FIVE: An ionic current flows through a ___ junction and stimulates the production of an action potential in the adjacent cardiac muscle cell. Thus, the action potential _____ to the adjacent cell.
action potential, propagates
ELECTRICAL SYNAPSE STEP FOUR: An ionic current stimulates the production of another _____ _____. Thus, the aciton potential ______ along the plasma membrane.
electrical
ELECTRICAL SYNAPSE STEP ONE: ______ Synapses connect cardio muscle cells.
ionic
ELECTRICAL SYNAPSE STEP THREE: An action potential in the plasma membrane generates _____ currents that flow to adjacent parts of the plasma membrane and through the gap junctions.
gap, connexons
ELECTRICAL SYNAPSE STEP TWO: An electrical synapse has ___ junctions in which the membranes of two cells are separated by a gap but are connected by proteins called ______.
The neurotransmitter glutamate opens channels that are permeable to sodium ions. What effect does glutamate produce on a postsynaptic neuron? IPSPs EPSPs neither IPSPs nor EPSPs both IPSPs and EPSPs
EPSPs
EPSPs are ___________. graded EPSPs have all of these characteristics. excitatory postsynaptic
EPSPs have all of these characteristics.
Structure of an axon
Each neuron has a single slender axon of uniform diameter arising from the axon hillock. Axons may occasionally branch along their length prior to reaching the axonal terminus. These 90 degree branches, if present, are called axon collaterals. Axonal terminal - the profusely branched terminus of an axon.
Which of the following is NOT true of efferent neurons?
Efferent neurons are bipolar
Which of the following interactions between electrical and chemical gradients does not lead to the establishment of a neuron's resting potential? Potassium ions are repulsed by positive charges outside the cell. Chemical forces tend to drive potassium ions out of the cell. Potassium ions are attracted to the negative charges inside the cell. Electrical forces push sodium ions out of the cell. Chemical and electrical forces both favor sodium ions entering the cell.
Electrical forces push sodium ions out of the cell.
Nerve Impulses are:
Electrical impulses carried along the length of axons Always the same regardless of stimulus The underlying functional feature of the nervous system
Surrounds the fibers of the peripheral nerves
Endoneurium
________ line the brain ventricles and spinal canal. Oligodendrocytes Astrocytes Microglia Satellite cells Ependymal cells
Ependymal cells
adrenaline
Epinephrine AKA
Dense, fibrous, outermost layer of CT in peripheral nerves
Epineurium
Somatic=
Everything else
Operation of voltage gated channels
Example: Na+ channel Closed when the intracellular environment is negative Open when the intracellular environment is positive Voltage-gated K+ channels function the same way
Operation of a Chemically Gated Channel
Example: Na+-K+ chemically gated channel Closed when a neurotransmitter is not bound to the extracellular receptor Open when a neurotransmitter is attached to the receptor
epsp
Excitatory Postsynaptic Potentials AKA
Cranial nerves VII..facial expression..tear/salivary glands..2/3 of tongue..mixed
Facial
The cerebellum consists of 2 lateral hemispheres separated by a layer of dura mater called the
Fall cereblli
Because many of the same cardiac cells are innervated by both parasympathetic and sympathetic fibers, the influence of the two divisions on the heart is synergistic. T/F
False
Synaptic cleft
Fluid-filled space separating the presynaptic and postsynaptic neurons Prevents nerve impulses from directly passing from one neuron to the next Transmission across the synaptic cleft: Is a chemical event (as opposed to an electrical one) Ensures one-way communication between neurons
ligand
For a chemical synapse, postsynaptic membrane receptors are usually regulated by ______ gated ion channels.
temporal
For graded potentials: Summation occuring from the graded potential that results when 2 or more APs arrive at a single synapse in rapid succession.
spatial
For graded potentials: Summation occuring when 2 or more APs arrive simultaneously at 2 or more presynaptic terminals that synapse with a single neuron.
The spinal cord originates where the nervous tissue leaves the cranial cavity a the level of the what
Foramen magnum
Myelin Sheath and Neurilemma: Formation
Formed by Schwann cells in the PNS only around axons A Schwann cell forms the Myelin Sheath: Envelopes an axon in a trough Encloses the axon with its plasma membrane Forms concentric inner layers of membrane locked together with special membrane proteins that make up the myelin sheath Neurilemma is the remaining nucleus and cytoplasm of a Schwann cell occupying the outer layer.
How are Myelin Sheaths in the CNS different from those in the PNS?
Formed by processes of oligodendrocytes, not the whole cells Nodes of Ranvier are present No neurilemma Thinnest fibers are unmyelinated
Visceral pain, nausea, information about stretch, pressure (bariorecption), chemical stimuli (chemoreception)
GVA
The 5 lobes of the cerebral hemisphere are the
Frontal lobe, parietal lobe, temporal lobe, occipital lobe & the insula
Controls & coordinates skeletal muscles & helps maintain posture
Functions of the cerebellum
Interpreting sensory info, initiating voluntary muscle activity, storing memory, retrieving memory & helps to determine intelligence & personality
Functions of the cerebrum
Motor impulses for voluntary movements
Functions of the corticospinal tracts
Sensations of touch, pressure & body movement
Functions of the fasciculus
Association areas carry on higher intellectual processes for concentrating, planning, complex problem solving & judging the consequences of behavior..motor areas control movements of voluntary skeletal muscles
Functions of the frontal lobes
Sensory areas are responsible for vision..association areas combine visual images with other sensory experiences
Functions of the occipital lobes
Sensory areas provide sensations of temperature, touch, pressure & pain involving the skin..association areas function in understanding speech & in using words to express thoughts & feelings
Functions of the parietal lobes
Control muscle tone & sweat gland activity
Functions of the reticulospinal tracts
Posture control & muscle coordination
Functions of the rubrospinal tracts
Muscle sensory information & coordination of muscles
Functions of the spinocerebellar tracts
Sensations of pain, temperature, touch & pressure
Functions of the spinothalmic tracts
Sensory areas are responsible for hearing..association areas interpret sensory experiences & remember visual scenes, music & other complex sensory patterns
Functions of the temporal lobes
Which of the following is true of G protein activation?
G protein activation occurs in response to all neurotransmitters within the peripheral nervous system except for nicotinic receptors
inhibitory
GABA is _____ in the CNS.
Consciously perceived sensory information
GSA
DO NOT originate in smooth muscle, cardiac muscle, or endocrine glands
GSA
Localized sensations
GSA
Pain, vibration, pressure, temperature, stretch, proprioceptive information back to CNS
GSA
Sensory neurons with cell bodies loacted in dorsal/posterior root ganglion
GSA
Sensory receptors located in skin, skeletal muscle, bone/ligament/tendons, special sense organs
GSA
Special senses like sight, smell, balance, taste, smell
GSA
Carry efferent outflow to skeletal muscle fibers and make the muscles contract
GSE
Motor nuerons with cell bodies located in ventral/anterior horn of spinal cord or anterior regions of brainstem
GSE
Somatic Motor Neurons
GSE
Voluntary Motor system
GSE
Visceral sensory neurons
GVA
Collections of nerve cell bodies outside the central nervous system are called ________.
Ganglia
Nodes of Ranvier
Gaps in the myelin sheath between adjacent Schwann cells They are the sites where axon collaterals can emerge They function to speed up transmission of nerve impulses
Function of an axon
Generate and transmit action potentials away from the soma Secrete neurotransmitters from the axonal terminals All substances needed for axonal activity must be transported down the axon by vesicular trafficking (involves molecular motors and microtubules) Movement along axons occurs in two ways Anterograde — toward axonal terminal Retrograde — away from axonal terminal
Potentials that are short-lived, local changes in membrane potential that can be either depolarized or hyperpolarized are called ________ potentials.
Graded
What are the two types of membrane potential changes that act as signals:
Graded potentials: incoming short-distance signals (depolarizations or hyperpolarizations) Action potentials: long-distance signals of axons (occurs in muscle cells and axons of neurons)
The horizontal bar of gray matter that is in the middle of the spinal cord that connects the wings of the gray matter on the R&L sides is called the
Gray commissure
Pat axons leaving the paravertebral ganglia pass through branches called
Gray rami
Neurotransmitters: Biogenic Amines
Include: Catecholamines - dopamine, norepinephrine (NE), and epinephrine Indolamines - serotonin and histamine Broadly distributed in the brain Play roles in emotional behaviors and our biological clock
Astrocytes
Highly branched glial cells Most abundant CNS glia They cling to neurons and their synaptic endings, and cover capillaries Astrocytes Functionally, they: Support and brace neurons Anchor neurons to their nutrient supplies Guide migration of young neurons Control the chemical environment New evidence suggests they may effect integration
myelin sheath
Impulses travel faster when fibers have a _____
myelinated
In a ____ axon, this keeps current in axons.
dendrite ends
In a bare plasma membrane, one with out voltage gated channels, voltage decays because current leaks across the membrane, and seaps through the ____ ___ as an example.
continuous conduction
In an unmyelinated axon, in which the voltage gated Na+ and K+ channels regenerate action potentials at each point along the axon, so voltage does not decay. Conduction is SLOWER because movements of ions and of the gates of channel proteins take tie and must occur before voltage regeneration occurs.
What is the basic difference between simple diffusion and facilitated diffusion across a cell membrane?
In facilitated diffusion, molecules only move with the aid of a protein in the membrane.
Dendrites
In motor neurons they are short, tapering, and diffusely branched processes but do take other forms in other neurons. They are the main receptive, or input, regions of the neuron. Electrical signals travel as graded potentials (not action potentials) toward the soma over dendritic fibers.
Which of the following is a difference between primary and secondary active transport?
In primary active transport, the transport protein gets phosphorylated; in secondary active transport, the transport protein is not phosphorylated.
continuous, saltatory
In terms of nerve impulse conduction, unmyelinated is to ____________ as myelinated is to ____________. A) oligodendrocytes; neurolemmocytes B) neurolemmocytes; oligodendrocytes C) continuous; saltatory D) saltatory; continuous
Neurotransmitters: Amino Acids
Include: GABA - Gamma ()-aminobutyric acid Glycine Aspartate Glutamate Found only in the CNS
Neurotransmitters: Peptides
Include: Substance P - mediator of pain signals Beta endorphin, dynorphin, and enkephalins Act as natural opiates; reduce pain perception Bind to the same receptors as opiates and morphine Gut-brain peptides - somatostatin, and cholecystokinin
What changes occur to voltage-gated Na+ and K+ channels at the peak of depolarization?
Inactivation gates of voltage-gated Na+ channels close, while activation gates of voltage-gated K+ channels open.
serotonin, histamine
Indolamines contain which two main neurotransmitters?
Lower masses of the corpora quadrigemina which contain the centers for certain auditory reflexes
Inferior colliculi
ipsp
Inhibitory Postsynaptic Potentials AKA
inhibitory postsynaptic potential
Inhibitory effect on downstream cell AKA
What component of the reflex arc determines the response to a stimulus?
Integration Center
What is the electrical "resting" state of a neuron?
Inside the cell is more negative; outside the cell is more positive.
Central branches of the thoracic spinal nerves do not enter a plexus, instead, they extend into spaces btwn the ribs as
Intercostal nerves
________ are the most numerous type of neuron in the CNS. Bipolar neurons Motor neurons Unipolar neurons Sensory neurons Interneurons
Interneurons
visual area
Interprets activity in visual cortex, found in occipital lobe (green)
What are Basal Ganglia and where are they found?
Islands of gray matter found deep inside the white matter of each cerebral hemisphere.
Which of these are not properties of the stretch reflex? It is activated by muscle elongation. Its receptor is muscle spindle. It is a disynaptic reflex. It regulates muscle length.
It is a disynaptic reflex.
threshold
It is called a stimulatory effect because the event brings the postsynaptic cell closer to _____.
What ion causes repolarization of the neuron during an action potential?
K+ (potassium)
During the hyperpolarization phase of the action potential, when the membrane potential is more negative than the resting membrane potential, what happens to voltage-gated ion channels?
K+ channels close. Na+ channels go from an inactivated state to a closed state.
Which of the following is the clearest example of a neuronal membrane's selective permeability?
K+ ions can diffuse across the membrane more easily than Na+ ions.
During an action potential, hyperpolarization beyond (more negative to) the resting membrane potential is primarily due to __________.
K+ ions diffusing through voltage-gated channels
The repolarization phase of the action potential, where voltage becomes more negative after the +30mV peak, is caused primarily by __________.
K+ ions leaving the cell through voltage-gated channels
The membranes of neurons at rest are very permeable to _____ but only slightly permeable to _____.
K+; Na+
pituitary gland
Known as the "Master Gland" it controls the hormone production of other glands; located at the base of the brain ( m )
In an adult, the conus medullaris is found at about L1. C1. L5. T10. T6.
L1.
What is Aphasia?
Language defects
cerebral peduncles *** not on test #12
Large fiber bundles located on the anterior surface of the midbrain. *** not on test #12
The 3 major descending tracts which conduct motor impulses from the brain are
Lateral & anterior corticospinal tracts, lateral anterior & medial reticulospinal tracts, rubrospinal tracts
Location of the corticospinal tracts, spinothalmic tracts & reticulospinal tracts
Lateral & anterior funiculi
Location of the spinocerebellar tracts & rubrospinal tracts
Lateral funiculi
Sometimes a protrusion of gray matter exists and is called the
Lateral horn
In the sympathetic division the preganglionic fibers originate from neurons in the
Lateral horn of the spinal cord
Spaces and brain regions produced by the telencephalon
Lateral ventricles; cerebrum & basal nuclei
Sodium and potassium ions can diffuse across the plasma membranes of all cells because of the presence of what type of channel?
Leak channels
Controls emotional experience & expression & can modify the way a person acts
Limbic system
Frontal & temporal bones connect with the thalamus, hypothalamus, basal nuclei & other deep nuclei to form the
Limbic system
Silvia divides each hemisphere into
Lobes
Thickening of the spinal cord in the lower back region that supplies nerves to the lower limbs is called what
Lumbar enlargement
Plexus of nerves to supply the lower abdomen, pelvis & lower ribs formed btwn T12-S5
Lumbosacral plexus
Supply's muscles of the forearms & muscles & skin of the hands
Median nerves
An enlarged continuation of the spinal cord which extends from the level of the foramen magnum to the pons
Medulla oblongata
Composed of tracts for information btwn the brain & the spinal cord
Medulla oblongata
The cardiac center, which increases/decreases heart rate, the vasomotor center, which contract the walls of blood vessels & the respiratory center, which maintains the basic rhythm of breathing are all located within the
Medulla oblongata
What are spinal nerves and how many does a human have?
Mixed nerves originating from spinal cord. 31 spinal nerves.
Which of the following is NOT true of association neurons?
Most association neurons are confined within the peripheral nervous system (PNS).
Which of the following is NOT true of association neurons? Association neurons account for over 99% of the neurons in the body. Most association neurons are confined within the peripheral nervous system (PNS). Association neurons are also known as interneurons. Most association neurons are multipolar.
Most association neurons are confined within the peripheral nervous system (PNS).
How are Autonomic Activities controlled?
Mostly under influence of brain and spinal cord. - Vital centers in Medulla react to stimuli from viscera. Send out motor impulses on autonomic nerves. - Hypothalamus regulates various homeostatic processes by influencing autonomic pathways. - Limbic system and cerebral cortex use autonomic pathways to regulate emotional expression and behavior.
Descending tracts that conduct efferent impulses from the brain are also called
Motor
Efferent=
Motor
Neuron Classification Structural
Multipolar — three or more processes Bipolar — two processes (axon and dendrite) Unipolar — single, short process
Structural classification of neurons
Multipolar: most neurons in CNS Bipolar: sensory in retina of the eye and nose Unipolar: single process that divides into two branches. Part that extends to the periphery has dendrite-like sensory receptors
Acetylcholine can combine with 2 types of cholinergic receptors called
Muscarinic & nicotinic receptors
Supply's muscles of the arm on the anterior side & the skin of the forearms
Musculocutaneous nerves
Posterior portion of the rhombencephalon
Myelencephalon
Describe Multiple Sclerosis
Myelin sheaths around axons wear away and axons are scleroted Signal is slowed or even stopped Pg. 405 in textbook
In which type of axon will velocity of action potential conduction be the fastest?
Myelinated axons with the largest diameter
reuptake
NEUROTRANSMITTER TERMINATION: ______ by astrocytes or the presynaptic terminal, where the neurotransmitter is stored or destroyed by enzymes, as with norepinephrine.
degradation
NEUROTRANSMITTER TERMINATION: _______ by enzymes associated with the postsynaptic membrane or present in the synapse, as with acetycholine.
The diffusion of what ion, across the neuronal membrane, is responsible for the local currents that depolarize regions of the axon to threshold? `
Na+
Which of the following is most likely to move through the cell membrane by facilitated diffusion?
Na+
The concentrations of which two ions are highest outside the cell.
Na+ and Cl-
During the action potential of a neuron, which ion is primarily crossing the membrane during the depolarization phase, and in which direction is the ion moving?
Na+ is entering the cell.
The Na+-K+ pump actively transports both sodium and potassium ions across the membrane to compensate for their constant leakage. In which direction is each ion pumped?
Na+ is pumped out of the cell and K+ is pumped into the cell.
What ion is responsible for the depolarization of the neuron during an action potential?
Na+ sodium
What prevents the Na+ and K+ gradients from dissipating?
Na+-K+ ATPase
These ion concentrations are a result of two processes
Na/k pump and membrane permeability
Motor (efferent) division
Nerve fibers that carry impulses away from the central nervous system
Sensory afferent division
Nerve fibers that carry information to the central nervous system
Synaptic cleft information transfer
Nerve impulses reach the axonal terminal and open Ca2+ channels Neurotransmitter is released into the synaptic cleft via exocytosis Neurotransmitter crosses the cleft and binds to receptors Ion channels open, causing an excitatory or inhibitory effect Synaptic Cleft: Information Transfer Termination of Neurotransmitter Effects Neurotransmitter bound to a postsynaptic neuron: Produces a continuous postsynaptic effect Blocks reception of additional "messages" Must be removed from its receptor
What are Choroid Plexuses?
Networks of capillaries that project from the Pia Mater into the Lateral (1st & 2nd) ventricles and into the roofs of the 3rd & 4th ventricles.
The two principal cell types of the nervous system are:
Neurons (10%) - excitable cells that transmit nerve impulses and perform integration Supporting cells (90%) - Called neuroglia or glial cells these cells surround and wrap neurons to perform tasks necessary for neuronal functioning.
Describe ELECTRICAL synapses
Neurons are electrically coupled (joined by gap junctions) Communication is very rapid, and may be unidirectional or bidirectional Are important in: - Embryonic nervous tissue - Some brain regions, eyes [Less common than chemical synapses]
Which of the following is NOT a characteristic of neurons?
Neurons are relatively small, simple-structured cells.
chemical synapse
Neurotransmission is mediated via release of chemical messengers from presynaptic cell that cross synaptic cleft and bind receptors on postsynaptic cell.
Clusters of RER and free ribosomes in neurons are called perikaryon. neurofibrils. microglia. Nissl bodies. neurofilaments.
Nissl bodies.
Electicical Synapses
No Neurotransmitters Are less common than chemical synapses Correspond to gap junctions found in other cell types Are important in the CNS in: Arousal from sleep Mental attention Emotions and memory Ion and water homeostasis
All-or-none principle
No matter how strong the stimulus, as long as it is greater than threshold, then action potential will occur.
A gap between Schwann cells in the peripheral system is called a(n) ________.
Node of Ranvier
What are the Myelin sheath gaps between adjacent Schwann cells called?
Nodes of Ranvier [These are sites where axon collaterals can emerge]
Postganglionic neurons in the sympathetic division release what
Norepinephrine & epinephrine
What is the difference between the clusters of cell bodies called nuclei and those known as ganglia?
Nuclei exist in the CNS, ganglia in the PNS.
Supply's the adductor muscles of the thighs
Obturator nerves
Cranial nerves III..eye movements..primarily motor
Occulomotor
Cranial nerves I..sense of smell..sensory
Olfactory
The 12 pairs of cranial nerves..(oh oh oh to touch and feel very good velvet ah ha..I II III IV V VI VII VIII IX X XI XII)
Olfactory, optic, occulomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, accessory & hypoglossal
insensitive
Once activation gate is opened; A timer starts and when it is up, the ____ gate closes.
same
Once the insensitive channel is shut; it will always reset after the __ amount of time.
What characterizes repolarization, the second phase of the action potential?
Once the membrane depolarizes to a peak value of +30 mV, it repolarizes to its negative resting value of -70 mV.
Describe the structure of an Axon
One axon per cell arising from the axon hillock Long axons (nerve fibers) Occasional branches (axon collaterals) Numerous terminal branches (telodendria) Knoblike axon terminals (synaptic knobs or boutons)
What effect did decreasing the extracellular sodium have on the resting membrane potential?
Only a small change occurred, because the resting neuron is not very permeable to sodium.
Cranial nerves II..sense of vision..sensory
Optic
Visceral=
Organs
Nerves that branch out from the CNS are what
PNS
Peripheral nervous system
PNS
In a spinal reflex, information flows from __________ to __________ to __________. PNS; PNS; CNS CNS; CNS; PNS PNS; CNS; PNS CNS; PNS; CNS
PNS; CNS; PNS
Peripheal Nervous System
Paired spinal and cranial nerves Carries messages to and from the spinal cord and brain): Two Functional Divisions Sensory (afferent) division Sensory fibers - carry impulses from sensory receptors in the body to the CNS Motor (efferent) division Motor fibers - Transmits impulses from the CNS to effector organs
Restful state is what division of the autonomic NS
Parasympathetic
The ganglia that lie just beneath the parietal pleura in the thorax & beneath the parietal peritoneum in the abdomen are called
Paravertebral ganglia
Brain, Spinal Cord
Parts of the CNS
Nerves outside the brain and spinal cord
Parts of the PNS
An example of a reflex behavior is the..simple monosynaptic reflex
Patellar tendon reflex
Binds peripheral nerves into smaller bundles called fascicles
Perineurium
C3-5 pass into this nerve which conducts motor impulses to the muscle fibers of the diaphragm
Phrenic nerves
Thin layer that contains many nerves as well as blood vessels that nourish the underlying cells of the brain & spinal cord
Pia mater
Define PREsynaptic neuron
Presynaptic neuron: conducts impulses toward the synapse
Absolute Refractory period
Prevents the neuron from generating a nerve impulse Ensures that each action potential is separate Enforces one-way transmission of nerve impulses
Supply's muscles of the arms on the posterior sides & the skin of the forearms & hands
Radial nerves
Describe the structure and function of Ependymal Cells
Range in shape from squamous to columnar; may be ciliated Line the central cavities of the brain and spinal column Separate the CNS interstitial fluid from the cerebrospinal fluid in the cavities (barrier)
Near the center of the midbrain this mass of gray matter plays a role in maintains posture
Red nucleus
What are the effects of beta blockers?
Reduce sympathetic stimulation and reduce heart rate and blood pressure.
Electrical Current and the Body
Reflects the flow of ions rather than electrons There is a potential across the plasma membrane of all cells called the resting membrane potential. This potential is created and maintained by the Na/K pumps.
The simplest form of a nerve pathway that occurs at the level of the spinal cord, has some sensory receptors is called a
Reflex arc
k+
Repolarization is caused by ___ flowing out of the cell.
Sensations, perceptions, memory, reasoning, motor commands, coordination of muscular activity & regulation of visceral activities are all what
Responsibilities of the brain
Parasympathetic
Resting functions, digestion and urinating
Filters incoming sensory information, activates the cerebral cortex to wakefulness & is connected to centers of the cerebrum, basal ganglia, hypothalamus & the cerebellum
Reticular formation
Scattered throughout the brainstem is a complex network of nerve fibers associated with tiny islands of gray matter known as the
Reticular formation
block reuptake
SSRI's such as prozac will ____ _____ of neurotransmitters at the cleft.
graded potentials
STEP FIVE OF THE SYNAPSE OF THE NERVOUS SYSTEM: Binding of neurotransmitter opens ion channels, resulting in ____ ______.
cleft, postsynaptic
STEP FOUR OF THE SYNAPSE OF THE NERVOUS SYSTEM: Neurotransmitter diffuses across the synaptic ____ and binds to specific receptors on the ________ membrane.
positive, action potential
STEP FOUR OF THE SYNAPSE: ACH binding causes the ligand gated sodium ion channels to open and sodium diffuses into the cell, making the membrane more _______. If the memmbrane reaches threshold, a ___ ____ will be produced.
axon terminal
STEP ONE OF THE SYNAPSE OF THE NERVOUS SYSTEM: Action potential arrives at _____ ______.
presynaptic terminal
STEP ONE OF THE SYNAPSE: Action potentials arriving at the ____ ____ cause voltage gated calcium ion channels to open.
reuptake, enzymatic, diffusion
STEP SIX OF THE SYNAPSE OF THE NERVOUS SYSTEM: Neurotransmitter effects are terminated by _____ through transport proteins, ______ degradation, or ____ away from the synapse.
calcium, exocytosis
STEP THREE OF THE SYNAPSE OF THE NERVOUS SYSTEM: _____ entry causes neurotransmitter-containing synaptic vesicles to release their contents by _______.
cleft, ligand, sodium
STEP THREE OF THE SYNAPSE; ACH molecules diffuse from the presynaptic terminal across the synaptic ___ and bind to their receptors in the ___ gated ____ ion channels.
voltage
STEP TWO OF THE SYNAPSE OF THE NERVOUS SYSTEM: _______-gated calcium channels open and calcium enters the axon terminal.
vesicles
STEP TWO OF THE SYNAPSE: Calcium ions diffuse into the cell and cause synaptic _____ to release ACH.
Oligodendrocytes
Schwann Cells, and Satellite Cells Oligodendrocytes - branched cells that wrap CNS nerve fibers and produce myelin sheaths
PNS neuroglia help to form myelin sheaths around larger nerve fibers in the PNS?
Schwann cells
Which of the following peripheral nervous system (PNS) neuroglia form the myelin sheaths around larger nerve fibers in the PNS?
Schwann cells
Which of the following peripheral nervous system (PNS) neuroglia form the myelin sheaths around larger nerve fibers in the PNS? Schwann cells astrocytes satellite cells oligodendrocytes
Schwann cells
what is vital to regeneration of damaged peripheral nerve fibres
Schwann cells
What two types of cells make up myelin sheaths?
Schwann cells (neurolemmocytes) in the PNS Oligodendrocytes in the CNS
Which of the following is described correctly?
Schwann cells provide the myelination in the peripheral nervous system.
The neurilemma of axons in the peripheral nervous system is formed by satellite cells. astrocytes. microglia. oligodendrocytes. Schwann cells.
Schwann cells.
Largest & longest nerves in the body
Sciatic nerves
Describe the structure and function of Myelin Sheaths
Segmented protein-lipoid sheath around most long or large-diameter axons In the PNS, Schwann cells wrap many times around the axon (look like little sausage links) It functions to: - Protect and electrically insulate the axon - Increase speed of nerve impulse transmission
Afferent=
Sensory
Ascending tracts that conduct afferent information to the brain are also called
Sensory
PNS components
Sensory receptors, nerves, ganglion, plexus
What type of functions does the brain stem perform?
Sensory, motor, and reflex functions.
Functional classification of neurons
Sensory: action potentials toward CNS Motor: action potentials away from CNS Interneurons: within CNS from one neuron to another
tentorium cerebelli
Separates Cerebellum and Brainstem from the occipital lobes of Cerebrum
ssri
Seratonin selective receptor inhibitor AKA
Patterns of Neural Processing
Serial Processing Input travels along one pathway to a specific destination Works in an all-or-none manner Example: spinal reflexes Parallel Processing Input travels along several pathways Pathways are integrated in different CNS systems One stimulus promotes numerous responses Example: smell may remind one of associated experiences
Describe the structure and function of Dendrites
Short, tapering, and diffusely branched Receptive region of a neuron [afferent] - receive sensory input Convey electrical signals toward the cell body as graded potentials
Graded potentials
Short-lived, local changes in membrane potential Decrease in intensity with distance Magnitude varies directly with the strength of the stimulus Alone or summed they can result in the initiation of nerve impulses on axons Only travel over short distances Occur only on dendrites Involved in the process of integration
That part of the nervous system that is voluntary and conducts impulses from the CNS to the skeletal muscles is the ________ nervous system.
So-ma-tic
Which of the following is true about the movement of ions across excitable living membranes? Ions always move passively across membranes. Ions always move actively across membranes through leakage channels. Sodium gates in the membrane can open in response to electrical potential changes. Ions always move from an area of higher concentration to an area of lower concentration
Sodium gates in the membrane can open in response to electrical potential changes.
The sodium-potassium exchange pump transports potassium and sodium ions in which direction(s)?
Sodium ions are transported out of the cell. Potassium ions are transported into the cell.
The 2 divisions of the PNS are the
Somatic & autonomic NS
Conscious activity is what division of the PNS
Somatic NS
Motor or efferent division
Somatic nervous system Conscious control of skeletal muscles Autonomic nervous system (ANS) Regulates smooth muscle, cardiac muscle, and glands 2 Divisions - sympathetic and parasympathetic
Why does the threshold increase when the internal between the stimuli decreases?
Some sodium channels have been inactivated and cannot be reopened immediately
What happens just after an axon is depolarized to threshold? Some potassium channels open. All potassium channels open. All sodium channels open. Some sodium channels open.
Some sodium channels open.
Slender column of nervous tissue that is continuous with the brain and extends down through the vertebral canal
Spinal cord
excitatory postsynaptic potential
Stimulatory effect on downstream cell AKA
Cerebrospinal fluid (CSF) is located in the
Subarachnoid space
Shallow grooves are called
Sulcus
Dense mass within the diencephalon that bulges into the 3rd ventricle on each side..acts a a central relay to & from the cerebral cortex
Thalamus
varies, on or off
The AMPLITUDE of a graded potential ____ while it is either ______ for an action potential.
permeability
The Action Potential is caused by ____ changes in the plasma membrane.
varies, same
The DURATION of a graded potential ___, while it will remain the ____ for an action potential.
trigger zone, axon
The LOCATION of the action potential is made for long distances; meaning that usually a gate will be at the ____ ____ and travel down the ____.
cell body, dendrite
The LOCATION of the graded potential is very localized for small distances; meaning that it usually consistes of the ___ ___ using a gate to the ____.
Which of the following best describes the Na+ and K+ concentrations across a neuron's plasma membrane?
The Na+ concentration is higher outside the cell compared to inside. The K+ concentration is higher inside the cell compared to outside.
arginine
The Nitric Oxide group of neurotransmitters contain what specific neurotransmitter discussed?
Imagine that the cell membrane from the previous problem becomes more permeable to . Predict how this will affect the RMP.
The RMP will be more positive.
postsynaptic
The ____ neuron is located at a synapse between neurons; the neuron recieving the signal.
presynaptic
The _____ neuron is located at a synapse between neurons; the neuron sending the signal.
electrical
The _____ synapse has a role in embrionic development of the nervous system.
sodium potassium pump, ATP
The _______ restores the original configuration, which requires ____
Tetraethylammonium (TEA) blocks voltage-gated K+ channels such that K+ cannot pass even when the channels are open. However, TEA leaves K+ leakage channels largely unaffected. How would you expect the action potential to change if you treated a neuron with TEA? The action potential would fail. Once the voltage reached threshold, it would return to the resting membrane potential. The membrane would depolarize and repolarize as usual, but no hyperpolarization beyond (more negative to) the resting membrane potential would occur. The action potential would depolarize as usual, but the repolarization phase would take longer, causing the action potential to be more broad in time. The membrane would depolarize as usual but then stay at that depolarized voltage (about +30 mV).
The action potential would depolarize as usual, but the repolarization phase would take longer, causing the action potential to be more broad in time.
etraethylammonium (TEA) blocks voltage-gated K+ channels such that K+ cannot pass even when the channels are open. However, TEA leaves K+ leakage channels largely unaffected. How would you expect the action potential to change if you treated a neuron with TEA?
The action potential would depolarize as usual, but the repolarization phase would take longer, causing the action potential to be more broad in time.
Multiple Sclerosis Treatment
The advent of disease-modifying drugs including interferon beta-1a and -1b, Avonex, Betaseran, and Copazone: Hold symptoms at bay Reduce complications Reduce disability
Why does the action potential only move away from the cell body?
The areas that have had the action potential are refractory to a new action potential.
Puffer fish poison blocks voltage-gated sodium channels like a cork. What effect would this neurotoxin have on the function of neurons? Action potentials would lack a repolarization phase. None, because the chemically-gated sodium channels would still function. Neurons would depolarize more rapidly. The absolute refractory period would be shorter than normal. The axon would be unable to generate action potentials
The axon would be unable to generate action potentials
arbor vitae
The branching tree looking structure of white matter found in the cerebellum.
Describe chemical concentrations of K+ and Na+ inside and outside a neuron.
The cell membrane is much more permeable/leaky to K+ ions Na+ / K+ pumps help to maintain resting gradients
Which of the following is true of the cerebral hemispheres of the human brain? Nearly the entire surface of the cerebral hemispheres is marked by elevated ridges called sulci. Nearly the entire surface of the cerebral hemispheres is marked by shallow grooves called gyri. The cerebral hemispheres account for about 83% of total brain mass. The longitudinal fissure separates the cerebral hemispheres from the cerebellum.
The cerebral hemispheres account for about 83% of total brain mass.
decussation
The crossing over of nerve fibers of a pathway from one side of the CNS to the other.
Neurons
The functional cell of the nervous system Composed of a soma (body), axon, and dendrites (fibers) Long-lived, amitotic, and have a high metabolic rate Plasma membranes function in electrical signaling
The gray horns of the spinal cord contain __________. neuroglia neuron cell bodies (somas) unmyelinated axons The gray horns contain all of these elements.
The gray horns contain all of these elements.
enkephalins, endorphins, angiotensin 2
The group Neuropeptides contain what three neurotransmitters?
Why does regeneration of the action potential occur in one direction, rather than in two directions?
The inactivation gates of voltage-gated Na+ channels close in the node, or segment, that has just fired an action potential.
negative, action potential
The inhibitory effect will cause the postsynaptic cell to become more _____ on the inside, and will therefore be further from threshold and less likely to fire a _____ _____.
If the potassium permeability of a resting neuron increases above the resting permeability, what effect will this have on the transmembrane potential? The inside of the membrane will become more negative. There will be almost no effect on transmembrane potential. The membrane will become depolarized. The membrane will depolarize to threshold. The inside of the membrane will become more positive.
The inside of the membrane will become more negative.
On average, the resting membrane potential is -70 mV. What does the sign and magnitude of this value tell you?
The inside surface of the plasma membrane is much more negatively charged than the outside surface.
Sodium and potassium ions do not diffuse in equal numbers through ligand-gated cation channels. Why?
The inside surface of the sarcolemma is negatively charged compared to the outside surface. Sodium ions diffuse inward along favorable chemical and electrical gradients.
The Nervous System
The master controlling and communicating system of the body Functions Sensory input -information gathered from sensory receptors monitoring stimuli Integration - interpretation of sensory input by the central nervous system (brain and spinal cord) Motor output - activates effector organs
What describes depolarization?
The membrane becomes less polarized
At rest, why is the transmembrane potential of a neuron (-70 mV) closer to the potassium equilibrium potential (-90 mV) than it is to the sodium equilibrium potential (+66 mV)?
The membrane is much more permeable to potassium ions than to sodium ions.
What characterizes depolarization, the first phase of the action potential?
The membrane potential changes from a negative value to a positive value.
What event triggers the generation of an action potential?
The membrane potential must depolarize from the resting voltage of -70 mV to a threshold value of -55 mV.
polarized fewer
The plasma membrane at rest is ______, meaning there are _____ positive ions inside the cell than outside the cell
Why is the parasympathetic nervous system referred to as the craniosacral division of the autonomic nervous system?
The preganglionic neurons of the parasympathetic nervous system either originate in the brainstem or the sacral spinal cord.
The resting membrane potential depends on two factors that influence the magnitude and direction of Na+ and K+ diffusion across the plasma membrane. Identify these two factors.
The presence of concentration gradients and leak channels
During action potential propagation in an unmyelinated axon, why doesn't the action potential suddenly "double back" and start propagating in the opposite direction?
The previous axonal segment is in the refractory period.
In an unmyelinated axon, why doesn't the action potential suddenly "double back" and start propagating in the opposite direction?
The previous axonal segment is refractory.
neurotransmission
The process by which a nerve impulse is transmitted from a neuron to another cell.
Which of the following statements about the action potential is false? During the depolarization phase, membrane potential becomes positive. Repolarization occurs as potassium ions leave the axon. In the after-hyperpolarization phase, membrane potential approaches the potassium equilibrium potential. During the repolarization phase, sodium channels close and potassium channels open. The rapid depolarization phase is caused by the entry of potassium ions.
The rapid depolarization phase is caused by the entry of potassium ions.
Which of the following statements about receptor potentials is FALSE? The receptor proteins respond to stimuli. The receptor potential is carried by neuroglia. They can trigger an action potential. Odor molecules can act as stimuli.
The receptor potential is carried by neuroglia.
Which of the following statements about receptor potentials is FALSE?
The receptor potential is carries by neuroglia
How does blocking retrograde axoplasmic transport in an axon affect the activity of a neuron? The soma becomes unable to export products to the synaptic terminals. The neuron becomes unable to produce neurotransmitters. The neuron becomes unable to produce action potentials. The soma becomes unable to respond to changes in the distal end of the axon. The neuron becomes unable to depolarize when stimulated.
The soma becomes unable to respond to changes in the distal end of the axon.
What is the primary difference between the somatic nervous system and the autonomic nervous system?
The somatic nervous system allows us to consciously control our skeletal muscles, and the autonomic nervous system controls activity that humans cannot consciously control, such as the pumping of the heart and the movement of food through the digestive tract.
The myelin on myelinated neurons can be degraded or destroyed in diseases such as multiple sclerosis-a process called demyelination. If a myelinated neuron was affected by demyelination, how would this affect action potentials in that neuron?
The speed of action potential propagation would be slower.
Select the correct statement regarding synapses.
The synaptic cleft prevents an impulse from being transmitted directly from one neuron to another.
Select the correct statement regarding synapses. The synaptic cleft prevents an impulse from being transmitted directly from one neuron to another. Cells with gap junctions use chemical synapases. Neurotransmitter receptors are located on the axons terminals of cells. The release of neurotransmitter molecules gives cells the property of being electrically coupled.
The synaptic cleft prevents an impulse from being transmitted directly from one neuron to another.
fast, slow
The synaptic delay states that all though an action potential propagates _____ the neurotransmission at the synapse is ______.
synaptic delay
The time required for neurotransmitters to be released from presynaptic cell, diffusion across the cleft, and binding of neurotransmitters to postsynaptic cell receptors.
Which brain waves are not normal for awake adults but are common for children? Alpha Delta Theta Beta
Theta
Which of the following is not characteristic of neurons? They have an exceptionally high metabolic rate. They conduct impulses. They have extreme longevity. They are mitotic.
They are mitotic.
Which of the following is NOT true of an electrical synapse?
They are specialized for release and reception of chemical neurotransmitters.
Which of the following is NOT true of an electrical synapse? Communication through these synapses may be unidirectional or bidirectional. They are less common than chemical synapses. They are specialized for release and reception of chemical neurotransmitters. Transmission across these synapses is very rapid.
They are specialized for release and reception of chemical neurotransmitters.
cerebellar peduncles **** not on test #15
Three thick nerve fiber tracts that link the cerebellum with the brainstem. *** not on test #15
schizophrenia
Too much dopamine causes what multiple personality disorder?
The funiculi of the white matter contain bundles of myelinated nerve fibers that compose major nerve pathways called
Tracts
descending tract
Tracts in the white matter of spinal cord that carry impulses away from the brain to effectors of the body
Which statement best characterizes a K+ leak channel? Common trans-membrane channels are always open for any ion to move through in the presence of K+. Chemically gated K+ channels that open and close according to the binding of other molecules. Trans-membrane protein channels that are always open to allow K+ to cross the membrane without the additional input of energy. Trans-membrane channels that use energy to allow the movement of K+ across the membrane.
Trans-membrane protein channels that are always open to allow K+ to cross the membrane without the additional input of energy
Which statement best characterizes a leak channel?
Trans-membrane protein channels that are always open to allow to cross the membrane without the additional input of energy.
saltatory conduction
Transmission of an action potential along a myelinated fiber in which the nerve impulse appears to leap from node (of ranvier) to node.
Cranial nerves V..largest..3 branches: opthalmic, maxillary, mandibular..mixed
Trigeminal
Cranial nerves IV..primarily motor
Trochlear
A postsynaptic potential is a graded potential that is the result of a neurotransmitter released into the synapse between two neurons.
True
A postsynaptic potential is a graded potential that is the result of a neurotransmitter released into the synapse between two neurons. T or F
True
A stimulus traveling toward a synapse appears to open calcium ion channels at the presynaptic end, which in turn promotes fusion of synaptic vesicles to the axonal membrane.
True
A stimulus traveling toward a synapse appears to open calcium ion channels at the presynaptic end, which in turn promotes fusion of synaptic vesicles to the axonal membrane. T or F
True
Acetylcholine is the substance released by the axonal endings of the somatic efferent fibers and by the parasympathetic nerve fiber endings T/F
True
An action potential is a phenomenon that either happens completely or doesn't happen at all.
True
Autonomic reflex centers occur in the spinal cord, medulla, and midbrain T/F
True
Axon diameter and degree of myelination determine nerve impulse conduction velocity.
True
Axon diameter and degree of myelination determine nerve impulse conduction velocity. T or F
True
Cell bodies of sensory neurons may be located in ganglia lying outside the central nervous system T/F
True
Cell bodies of sensory neurons may be located in ganglia lying outside the central nervous system.
True
Cell bodies of sensory neurons may be located in ganglia lying outside the central nervous system. T or F
True
Dendrites and axons are both armlike processes that extend from cell bodies.
True
During depolarization, the inside of the neuron's membrane becomes less negative.
True
During depolarization, the inside of the neuron's membrane becomes less negative. T or F
True
Efferent nerve fibers may be described as motor nerve fibers T/F
True
Efferent nerve fibers may be described as motor nerve fibers.
True
Efferent nerve fibers may be described as motor nerve fibers. T or F
True
Enkephalins and endorphins are peptides that act like morphine.
True
Enkephalins and endorphins are peptides that act like morphine. T or F
True
If bacteria invaded the CNS tissue, microglia would migrate to the area to engulf and destroy them.
True
If bacteria invaded the CNS tissue, microglia would migrate to the area to engulf and destroy them. T or F
True
If bacteria invaded the CNS tissue, microglia would migrate to the areal to engulf and destroy them T/F
True
In myelinated axons the voltage-regulated sodium channels are concentrated at the nodes of Ranvier.
True
Supply's muscles of the forearms & hands & the skin of the hands
Ulnar nerves
membrane potentials
Used to integrate, send, and receive information Types of signals - graded potentials and action potentials Changes are caused by three events Depolarization - the inside of the membrane becomes less negative Repolarization - the membrane returns to its resting membrane potential Hyperpolarization - the inside of the membrane becomes more negative than the resting potential
Cranial nerves X..longest nerve..some taste..heart & smooth muscles & glands of thorax/abdomen..mixed
Vagus
What nerve carries roughly 75% of all fibers in the parasympathetic division
Vagus
The 4 interconnected cavities that lie in the cerebral hemisphere and the brain stem are know as what
Ventricles
Structure that connects the cerebellar hemispheres at the midline is called the
Vermis
Cranial nerves VIII..balance & hearing..sensory
Vestibulocochlear
both of the above
What accounts for the gray color of gray matter? A) presence of Nissl bodies B) absence of myelin C) both of the above D) neither of the above
resting potential, depolarization, peak depolarization, repolarization, hyperpolarization
What are the five basic steps of generating an action potential?
neuron, muscle, gland
What are the three postsynaptic membrane receptors for a chemical synapse?
neuromuscular junction
What example of a neuron to effector chemical synapse did we discuss that plays a role in muscle excitation?
in parallel after discharge circuits, a single input leads to multiple individual outputs
Which statement is false regarding neural circuits? A) converging circuits provide multiple input to a single postsynaptic neuron B) diverging circuits spread information from one neuron or pool to several others C) in parallel-after-discharge circuits, a single input leads to multiple individual outputs D) in reverberating circuits, feedback repeatedly stimulates the circuit in a cyclic pattern
Multiple sclerosis (MS) is a disease that stops action potential propagation by destroying the myelin around (normally) myelinated axons. Which of the following best describes how MS stops action potential propagation?
Without myelin, the internode membrane resistance decreases, preventing local currents from reaching adjacent nodes.
Potassium, Sodium
_____ rushes out of the neuron after _____ rushes in, which repolarizes the membrane
fourth ventricle
a CSF filled cavity in the brainstem just anterior to the cerebellum ( 5 )
What is a seizure disorder?
a disorder characterized by abnormal, uncooordinated tetanic contracttions of varying groups of muscles. The result of sudden bursts of abnormal neuron activity.
Describe the shape of the thalamus:
a dumbbell-shaped mass of gray matter made up of many nuclei.
interventricular foramen
a foramen between the lateral ventricles & the third ventricle where CSF passes ( 2 )
What is dementia?
a general syndrome that includes loss of: memory, attention span, intellectual capacity, personality, and motor control.
Define the term Electroencephalogram:
a graphic record of the brain's action potentials used to evaluate nerve tissue function.
When the stimulus voltage is increased,
a greater-than-threshold depolarization results and sodium permeability into the cell increases to overcome the potassium exiting
glossopharyngeal nerve ( IX )
a mixed nerve; sensory: from pharynx, & TONGUE; motor: to salivary glands, & MUSCLES OF THE PHARYNX for SWALLOWING ( L )
trigeminal nerve ( V )
a mixed nerve; sensory: ophthalmic division for sensory from surface of & around the eye; maxillary division: sensory from upper teeth. motor: the muscles of mastication, throat, & in the floor of mouth ( H )
vagus nerve ( X )
a mixed nerve; sensory: pharynx, esophagus, & viscera. somatic motor: speech & swallowing. autonomic motor: viscera & heartbeat ( M )
oculomotor nerve ( III )
a motor nerve: it carries impulses to muscles that raise eyelids, move the eyes, focus lens, controls the iris ( F )
abducens nerve ( VI )
a motor nerve: it carries impulses to the rectus muscles that move the eye ( I )
What type of stimulus is required for an action potential to be generated? a) a threshold level depolarization b) a suprathreshold stimulus c) hyperpolarization d) multiple stimuli
a) a threshold level depolarization
What is the Pituitary gland?
a neuroendocrine gland formed from the hypothalamus.
A postsynaptic cell can be a neuron, a muscle cell, or a secretory cell. What is an example of a presynaptic cell?
a neuron
A postsynaptic cell can be a neuron, a muscle cell, or a secretory cell. What is an example of a presynaptic cell? a muscle cell a neuron a secretory cell a Schwann cell
a neuron
In which of the following would the delay between stimulus and response be greater? a monosynaptic reflex a polysynaptic reflex
a polysynaptic reflex
The membrane potential that occurs when neurotransmitters bind to their receptors is called
a postsynaptic potential
Multiple sclerosis
a progressive, autoimmune disease in which a protein component of the myelin sheath is attacked and the sheath is destroyed Symptoms- depend on location of nerve damage: vision, sensation, coordination, movement, speech, bladder control, and bowel control Women ages 20-40 Therapies but no cure
Which of the following describes a change from the resting membrane potential? a receptor potential an action potential a receptor potential, a synaptic potential or an action potential a synaptic potential
a receptor potential, a synaptic potential or an action potentia
Which of the following describes a change from the resting membrane potential?
a receptor potential, a synaptic potential, or an action potential
When the interval between the stimuli decreases,
a second action potential is generated until the interval reaches the absolute refractory period
vestibulocochlear nerve ( VIII )
a sensory nerve; sensory from hearing receptors, & equilibrium receptors of the ear ( K )
A weak, subthreshold stimulus will result in _______.
a small depolarization at the receiving end of the neuron
The velocity of the action potential is fastest in which of the following axons?
a small myelinated axon
What is the dorsal root ganglion?
a small region of grey matter, shaped like a bump, that is comprised of the cell bodies of the unipolar nerves in the dorsal nerve root.
What is formed by thee joining of the dorsal and ventral nerve roots?
a spinal nerve
Define consciousness:
a state of awareness of one's self, one's environment, and other beings.
Depolarization
a stimulus depolarizes the neuron's membrane
If the axolemma becomes more permeable to potassium ion: the inside of the membrane will have a positive charge the membrane will depolarize to threshold a stronger stimulus will be required to cause an action potential the membrane will depolarize to +30 mV sodium ions will enter the cell to replace the lost potassium ions
a stronger stimulus will be required to cause an action potential
arachnoid mater
a thin web-like membrane located between dura mater & pia mater ( 14 )
What type of stimulus is required for an action potential to be generated?
a threshold level stimulas
pineal gland
a tiny structure at the base of the brain that produces melatonin ( k )
What is a membrane potential?
a voltage or electrical charge across the plasma membrane
Which of the following is the conducting region of the neuron? a) Axon b) Dendrites c) Ganglia d) Neurofibrils
a) Axon
Which of the following is true of axons? a) Each neuron has a single axon. b) Each dendrite may have occasional branches along its length, which are called axons. c) Each axon may have occasional branches along its length, which are called dendrites. d) Each neuron has hundreds of axons.
a) Each neuron has a single axon.
Which of the following PNS neuroglia help to form myelin sheaths around larger nerve fibers in the PNS? a) Schwann cells b) Oligodendrocytes c) Astrocytes d) Satellite cells
a) Schwann cells
Which of the following peripheral nervous system (PNS) neuroglia form the myelin sheaths around larger nerve fibers in the PNS? a) Schwann cells b) oligodendrocytes c) satellite cells d)astrocytes
a) Schwann cells
Which of the following allows us to consciously control our skeletal muscles? a) The somatic nervous system b) The sympathetic division of the autonomic nervous system c) The parasympathetic division of the autonomic nervous system d) The involuntary nervous system
a) The somatic nervous system
Which of the following neurotransmitters is released at the neuromuscular junction by motor neurons?
acetylcholine
Which of the choices below describes the ANS? a) motor fibers that conduct nerve impulses from the CNS to smooth muscle and glands b) sensory neurons that convey information from somatic receptors in the head, body wall, and limbs and from receptors form the special senses of vision, hearing, taste, and smell to the CNS c) sensory and motor neurons that supply the digestive tract d) motor fibers that conduct nerve impulses from he CNS to skeletal muscles
a) motor fibers that conduct nerve impulses from the CNS to smooth muscle and glands
The substance released at axon terminals to propagate a nervous impulse is called a(n) ________. a) neurotransmitter b) cholinesterase c) ion d) biogenic amine
a) neurotransmitter
Which of the following are gaps found along a myelin sheath? a) nodes of Ranvier b) axolemma c) terminal boutons d) outer collare of perinuclear cytoplasm
a) nodes of Ranvier
Which of the following is NOT a type of circuit? a) per-discharge circuits b) converging circuits c) reverberating circuits d) diverging circuits
a) per-discharge circuits
An impulse from one nerve cell is communicated to another nerve cell via the ________. a) synapse b) effector c) receptor d) cell body
a) synapse
Saltatory conduction is made possible by _______. a) the myelin sheath b) erratic transmission of nerve impulses c) diphasic impulses d) large nerve fibers
a) the myelin sheath
Irritability
ability to respond to stimuli
Conductivity
ability to transmit an impulse
why are myelin sheaths exceptionally good electrical insulators
absence of channel and carrier proteins
The period after an initial stimulus when a neuron is not sensitive to another stimulus is the ________.
absolute refractory period
Astrocytes
abundant, star shapes cells that brace the neurons they form barrier between capillaries and neurons AND control chemical environment of the brain
how are neurons classified
according to number of processes extending from their cell body- multipolar, bipolar, unipolar
Cholinergic synapses release the neurotransmitter acetylcholine. adrenalin. serotonin. GABA. norepinephrine.
acetylcholine
In myasthenia gravis, antibodies attack __________ receptors at the neuromuscular junction of skeletal muscles.
acetylcholine
The mechanism by which the neurotransmitter is returned to a presynaptic neuron's axon terminal is specific for each neurotransmitter. Which of the following neurotransmitters is broken down by an enzyme before being returned?
acetylcholine
The neurotransmitter used between preganglionic and postganglionic cells in the autonomic nervous system is __________.
acetylcholine
What is the neurotransmitter in the somatic nervous system?
acetylcholine
Which of the following is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle?
acetylcholine
Which of the following is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle? cholinesterase gamma aminobutyric acid acetylcholine norepinephrine
acetylcholine
motor
action potentials from CNS to receptors
sensory
action potentials from receptors to CNS
The obturator nerve is distributed to the skin over buttocks. skin over the perineum. extensors of the hip. adductors of the hip. biceps femoris.
adductors of the hip.
The part of the peripheral nervous system that carries sensory information to the CNS is designated autonomic. efferent. afferent. somatic. motor.
afferent
The all-or-none principle states that all stimuli great enough to bring the membrane to threshold will produce identical action potentials. all stimuli will produce identical action potentials. only motor stimuli can activate action potentials. only sensory stimuli can activate action potentials. the greater the magnitude of the stimuli, the greater the magnitude of the action potential
all stimuli great enough to bring the membrane to threshold will produce identical action potentials.
For the receptor potential
amplitude can vary with the stimulus intensity, requires the appropriate stimulus and can be graded with a stimulus intensity
Which of the following correctly describes a graded potential?
amplitude of various sizes
A depolarizing synaptic potential is also known as _______.
an excitatory postsynaptic potential
plexus
an extensive network axons outside CNS
A stimulus that changes a postsynaptic neuron's membrane from resting potential to -85 mV is: a saltatory stimulus an excitatory stimulus an inhibitory stimulus a depolarizing stimulus a temporal stimulus
an inhibitory stimulus
Products from the soma of a neuron are transported to the synaptic terminals by ________ axoplasmic transport.
anterograde
what is movement toward the axon terminals called
anterograde movement
The subarachnoid space lies between what two layers of meninges? arachnoid and dura arachnoid and epidura arachnoid and pia dura and epidura
arachnoid and pia
All of the following are true of polysynaptic reflexes, except that they involve pools of interneurons. have reverberating circuits that prolong the reflexive motor response. are intersegmental in distribution. involve reciprocal innervation. are arranged according to dermatomes
are arranged according to dermatomes.
Nerve cell adhesion molecules (N-CAMs) ________.
are crucial for the development of neural connections
Nerve cell adhesion molecules (N-CAMs) ________. are crucial for the development of neural connections are crucial in the production of neurotransmitters release nerve growth factor are found on "pathfinder" neurons
are crucial for the development of neural connections
All of the following are true of muscle spindles, except that they consist of specialized fibers called intrafusal fibers. are innervated by gamma motor neurons. are the receptor for the stretch reflex. are found in tendons. are found within skeletal muscle.
are found in tendons.
IPSPs (inhibitory postsynaptic potentials) are local depolarizations. block the efflux of calcium ions. increase membrane permeability to sodium ions. are local hyperpolarizations. block the efflux of potassium ions.
are local hyperpolarizations.
Cl- inside cell
are repelled by proteins and exit through always open non gated channels
lumbar subarachnoid space
area of the subarachnoid space that contains the most CSF due to spinal cord growth
Neurons that have one axon and one dendrite, with the soma in between, are called bipolar. multipolar. anaxonic. unipolar. tripolar.
bipolar.
Which of the following functions does NOT increase during the fight-or-flight response?
blood flow to gastrointestinal organs
How could a CVA cause Hemiplegia?
by temporarily disabling or by killing all the motor neurons on one side of the brain, primarily the precentral gyrus. - this would cause all muscles on one side of the body to become paralyzed.
What type of stimulus is required for an action potential to be generated? a) multiple stimuli b) a single stimulus generated by the neuron that is to produce the action potential c) a threshold level stimulus d) a single stimulus followed immediately by a second stimulus
c) a threshold level stimulus
What is the effect of norepinephrine on the heart? a) a decrease in heart rate b) a decrease in stroke volume c) an increase in heart rate d) Norepinephrine does not affect the heart
c) an increase in heart rate
Which part of the neuron is responsible for generating a nerve impulse? a) dendrite b) Nissl substance c) axon d) soma
c) axon
Which of the following is responsible for the overall integration of the autonomic nervous system (ANS)? a) brain stem b) cerebral cortex c) hypothalamus d) spinal cord
c) hypothalamus
Schwann cells are functionally similar to ________. a) astrocytes b) microglia c) oligodendrocytes d) ependymal cells
c) oligodendrocytes
Which of the following types of glail cells produces myelin sheaths that insulate axons, or nerve fibers, in the central nervous system (CNS)? a) ependymal cells b) microglia c) oligodendrocytes d) astrocytes
c) oligodendrocytes
Immediately after an action potential has peaked, which cellular gates open? a) calcium b) chloride c) potassium d) sodium
c) potassium
For which of the following activities is the parasympathetic nervous system generally responsible? a) vigorous physical activity b) fight-or-flight responses c) resting and digesting d) sweating and dilating pupils
c) resting and digesting
Which of the following is NOT an autonomic nervous system (ANS) effector? a) glands b) cardiac muscle c) skeletal muscle d) smooth muscle
c) skeletal muscle
Which ion channel opens in response to a change in membrane potential and participates in the generation and conduction of action potentials? a) mechanically gated channel b) ligand-gated channel c) voltage-gated channel d) leakage channel
c) voltage-gated channel
Which ion triggers synaptic vesicles to discharge neurotransmitter into the synaptic cleft? potassium calcium magnesium sodium
calcium
Presynaptic facilitation by serotonin is caused by blockage of calcium channels in the presynaptic membrane. increased extracellular concentration of sodium ion. calcium channels in the presynaptic membrane remaining open longer. increased extracellular concentration of potassium ion. temporal summation.
calcium channels in the presynaptic membrane remaining open longer.
graded potentials
can summate and spread in decremental fashion
All of the following are true of neural reflexes, except that they involve at least two neurons. are automatic motor responses. are the simplest form of behavior. cannot be modified by the brain. help preserve homeostasis.
cannot be modified by the brain.
Nissl substance
chromatophilic substance = rough E.R: primary site of protein synthesis
If extracellular concentration of Ca2+ increases- gates ____ and membrane repolarizes or becomes _______.
close, hyperpolarized
what are nuclei
clusters of cell bodies in the CNS
what are ganglia
clusters of cell bodies in the PNS
Nuclei
clusters of cell bodies within the central nervous system
Branches that may occur along an axon are called hillocks. synapses. collaterals. telodendria. synaptic terminals.
collaterals.
nerve
collection of axons in PNS
ganglion
collection of neuron cell bodies outside PNS
Ganglia
collections of cell bodies outside the central nervous system
In the spinal cord, white matter is separated into ascending and descending tracts organized as ganglia. nuclei. columns. nerves. horns.
columns
how do astrocytes signal each other
creating slow paced intracellular calcium pulses, releasing extracellular messengers
The ________ reflex complements the flexor reflex by activating contralateral muscles. crossed extensor flexor tendon stretch reciprocal
crossed extensor
The __________ reflex involves activating muscles contralateral to the receptor. crossed extensor stretch tendon flexor
crossed extensor
post-central gyrus
cutaneous sensory area pressure, pain, temperature, and position and movement sensation are received and interpreted.
Which of the following does not describe the ANS? a) general visceral motor system b) a system of motor neurons that innervates smooth and cardiac muscle and glands c) involuntary nervous system d) a system of motor neurons that innervates all muscle cells
d) a system of motor neurons that innervates all muscle cells
The two divisions of the autonomic nervous system (ANS) normally have a(n)_______ relationship. a)disruptive b) synergistic c) mutualistic d) antagonistic
d) antagonistic
An inhibitory postsynaptic potential (IPSP) is associated with ________. a) lowering the threshold for an action potential to occur b) a change in sodium ion permeability c) opening of voltage-regulated channels d) hyperpolarization
d) hyperpolarization
Which of the following is not a function of the autonomic nervous system? a) innervation of cardiac muscle b) innervation of glands c) innervation of smooth muscle of the digestive tract d) innervation of skeletal muscle
d) innervation of skeletal muscle
Which of the choices below describes the ANS? a) sensory and motor neurons that supply the digestive tract b) sensory neurons that convey information from somatic receptors in the head, body wall, and limbs and from receptors from the special senses of vision, hearing, taste, and smell to the CNS c) motor fibers that conduct nerve impulses from the CNS to skeletal muscles d) motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands
d) motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands
In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment? The interior is ________. a) positively charged and contains more sodium b) positively charged and contains less sodium c) negatively charged and contains more sodium d) negatively charged and contains less sodium
d) negatively charged and contains less sodium
Which of the following circuit types is involved in the control of rhythmic activities such as the sleep-wake cycle, breathing , and certain motor activities (such as arm swinging when walking)? a) converging circuits b) diverging circuits c) parallel after-discharge circuits d) reverberating circuits
d) reverberating circuits
Increasing the amount of myelination
decreases the time between action potentials
ncreasing the amount of myelination _______.
decreases the time between action potentials
Which of the following is a factor that determines the rate of impulse propagation, or conduction velocity, along an axon?
degree of myelination of the axon
what do astrocytes look like
delicate branching sea anemones 'star cells' s
where is the main receptive or input region
dendrite
Which of the following are the main receptive or input regions found in neurons?
dendrites
what are the two types of neuron processes and how do they differ
dendrites, axons. differ in structure and function of plasma membranes
white matter
dense collections of myelinated fibers
how are cells in the CNS packed
densely packed, tightly intertwined
Calcium and magnesium are both
divalent cations
Calcium and magnesium are both _______.
divalent cations
Which of the following circuit types is exemplified by impulses that travel from a single neuron of the brain, activate one hundred or more motor neurons in the spinal cord, and excite thousands of skeletal muscle fibers?
diverging circuits
The __________ gray horns contain sensory nuclei. intermediate ventral dorsal lateral
dorsal
The ________ of each spinal nerve innervates the skin and muscles of the back. gray ramus communicantes ventral ramus dermatome dorsal ramus white ramus communicantes
dorsal ramus
The tough, fibrous, outermost covering of the spinal cord is the periosteum. arachnoid. epidural block. pia mater. dura mater.
dura mater.
The connective tissue layer that covers Schwann cells is the __________. endomysium endoneurium epineurium perineurium
endoneurium
The layer of connective tissue that surrounds individual axons within a peripheral nerve is termed the subneurium. metaneurium. endoneurium. aponeurium. perineurium.
endoneurium
Which of the following neurotransmitters inhibits pain and is mimicked by morphine, heroin, and methadone?
endorphin
Which neurotransmitter(s) is/are the body's natural pain killer?
endorphins
To reach threshold, the amount of sodium _______.
entering the cell must overcome the potassium exiting
Caveolae are closely associated with all of the following except ________.
enzymes involved in cell metabolism
What are ciliated CNS neuroglia that play an active role in moving the cerebrospinal fluid called?
ependymal cells
What are ciliated CNS neuroglia that play an active role in moving the cerebrospinal fluid called? Schwann cells astrocytes oligodendrocytes ependymal cells
ependymal cells
What cells line the ventricles of the brain? astrocytes epithelial cells neurons ependymal cells
ependymal cells
Which of the following types of glial cells line the central cavities of the brain and spinal cord, where they help to circulate the cerebrospinal fluid?
ependymal cells
what is the role of astrocytes
exchange between capillaries and neurons, determine capillary permeability, guiding migration of young neurons, synapse formation, control chemical environment around neuron, mop up leaked K ions and recapture released neurotransmitters
Which membrane potential occurs because of the influx of Na+ through chemically gated channels in the receptive region of a neuron?
excitatory postsynaptic potential
Which membrane potential occurs because of the influx of Na+ through chemically gated channels in the receptive region of a neuron? inhibitory postsynaptic potential inhibitory action potential excitatory postsynaptic potential action potential
excitatory postsynaptic potential
what do the neurotransmitters do
excite or inhibit neurons (or effector cells) witch which the axon is in close contact
Which of the following best describes the cerebrum? visceral command center decussation center executive suite motor command center
executive suite
A vesicle fuses with the plasma membrane and releases its contents to the extracellular fluid. This statement describes _____.
exocytosis
Neurotransmitter is released from presynaptic neurons through what mechanism?
exocytosis
Action potentials travel the length of the axons of motor neurons to the axon terminals. These motor neurons __________.
extend from the brain or spinal cord to the sarcolemma of a skeletal muscle fiber
axon
extends from cell body to terminal endings
EPSPs (excitatory postsynaptic potentials) occur when more potassium ions than usual leak out of a cell. chloride ions enter a cell. extra sodium ions enter a cell. more calcium ions than usual leak out of a cell. hyperpolarizations occur.
extra sodium ions enter a cell.
crossed-extensor reflex **** not on test #3`
flexor muscles contract in response to stimulus, contralateral flexor muscles are inhibited, & contralateral extensor muscles contract to maintain balance *** not on test #3
Define Cerebrospinal Fluid:
fluid found in the cavities and canals of the brain and spinal cord.
Define Ventricles: How many are there?
fluid-filled spaces (4) within the brain.
Damage to ependymal cells would most likely affect the formation of cerebrospinal fluid. formation of ganglia. transport of neurotransmitters within axons. formation of myelin sheaths. repair of axons.
formation of cerebrospinal fluid.
In the peripheral nervous system, Schwann cells participate in the repair of damaged nerves by regenerating cell bodies for the neurons. clearing away cellular debris. producing more satellite cells that fuse to form new axons. forming a cellular cord that directs axonal regrowth. producing new axons.
forming a cellular cord that directs axonal regrowth.
where is the golgi apparatus in a neuron
forms arc or complete circle around nucleus
Schwann cells
forms the myelin sheath in the peripheral nervous system
globus pallidus
found deep within cerebrum, inhibit neurotransmitter dopamine
Bipolar neurons are commonly ________.
found in the retina of the eye
Bipolar neurons are commonly ________. motor neurons called neuroglial cells found in the retina of the eye found in ganglia
found in the retina of the eye
auditory area
found in the temporal lobes, contain the centers for hearing
Which of the following is the most important excitatory neurotransmitter in the brain that is important in learning and memory? glycine gamma aminobutyric acid glutamate noradrenaline serotonin
glutamate
________ potentials are short-lived, local changes in membrane potential that can be either depolarized or hyperpolarized
graded
spatial summation
graded potentials at two different dendrites
A typical spinal nerve has a __________ ramus consisting of unmyelinated axons that innervate smooth muscles. dorsal ventral gray whitw
gray
Axons crossing from one side of the spinal cord to the other within the gray matter are found in the gray commissures. lateral gray horns. posterior gray horns. anterior gray horns. white commissures.
gray commissures.
The postganglionic fibers that connect an autonomic ganglion in the thoracic or lumbar region with the spinal nerve and contain postganglionic fibers that innervate glands in the body wall or limbs are white rami communicantes. ventral ramus. gray rami communicantes. dorsal ramus. dermatomes.
gray rami communicantes
what is the functional classification of a neuron
groups neurons according to direction in which the nerve impulse travels relative to the CNS. sensory neurons, motor neurons, interneurons
Ridges of tissue on the surface of the cerebral hemispheres are called ________. ganglia fissures sulci gyri
gyri
long term memory *** not on test #9
it changes the structure or function of neurons in ways that enhance synaptic transmission by establishing certain patterns of synaptic connections *** not on test #9
why could the peripheral process of a unipolar neuron be classified as the axon
it generates and conducts an impulse, when large is heavily myelinated, has a uniform diameter and is indistinguishable microscopically from an axon
functions of the spinal cord
it transmits nerve impulses to and from the brain & is the center for reflexes
If a nerve cell receives many IPSPs at the same time, __________. the membrane potential will depolarize it will show temporal summation the nerve cell will approach threshold the nerve cell will be strongly excited
it will show temporal summation
If an increase in extracellular potassium hyper polarizes a neuron,
it would change the membrane potential to a more negative value
what does an axon depend on
its cell body to renew the necessary proteins and membrane components and on efficient transport mechanisms to distribute them. axons decay if cut or severely damaged
massa intermedia
joins the two lobes of the thalamus ( 12 )
Synapse
junction between nerves
in motor neurons the impulse is generated where
junction of the axon hillock and axon (trigger zone)
Where is the Pineal body located?
just above and behind the midbrain.
Where is the cerebellum located?
just below the posterior portion of the cerebrum.
what is structurally important about dendrites
large surface area for receiving signals from other neurons
Type A nerve fiber
large-diameter, myelinated. Conduct at 15-120 m/s. Motor neurons supplying skeletal and most sensory neurons
Neural tracts that convey life-saving information to the brain concerning burning pain would be ________. posterior spinothalamic anterior spinothalamic lateral spinothalamic reticulospinal
lateral spinothalamic
The frontal lobe is separated from the temporal lobe by the ________. lateral sulcus central sulcus cranial fossa longitudinal fissure
lateral sulcus
meninges
layers of CT that surround & protect the brain and spinal cord & form a complete enclosure & contain CSF
A viral disease that destroys the cells of the anterior gray horn will mainly interfere with crude touch and temperature sense. block autonomic regulation. affect visceral motor function. interfere with position sense. lead to skeletal muscle weakness or paralysis.
lead to skeletal muscle weakness or paralysis.
The channels that provide for the movement of potassium in the resting neuron are _______.
leakage
Which type of ion channel opens when a chemical binds to it?
leakage channels
Bill contracts a viral disease that destroys cells in the posterior gray horns in his spinal cord. As a result, which of the following would you expect? inability to breathe problems with moving his legs uncontrollable sweating of his feet loss of sensation in his torso problems with moving his arms
loss of sensation in his torso
what do lumbar nerves control and how many?
lower abdomen hips legs 5
The typical concentration of sodium is
lower than potassium intracellularly
The typical concentration of sodium is
lower than potassium intracellularly.
What is the major role of the Na+-K+ pump in maintaining the resting membrane potential?
maintaining the concentration gradients for Na+ and K+ across the cell membrane
Multipolar neurons
many extensions directly from the cell body includes all motor and inter-neurons
basal nuclei *** not on test #1
masses of grey matter called caudate nucleus, putamen, & globus pallidus deep within the cerebral hemispheres; they produce the neurotransmitter dopamine; controls certain muscular movements *** not on test #1
Graded potentials produce an effect that spreads actively across the membrane surface. are often all-or-none. may be either a depolarization or a hyperpolarization. cause repolarization. produce an effect that increases with distance from the point of stimulation.
may be either a depolarization or a hyperpolarization.
Which of the following describes a B fiber?
medium diameter, lightly myelinated
Which of the following is not involved in creating the resting potential of a neuron? membrane permeability for sodium ions greater than potassium ions membrane permeability for potassium ions greater than sodium ions diffusion of sodium ions into the cell diffusion of potassium ions out of the cell The interior of the plasma membrane has an excess of negative charges.
membrane permeability for sodium ions greater than potassium ions
Hyper polarization
membrane potential is more negative, move further from 0
Depolarization
membrane potential is more positive, closer to 0
septum pellucidum
membranous structure that separates the lateral ventricles of the cerebral hemispheres ( b )
Which of the following is not a function of the neuroglia? secretion of cerebrospinal fluid memory support phagocytosis maintenance of blood-brain barrier
memory
The blood-brain barrier is effective against ________. nutrients such as glucose metabolic waste such as urea alcohol anesthetics
metabolic waste such as urea
After a stroke, what type of glial cell accumulates within the affected brain region? oligodendrocytes ependymal cells Schwann cells satellite cells microglia
microglia
Which of the following types of glial cells monitors the health of neurons, and can transform into a special type of macrophage to protect endangered neurons?
microglia
Which of the following types of glial cells monitors the health of neurons, and can transform into a special type of macrophage to protect endangered neurons? ependymal cells oligodendrocytes microglia astrocytes
microglia
Small, wandering cells that engulf cell debris and pathogens in the CNS are called astrocytes. ependymal cells. satellite cells. microglia. oligodendrocytes.
microglia.
what is important in maintaining cell shape and integrity in a neuron
microtubules, neurofibrils
The middle primary brain vesicle, the mesencephalon, gives rise to which adult brain structure? cerebrum midbrain diencephalon medulla oblongata
midbrain
The brain stem consists of the ________. midbrain, medulla, and pons pons, medulla, cerebellum, and midbrain midbrain only cerebrum, pons, midbrain, and medulla
midbrain, medulla, and pons
If a person has a crush injury to the C3-C5 spinal segments, you would expect that he would have full range of motion in all extremities. would be in a coma. could walk without difficulty. might be unable to breathe on his own. would have difficulty chewing and moving the tongue.
might be unable to breathe on his own.
what do microglia do when they detect an injured neuron
migrate towards it and turn into macrophage that phagocytes' the the invading microorganisms or neuronal debris
what substances are moved in the retrograde direction
mostly organelles being returned to the cell body for degradation or recycling, also an important means of intracellular communication for advising the cell body of conditions at the axon terminals, for delivering to the cell body vesicles containing signal molecules
gray matter
mostly soma and short unmyelinated fibers
Which of the following types of neurons carry impulses away from the central nervous system (CNS)?
motor
Which of the following types of neurons carry impulses away from the central nervous system (CNS)? motor association sensory afferent
motor
Which of the choices below describes the ANS?
motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands
Which of the choices below describes the ANS? motor fibers that conduct nerve impulses from the CNS to skeletal muscles sensory and motor neurons that supply the digestive tract sensory neurons that convey information from somatic receptors in the head, body wall, and limbs and from receptors from the special senses of vision, hearing, taste, and smell to the CNS motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands
motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands
What is the function of the Vagus nerve?
motor impulses to heart & smooth muscles and glands in viscera.
What is the function of the Glosspharygeal nerve?
motor impulses to swallowing muscles & salivary glands.
Nerve cells (neurons) that control peripheral effectors are known as __________. motor neurons peripheral neurons axons afferent fibers
motor neurons
Which of the following best explains diffusion?
movement of molecules from an area of high concentration to an area of low concentration
Complete the following sentence. The operation of the ATPase pump __________.
moves 3 to the ECF and 2 to the cytoplasm
A distinction about the flexor reflex is that it __________. prevents a muscle from overstretching moves a limb away from a painful stimulus prevents a muscle from generating excessive tension is an example of a monosynaptic reflex
moves a limb away from a painful stimulus
The flexor reflex usually depends on cranial neurons. moves a limb away from a painful stimulus. is an example of a monosynaptic reflex. prevents a muscle from overstretching. prevents a muscle from generating damaging tension.
moves a limb away from a painful stimulus.
Which of the following diseases is directly related to demyelination?
multiple sclerosis
Most CNS neurons fall into which structural category? anaxonic unipolar bipolar multipolar
multipolar
Neural circuits occur in all of these patterns except __________. multipolar divergent convergent reverberating
multipolar
Which of the following is NOT a functional classification of neurons?
multipolar
Which of the following is NOT a functional classification of neurons? multipolar efferent sensory interneurons
multipolar
Neurons that have several dendrites and a single axon are called bipolar. unipolar. multipolar. anaxonic. tripolar.
multipolar.
Recognized neuronal circuit patterns include all of the following, except parallel processing. reverberating. convergent. divergent. multipolar.
multipolar.
The most abundant class of neuron in the central nervous system is pseudopolar. multipolar. bipolar. unipolar. anaxonic.
multipolar.
What does the somatic nervous system innervate?
muscle
Saltatory propagation occurs in _________ axons, in which action potentials _________. Select the best answer. myelinated; move from one node of Ranvier to another unmyelinated; move from one node of Ranvier to another unmyelinated; spread by depolarizing the adjacent region of the axon membrane myelinated; move continuously along the axon toward the axon hillock
myelinated; move from one node of Ranvier to another
what do cervical nerves control and how many?
neck shoulders arms hands 8
In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment? The interior is ________.
negatively charged and contains less sodium
In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment? The interior is ________. negatively charged and contains more sodium negatively charged and contains less sodium positively charged and contains more sodium positively charged and contains less sodium
negatively charged and contains less sodium
Each of the following is an example of a neuroeffector junction, except the junction between a neuron and a(n) smooth muscle cell. exocrine gland cell. skeletal muscle cell. nerve cell. endocrine gland cell.
nerve cell
Neurons
nerve cell specialized to transmit messages
The gray horns of the spinal cord contain mainly nerve cell bodies. funiculi. columns. nerve tracts. meninges.
nerve cell bodies.
what is any long axon called
nerve fibre
the 12 cranial nerves labeled
nerves labeled
what are exceptions to the amitotic rule
olfactory epithelium and hippocampal regions contain stem cells that can produce new neurons throughout life
In multiple sclerosis, the cells that are the target of an autoimmune attack are the _________. neurons muscle cells Schwann cells oligodendrocytes
oligodendrocytes
Schwann cells are functionally similar to ________.
oligodendrocytes
Schwann cells are functionally similar to ________. ependymal cells oligodendrocytes astrocytes microglia
oligodendrocytes
Which of the following types of glial cells produces the myelin sheaths that insulate axons, or nerve fibers, in the central nervous system (CNS)?
oligodendrocytes
Which of the following types of glial cells produces the myelin sheaths that insulate axons, or nerve fibers, in the central nervous system (CNS)? ependymal cells astrocytes microglia oligodendrocytes
oligodendrocytes
what cells form myelin sheaths in the CNS
oligodendrocytes
The myelin sheath that covers many CNS axons is formed by ependymal cells. astrocytes. microglia. satellite cells. oligodendrocytes.
oligodendrocytes.
contralateral *** not on test #5
on or relating to the opposite side (of the body) *** not on test #5
ipsilateral *** not on test #4
on or relating to the same side (of the body) *** not on test #4
how many axons does each neuron have
one but may have occasional branches
which part of the sensory neurons acts as an impulse receptor sites
only the most distal part
Gated ion channels
open and close because of some sort of stimulus, change permeability
Ligand-gated
open or close in response to ligand such as ACh binding to receptor protein
Voltage-gated
open or close in response to small voltage changes across the cell membrane
If extracellular Ca2+ concentration decreases- Na+ gates ____ and membrane ______
open, depolarizes
What are some examples of molecules and organelles moved along an axon toward its cell body?
organelles to be degraded, signal molecules, viruses, and bacterial toxins
Which of these is not one of the essential components of a reflex arc? output to upper motor neuron integration process in the CNS output to a peripheral effector receptor activation
output to upper motor neuron
When information is delivered within the CNS simultaneously by different parts of the neural pathway, the process is called ________ processing.
parallel
An individual accidentally transected the spinal cord between T1 and L1. This would result in ________. hemiplegia paraplegia spinal shock only quadriplegia
paraplegia
Which branch of the peripheral nervous system is most active during rest?
parasympathetic
caudate nucleus *** not on test #10
part of the basal ganglia, which controls voluntary behavior. *** not on test #10
Satellite cells
protect neuron cell bodies
what is the purpose of myelin
protects and electrically insulates fibres and it increases the speed of transmission of nerve impulses
function of blood-ganglia barrier
provide homeostasis of the fluid surrounding peripheral nerve cell bodies
Which of the following is not a function of astrocytes?
provide the defense for the CNS
Which of the following is not a function of astrocytes? control the chemical environment around neurons guide the migration of young neurons, synapse formation, and helping to determine capillary permeability provide the defense for the CNS support and brace neurons anchor neurons to blood vessels
provide the defense for the CNS
Neuroglia/Glia Cells
support cells of the CNS
Satellite cells and Schwann cells
supporting cells of the PNS
what are the 2 principle types of cells hat make up nervous tissue
supporting cells- neuroglia, neurons
Which of the following hypothalamic control centers would you predict is the LEAST important for survival? suprachiasmatic nucleus autonomic control center temperature control center thirst center
suprachiasmatic nucleus
Which brain nucleus is the body's "biological clock"? suprachiastmatic nucleus subthalamic nucleus dorsomedial nucleus lentiform nucleus
suprachiastmatic nucleus
what do schwann cells do
surround and form myelin sheaths around larger nerve fibres in PNS, functionally similar to oligodendrocytes
Schwann cells
surround fibers of the PNS and produce myelin sheaths. Vital to nerve regeneration
connective tissue sheathes
surround individual neurons, groups of neurons, and whole nerves
Satellite cells
surround neuron cell bodies in the PNS, function largely unknown
where are satellite cells located
surround neuron cell bodies located in PNS, same functions as astrocytes
Which general aspect of the autonomic nervous system increases cardiac output?
sympathetic
The __________ nervous system controls glandular secretion. sympathetic parasympathetic sympathetic and parasympathetic afferent
sympathetic and parasympathetic
what are the 2 subdivisions of the ANS
sympathetic division, parasympathetic division
Postganglionic fibers of the autonomic nervous system that innervate internal organs do not rejoin the spinal nerve but form sympathetic nerves. dorsal rami. gray rami. white rami. ventral rami.
sympathetic nerves.
The two branches of the autonomic nervous system are the __________ and __________.
sympathetic; parasympathetic
An impulse from one nerve cell is communicated to another nerve cell via the ________.
synapse
The site of intercellular communication between a neuron and another cell is the hillock. synaptic terminals. telodendria. synapse. collateral.
synapse.
Which of the following blocks voltage-gated sodium channels?
tetrodotoxin and lidocaine
During an epileptic seizure, the triggering of convulsions would not directly involve the uncontrolled activity of neurons located in the ______. pyramidal tracts primary motor cortex thalamus medulla oblongata
thalamus
Second-order neurons of both the specific and nonspecific ascending pathways terminate in the ________. medulla thalamus somatosensory cortex spinal cord
thalamus
Which part of the brain is considered the "gateway" to the cerebral cortex? thalamus hypothalamus mesencephalon pons
thalamus
Gap junctions
that allow graded current to flow between adjacent cells
Define Diencephalon:
the "between" brain; parts of the brain between cerebral hemispheres and the midbrain.
proprioception
the ability of the brain to know the positions of its body parts at all times
At a chemical synapse, the intensity of the stimulus is coded by
the amount of neurotransmitter released and the amount of calcium that enters the axon terminal
At a chemical synapse, the intensity of the stimulus is coded by _______.
the amount of neurotransmitter released and the amount of calcium that enters the axon terminal
When magnesium was added to the extracellular solution,
the amount of neurotransmitter released decreased
When magnesium was added to the extracellular solution, _______.
the amount of neurotransmitter released decreased
broca's area
the area in the frontal lobe, usually in one hemisphere, just anterior to the motor cortex that controls motor speech
the primary motor area
the area of the cerebral cortex that lies in the pre-central gyri & controls voluntary muscles
major parts of the brain are___
the brainstem, cerebellum, cerebrum, diencephalon are the___
lateral ventricles
the cavities within each cerebral hemisphere separated by the Septum Pellucidum ( 1 )
cervical nerve plexus C! / C4
the cervical nerves that lie & supply the muscles of the neck & skin
Sensory transduction is defined as
the conversion of a stimulus to a change in membrane potential
longitudinal fissure
the deep groove that separates the left & right hemispheres
Which criterion is used to functionally classify neurons?
the direction in which the nerve impulse travels relative to the central nervous system
Which criterion is used to functionally classify neurons? the number of processes extending from the cell body neuron whether the nerve fibers are myelinated or unmyelinated the direction in which the nerve impulse travels relative to the central nervous system whether the neurons are found within the CNS or the PNS
the direction in which the nerve impulse travels relative to the central nervous system
Cell bodies of the sensory neurons of the spinal nerves are located in ________. sympathetic ganglia the thalamus the dorsal root ganglia of the spinal cord the ventral root ganglia of the spinal cord
the dorsal root ganglia of the spinal cord
The subdural space lies between the arachnoid mater and the pia mater. the endosteum and the periosteum. the pia mater and the subarachnoid space. the dura mater and the arachnoid mater. the pia mater and the dura mater.
the dura mater and the arachnoid mater
Imagine you changed the concentration of K+ outside a neuron such that the resting membrane potential changed to -80 mV (from the normal resting value of -70 mV). What have you changed?
the electrical gradient for K+ and the concentration gradient for K+
dura mater
the outermost, toughest layer of the three meninges covering the brain and spinal cord ( 15 )
If the sodium-potassium pumps in the plasma membrane fail to function, all of the following occur, except the membrane will slowly lose its capacity to generate action potentials. the intracellular concentration of sodium ions will increase. the neuron will slowly depolarize. the inside of the membrane will have a resting potential that is more positive than normal. the intracellular concentration of potassium ions will ncrease.
the intracellular concentration of potassium ions will increase.
The time interval for conduction would be shortest with
the largest and most heavily myelinated axons
The time interval for conduction would be shortest with,
the largest and most heavily myelinated axons
cerebral cortex
the layer of gray matter that makes up the outermost portion of the cerebrum, making up 75% of all neuron in the nervous system
What are the cerebral hemispheres?
the left and right halves of the cerebrum.
cerebrospinal fluid
the liquid secreted by choroid plexus that circulates in spaces in the brain, in subarachnoid spaces of meninges, ventricles & central canal; Cushions, brings in nutrients, and helps maintain stable ion concentration in CNS
parietal lobe
the lobe of the brain that Interprets sensations such as pain, pressure, touch ,hot and cold. (green area)
A second nerve impulse cannot be generated until ________.
the membrane potential has been reestablished
A second nerve impulse cannot be generated until ________. the Na ions have been pumped back into the cell proteins have been resynthesized the membrane potential has been reestablished all sodium gates are closed
the membrane potential has been reestablished
Which stimulus was at or above threshold?
the moderate and strong stimuli
If the axon terminal of a motor neuron suddenly became permeable to calcium ion, neurotransmitter release will be blocked. the motor end plate will be hyperpolarized. the motor end plate will be depolarized. the neuron will become unable to stimulate the muscle cell. the neuron will fire an action potential.
the motor end plate will be depolarized.
Saltatory conduction is made possible by ________.
the myelin sheath
third ventricle
the narrow space at the midline of the brain beneath the corpus callosum & filled with CSF ( 3 )
brachial plexus nerves C5 / T1
the nerves that supply ulnar, radial, & axillary nerves
In a myelinated axon, how do the nodes of Ranvier differ from other segments of the same axon?
the nodes are more permeable to ions
Which criterion is used to structurally classify neurons?
the number of processes extending from their cell body
Acetylcholine binds to its receptor in the sarcolemma and triggers __________.
the opening of ligand-gated cation channels
The repolarization phase of an action potential results from __________.
the opening of voltage-gated K+ channels
A neuron that receives neurotransmitter from another neuron is called the postsynaptic neuron. an oligodendrocyte. an interneuron. the motor neuron. the presynaptic neuron.
the postsynaptic neuron.
If a signal from a sending neuron makes the receiving neuron more negative inside,
the receiving neuron is less likely to generate an action potential.
If a signal from a sending neuron makes the receiving neuron more negative inside, the receiving neuron is less likely to generate an action potential. the sending neuron becomes more negative inside. the sending neuron becomes more positive inside. the receiving neuron is more likely to generate an action potential. the receiving neuron immediately generates an action potential.
the receiving neuron is less likely to generate an action potential.
The frequency of action potentials is
the reciprocal of the interspike interval, and measured in Herz
what are Nissl bodies
the rough ER in a neuron
In this activity, the stimulus voltage used was
the same for all of the axons and suprathreshold for all of the axons
In this activity, the stimulus voltage used was _______.
the same for all of the axons and suprathreshold for all of the axons
sulci
the shallow grooves located on the cerebral cortex, between the gyri
In a neuron, sodium and potassium concentrations are maintained by the sodium-potassium exchange pump such that __________.
the sodium concentration is higher outside the cell than inside the cell and the potassium concentration is higher inside the cell than outside the cell.
Which of the following allows us to consciously control our skeletal muscles?
the somatic nervous system
Which of the following allows us to consciously control our skeletal muscles? the afferent division of the nervous system the somatic nervous system the sympathetic division of the autonomic nervous system the parasympathetic division of the autonomic nervous system
the somatic nervous system
subarachnoid space
the space between the pia mater & the arachnoid membrane filled with CSF. ( 13 )
During the relative refractory period
the stimulus must be above threshold to generate action potential
What is the electrochemical gradient of an ion?
the sum of the electrical and chemical gradients for that ion
What is the electrochemical gradient of an ion?
the sum of the electrical and concentration gradients for that ion
Sympathetic preganglionic cell bodies are located in the __________ and __________ regions of the spinal cord.
thoracic; lumbar
The minimum voltage that is required to generate an action potential is called the _______.
threshold voltage
The minimum voltage that is required to generate and action potential is called the
threshold voltage
integration
to process and interpret sensory input and decide if an action is needed
Which of the following is NOT a function of the myelin sheath?
to recapture and recycle released neurotransmitters
Potential difference
unequal distribution of charge exists between the immediate inside and immediate outside of the plasma membrane: -70 to -90 mV
In a(n) ________ neuron, the dendrites and axon are continuous or fused. unipolar interneuron anaxonic bipolar multipolar
unipolar
Neurons in which dendritic and axonal processes are continuous and the soma lies off to one side are called tripolar. multipolar. bipolar. unipolar. anaxonic.
unipolar.
Sensory neurons of the PNS are bipolar. unipolar. anaxonic. multipolar. tripolar.
unipolar.
Gray matter
unmyelinated axons, cell bodies, dendrites, neuroglia. Integrative functions
Gray matter
unmyelinated fibers (mainly cell bodies)
Spastic paralysis suggests involvement of the ________. spinal nerve roots lower motor neurons neuromotor junction upper motor neurons
upper motor neurons
frontal lobes of the brain
used for reasoning, emotions, judgement, and voluntary movements. (blue area)
what is in the soma/perikaryon
usual organelles
nerve fiber
usually refers to axons
The ________ innervates the ventrolateral body surface, structures in the body wall, and the limbs. ventral ramus white rami communicantes gray rami communicantes dorsal ramus dermatomes
ventral ramus
Nerve tracts or fasciculi make up the central canal. gray commissures. posterior gray horns. white columns. anterior gray horns.
white columns.
The preganglionic fibers that connect a spinal nerve with an autonomic ganglion in the thoracic and lumbar region of the spinal cord and carries visceral motor fibers that are myelinated form the dermatomes. ventral ramus. gray rami communicantes. dorsal ramus. white rami communicantes.
white rami communicantes.
what is a myelin sheath
whitish fatty segmented sheath that covers nerve fibres long or large in diametre
neuron
whole nerve cell
Most CNS neurons lack centrioles. This observation explains the ability of neurons to generate an action potential. the ability of neurons to communicate with each other. the ability of neurons to produce a resting potential. why CNS neurons grow such long axons. why CNS neurons cannot divide to regenerate damaged tissue.
why CNS neurons cannot divide to regenerate damaged tissue.
Which of the following is not true about a positive Babinski reflex? flaring of the toes when the sole is stroked a sign of injury to descending spinal tracts normal in newborns why you close your eyes when you sneeze abnormal in adults
why you close your eyes when you sneeze
If an increase in extracellular potassium depolarizes a neuron, which of the following would be correct?
would change the membrane potential to a less negative value.
what do oligodendrocytes do
wrap processes tightly around fibres producing insulating coverings called myeline sheaths
is the functional and anatomical organization of sensory processing networks hierarchical?
yes, the lower the neuron on the spine, the lower the order, the head has a 3rd order neuron where as the sacral region has a 1st order neuron
How are spinal nerves named? Give an example:
~ According to level where they arise. - Ex: C5 - arises from cord beneath 5th cervical vertebra.
Where is the cerebrum's primary somatic motor area? What is controlled from this area?
~ Precentral Gyrus - mechanisms controlling voluntary movement
What can produce a synaptic change and what does that change facilitate?
~ Repeated impulses over a neuronal circuit. - The change facilitaes (in theory): 1) an increase in the number of presynaptic axon terminals or 2) an increase in the number of receptor proteins in the postsynaptic neuron's membrane.
What are 2 types of memory and what is the difference between the two?
~ Short term and long term memory. - Short term memory involves the storage of information for a few seconds to a few minutes. - Long term memory involves the storage of information for days to years.
What is cerebral palsy and what are some of its causes?
~ permanant, non-progressive damage to motor control areas of the brain. - Possible causes: prenatal infecctions; mechanical trauma to the head beforem during, or after birth; reduced oxygen supply.