Anatomy Exam 3
how are neurons with several processes branching off the cell body, such as motor neurons and interneurons, structurally classified?
multipolar
Saltatory conduction is made possible by ________.
myelin sheath
The interior surface of a neuron's plasma membrane at resting membrane potential will have a ________.
negative charge and contains less sodium than oustside the cell
afferent or sensory neurons
neurons that send messages from the sense organs to the brain
In the central nervous system myelin is formed by
oligodendrocytes
Schwann cells are functionally similar to ________.
oligodendrocytes
A shallow groove or depressions between a gyrus on the surface of the cortex is called a ________.
sulcus
subdivisions of autonomic nervous system
sympathetic and parasympathetic
Which branch of the autonomic nervous system (ANS) mobilizes the body during extreme situations, such as rage or fear?
sympathetic division
Neurons either conduct action potentials along the length of their axons, or they remain at rest. This statement best describes ____.
the all-or-none response
sympathetic nervous system
the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations
parasympathetic nervous system
the division of the autonomic nervous system that calms the body, conserving its energy
somatic nervous system
the division of the peripheral nervous system that controls the body's skeletal muscles
autonomic nervous system
the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.
During the relative refractory period of an action potential, a larger than normal stimulus is needed to cause another action potential. This is due to the fact that ________.
the voltage gated potassium ion channels remain open long enough to hyperpolarize the axon membrane
function of myelin sheath
to protect the neuron, provide insulation, and increase the speed of impulse transmission
Function of neurotransmitters
to transmit nerve impulses across synapses
Axon diameter and degree of myelination determine nerve impulse conduction velocity T or F
true
Cerebrospinal fluid circulates within the ventricles of the brain and in the subarachnoid space. T or F
true
During depolarization, the inside of the neuron's membrane becomes less negative. T or F
true
In myelinated axons the voltage-regulated sodium channels are concentrated at the nodes of Ranvier.
true
Reflexes are rapid, automatic responses to stimuli that will produce the same effect every time. T or F
true
The adult spinal cord ends between the level L1 and L2 of the vertebral column. T or F
true
The main neurotransmitter of the sympathetic nervous system is Epinephrine (Adrenaline).
true
The sciatic nerve is the largest nerve of the body.
true
Which area of the spinal cord contains cell bodies of motor neurons leaving the spinal cord?
ventral horn
The interconnected fluid-filled cavities in the brain are called
ventricles
immediately after an action potential has peaked, which of the following channels will open?
voltage gated potassium channels
Which of the following is not a function of the autonomic nervous system?
innervation of skeletal muscle
Which of the following correctly describes a graded potential?
it can have amplitudes of various sizes
Which fissure separates the cerebral hemispheres?
longitudinal fissure
Vital centers for the control of heart rate, respiration, and blood pressure are located in the ________.
medulla oblongata
the brain and the spinal cord are protected and cushioned by three connective tissue membranes that are collectively called
meninges
Meningitis can be caused by infection of the central nervous system by bacteria. Which cells would be most responsible for removing the infection?
microglia
Describe the ANS
motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands
Mr. Warren has spinal cord damage that prevents nerve impulses from being carried from the CNS to muscles or glands. What specific type of neuron has been damaged?
motor neuron
function of synaptic vesicles
store neurotransmitters
Within the meninges, cerebrospinal fluid occupies the
subarachnoid space.
The outermost layer of the meninges is the ________ mater.
dura
Control of temperature, endocrine activity, and thirst are functions associated with the ________.
hypothalamus
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
How many pairs of cranial nerves branch from the surface of the brain?
12
Which of the following is correct sequence of events that correlates to the sequence of events of a nerve impulse? 1. the membrane becomes depolarized 2. sodium channels open and sodium ions diffuse inward 3. the membrane becomes repolarized 4. potassium channels open and potassium ions diffuse outward
2,1,4,3
how many pairs of spinal nerves emerge from the spinal cord?
31
Which of the following is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle? A) acetylcholine B) cholinesterase C) gamma aminobutyric acid D) norepinephrine
A) acetylcholine
When a neurotransmitter like GABA is acting in an inhibitory manner which of the following is likely a result of the GABA acting on the post synaptic cell? A) hyperpolarization of the postsynaptic cell membrane B) depolarization of the postsynaptic cell membrane C) influx of positively charged ions into the postsynaptic cell D) opening of chemically gated sodium channels
A) hyperpolarization of the postsynaptic cell membrane
Which of the following is not a function of astrocytes? A) guide the migration of young neurons, synapse formation, and helping to determine capillary permeability B) provide the defense for the CNS C) anchor neurons to blood vessels D) support and brace neurons
B) provide the defense for the CNS
Sally has a brain injury; she knows what she wants to say but can't vocalize the words. The part of her brain that deals with the ability to speak is the:
Broca's area
Select the correct statement regarding chemical synapses. A) Cells with gap junctions use chemical synapses. B) Neurotransmitter receptors are located on the axons terminals of cells. C) The synaptic cleft uses the action potential to transmit a chemical signal to the post synaptic cell. D) The release of neurotransmitter molecules gives cells the property of being electrically coupled.
C) The synaptic cleft uses the action potential to transmit a chemical signal to the post synaptic cell.
When a neurotransmitter like acetylcholine is acting in an excitatory manner which of the following is likely a result of the acetylcholine acting on the post synaptic cell?
Chemically gated sodium channels will open.
Which describes the ion concentrations inside and outside of a neuron? A) Sodium and potassium ions are both at higher concentration on the outside of the cell. B) The concentrations of sodium and potassium ions are both equal inside and outside of the cell. C) Sodium and potassium ions are both at higher concentration on the inside of the cell. D) The sodium ion concentration is higher on the outside of the cell and potassium ion concentration is higher on the inside of the cell. E) The sodium ion concentration is higher on the inside of the cell and potassium ion concentration is higher on the outside of the cell.
D) The sodium ion concentration is higher on the outside of the cell and potassium ion concentration is higher on the inside of the cell.
Which of the following is not characteristic of neurons? A) They have extreme longevity. B) They have an exceptionally high metabolic rate. C) They conduct impulses. D) They are mitotic.
D) They are mitotic.
Loss of function in the enzyme acetylcholinesterase would result in which of the following? A) stimulation of the production of acetylcholine B) amplify or enhance the effect of ACh C) inability to release acetylcholine D) inability to destroy and remove acetylcholine from the synaptic cleft
D) inability to destroy and remove acetylcholine from the synaptic cleft
Which of the following is NOT a type of neuroglia? A) Ependymal cell B) Microglial cell C) Oligodendrocyte D) Neuron E) Astrocyte
D) neuron
Which of the following lists parts of a reflex arc in the correct sequence? A) Effector, receptor, sensory neuron, motor neuron B) Receptor, motor neuron, sensory neuron, effector C) Effector, sensory neuron, receptor, motor neuron D) Receptor, effector, sensory neuron, motor neuron E) Receptor, sensory neuron, motor neuron, effector
E) Receptor, sensory neuron, motor neuron, effector
Interneurons are specialized to carry impulses from peripheral receptors into the brain or spinal cord. T or F
False
Nodes of Ranvier connect adjacent neurons. T or F
False
The arbor vitae is part of the cerebrum. T or F
False
efferent or motor neurons
Nerve cell that carries messages away from the central nervous system toward the muscles and glands
what is the name of cranial nerve III
Oculomotor
What cells form the myelin sheaths around nerve fibers in the PNS?
Schwann cells
function of synaptic terminals
Store and release neurotransmitters Helps regulate exocytosis of neurotransmitters Synapses w/ bipolar cells in photoreceptors
The depolarization phase of an action potential is punctuated by the closing of inactivation gates in the voltage gated sodium ion channels. what is not a consequence of the closing of inactivating gates
This allows for the efflux (diffusion out) of potassium ions, resulting in the repolarization of the cell.
function of axon hillock
To help determine if the action potential is strong enough to send
A synapse is the functional connection between two neurons. T or F
True
Astrocytes provide structural support in the nervous system. T or F
True
Cell bodies of motor neurons are located in the anterior horns of the spinal cord. T or F
True
If a post synaptic neuron is stimulated to threshold by spatial summation this implies that ________.
a presynaptic neuron is sending frequent EPSP
The period after an initial stimulus when a neuron is not sensitive to another stimulus is the ________. (ie, no other action potential may be produced)
absolute refractory period
which of the following is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle?
acetylcholine
Function of Nodes of Ranvier
allow an action potential to propagate quickly down an axon
Bacteria in the blood can be prevented entry to the fluids surrounding the brain. Which cells are most responsible for preventing bacteria from entering the fluids of the brain?
astrocytes
the concentration of ions in the chemical environment surrounding the neurons must be tightly regulated for neurons to function properly. what cell is responsible for this?
astrocytes
Control of temperature, endocrine activity, metabolism, and thirst are functions associated with the ________.
hypothalamus
function of cerebrospinal fluid
bathes the brain, acts as a shock absorber, transports nutrients, chemical messengers, and waste products.
Major Organs of the Central Nervous System
brain and spinal cord
The term central nervous system refers to the
brain and spinal cord
The term central nervous system refers to the ________.
brain and spinal cord
The midbrain, pons, and medulla oblongata are housed in the
brain stem
In the case of a subdural hematoma (blood accumulating beneath the dura) resulting from a blow to the head, blood accumulates between the
dura mater and arachnoid mater.
function of axon
carries nerve impulses away from the cell body
function of motor neurons
carry impulses from the CNS to effectors
Ganglia are collections of ________.
cell bodies
What are the two main divisions of the nervous system?
central and peripheral
The arbor vitae refers to ________.
cerebellar white matter
The brain area responsible for maintaining balance and coordinates movements is the _________..
cerebellum
The part of the brain that coordinates voluntary muscle movements is the
cerebellum
function of interneurons
connect sensory and motor neurons
function of cell body (soma)
contains the nucleus of the neuron
function of sensory neurons
deliver information to CNS
The cellular processes of neurons that provide receptive surfaces for input from other neurons are
dendrites
The ________ is a connective tissue wrapping around a single neuron fibers.
endoneurium
These cells in the CNS have cilia that move in order to circulate cerebrospinal fluid ________.
ependymal cells
What type of cells line the ventricles of the brain?
ependymal cells
All cranial nerves are mixed nerves.
false
Meningitis is the most accurate term for inflammation of neurons. T or F
false
The wrinkles on the cerebellum are called a gyrus.
false
Bipolar neurons are commonly ________.
found in the retina of the eye
Which ventricle is continuous with the central canal of the spinal cord?
fourth
Collections of nerve cell bodies outside the central nervous system are called ________.
ganglia
Ridges of tissue on the surface of the cerebral hemispheres are called ________.
gyri
Nervous control
hormonal control
Endocrine control
hormones; slow & long lasting
An inhibitory postsynaptic potential (IPSP) is associated with ________.
hyperpolarization
when a neurotransmitter like GABA is acting in an inhibitory manner what is a likely result of the GABA acting on the post synaptic cell?
hyperpolarization of the postsynaptic cell membrane
What division of the autonomic nervous system is often called the "rest-and-digest" division?
parasympathetic
Nerve impulses are sent to slow the heart's rate of contraction. The nerve fibers sending these signals will most likely belong to which division of the nervous system?
parasympathetic division
during repolarization, what ions are pumped out of the cell?
potassium
During an action potential, repolarization occurs as a result of
potassium ions diffusing to the outside of the cell membrane.
function of synaptic cleft
prevents nerve impulses from directly passing from one neuron to the next
function of nissl bodies
protein synthesis
function of dendrites
receive incoming signals from other neurons
what is the correct sequence in a typical reflex arc?
receptor, sensory neuron, integration center, motor neuron, effecter
function of neurilemma
regeneration of damaged axons
A special group of neurons in the gray matter of the brain stem that plays a role in consciousness and the awake/sleep cycle is the
reticular activating system (RAS)
A special group of neurons in the gray matter of the brain stem that plays a role in consciousness and the awake/sleep cycles is the ________.
reticular activating system (RAS)
nerve impulse transmission occurring along myelinated neurons are called
saltatory conduction
Cranial nerve II, the optic nerve sends nerve impulses to the brain carrying information about the things we see. These nerve fibers most likely belong to which division of the nervous system?
sensory (afferent) division
Nerve impulses leading to the brain carry information about cool temperatures on the skin. The nerve fibers sending these signals will most likely belong to which division of the nervous system?
sensory (afferent) division
During an action potential, depolarization occurs as a result of
sodium ions diffusing to the inside of the cell membrane
Nerve impulses leading to the skeletal muscle carry information to direct movement. The nerve fibers sending these signals will most likely belong to which division of the nervous system?
somatic nervous system
subdivisions of efferent division
somatic nervous system and autonomic nervous system
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
Masses of myelinated nerve fibers appear
white
Myelinated fibers (tracts) form ________ matter while unmyelinated fibers form ________ matter.
white; gray
