General A&P Nervous System
nervous system
CNS and PNS
Which of the cell types shown is most associated with the production and flow of cerebrospinal fluid (CSF)
D
Destruction of which of the neuroglia cell types leads to the disease multiple sclerosis (MS)
A
Which of the neuroglial cell types shown form myelin sheaths within the CNS?
A
movement through a neuron
Dendrite; cell body; axon hillock; axon; postsynaptic membrane
Parts of the Neuron
Dendrites, cell body, nucleus, chromatophilic substance, axon hillock, initial segment of axon, axon, Schwann cell, myelin sheath gap, axon terminals
Exteroceptor
Sensitive to stimuli arising outside of the body
Proprioceptor
Sensitive to stimuli associated with body movements (muscle spindle is responsive to muscle stretch)
Cranial Nerve II, 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
Motor Integration
Sensory input, integration, motor output
Which of these statements is NOT correct regarding our limbic system? - Your amygdala judges facial expressions for danger - Emotional states can alter our blood pressure - Sights often create strong emotiona responses - the cingulate gyrus helps you express your emotional state
Sights often create strong emotional responses
Which organ receives major input from the sympathetic, but not parasympathetic, division?
Skin
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.
On average, the resting membrane potential is -70mV. 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.
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
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.
Perpheral Nervous System (PNS)
The network of neurons outside the CNS
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 hyper polarize the axon membrane
Which of the following is NOT a characteristic of neurons? - They have an exceptionally high metabolic rate - They have extreme longevity. - They are mitotic - They conduct impulses
They are mitotic
True or False In myelinated axons the voltage-regulated sodium channels are concentrated at the nodes of ranvier
True
True or False Most blood vessels are innervated by the sympathetic division alone.
True
True or False The blood brain barrier is the protective mechanism that helps maintain the brain's stable environment
True
The period after an initial stimulus when a neuron is not sensitive to another stimulus is the ________.
absolute refractory period
Which of the following mechanisms is most significant in returning the ion concentrations to the resting sate (from point D to point E)?
active transport by the Na+-K+ pump
What condition will increase the diffusion of molecules, such as neurotransmitters?
an increase in the amount of neurotransmitter exocytized by the presynaptic axon
Which protective covering of the brain provides passageways for cerebrospinal fluid (CSF) to drain into the superior sagittal sinus?
arachnoid mater
The vital centers for the control of heart rate, respiration, and blood pressure are located in the ________.
medulla oblongata
If the membrane of a postsynaptic dendrite is setting up a graded potential, what must have happened after neurotransmitter was released by the presynaptic terminal?
bound at postsynaptic receptors to open postsynaptic ion channels
The term central nervous system refers to the ________.
brain and spinal cord
Which part of the brain is the "executive suite" that controls conscious brain activity?
cerebral cortex
The Phrenic nerve is a branch from the
cervical plexus
Which reflex has a contralateral component? -crossed-extensor -flexor -tendon -stretch
crossed- extensor
Which of the following is not associated with the parasympathetic division of the autonomic nervous system (ANS)
emergency action
Which of the following best describes the cerebrum?
executive suite
By which method does the structure at B release neurotransmitter?
exocytosis
Collections of nerve cell bodies outside the central nervous system are called ________.
ganglia
Which of the following is responsible for the overall integration of the autonomic nervous system? -hypothalamus -frontal lobe of the cerebral cortex -reticular formation -brain stem
hypothalamus
Loss of function in the enzyme acetylcholine esterase would result in which of the following?
inability to destroy and remove acetylcholine from the synaptic cleft
A mugger steals your wallet causing all of the following to happen EXCEPT -increased metabolic rate -inability to read close-up print -increased rate and force of heartbeat -increased glucose uptake to the liver from blood
increased gluscose uptake to the liver from the blood
Where do most action potentials originate?
initial segment
Which of the following is NOT required for a reflex arc? -Interneurons -Receptors -Motor neurons -Sensory neurons
interneurons (integration point for reflexes, but not necessary)
Let's consider a scenario in which the resting membrane potential changes from −70 mV to +70 mV, but the concentrations of all ions in the intracellular and extracellular fluids are unchanged. Predict how this change in membrane potential affects the movement of Na+. The electrical gradient for Na+ would tend to move Na+ __________ while the chemical gradient for Na+ would tend to move Na+ __________.
out; in
Which of the following choices best represents synaptic transmission?
presynaptic axon ot synapse to dendrite or postsynaptic cell body
Frontal lobe
primary (somatic) motor cortex; Motor speech (Broca's) area; Premotor cortex; Seat of intelligence, abstract reasoning
Parietal lobe
primary somatosensory cortex
Which of the following is mismatched? -gallbladder contracts to expel bile; parasympathetic -bronchiole dilation in lungs; sympathetic -promotes urination; sympathetic -penis ejaculation; sympathetic
promotes urination; sympathetic
Regions of a neuron
receptive region, Biosynthetic center and receptive region, impulsive generating and conducting region, impulse direction, secretory region
Simple spinal reflex arc
receptor, afferent neuron, integration center, efferent neuron, effector
which of the following is(are) involved with motor activity (either initiation or coordination)?
red nuclei
Which of the following is NOT a function of the hypothalamus? - regulate the thalamus - regulate food intake - regulate body temperature - regulate emotional responses
regulate the thalamus
Mechanoreceptor
respond to mechanical force such as pressure, vibrations, stretch, and touch.
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.
Which of the following is NOT a different between graded potentials and action potentials
the magnitude of action potentials decrease as the impulse travels further away from the start of the impulse while graded potentials do not decrease in magnitude
A second nerve impulse cannot be generated until ________.
the membrane potential has been reestablished
Somatic Nervous System (SNS)
the part of the peripheral nervous system that controls voluntary movement of skeletal muscles
A patient has an injury of the spine and is now suffering from a loss of motor function in his right arm. However, he still has normal sensory function in the arm. Based on this information it is likely that the patient has nervous tissue damage located at...
the ventral root located at one or more of the cervical vertebra
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.
Sodicum and potassium ions can diffuse across the plasma membranes of all cells because of the presence of what type of change?
Leak Channels
In which type of axon will velocity of action potential conduction be the fastest?
Myelinated axons with the largest diameter
The concentration of __ is higher outside than inside the cell.
Na+
The concentrations of which town ions are highest outside the cell?
Na+ and Cl-`
Which of the following correctly states the direction followed by the specified ions when their voltage-gated channels open?
Na+ ions move into the axon; K+ ions move out
Although it plays a role, it is not a primary determinant of the resting membrane potential
Na+ permeability
What prevents the Na+ and K+ gradients from dissipating
Na+-K+ ATPase (Na+-K+ pump)
Action potential events
1. Threshold stimulus Na+channels open 2. Na+ influx depolarization 3. Na+ channels close K+ channels open 4. K+ eflux Repolarization 5. hyper polarization K+ channels close
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
An action potential is regarded as an example of a positive feedback. Which of the following examples below best illustrates the positive feedback aspect of an action potential?
A threshold stimulus will cause the opening of voltage gated sodium ion channels that will cause further depolarizing stimulus. This stimulus will open still more voltage gated sodium ion channels.
Temporal lobe
Auditory area
Choose the FALSE statement about nerves: -Nerve axons are surrounded by a loose connective tissue layer called the endoneurium. -Nerves consist of parallel bundles of myelinated and non myelinated axons. -Nerves can carry only sensory information, only motor information, or a mixture of sensory and motor information. -Axons make up a majority of the matter in a nerve
Axons make up a majority of the matter in a nerve
At which point of the illustrated action potential would voltage-gated Na+ channels be mostly open but voltage-gated K+ channels be mostly closed?
B
Which of the cell types shown helps determine capillary permeability in the CNS?
B
Which of the receptor types shown here functions exclusively as a proprioceptor?
B
Which pathway(s) compose the autonomic nervous system?
B and C
In which area of the neuron is an action potential initially generated?
C
Which of the following membrane regions would have significant numbers of voltage-gated ion channels?
C and D
Which of these receptor types functions as an exteroceptor?
C, D, E
What type of conduction takes place in unmyelinated axons?
Continuous conduction
Which of the neuroglial cell types shown are found in the peripheral nervous system (PNS)?
E
True or False The ANS stimulates smooth muscles, skeletal muscles and glands, whereas the somatic nervous system innervates skeletal muscles only.
False
True or False the sympathetic and parasympathetic divisions of the ANS have the same effect on most body organ systems
False
True or False A dermatome represents the motor innervation of muscles in that area
False - Dermatomes represent sensory innervations of the underlying skin.
Insula
Gustatory (taste) area
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.
The concentration of __ is higher inside than outside the cell
K+
the membrane is more permeable to __
K+
The primary determinant of the resting membrane potential
K+ permeability
The resting membrane potential is maintained by Na+-K+ pumps that actively transport ___ into and __ out of the cell.
K+; Na+
Predict the possible effect of a drug that totally blocks the neurotransmitter receptor on the postsynaptic membrane. For example, curare is a neurotoxin used by several South American cultures. The primary effect of curare is that acetylcholine, a major neuromuscular neurotransmitter, cannot bind at its receptor because curare is blocking it. Predict the possible effects of curare on the postsynaptic membrane and muscle.
Local graded potential and action potential transmission is blocked, and there is no response by the postsynaptic cell, the muscle.
Which type of sensory receptor allows us to feel an insect landing on our skin?
Mechanoreceptor
Which statement best describes exocytosis?
Membrane organelles fuse with the membrane and release contents out of the cell.
The resting membrane potential of the cell
Membrane potential of -70 mV
The point at which there is no net movement of K+ into or out of the cell
Membrane potential of -90 mV
changes in membrane potential
More positive, more negative, largely unchanged
Are biogenic amine neurotransmitters such as dopamine considered to be proteins?
No, it simply means that dopamine has at least one anime functional group in its molecular structure
____ are receptors that can respond to painful stimuli
Nociceptors
What characterizes repolarization, the second phase of the action potential?
Once the membrane depolarizes to a peak value of +30 mV, it depolarized to its negative resting value of -70 mV
Membrane potential
Outside is positive; Inside is negative
signal transmission
Presynaptic axon; Ca+2 channels; mitochondrion; synaptic vesicles; bound neurotransmitter at postsynaptic receptor; synaptic cleft; neurotransmitter diffusing
The letter E would represent which of the following muscles during the knee-jerk reflex? -rectus femoris -soleus -biceps femoris -tibialis anterior
Rectus femoris
Which of the following is NOT one of the basic functions of the nervous system? -Generate direct, electrical signals -Release hormones into the bloodstream that travel around the systemic blood circulation to communicate with cells in multiple locations within the body - Integrate sensory input for decision making - Decode sensory information from the environment
Release hormones into the bloodstream that travel around the systemic blood circulation to communicate with cells in multiple locations within the body
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 (RMP)
Prozac belongs to a class of drugs known as selective serotonin reuptake inhibitors (SSRIs), which block the removal of serotonin from its receptor, thereby enhancing a patient's mood. What mechanism allows serotonin to remain on its receptors longer?
SSRIs inhibit the reuptake of serotonin back into the presynaptic neuron, which increases the level of serotonin in the synaptic cleft.
name the glial cell at F
Schwann cell
Which part of the CNS sorts almost all of the ascending sensory information?
Thalamus
Which of the following statements about the cerebellum is NOT correct? - Damage to the cerebellum could affect posture - the cerebellum has a cortex and homunculus, just like the motor cortex - The cerebellum generates conscious motor commands - The cerebellum plays a role maintaining your balance
The cerebellum generates conscious motor commands
Which cranial nerve innervates most of the visceral organs?
Vagus
synaptic cleft
Vesicle; neurotrasmitter; synaptic terminal; receptro for neurotrasnmitter; synaptic cleft; calcium channel
Occipital lobe
Visual area
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
Over 90% of all parasympathetic fibers are derived from the cranial nerve...
X (vagus)
IF the ventral root of a spinal nerve were cut, what would be the result in the tissue or region that nerve supplies?
a complete loss of voluntary movement
Which of the following does NOT describe the ANS? -involuntary nervous system -a system of motor neurons that innervates all muscle cells -a system of motor neurons that innervates smooth and cardiac muscle and glands -general visceral motor system
a system of motor neurons that innervates all muscle cells
What type of event is required for an action potential to be generated?
a threshold level depolarization
Which areas of this neuron would be classified as receptive regions?
both A and B
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 is the structure at A?
dendrite
An action potential is self-regenerating because __________.
depolarizing current established by the influx of Na+ flow down the axon and trigger an action potential at the next segment.
The blood-brain barrier is effective against
metabolic waste such as urea
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 following is not an autonomic nervous system (ANS) function?
skeletal muscle reflex
Which of the following best characterizes depolarization
small, consecutive steps of Na+ penetration into the axon along its length
What division of the nervous system is most specifically responsible for voluntary motor control?
somatic nervous system
Preparing the body for the "fight-or-flight" response is the role of the
sympathetic division
Secretions of the adrenal medulla act to supplement the effects of
sympathetic simulation
membrane potential
voltage across a membrane
The generation of an action potential in a neuron requires the presence what type of membrane channels?
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 toward the cell membrane and eventually release their contents.
voltage-gated membrane channels open and Ca+2 enters the cytoplasm, increasing intracellular calcium
Immediately after an action potential has peaked, which channels will open
voltage-gated potassium channels