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66 Cards in this Set
- Front
- Back
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What would be the effect of damage to the afferent division of the PNS? |
afferent= nerves that carry sensory info to brain and spinal cord
it would interfere with a person's ability to experience a variety of sensory stimuli |
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Are unipolar neurons in a tissue sample more likely to be sensory or motor neurons?
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sensory, most sensory neurons of the PNS are unipolar
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Which type of neuroglia would occur in larger-than-normal numbers in the brain tissue of a person with a CNS infection?
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microglial cells, they are phagocytic cells that occur in increased number in damaged and diseased areas of the CNS
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What effect would a chemical that blocks the sodium channels in neuron cell membranes have on a neuron's ability to depolarize?
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a neuron would not be able to depolarize
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What effect would decreasing the concentration of extracellular potassium ions have on the transmembrane potential of a neuron?
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more potassium would leave the cell, transmembrane potential would increase, it's called hyperpolarization
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Which of the following axons is myelinated: one that propogates APs at 50 m/s or one at 1m/s?
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50 m/s, myelinated axons propogate APs faster
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What effect would blocking voltage-regulated calcium channels at a cholinergic synapse have on synaptic communication?
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ACh would not be released from the presynaptic terminal and transmission across the synapse would cease
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One pathway in the CNS consists of 3 neurons, another of 5. If the neurons are all identical, which pathway will transmit impulses more rapidly?
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3, because of synaptic delay, the pathway with fewer neurons would be faster
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An ESPS depolarizes from -70 to -65 when the threshold is -60. Will an AP happen?
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no
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After the first ESPS depolarizes from -70 to -65, another identical one comes. The threshold is -60. Will an AP happen?
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yes
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If 2 ESPS occur simultaneously, which type of summation would occur?
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spatial summation (temporal is one after another)
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Damage to which root of a spinal nerve would interfere with motor function?
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the ventral root
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Where is the cerebrospinal fluid that surrounds the spinal cord located?
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the subarachnoid space
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A person with polio has lost the use of his leg muscles. In which area of his spinal cord would you expect the virus-infected motor neurons to be?
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It would be in the somatic motor neurons, located in the anterior gray horns of the spinal cord, where the cell bodies of these neurons are
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Which portion of the spinal cord would be affected by a disease that damages myelin sheaths?
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it would affect the columns of the spinal cord, which are made of bundles of myelinated axons
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What would happen if an interventricular foramen became blocked?
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the CSF would not flow from the lateral ventricle to the third ventricle, it would build up in the lateral ventricle, called hydrocephalus
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How would decreased diffusion across the arachnoid granulations affect the volume of cerebrospinal fluid in the ventricles?
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CSF could not diffuse back into the bloodstream, would build up in the ventricles, damage to the brain
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Many water-soluble molecules that are relatively abundant in the blood occur in small amounts or not at all in the extracellular fluid of the brain. Why?
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blood-brain barrier restricts & regulates movement of water-soluble molecules from the blood to the extracellular fluid of the brain
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Regulation by the nervous system provides
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swift but brief responses to stimuli
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The afferent division of the PNS
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brings sensory info to the CNS
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The part of the nervous system that controls voluntary contractions of skeletal muscles is the
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somatic nervous system
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Smooth muscle, cardiac muscle, and glands are among targets of the
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autonomic nervous system
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In the CNS, a neuron typically receives info from other neurons at its
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dendrites
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Phagocytic cells in neural tissue of the CNS are
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microglia
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The nerual cells responsible for the analysis of sensory inputs and coordination of motor outputs are
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interneurons
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Depolarization of a neuron cell membrane will shift the membrane potential toward
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0 mV
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The primary determinant of the resting membrane potential is
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the membrane permeability to potassium
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Receptors that bind ACh at the postsynaptic membrane are
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chemically regulated channels
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If the resting membrane potential is -70mV and the threshold is -55mV, a membrane potential of -60mV will
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make it easier to produce an action potential
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A graded potential
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decreases w/ distance from the point of stimulation, spreads passively because of local currents, and may involve either depolarization or hyperpolarization
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During an absolute refractory period, the membrane
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cannot respond to further stimulation
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A neuron exhibiting facilitation requires a ___ additional stimulus to trigger an AP
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smaller depolarizing
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What are the major components of the central nervous system?
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the brain and spinal cord
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What are the major components of the peripheral nervous system?
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all nerve fibers other than the brain and spinal cord, divided between efferent division ( somatic nervous system and autnomic nervous system) and afferent division ( receptors and sensory neurons)
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Which 2 types of neuroglia insulate neuron cell bodies and axons in the PNS from their surroundings?
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satellite cells and Schwann cells
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What 3 functional groups of neurons are found in the nervous system? What is the function of each type of neuron?
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sensory neurons-transmit impulses from the PNS to the CNS
motor neurons-transmit impulses from the CNS to peripheral effectors interneurons-analyze sensory inputs and coordination of motor outputs |
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Why can't most neurons in the CNS be replaced when they are lost to injury or disease?
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neurons lack centrioles so they can't divide and replace themselves
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What is the difference between anterograde flow and retrograde flow?
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anterograde is movement of products from cell body to synaptic knobs
retrograde is movement toward the cell body |
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State the all-or-none principle of action potentials.
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if a stimulation depolarized to the threshold an AP will be produced, the strength of the AP will not change regardless of the degree of stimulation above threshold
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Describe the steps involved in the generation of an action potential.
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1-membrane depolarizes to threshold
2-voltage-regulated Na channels open, membrane rapidly depolarizes 3-Na channels inactivated, K channels activated, normal permeability returns |
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What is the difference between saltatory and continuous propogation?
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saltatory occurs in myelinated axons, the AP jumps from node to node
continuous occurs in unmyelinated axons, the AP travels in tiny steps |
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What are the functional differences between type A, B, and C fibers?
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A-largest diameter, myelinated, fastest transmission
B-smaller than As, myelinated, slower transmission C-smallest, unmyelinated, slowest transmission |
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Describe the steps that take place at a typical cholinergic synapse.
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1-AP arrives at synaptic knob, depolarizing it
2-calcium enters the knob triggering exocytosis of ACh 3-ACh binds to postsynaptic membrane and depolarizes the next neuron in the chain 4-ACh is removed by AChE |
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What is the difference between temporal summation and spatial summation?
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temporal summation is the addition of stimuli that arrive in rapid succession (single synapse, active repeatedly)
spatial summation is when simultaneous stimuli have a cumulate effect on the transmembrane potential (multiple synapses active simultaneously) |
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What factor would determine the maximum frequency of action potentials that could be conducted by an axon?
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the absolute refractory period, the membrane is not able to conduct an AP at this time, a new depolarization could not occur until after the refractory period had passed
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The ventral roots of each spinal segment
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control peripheral effectors and
contain the axons of somatic motor and visceral motor neurons |
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Spinal nerves are called mixed nerves because they
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contain sensory and motor fibers
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Which of the following statements is false concerning the gray matter of the spinal cord?
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the gray matter is primarily involved in relaying info to the brain
TRUE statements: -located in the interior of the spinal cord around the central canal -contains motor neurons -divided into regions called horns |
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What are the steps involved in a reflex?
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1-arrival of a stimulus and activation of receptor
2-activation of a sensory neuron 3-information processing 4-activation of a motor neuron 5-response by an effector |
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The synapsing of several neurons on the same postsynaptic neuron is called
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convergence
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The subarachnoid space contains
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cerebrospinal fluid
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Side-to-side movements of the spinal cord are prevented by the
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denticulate ligaments
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Ascending tracts
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carry sensory info to the brain
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If the anterior gray horns of the spinal cord were damaged, what type of control would be affected?
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motor control, because the cell bodies of spinal motor neurons are located in the anterior gray horns
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List all areas of the CNS where CSF is located.
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central canal, ventricles, subarachnoid space
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What are the functions of CSF?
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shock absorption, diffusion medium for dissolved gasses, nutrients, chemical messengers, & waste products
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Which of the following is the site of cerebrospinal fluid production and secretion?
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the choroid plexus
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The dural fold that divides the 2 cerebellar hemispheres is the
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falx cerebelli
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The primary purpose of the blood-brain barrier is to
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isolate neural tissue in the CNS from the general circulation
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The establishment of emotional states is a function of the
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limbic system
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The 2 cerebral hemispheres are functionally different, even though anatomically they appear the same. True or false?
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true
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What are the 3 important functions of CSF?
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1-cushioning neural structures
2-supporting the brain 3-transporting nutrients, chemical messengers, & waste products |
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Which 3 areas in the brain are not isolated from the general circulation by the blood-brain barrier?
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1-portions of the hypothalamus where the capillary endothelium is extremely permeable
2-capillaries in the pineal gland 3-capillaries at the choroid plexus |
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Briefly summarize the overall function of the cerebellum
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adjusting voluntary and involuntary motor activies based on the basis of sensory info and stored memories of previous experiences
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If symptoms characteristic of Parkinson's disease appear, which part of the mesencephalon is inhibited from secreting a neurotransmitter? Which neurotransmitter is it?
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the substantia nigra, which releases the nuerotransmitter dopamine at the basal nuclei
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What are the principal functional differences between the right and left hemispheres of the cerebrum?
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left- general interpretive and speech centers, language-based skills (reading, writing, speaking, performing analytical tasks, logical decision making)
right- analyzes sensory info and relates the body to the sensory environment, identification of familiar objects (touch, smell, sight, taste, feel), 3 dimensional relationships and emotional context |
