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PHYSIOLOGY SEMESTER 2 > Lecture 2-CNS organization > Flashcards

Lecture 2-CNS organization Flashcards

(65 cards)

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1
Q

what does the CNS include

A

brain and spinal cord

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2
Q

what are the main roles of the brain (CNS)

A

sorts through and properly routes incoming sensory info
initiates, controls, and coordinates most muscular activity except simple reflexes
site of origin of 12 cranial nerve pairs (3,7,9,10)

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3
Q

what are the general functional categories of the brain

A

sensory
motor
cognitive

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4
Q

what are the roles of the spinal cord in the CNS

A

first CNS structure encountered by most incoming sensory info except sensory fibers in cranial nerves
last relay station for most motor info except ANS motor fibers
site of coordination of most reflex arcs

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5
Q

what is the PNS made up of

A

transmission pathways carrying info between the CNS and external/internal environments

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6
Q

what does the PNS include

A 
cranial nerves (12 pairs)
spinal nerves (31 pairs)
sensory receptors in the skin and wall of the gut as well as in tendons and skeletal muscles
motor end plates between motor neurons and skeletal muscle fibers
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7
Q

what does the ANS innervate

A

smooth muscle and glands (viscera)

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8
Q

what is another name for the sympathetic branch of the ANS

A

thoracolumbar

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9
Q

what is another name for the parasympathetic system of the ANS

A

craniosacral

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10
Q

define nucleus

A

aggregation of dendrites and nerve cell bodies in the CNS

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11
Q

define ganglion

A

aggregation of dendrites and nerve cell bodies in the PNS

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12
Q

define nerve

A

bundle of fibers (axons) in the PNS

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13
Q

define tract

A

bundle of fibers (axons) in the CNS

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14
Q

define commissure

A

tract in the CNS that crosses from one side to the other

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15
Q

what is the difference between dendrites and axon

A

dendrites are the receptive unit and axon is the conductive unit

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16
Q

define cell body

A

part of a neuron that encloses the nucleus and other organelles necessary to maintain and repair the neuron

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17
Q

define dendrites

A

branches off the cell body that carry info to the cell body

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18
Q

what are characteristics of dendrites

A

usually several to many dendrites per neuron
relatively short, especially compared to the axon
often branched
have receptors for neurotransmitters
conduct local potentials

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19
Q

define axon

A

part of the neuron that carries info to another neuron or muscle cell

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20
Q

what are characteristics of axons

A 
usually relatively long
single (one per neuron)
conducts AP (nerve impulse)
release neurotransmitter
axon ends in short branches (telodendria)
may have collateral branches
cell membrane (axolemma)
cytoplasm (axoplasm)
covered by a neurolemma
contains mitochondria, neurofilaments, and neurotubules
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21
Q

define telodendria

A

short branched processes that axons end in

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22
Q

what are the endings that telodendria give off

A

terminal bouton

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23
Q

what are the synaptic vesicles that are contained by terminal boutons filled with?

A

neurotransmitters

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24
Q

what is the only part of a neuron that is ever myelinated

A

axon

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25
what are the 2 major branches of rami
ventral and dorsal
26
what do white rams communicants carry
myelinated preganglionic fibers
27
what do gray rams communicants carry
unmyelinated postganglionic fibers back to spinal nerve
28
what are paravertebral ganglia the site of
site of cell bodies of postganglionic sympathetic nerves site of synapses between preganglionic myelinated sympathetic neurons and postganglionic non-myelinated sympathetic neurons
29
define splanchnic nerve
nerve supplying viscera
30
where are pre vertebral ganglion typically found
anterior to abdominal aorta
31
what are pre vertebral ganglion the site of
site of synapses between preganglionic myelinated sympathetic neurons and postganglionic non-myelinated neurons
32
define reflex arc
pathway that leaves from and returns to the CNS. consists minimally of a sensory pathway and a motor pathway
33
what do somatic afferent pathways carry
sensation from non-visceral structures such as the skin and skeletal muscle
34
what do visceral (splanchnic) afferent pathways carry
sensations from viscera
35
what do somatic efferent pathways carry
motor signals to skeletal muscles
36
what do visceral (splanchnic) motor pathways carry
motor signals to smooth or cardiac muscles
37
what are the components of a synapse
presynaptic membrane synaptic cleft postsynaptic membrane
38
what are presynaptic membranes of a synapse associated with
synaptic vesicles filled with neurotransmitters
39
what are postsynaptic membranes of a synapse associated with
receptors for neurotransmitters
40
define monosynaptic pathways
pathways consisting only of afferent neurons and efferent neurons. each pathway has a single synapse
41
define polysynaptic pathways
pathways that include interneurons as well as afferent and efferent neurons. each pathway has multiple synapses
42
what are the components of the somatosensory axis
``` peripheral receptors afferent neurons spinal cord or brainstem reticular substance (medulla, pons, mesencephalon) cerebellum thalamus somesthetic areas of cerebral cortex ```
43
where do primary afferent neurons synapse
synapse in the posterior horns of spinal cord or sensory nuclei in the brain
44
where do secondary afferent neurons synapse
synapse in the thalamus
45
where do tertiary afferent neurons synapse
synapse in the somesthetic areas of cerebral cortex
46
what does the skeletal motor nerve axis include
motor cortex of cerebrum efferent pathways made up of upper motor neurons extending from cortical areas to the anterior horns of the spinal cord & alpha motor neurons (lower motor neurons) extending to the skeletal muscles effectors (skeletal msucles)
47
what are the processing areas of the skeletal motor nerve axis
basal nuclei (ganglia) in the telencephalon (putamen, globus pallidus, subthalamic nuclei) thalamus in the diencephalon spinal cord reflexes
48
what is acetylcholine secreted by
pyramidal cells some neurons in the basal nuclei alpha motor neurons preganglionic neurons of ANS postganglionic neurons of the parasympathetic system some postganglionic neurons of the sympathetic system
49
what is norepinephrine secreted by
many neurons located in the brain stem and hypothalamus some neurons located in the pons most postganglionic neurons of the sympathetic system
50
what is dopamine secreted by
most neurons originating in the substantial nigra
51
what is glycine secreted by
synapses in the spinal cord
52
what is GABA secreted by
many areas in the spinal cord and cerebral cortex
53
what is glutamate secreted by
many sensory pathways entering the CNS | many areas of cerebral cortex
54
define electrotonic conduction
direct spread of electrical current by ion conduction in the dendritic fluids without generating an action potential
55
what dendritical characteristics result in electronic conduction
few voltage-gated sodium channels in dendritic membranes | thresholds too high for action potentials to occur
56
what does the firing rate depend on
the normal excitatory rate and on the changes in the excitatory rate due to superimposition of additional excitatory or inhibitory signals
57
define synaptic delay
the time it takes to transmit a signal from a presynaptic neuron to a postsynaptic neuron
58
what does synaptic delay depend on
time it takes to release the neurotransmitter from the presynaptic neuron time it takes for the neurotransmitter to diffuse across the synaptic cleft how the neurotransmitter acts on the postsynaptic membrane the time it takes for the receptor to increase membrane permeability time it takes for the inward diffusion of sodium ions
59
what are the 2 sources of blood supply to the brain
vertebral arteries and internal carotids
60
what do basillar arteries give off
cerebellar arteries and then divide into 2 posterior cerebral arteries
61
define internal carotids
terminal branches of the common carotids
62
how do internal carotids enter the cranial cavity
through carotid canal in temporal bone
63
where do the vertebral arteries unite
caudal border of pons to form basilar arteries
64
what are the components of the circle of willis
``` posterior cerebral arteries posterior communicating arteries internal carotids anterior cerebral arteries anterior communicating artery (unpaired) ```
65
what do the posterior communicating arteries connect
connect the posterior cerebral arteries to the internal carotids

PHYSIOLOGY SEMESTER 2 (20 decks)

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