PNS and Spinal Cord

Question 1

what is the difference b/w afferent and efferent nerve fibers

Answer 1

afferent carries info in to CNS

efferent carries info out (exit )

Question 2

which horn of the spinal nerve is responsible for motor impulses

Answer 2

anterior/ventral horn (efferent fibers)

Question 3

which horn of the spinal nerve is responsible for sensory information

Answer 3

posterior/dosral horn (afferent)

Question 4

what are the 3 wrappings around peripheral nerves

Answer 4

epinuerium, perineurium, and endoneurium

Question 5

which nerve wrapping would surround the entire nerve fascicle and is continuous with the dura mater

Answer 5

epineurium

Question 6

which nerve wrapping is continuous with the arachnoid mater

Answer 6

perineurium

Question 7

major blood vessels in the brain exist b/w what 2 nerve wrappings

Answer 7

epineurium and perineurium

Question 8

this part of a myelinated axon contains many Na channels and is involved in signal propagation down an axon

Answer 8

Nodes of Ranvier

Question 9

what is the function of myelin

Answer 9

surrounds axons and insulates them which increases conduction velocity

Question 10

what is the difference b/w the 2 types of cells that produce myelin

Answer 10

Oligodendrocytes - only in CNS and 1 cell can myelinate many axons
Schwann cells - only in PNS and 1 cell only myelinate 1 axon

Question 11

Saltatory conduction

Answer 11

depolarization jumps from node to node reknewing at each node

Question 12

amplitude of signal conduction depends on ?

Answer 12

axon thickness

Question 13

velocity of signal conduction depends on ?

Answer 13

myelination

Question 14

what is a nociceptor

Answer 14

pain receptor

Question 15

what is the general organization of a nerve receptor

Answer 15

specific receptive area, synaptic area (sends signal to CNS)

Question 16

what is a receptive field

Answer 16

ability to convey information on the location of stimulus

Question 17

T/F sensory receptors have the ability to adapt over time

Answer 17

T - adaptation occurs at receptor level but CNS can regulate receptor sensitivity

Question 18

what are the 2 types of encapsulated receptors

Answer 18

muscle spindles, and golgi tendon organs

Question 19

what do muscle spindles detect

Answer 19

detect muscle length

Question 20

what do golgi tendon organs detect

Answer 20

detect muscle tension

Question 21

what is the organization of the spinal cord segments

Answer 21

8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccyx

Question 22

all spinal nerves each innervate ____ dermatome except ?

Answer 22

1, C1

Question 23

what is the conus medullaris

Answer 23

caudal end of the spinal cord

Question 24

where are the 2 enlargements of the spinal cord ?

Answer 24

cervical (C5-T1) and lumbar (L2-S3)

Question 25

what level cross section of the spinal cord would reveal an oval shape

Answer 25

cervical transverse section

Question 26

a cross section at what level of the spinal cord would have the most gray matter

Answer 26

lumbosacral transverse section

Question 27

what is the point of communication of the spinal cords at the midline called

Answer 27

anterior white commisure

Question 28

gray matter at all transverse sections of the spinal cord is what shape

Answer 28

H-shaped

Question 29

the substantia gelatinosa is found where on the spinal cord and is responsible for what ?

Answer 29

located in the posterior/dorsal horn | area that responds to pain and temperature sensory info.

Question 30

alpha or lower motor neurons innervate muscles _____ whereas gamma motor nuerons innervate ____ ?

Answer 30

``` alpha = muscle fibers gamma = muscle spindles ```

Question 31

what are the 2 specialized collumns that are found in the anterior horn at the cervical level

Answer 31

spinal accessory nucleus - forms accesory nerve | phrenic nucleus - forms phrenic nerve

Question 32

preganglionic sympathetic neurons are located where

Answer 32

T1-L3 in intermediate horn

Question 33

where is Clarke's nucleus found and what is it responsible for ?

Answer 33

intermediate horn from T1-L2 and involved with proprioception of the leg

Question 34

which cross section of the spinal cord would show the least white matter

Answer 34

sacral cross section

Question 35

where would you perform a lumbar puncture and why ?

Answer 35

L4-L5 because the actual spinal cord stops at L1-L2

Question 36

how is the spinal cord attacthed to the dura mater

Answer 36

filum terminale - anchors the conus medullaris to end of dural sheath

Question 37

where are the cauda equina nerve fibers found

Answer 37

L1-S2 (from end of cord to end of dura)

Question 38

what is the function of denticulate ligaments

Answer 38

lateral anchoring of the spinal cord

Question 39

what type of reflex does not involve interneurons

Answer 39

stretch reflex

Question 40

the stretch reflex is monosynaptic, what does that mean

Answer 40

1 synapse b/w 2 neurons

Question 41

muscle tension can inhibit motor neurons, what encapsulated receptor sensed this

Answer 41

golgi tendon organ

Question 42

what is another name for the great vertebral radicular artery

Answer 42

artery of Adamkiewicz