CNS spinal cord

Question 1

where does the spinal cord end

Answer 1

at the medulla oblongata down the the level of L2/

Question 2

what is the end point called

Answer 2

conus medullaris

Question 3

what are the 2 enlargements within the spinal cord

Answer 3

cervical and lumbar

Question 4

what is formed and innervated from the cervical enlargement

Answer 4

the brachial plexus

inn upper extremities (C5-T1)

Question 5

what is formed and innervated from the lumbar enlargement

Answer 5

lumbar plexus

inn lower extremities (L1-S4)

Question 6

what is the spinal cord divided into R/L halves by

Answer 6

anterior median fissure and posterior median sulcus

Question 7

t/f a sulcus is deeper than a fissure

Answer 7

false

Question 8

what is the H-form in the center of the spinal cord

Answer 8

grey commissure, comprised of nuclei (grey matter)

Question 9

what is at the center of the grey matter

Answer 9

the central canal

Question 10

what is the central canal

Answer 10

continuous with the 4th ventricle
continuous through the length of the spinal cord
filled with CSF

Question 11

what surrounds the H-form

Answer 11

white matter, bundles of myelinated nerve fibers (oligodendrocytes)

Question 12

what is each bundle of white matter called

Answer 12

a tract

Question 13

what are the 2 types of tracts

Answer 13

ascending and descending

Question 14

what are the ascending tracts

Answer 14

afferent
sensory tracts
relay impulses from the periphery or spinal levels to the brain

Question 15

what are descending tracts

Answer 15

efferent
motor tracts
relay impulses from the brain to diff spinal levels and the periphery

Question 16

what are the horns of the grey commissure

Answer 16

2 ant (ventral horns)
2 post (dorsal horns)
*lateral horns only found in t spine and upper L-spine

Question 17

what enters the dorsal horn

Answer 17

dorsal roots

Question 18

what enters the ventral horn

Answer 18

ventral roots

Question 19

dorsal roots:

Answer 19

contain sensory neurons

cell bodies lie outside the s.c. in the intervertebral foramen (dorsal ganglia of spinal ganglia)

Question 20

ventral roots:

Answer 20

contain axons of motor neurons

cell bodies are contained within the ant and lat horns

Question 21

what forms the spinal nerve

Answer 21

the mix of the dorsal and ventral roots

Question 22

what does the spinal nerve divide into

Answer 22

dorsal and ventral rami

Question 23

what does the dorsal rami supply

Answer 23

deep vertebral m. and skin of the back

Question 24

what does the ventral rami supply

Answer 24

all ventral and lateral musculature

Question 25

t/f the spinal nerves are mixed

Answer 25

true, both sensory and motor

Question 26

how many pairs of nerves

Answer 26

``` 31 8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccyx ```

Question 27

what are meninges

Answer 27

protect brain and spinal cord

Question 28

Meninges form the supporting framework for

Answer 28

arteries veins and venous sinuses

Question 29

what do the meninges enclose

Answer 29

subarachnoid space for circulation of the CSF

Question 30

what are the 3 layers of meninges

Answer 30

``` dure mater (diaphragm sellae) arachnoid( subarachnoid space contains CSF) pia mater (denticulate lig specific to sc) ```

Question 31

t/f all 3 layers cover spinal nerves all the way

Answer 31

false, cover until they exit through intervertebral foramina

Question 32

what are the specialized nerve endings

Answer 32

free nerve endings | encapsulated sensory endings

Question 33

free nerve endings

Answer 33

branch btw epithelial cells, connective cells, m cells, etc. act as primarily pain receptors of the body act as tickle, itch and thermal and touch receptors

Question 34

encapsulated sensory endings (6)

Answer 34

surrounded by connective tissue capsule

Question 35

what are the 6 encapsulated sensory endings

Answer 35

``` meissner corpuscules pacinian corpuscules end bulbs of krause ruffini corpuscules muscle spindles golgi tendon organs ```

Question 36

meissner corpuscles

Answer 36

surround spinal ending of a dendrite sensitive to light touch, pressure and slow vibrations rapid adapting

Question 37

where are the meissner corp found

Answer 37

skin (finger tips) mucous membrane of tongue other sensitive regions of the body ex eyelids

Question 38

pacinian corpuscules

Answer 38

located in dermis and subcutaneous tissue, submucosa, joints, periosteum, and some viscera adapt rapidly stimulated by heavy pressure, fast vibrations, tickling

Question 39

end-bulbs of krause

Answer 39

located in mucous of the lips, tongue, conjunctiva external genitalia dermis of skin serve as cold receptors

Question 40

ruffini corpuscules

Answer 40

located in subcutaneous tissue, lig and tendons slow-adapting respond to stretching of the skin (specially in joints)

Question 41

what do the ruffini corp contribute to

Answer 41

kinesthetic sens of and control of joint position and movement

Question 42

muscle spindles

Answer 42

found in skeletal m. react to changes in m. length contained in a capsule supplied by sensor neurons

Question 43

what happens when the muscle is stretched

Answer 43

intrafusal fibers send afferent nerve impulse to spinal nerve efferent neurons do the same and m. contracts stretch is reflexively resisted

Question 44

golgi tendon organs

Answer 44

composed of dendrites that have many branches on the muscle tendon junction react to muscle tension

Question 45

what happens when there is muscle tension

Answer 45

stimulus will go back to s.c. where motor neurons inhibit the m. = relaxation of the m. **principle of PNF stretching and hold/relax stretch

Question 46

dermatomes

Answer 46

motor and sensory all spinal nerves except C1 and cutaneous each spinal nerve innervates a portion of the skin important diagnostic technique

Question 47

what are 3 types of reflexes

Answer 47

cranial somatic autonomic /

Question 48

reflex arc

Answer 48

``` sensory receptor sensory neuron integrating center motor neuron effector ```