Dermatomes/myotomes

Question 1

where does somite come from

Answer 1

paraxial mesoderm

Question 2

anterior portion of somite becomes what

Answer 2

sclerotome

Question 3

the somitic mesoderm separates into

Answer 3

dermatome, myotome, sclerotome

Question 4

myotome separates into what

Answer 4

epimere (dorsal) and hypomere (ventral)

Question 5

what do the epaxial muscles become

Answer 5

deep muscles of back such as erector muscles and spinal muscles

Question 6

hypaxial muscles make up

Answer 6

the lateral and ventral body wall

Question 7

sclerotome ends up wrapping around the notochord to form what

Answer 7

verterbrae

Question 8

notochord contributes to the

Answer 8

nucleus pulposus of the intervertebral disk

Question 9

dermatome is

Answer 9

the area of skin supplied with afferent nerve fibers by a single posterior spinal root

Question 10

sensory part

Answer 10

afferent - dorsal root (the cell bodies are in the dorsal root ganglion)

Question 11

motor part

Answer 11

efferent - ventral root

Question 12

from posterior to anterior what are the divisions of the cord

Answer 12

somatic and visceral (sensory) and then autonomic and somatic (motor)

Question 13

dermatome

Answer 13

unilateral area of skin innervated by the sensory fibers of a single spinal nerve

Question 14

myotome

Answer 14

unilateral muscle mass receiving innervation from the fibers conveyed by a single spinal nerve

Question 15

the posterior ramus innervates what

Answer 15

epaxial muscles of the back

Question 16

the anterior ramus innervates what

Answer 16

hypaxial muscle

Question 17

why is the anterior ramus larger than the posterior one

Answer 17

there are more muscles and tissues to innervate for a dermatome/myotome anterior to the spine

Question 18

what is the difference between a segmental arrangement and plexus

Answer 18

segmental nerves form a more linear arrangement

plexus arrangement have more overlapping nerves
-since they are overlapping areas are less sensitive to deficits

Question 19

autonomic plexuses control what

Answer 19

visceral sensory and visceral motor functions

Question 20

what is the cervical plexus made of? what does it do?

Answer 20

C1-C4, innervates anterior neck; skin of head neck and shoulders

Question 21

lumbosacral plexus

Answer 21

L2-S3

Question 22

what branch is c6-t1

Answer 22

median n.

Question 23

what branch is c8-t1

Answer 23

ulnar n.

Question 24

what branch is c5-t1

Answer 24

radial n.

Question 25

what branch is c8-t2

Answer 25

medal brachial cutaneous n.

Question 26

what branch is CA-T1

Answer 26

medial antebrachial cutaneous n.