Somatic Nervous System

Question 1

somatic innervartion

Answer 1

skin and MSK system
includes skin, muscle, bone, ligaments, tendons, fascia

Question 2

somatic sensory innervation

Answer 2

touch, pain and proprioception

Question 3

somatic motor innervation

Answer 3

skeletal muscle

Question 4

somatic

Answer 4

innervation of cutaneous and musculoskeletal

Question 5

visceral

Answer 5

internal structures of of head, thorax, abdomen, pelvic cavity

Question 6

afferent

Answer 6

input to CNS
Somatosensory & viscerosensory

Question 7

efferent

Answer 7

output from CNS
motor - muscle & glands

Question 8

4 categories of SNS

Answer 8

somatic afferent, somatic efferent, visceral afferent, visceral efferent
SA: somatosensation
SE: motorneuron innervation of skeletal msucle
VA: viscerosensation, painful or non-painful, inside head/body
VE: visceromotor, to smooth muscle, glands, organs

Question 9

What is included at every segment of spinal cord?

Answer 9

somatosensory system (touch/pain/temperature/pain/proprioception), motor system (voluntary/skeletal muscle), reflexes

Question 10

anterior horn cells receive what from brain

Answer 10

mediating voluntary movement

Question 11

anterior horn cells receive what from sensory neurons?

Answer 11

mediating reflexes

Question 12

anterior horn cells recieve what from brain, associated with coordination

Answer 12

mediating non-conscious control of balance & motor condition

Question 13

upper extremities innervated by what segmental level?

Answer 13

brachial plexus, C5-T1

Question 14

lower extremities innervated by what segmental level?

Answer 14

lumbosacral plexus, L1-S5

Question 15

circuitry initial path

Answer 15

motor neuron cell body in ventral horn, axon projects via ventral root to spinal nerve, from spinal nerve to dorsal or ventral rami or named nerve to NMJ

Question 16

Corticospinal motor system - voluntary movement

Answer 16

2 consecutive neurons
- upper motorneuron in cerebral cortex to brain stem and cross side until at the level of synapse on lower neuron
- lower motorneuron in ventral horn then projects onto the muscle

Question 17

Projection from upper motor neuron regulate lower motor neuron

Answer 17

both excitatory and inhibitory projections depending on the muscle activation needed
if want something to flex, will use glutamate to excite flexors and then inhibit the extensor with GABA

Question 18

Cutaneous somatosensory nerve endings

Answer 18

merkel’s touch domes, pacinian corpuscles, meissner’s, ruffini, free nerve endings

Question 19

fine and discriminative touch used in

Answer 19

hair - motion
merkel’s touch domes (pressure, edges, textures)

Question 20

Pacinian corpuscles

Answer 20

vibration (even if eyes closed)

Question 21

Meissner’s

Answer 21

Crude touch with low spatial resolution
tap, flutter, texture

Question 22

Ruffini

Answer 22

proprioception
skin stretch, joint movement

Question 23

free nerve endings

Answer 23

pain & temperature
ONLY somatosensory neuron that stops in spinal cord to synapse

Question 24

muscle spindle

Answer 24

senses stretch

Question 25

golgi tendon organ

Answer 25

senses contraction

Question 26

Why are dermatomes clinically important

Answer 26

identify different problems in spine if certain dermatome path followed for region of impact

Question 27

loss of sensation in single dermatome

Answer 27

single disc herniation and pinched nerve/root
can induce dermatomal pattern of pain/parathesias

Question 28

common levels of herniation

Answer 28

C5-6 disc & C6 root/nerve
C6-7 disc & C7 root/nerve
L4-5 disc & L4 root/nerve
L5-S1 disc & L5 root/nerve

Question 29

nerve conduction study

Answer 29

stimulate nerve in one spot and record latency & amplitude in muscles innervated by it

Question 30

amplitude

Answer 30

height of response
if decreased, means decreased neuronal activity (dead axons or decreased number

Question 31

velocity

Answer 31

speed of response
mostly affected by loss of myelination

Question 32

What happens when inputs of neurons converge in spinal cord

Answer 32

visceral and somatic receptors go to same region or level

Question 33

Stretch reflex (deep tendon reflexes)

Answer 33

mediated by muscle spindles as only stretch is what is sensed in reflexes
Tap on reflex creates mild stretch and detect by sensory neuron around spindle muscle fiber then this neuron fires to release excitatory NT on motor neuron

Question 34

What level does the knee jerk reaction occur at?

Answer 34

L4, femoral peripheral nerve

Question 35

3 components of muscle spindle stretch reflex circuitry

Answer 35

muscle spindle, sensory arc, motor arc

Question 36

muscle spindle

Answer 36

what is stretched, embedded in extrafusal muscle, contains intrafusal muscle fibers

Question 37

sensory arc

Answer 37

stretch muscle spinfle fibers to activate sensory neurons that are wrapped around intrafusal muscle fibers

Question 38

motor arc

Answer 38

sensory fiber form excitatory synapse on alpha motorneurons, activate extrafusal muscle contraction and movement

Question 39

GTO Reflex path

Answer 39

GTO detect tension/contraction, muscle contraction excites sensory neuron, sensory neuron axon projection to inhibitory interneuron, sensory neuron releases NT that excite inhibitory interneuron that releases NT that inhibits motorneuron

Question 40

Muscle energy using isometric contraction

Answer 40

isometri contract of hypertonic, follow by post isometric relaxation allows refractory period in hyperactive muscle so that motor neuron decreases tension in the golgi tendon organ, allow for manipulation of previosuly too tight muscle

Question 41

muscle energy using antagonist

Answer 41

use antagonist contraction to engage reciprocal inhibition
if bicep too tight, activate tricep which engages antagonistic relaxation of bicep, allowing for work to then be done on bicep