CHAPTER 13

Question 1

Functions of the Spinal Cord

Answer 1

Conduction—nerve fibers conduct sensory and motor
information up/down the spinal cord
Neural integration—spinal neurons receive input
(eg. bladder control)
Locomotion—central repetitive (eg walking)
Reflexes—responses to stimuli

Question 2

Surface Anatomy of spinal cord

Answer 2

-spinal cord- from foramen magnum down to L1 L2
-segment- 31 pairs of spinal nerves
-cauda equina- horse tail L2-L5
-divided into cervical, thoracic, lumbar, and sacral
-thicker/enlargement areas areas- cervical and lumbosacral
-medullary cone

Question 3

Epidural Space

Answer 3

-yellow balls
-on top
-for epidural

Question 4

subarachnoid space

Answer 4

contains CSF
below
blue with spider- harder to see

Question 5

three meninges

Answer 5

-fibrous membranes that enclose the brain and spinal cord

-From superficial to deep: -dura mater (orange, tough, outer, sheath)
-arachnoid mater (light blue, middle, CSF)
-pia mater (most delicate, pink, inner)

Question 6

grey and white matter cross sectional anatomy

Answer 6

Grey- butterfly, less myelinated, info processing, neuron cell bodies, horns

white- outer, myelinated, carries signals from one part of CNS to another

Question 7

hole between grey matter butterfly is called

Answer 7

central canal

Question 8

another name for nerves

Answer 8

axons of neurons in PNS

Question 9

tracts

Answer 9

-mostly myelinated axons in CNS
-Ascending tracts- carry sensory info up
-descending tracts- carry motor info down
- tracts are named for their origin followed by their destination

Question 10

Lumbar Puncture

Answer 10

Where? Below L2
Space? Subarachnoid space
Collecting? CSF
Procedure testing? Meningitis

Question 11

Grey matter dorsal horns vs ventral horns

Answer 11

d: posterior sensory
v: anterior motor

Question 12

Poliomyelitis

Answer 12

cause destruction of motor neurons, leading to muscle atrophy
-from poliovirus
-muscle pain, weakness, paralysis

Question 13

Amyotrophic lateral sclerosis (ALS) disease

Answer 13

-destruction of motor neuron, leading to muscle atrophy
-Sensory/intellectual functions remain unaffected, therefore still feel pain
-muscular weakness; difficulty speaking

Question 14

whats a nerve

Answer 14

cord composed of axons bound by connective tissues containing both afferent and efferent fibres

Question 15

three connective tissue layers

Answer 15

endoneurium- inner
perineurium
epineurium- outer

Question 16

sensory, motor, and mixed nerves

Answer 16

sensory- afferent, carries signals to CNS

Motor- efferent, signals from CNS to effectors

mixed- consist of both

Question 17

ganglion

Answer 17

cluster of neurosomas outside CNS

Question 18

Each spinal nerve is formed from two roots

Answer 18

-Posterior (dorsal) root is sensory input to spinal cord

-Anterior (ventral) root is motor output out of spinal cord

Question 19

Beyond the vertebra, the nerve divides into distal branches

Answer 19

-anterior ramus
-posterior ramus

Question 20

five nerve plexuses

Answer 20

-cervical- neck phrenic nerve (can’t breathe without) to diagram
-brachial- upper limb (median and radial nerve)
-lumbar- abdominal area
-sacral- lower trunk
-coccygeal

Question 21

Radial nerve injury

Answer 21

-crutch paralysis
-wrist drop

Question 22

Sciatica

Answer 22

sharp pain that travels from gluteal region to ankle

Question 23

Cutaneous Innervation and Dermatomes

Answer 23

D: area of skin that covers sensory input to spinal nerve

D map: shows cutaneus regions

Question 24

chicken pox

Answer 24

-early childhood caused by
varicella-zoster virus; itchy rash that clears up without
complications

-remains for life

Question 25

shingles

Answer 25

-caused by the virus traveling down the sensory nerves
-immune system compromised

Question 26

Somatosensory function and motor function

Answer 26

S: carries signals, proprioceptors, sensation

M: stimulates muscle contraction

Question 27

whats a reflex

Answer 27

preprogrammed response to stimulus

Question 28

Somatic reflex arc

Answer 28

1. Sensory receptor – site of stimulus action
2. Sensory neuron – transmits afferent impulses to CNS
3. Integration centre – receives, processes sensory info and transfers it to motor neurons and/or CNS
4. Motor neuron – conducts efferent impulses from Integration centre to an effector
5. Effector = skeletal muscle fibers – responds to efferent impulses by contracting =
   final response to the original stimulus

Question 29

proprioceptors

Answer 29

sense organs to monitor movement of body parts

Question 30

muscle spindles

Answer 30

Stretch detector

Question 31

stretch reflex

Answer 31

when a muscle is stretched, it “fights back” and contracts

Question 32

Knee-jerk (patellar) reflex is a _________reflex

Answer 32

monosynaptic

Question 33

Reciprocal inhibition

Answer 33

prevents muscles from working against each other

Question 34

flexor reflex

Answer 34

quick contraction

Question 35

Polysynaptic reflex arc

Answer 35

signals travel over
many synapses on their way to the muscle

Question 36

Crossed extension reflex

Answer 36

contraction of extensor muscles in limb opposite of the one that is withdrawn
* Maintains balance by extending other leg

Question 37

tendon reflex

Answer 37

in response to excessive
tension on the tendon

Question 38

spinal cord trauma

Answer 38

loss of motor control
paralysis

Paraplegia—paralysis of both lower limbs
* Quadriplegia—paralysis of all four limbs
* Hemiplegia—paralysis on one side of the body
* Paresis—partial paralysis or weakness of the limbs