Ap Spinal Cord, Nerves & Reflexes

Front 1

Each pair of spinal nerves receives sensory info and...

Back 1

relays motor signals to muscles/glands

Front 2

The spinal cord is part of which nervous system?

Back 2

CNS

Front 3

Spinal nerves are part of which nervous system?

Back 3

PNS

Front 4

Functions of the spinal cord: Conduction

Back 4

bundles of fibers pass info up & down

Front 5

Functions of the spinal cord: Locomotion

Back 5

* Repetitive, coordinated actions of several muscle groups
* Central pattern generators are pools of neurons providing control of flexors & extensors
(ex = walking)

Front 6

Functions of the spinal cord: Reflexes

Back 6

* involuntary, stereotyped responses to stimuli (ex = remove hand from hot stove)

Front 7

Anatomy of the spinal cord

Back 7

* nerve tissue cylinder within vertebral canal
* thick as a finger
* only extends to L1
* cervical & lumbar enlargements
* 31 pairs of spinal nerves

Front 8

Spinal nerves (how many, regions)

Back 8

* 31 pairs of spinal nerves
* Cervical, thoracic, lumbar & sacral regions
* Named for level of vertebral column where nerves exit
* Each segment gives rise to a pair of spinal nerves

Front 9

Medullary Cord (conus medullaris)

Back 9

tapered tip

Front 10

Cauda Equinae

Back 10

* L2-S5
* Nerve roots resemble horse's tail
* Spinal nerves L2-S5 that come off of bottom portion of cord

Front 11

3 Meninges of spinal cord

Back 11

* Dura Mater > Arachnoid Mater > Pia Mater

Front 12

Spinal Dura Mater

Back 12

* tough collagenous memebrane
* surrounded by epidural space - filled with fat, blood vessels - epidural anesthesia

Front 13

Spinal Arachnoid Mater

Back 13

layer of simple squamous epithelium lining dura mater & loos mesh of fibers filled with CSF

Front 14

Spinal Pia Mater

Back 14

delicate membrane adherent to spinal cord

Front 15

Filium Terminale (terminal filum)

Back 15

forms part of coccygeal ligament to anchor cord to coccyx

within pia mater

Front 16

Denticulate Ligaments

Back 16

extend from pia mater thru arachnoid to dura and anchor cord

Front 17

Spinal Bifida

Back 17

* Neural tube defects - congenital, abnormal fetal development of neural tube & vert column
* 1/1000
* 1+ ver fail to form complete neural arch to enclose cord
* Common in lumbosacral region
* Risks reduced by folic acid during pregnancy

Front 18

Spina Bifida Cystica

Back 18

sac protrudes from spine

Front 19

Cross-sectional anatomy of spinal cord

Back 19

gray matter surrounded by 3 columns of white matter

Front 20

Gray matter

Back 20

neuron cell bodies w/ little myelin

Front 21

White matter

Back 21

myelinated axons

Front 22

Where are the sensory fibers in the spinal cord?

Back 22

dorsal or posterior horns

Front 23

Where are the motor fibers in the spinal cord?

Back 23

ventral or anterior horns

Front 24

Another name for white matter columns in the spinal cord and where/what are they?

Back 24

Funiculi - dorsal, lateral and anterior.

Myelinated axons carring signals up/down cord and to/from brainstem

Front 25

Decussation

Back 25

nerve fibers cross sides

Front 26

Contralateral

Back 26

origin & destination are on opposite sides

Front 27

Ipsilateral

Back 27

origin & destination are on same side

Front 28

How many spinal tracts are there and what are they called?

Back 28

2 - ascending & descending

Front 29

Polioyelitis (Polio) - what is it & what are the symptoms (8)?

Back 29

* virus that destroys motor neurons in brainstem & ventral horn
* spread via fecal contam. in water
* signs - muscle, pain, weakness, reflex loss, paralysis, muscular atrophy, respiratory arrest

Front 30

Amyotrophic Lateral Sclerosis (ALS, Lou Gehrig disease)

Back 30

* Unknown cause
* sclerosis (tissue hardening) of spinal cord - astrocytes fail to reabsorb glutamate neurotransmitter.
* sensory/intellectual functions UNAFFECTED
* signs = muscular weakness, difficulty speaking, swallowing

Front 31

A nerve is a bundle of...

Back 31

nerve fibers (axons)

Front 32

Epineurium

Back 32

covers nerve - most superior

Front 33

Perineurium

Back 33

surrounds a fascicle - middle membrane

Front 34

Endoneurium

Back 34

separates individual nerve fibers - deepest/most interior membrane

Front 35

To what level of nerve membranes due blood vessels go?

Back 35

perineurium

Front 36

What is a Ganglia in the PNS

Back 36

cluster of neuron bodies within nerve

Front 37

What kind of cells are in a dorsal root ganglion?

Back 37

sensory cell bodies. Remember - dorsa/posterior horns contain sensory fibers

Front 38

Where does the most superior spinal nerve come out of the spinal column?

Back 38

Above C1

Front 39

Where does the most inferior spinal nerve come out of the spinal column?

Back 39

coccygeal region

Front 40

Ventral root of proximal branch is _________ ________ of spinal cord

Back 40

motor output

Front 41

Dorsal root of proximal branch is _________ ________ of spinal cord

Back 41

sensory input

Front 42

The dorsal ramus of the distal branch supplies....

Back 42

dorsal body muscle & skin

Front 43

The ventral ramus supplies.....

Back 43

ventral skin, muscles & limbs

Front 44

Meningeal branch goes to ....

Back 44

meninges, vertebrae & ligaments

Front 45

Three parts of the distal branches of spinal nerves?

Back 45

dorsal ramus, ventral ramus, meningeal branch

Front 46

Spinal nerves per region?

Back 46

Cervical - 8
Thoracic - 12
Lumbar - 5
Sacral - 5
Coccygeal - 1

* Dorsal & Ventral ramus for each

Front 47

Where are spinal roots?

Back 47

They run from just anterior of the vertebral processes and go in/out of the spinal cord. (so they run lateral-medial)

Front 48

Where are the spinal rami?

Back 48

Dorsal & ventral roots combine to become the ventral ramus - the dorsal ramus splits off of the ventral ramus

Front 49

plexus

Back 49

where the spinal cord branches meet up with other nerves

Front 50

What is the purpose of a plexus?

Back 50

provides alternate pathways for nerve signals

Front 51

Ventral rami do what to form what? (anastomose)

Back 51

anastomose repeatedly to form the 5 nerve plexuses

anastomose - reconnecting of branches

Front 52

Location of the 5 nerve plexuses

Back 52

CERVICAL C1-C5 (neck) - neck & phrenic
BRACHIAL C5-T1 (armpit) - upper limb & some shoulder/neck
LUMBAR L1-L4 (low back) - abdominal wall, anterior thigh & genitalia
SACRAL L4,L5 & S1-S4 (pelvis) - remainder of butt & lower limbs
COCCYGEAL S4,S5 & C0

Front 53

Phrenic Nerve

Back 53

plexus at C5, C4, C3

Front 54

Sciatic Nerve

Back 54

longest nerve in the body

Front 55

Dermatome

Back 55

area of skin specific to each nerve that nerve receives sensory input from - overlap at edges by 50%

Front 56

Shingles

Back 56

* skin eruptions along path of nerve
* varicella-zoster or herpes-zoster virus (chicken pox) remains for life in dorsal root ganglia
* After age 50 if immun compromised
* No special treatment

Front 57

Varicella-zoster or Herpes-Zoster

Back 57

Chicken Pox

Front 58

Somatic reflexes are....

Back 58

quick, involuntary, stereotyped reactions to sensory stimulation

Front 59

Somatic reflexes function by means of a....

Back 59

somatic reflex arc

* stimulation of somatic receptors
* afferent fibers carry signals to dorsal horn
* 1+ more interneurons integrate info
* efferent fibers carry impulses to skeletal muscles
* muscles respond

Front 60

What is the muscle spindle

Back 60

Proprioceptor (sense organ) - monitors length of muscles & how fast length changes

Front 61

Stretch (Myotatic) Reflex

Back 61

When muscle is stretched, it contracts & maintains increased tonus

Tonic contraction of the muscles in response to a stretching force, due to stimulation of muscle proprioceptors

Front 62

What is the purpose of stretch reflexes & example

Back 62

* Helps maintain equilibrium & posture
* Stabilize joints by balancing tension in extensors & flexors smoothing muscle actions
Ex = head tips forward when you fall asleep in class --- muscles contract to raise head

Front 63

Tendon reflex

Back 63

very sudden muscle stretch

ex = knee-jerk (patellar) reflex

Front 64

testing somatic reflexes helps...

Back 64

diagnose many diseases

Front 65

Reciprocal inhibition prevents...

Back 65

muscles from working against each other

Front 66

Flexor (withdrawal) Reflex

Back 66

withdrawl of foot from pain

Front 67

Crossed-Extensor Reflex

Back 67

maintains balance by extending other leg

Front 68

The patellar tendon reflex arc includes which 2 reflexes?

Back 68

flexor (withdrawl) and crossed-extensor (balance w/ other leg)

Front 69

Neural circuitry in spinal cord controls sequence and duration of...

Back 69

muscle contractions

Front 70

Golgi Tendon Reflex

Back 70

* Proprioceptors in tendon near its juction w/ muscle
* 1mm encapsulated nerve bundle
* Excessive tension on tendon INHIBITS motor neurons (muscle contraction decreased)
* Also functions when muscles contract unevenly

Front 71

Which is a known viral disease of the central nervous system - myasthenia gravis, spina bifida cystica, Amyotrophic Lateral Sclerosis (ALS), Lou Gehrig's disease, Poliomyelitis??

Back 71

Poliomyelitis

Front 72

General points about spinal cord trauma

Back 72

* 10-12K people/yr paralyzed
* 55% from traffic accidents
* Risk of respiratory failur
* Early symptoms called spinal shock
* Tissue damage at time of injury is followed by post-traumatic infarction

Front 73

where are the enlargements of the spinal cord?

Back 73

cervical & lumbar regions

Front 74

The _____ nerves arise from the cervical plexus & innervate the diaphram

Back 74

phrenic

Front 75

Proprioception

Back 75

non-visual awareness of a body's position & movements

Front 76

The tibial nerve & common fibular nerve collectively make up what nerve?

Back 76

sciatic

Front 77

T/F - some spinal nerves are sensory & others are motor

Back 77

false - all are mixed, none are purely 1 or the other

Front 78

T/F - somatic reflexes are those that don't involve the brain

Back 78

false - the are mediated primarily thru the b rain & cerebellum