A&p Spinal Cord Exam 4

Front 1

spinal cord

Back 1

begins at foreamen magnum
ends at conus medullaris

Front 2

spinal cord ends at

Back 2

lumbar vertebrae (L1-L2)

Front 3

spinal nerves

Back 3

connected to spinal cord via posterial and anterior roots

Front 4

spinal cord segments

Back 4

31, each has a pair of spinal nerves

Front 5

posterior

Back 5

dorsal

Front 6

anterior

Back 6

ventral

Front 7

afferent

Back 7

travel to the spinal cord

Front 8

efferent

Back 8

travel away from the spinal cord

Front 9

afferent nerves

Back 9

enter SC via posterior roots

Front 10

efferent nerves

Back 10

leaves SC through the anterior roots

Front 11

gray matter

Back 11

H-shaped, butterfly shaped, surrounded by white matter,
contains nerve cell bodies, axons, and synapses

Front 12

lateral horns

Back 12

found in segments T1-T12, L1-L2

Front 13

dorsal and ventral horns

Back 13

found in all segments

Front 14

3 neuron groups in gray matter

Back 14

sensory relay neurons
anterior motor neurons
interneurons

Front 15

anterior motor neurons

Back 15

located in anterior horns of gray matter
-several thousand in each segment
-axons leave cord via anterior roots
-innervate skeletal muscle fibers

Front 16

2 types motor neurons

Back 16

alpha motor neurons

gamma motor neurons

Front 17

alpha motor neurons

Back 17

give rise to A-alpha nerve axons
-innervate extrafusal skeletal muscle fibers
-comprise 2/3 total motor neuron pool

Front 18

gamma motor neurons

Back 18

make up 1/3 motor neurons in anterior horns
-smaller
-give rise to A-gamma axons

Front 19

A-gamma axons

Back 19

innervate intrafusal fibers in muscle spindles

Front 20

motorneurons

Back 20

some sensory input, most of input is derived from interneurons

Front 21

interneurons

Back 21

present in all gray matter
-most numerous cells in gray matter
-both excitatory and inhibitor

Front 22

white matter

Back 22

surrounds gray matter
-contain numerous bundles, or tracts of nerve axons

Front 23

ascending tracts white matter

Back 23

lateral spinothalamic tracts
posterior spinothalamic tracts

Front 24

lateral spinothalamic tracts

Back 24

transmission of pain and temp sensation

Front 25

posterior spinothatlmic tracts (dorsal columns)

Back 25

transmission of tactile (touch, pressure) and proprioceptive sensations (position, mvt of limbs)

Front 26

descending tracts of white matter

Back 26

coritcospinal (pyramidal tracts)
nerve tracts associated with sympathetic nervous system

Front 27

corticospinal (pyramidal) tracts

Back 27

motor nerve tracts originate motor cortex and terminate on interneurons in SC gray matter

Front 28

nerve tracts with SNS

Back 28

originate in brainstem, terminate T1-T12, L1-L2

Front 29

3 layers connective tissue around SC

Back 29

pia mater
dura mater
arachnoid mater

Front 30

subarachnoid space

Back 30

contains CSF
provides cushion, prevent cord from hitting vertebrae

Front 31

epidural space

Back 31

contains fat, connective tissue, and venous plexuses
-extends foramen magnum-sacral hiatus

Front 32

ligaments

Back 32

ligamentus flavum
interspinous ligament
suraspinous ligament

Front 33

ligamentum flavum

Back 33

lies posterior to epidural space- last ligament epidural needle passes through

Front 34

interspinous ligament

Back 34

between vertebrae (2nd ligament epidural needle passes through)

Front 35

supraspinous ligament

Back 35

runs longitudanally along vertebral process, 1st ligament epidural needle passes through

Front 36

blood supply SC

Back 36

vertebral arteries
thoracic and abd aorta

Front 37

anterior spinal artery

Back 37

supplies the anterior 2/3 of cord
-originates from vertebral arteries at base of skull

Front 38

posterior spinal arteries

Back 38

supply posterior 1/3 of cord,
arise from posterior inferior cerebellar arteries

Front 39

radicular arteries

Back 39

supply blood to the anterior and posterior spinal arteries

Front 40

artery of adamkiewics
(arteria radicularis magna)

Back 40

single branch of aorta arises on left side
-supplies nearly all blood to lower thoracic and lumbar cord

Front 41

spinal nerves

Back 41

part of PNS
formed by joining anterior and posterior roots at each sc segment

Front 42

intervertebral foramina

Back 42

openings between the vertebrae where spinal nerves exit

Front 43

pairs of spinal nerves
cervical

Back 43

8

Front 44

spinal nerve pairs thoracic

Back 44

12

Front 45

spinal nerve pairs lumbar

Back 45

5

Front 46

spinal nerve pairs sacral

Back 46

5

Front 47

spinal nerve pairs coccygeal

Back 47

1

Front 48

cauda equina

Back 48

where lower lumbar and sacral nerves descend before exiting vertebral column

Front 49

mixed nerves

Back 49

contain somatic (sensory and motor) and autonomic nerve fibers

Front 50

dermatome

Back 50

specific region of the skin supplied by each spinal segment

Front 51

2 major branches rami

Back 51

anterior primary division
posterior primary division

Front 52

anterior ramus

Back 52

major portion of spinal nerve

Front 53

posterior ramus

Back 53

supplies long muscles of back and tissue

Front 54

plexus

Back 54

intermingling collection of nerves that emanate from different cord segments

Front 55

cervical plexus

Back 55

anterior rami of spinal nerves C1-C4 form in neck

Front 56

phrenic nerve

Back 56

cervical plexus emerges to innervate the diaphragm

Front 57

brachial plexus

Back 57

anterior rami of spinal nerves C5-C8 and T1

Front 58

peripheral nerves of brachial plexus

Back 58

musculocutaneous, median and ulnar innervate the upper limbs, shoulders, and pectoral muscles

Front 59

cervical plexus innervate

Back 59

limbs, neck

Front 60

lumbosacral plexus

Back 60

anterior rami spinal nerves L1-L5, S1-S4

Front 61

peripheral nerves lumbosacral plexus

Back 61

obtrurator, femoral, sciatic, innervate lower limbs and pelvis

Front 62

propriocepters

Back 62

muscle receptors

Front 63

what do muscle receptors do?

Back 63

provide continuous feedback information to CNS with respect to muscle length and tension

Front 64

Where is the feedback info from muscle receptors directed to?

Back 64

spinal cord, cerebellum, motor cortex

Front 65

what is a muscle spindle?

Back 65

-type of muscle receptor
-fx as stretch receptors
-detect changes in muscle length

Front 66

Where are intrafusal muscle attached to?

Back 66

glycocalyx of surrounding extrafusal fibers

Front 67

what is the central region of the spindle innervated by?

Back 67

sensory nerves type 1a and II.
-very sensitive to stretch of muscle

Front 68

What do the A-gamma motor fibers do?

Back 68

regulate the tension in the intrafusal fibers and the sensitivity of spindles to stretch.

Front 69

What are golgi tendon organs?

Back 69

sensory receptor(nerve endings) located in muscle tendons.

Front 70

Where are goldi tendon organs located?

Back 70

near the point of attachment of tendons to the skeletal muscle fibers

Front 71

What are golgi tendon receptors sensitive to?

Back 71

tension developed within the muscle.

Front 72

What do type Ib sensory nerves do?

Back 72

Transmit info from golgi tendon organs to CNS.

Front 73

Where are the Type Ib sensory signals directed?

Back 73

spinal cord, cerebellum, and cerebral cortex.

Front 74

What is a monosynaptic reflex?

Back 74

only one synapse, operates rapidly with very little delay.

Front 75

Review what happens when stretch activates muscle spindles.

Back 75

sensory info delivered via type Ia sensory fibers to dorsal root-then to A-alpha motor neurons-activation of alpha motor neurons that innervate the same muscle that was stretched-muscle ctx to oppose stretch.

Front 76

What does a Knee-jerk (stretch reflex) test?

Back 76

excitiability of motor neurons.

Front 77

What is a withdrawl reflex stimulated by?

Back 77

a painful stimulus

Front 78

review pattern of withdrawl reflex

Back 78

activation of sensory(pain) receptors-info directed to interneurons in sp cord-excitation of alph-motorneurons that innervate approp flexor muscles-ctx of flexor muscles to remove affected body area from painful stimulus.

Front 79

What is crossed extension?

Back 79

flexion of one limb is accompanied by extension of the opposite limb.

Front 80

How long is the delayed reflex in the crossed extension?

Back 80

200-500msec

Front 81

What is a muscle spasm?

Back 81

a reflex response to irritation of muscle.

Front 82

Examples of muscle spasms.

Back 82

fractures-local spasm
peritonitis-ctx of abd muscles
ischemia/excess excercise-local spasm

Front 83

List some of the insults that can cause spinal cord injury?

Back 83

-trauma
-demyelinating disorders
-tumors
-infections
-ischemia

Front 84

what is spinal shock?

Back 84

somatic and autonomic reflexes below the lesion are temporarily interrupted.
-may cause drop in BP

Front 85

What is autonomic hyperreflexia?

Back 85

overactivity of the sympathetic nervous system.

Front 86

What type of patients typically develop autonomic hyperreflexia?

Back 86

pts with cord transection at T5 or above.

Front 87

What can trigger an autonomic hyperreflexia response?

Back 87

cutaneous(incision) or
visceral (distended bladder)

Front 88

What are some symptoms of autonomic hyperreflexia?

Back 88

-reflex bradycardia
-hypertension
-cardiac dysrhythmias

Front 89

Hemisection of spinal cord is called what?

Back 89

Brown-Sequard syndrome

Front 90

Where is a subarachnoid (spinal) block usually performed?

Back 90

below the end of the spinal cord at L3-4 or L4-5

Front 91

Where are the local anesthetics injected to for a spinal block?

Back 91

the subarachnoid space

Front 92

T or F CSF circulation does not affect the distribution of the drug?

Back 92

True-CSF circulation has no affect on distribution of the drug.

Front 93

Name two complications of a spinal block.

Back 93

1-hypotension
2-postspinal headache

Front 94

At what level and in what space is an epidural block placed?

Back 94

at the lumbar level and into the epidural space

Front 95

What does the epidural space in the spinal cord contain?

Back 95

fat, connective tissue, and venous plexuses

Front 96

What is the major site of action for the epidural block?

Back 96

spinal nerve roots

Front 97

What are the sites of action for a spinal block?

Back 97

-spinal nerve root-main site
-dorsal root ganglia
-spinal cord itself

Front 98

T or F onset of sympathetic blockade is faster than spinal block and an abrupt fall in BP usally occurs?

Back 98

False-onset is usally slower and an abrupt fall in BP usually does not occur.

Front 99

When does sensation begin?

Back 99

When a stimulus is detected by a sensory receptor

Front 100

What is a transducer?

Back 100

it converts the natural form of the stimulus into electrical impulses.

Front 101

What are some examples of a stimulus?

Back 101

light, sound, heat, pressure, or chemical

Front 102

What does the stimulus do?

Back 102

causes a change in membrane potential causing depolarization.

Front 103

What determines the magnitude of the receptor potential?

Back 103

the stimulus strength or intensity

Front 104

What is the area called over which the receptor will detect a stimulus?

Back 104

a receptive field

Front 105

T or F all sensory receptors(except some pain receptors) show some degree of adaptation?

Back 105

true, some adapt quicky while others adapt more slowly.

Front 106

List some types of sensory receptors.

Back 106

-mechanoreceptors
-thermoreceptors
-nociceptors
-electrmagnetic receptors
-chemoreceptors

Front 107

What is a mechanoreceptor?

Back 107

they detect mechanical deformation of tissue including touch.

Front 108

These receptors detect changes in tissue temperature?

Back 108

thermoreceptors

Front 109

What are nociceptors?

Back 109

detect tissue injury, pain receptors

Front 110

These receptors detect lightwaves?

Back 110

electromagnetic receptors

Front 111

What do chemoreceptors do?

Back 111

detect changes in the local chemical composition of environment

Front 112

What are some chemical composition changes chemorecptors will detect?

Back 112

pH,PO2, Pco2

Front 113

What do sensory nerves do?

Back 113

transmit action potentials from sensory receptors to CNS

Front 114

What are the general classifications of sensory nerves?

Back 114

Type A fibers
Type C fibers

Front 115

Myelinated fibers of spinal nerves are what kind of fibers?

Back 115

Type A

Front 116

What are the four subgroups of myelinated fibers?

Back 116

alpha, beta, gamma, delta

Front 117

These fibers are smaller in diameter and are nonmyelinated?

Back 117

Type C fibers

Front 118

T or F Type C fibers have low conduction velocity?

Back 118

True

Front 119

Which fibers comprise more than 50% of peipheral sensory nerve fibers?

Back 119

Type C

Front 120

What are group Ia fibers?

Back 120

muscle spindles

Front 121

What are group Ib sesnory fibers?

Back 121

golgi tendon organs

Front 122

Muscle spindles and most tactile receptors are what kind of sensory nerve?

Back 122

group II

Front 123

Group III is what kind of sensory nerves?

Back 123

thermoreceptors and some nociceptors (fast pain)

Front 124

This group has thermoreceptors and some nociceptors (slow pain)?

Back 124

Group IV

Front 125

What are the two types of sensations?

Back 125

1-special senses
2-somatic sensations

Front 126

list some of the "special" senses.

Back 126

-vision
-hearing
-taste
-smell
-equilibrium

Front 127

These sensations arise from the body surfact as well as deep tissues like viscera, muscles, and bone?

Back 127

somatic sensations

Front 128

What are some examples of tactile sensations?

Back 128

touch, pressure, vibration

Front 129

The sensation of body and limb mvoements is?

Back 129

Kinesthesis

Front 130

Where are free nerve endings found?

Back 130

extensively in the skin and other tissues such as cornea.

Front 131

Where does sensory information enter and where is it directed?

Back 131

Enters spinal cord via dorsal roots and is directed to brain

Front 132

What does decussate mean?

Back 132

to cross-over

Front 133

Where do the third order fibers project to?

Back 133

the somatic sensory cortex

Front 134

where is the somatic sensory cortex located?

Back 134

postcentral gyrus of parietal lobe

Front 135

What is sensory homunculus?

Back 135

the areas of the body are represented accoring to the density of their sensory recetors-some areas are over-represented compared to their actual size.

Front 136

Which body parts are highly represented?

Back 136

lips, face, and hands

Front 137

Which parts are underrepresented?

Back 137

trunk and lower parts of the body

Front 138

facts about the somatic sensory cortex columns...

Back 138

-0.3-0.5mm in diameter
-extend through all six layers
-each column contains about 10,000 neurons
-each column responds to a specific sensory modality

Front 139

What can injury to the somatic sensory cortex I cause?

Back 139

-loss of discrete tatctile sense
-inability to judge pressure against body surfaces
-inability to judge shapes
-inability to judge texture of an object

Front 140

What is asterognosis?

Back 140

the inability to judge the shapes of objects

Front 141

Where is the somatic association cortex located, and where does it receive input from?

Back 141

located in parietal lobe behind SSI.
-input from thalamus, visual cortex, and auditory cortex

Front 142

What is amorphosynthesis?

Back 142

forgetting that one side of the body exits

Front 143

When can amorphosynthesis occur?

Back 143

if damage to somatic association cortex in the non-dominant hemisphere

Front 144

What does the somatic association cortex do?

Back 144

plays role in interpretation of sensory info.

Front 145

Where are sensory endings of propriocetpive sensations located?

Back 145

joint capsules, ligaments, tissue around the joints, and muscle spindles

Front 146

What is an unpleasant sensory and emotional experience associated with actual or potential tissue damage?

Back 146

pain

Front 147

T or F pain is an experience affected by past events, suggestions, and emotional arousal?

Back 147

True

Front 148

acute pain, sharp pain, and pricking pain are what types of pain?

Back 148

fast (first) pain

Front 149

What is the onset of fast pain response to painful stimulus?

Back 149

0.1sec

Front 150

Where is fast pain found?

Back 150

superficial, NOT deeper tissues

Front 151

What type of sensory nerve fibers transmit fast pain signals?

Back 151

type A-delta fibers

Front 152

This type of pain is reffered to as throbbing, burning, aching or chronic pain?

Back 152

slow (second) pain

Front 153

What is the onset of slow pain response to painful stimulus?

Back 153

1sec or more

Front 154

T or F slow pain is often poorly localized?

Back 154

true

Front 155

Where can slow pain arise?

Back 155

superficially and deeper tissues

Front 156

What nerve fibers transmit slow pain signals to CNS?

Back 156

type C non-myelinated

Front 157

What are alogens?

Back 157

chemical stimuli

Front 158

What are the two locations for nociceptors?

Back 158

1-somatic nociceptors
2-visceral nociceptors

Front 159

Somatic nociceptors are located where?

Back 159

skin, deep tissues like muscles, tendons, fascia, and bone

Front 160

Where are visceral nociceptors located?

Back 160

Gi tract and kidneys

Front 161

What is hyperalgesia?

Back 161

persistent stimulation of pain receptors increases sensitivity

Front 162

In fast fibers where do the A-delta axons synapse?

Back 162

with second-order interneurons in laminae I of gray matter

Front 163

Type C axons synapse primarily with interneurons in laminae_______, and ___ of sp cord, project signals to second order neurons in laminae__________?

Back 163

II,III, V

Front 164

What is WDR?

Back 164

Wide dynamic range
-second order neurons most abundant in laminae V.
-increase their firing rate in response to persistent pain stimulus.

Front 165

Axons fo the second order neurons cross over and ascend where ?

Back 165

lateral spinthalamic tracts

Front 166

Where is fast pain drected?

Back 166

ventrobasal nuclei of thalamus and then to third oder neurons in SS cortex

Front 167

Where is slow pain directed?

Back 167

midbrain reticular formation, the periaqueductal gray area, intralaminar nuclei of thalamus and limbic system

Front 168

Bradykinin and prostaglandin E are what kind of mediators of pain?

Back 168

chemical

Front 169

What is primary hyperalgesia mediated by?

Back 169

histamine and serotonin

Front 170

What does substance P stimulate?

Back 170

mast cells and platelets to release alogens

Front 171

afferent pain fibers release what in the dorsal horn?

Back 171

glutamate and substance P

Front 172

Which receptors do glutamate activate?

Back 172

AMPA, NMDA

Front 173

Substance P activates what receptors?

Back 173

NK-1 (neurokinan)

Front 174

What is a common mechanism of central sensitization?

Back 174

increased intracellular calcium

Front 175

T or F once central sensitization is established it is very difficult to interrupt even with opiods?

Back 175

True

Front 176

Where is the periaqueductal gray area located?

Back 176

upper pons and midbrain, surrounding the aqueduct of Sylvius.

Front 177

Which tracts does the Raphe magnus nucleas activate?

Back 177

descending serotoninergic tracts to spinal cord

Front 178

Descending adrenergic axons release which NT to activate alpha-2-receptors?

Back 178

Norepinephrine

Front 179

Descending serotoninergic axons stimulate interneurons to release what?

Back 179

Enkephalins

Front 180

What does the release of endorphins in the periaqueductal gray area and limbic system do?

Back 180

interferes with pain transmission and modulation of pain perception

Front 181

Which two endorphins are physiologically important endorphins released in periaqueductal gray area and limbic system?

Back 181

Beta-endorphin
dynorphin

Front 182

Which two enkephalins act in the spinal cord to inhibit pain transmission?

Back 182

met-enkephalin, leu-enkephalin

Front 183

Pain perceived in a part of the body that is removed form the actual site of painful stimulus is what kind of pain?

Back 183

Referred pain

Front 184

Referred pain that is sent to body surface frequently originates where?

Back 184

viscera

Front 185

T or F the viscera have somatic sensory receptors?

Back 185

False, the viscera have no somatic senosry receptors except for sparsely distributed pain receptors.

Front 186

Visceral pain typically involves diffuse activation of pain receptors due to?

Back 186

-ischemia
-chemical irritation
-distention/spasm of visceral sm muscle
-stretching of ligaments

Front 187

Visceral pain is transmitted to CNS via what sensory fibers?

Back 187

autonomic type C

Front 188

Injury to or disease of, a visceral organ may also affect the parietal wall of the cavity causing what kind of pain?

Back 188

parietal pain

Front 189

parietal pain is transmitted to spinal cord via what sensory nerves?

Back 189

somatic- type a-delta & type c somatic sensory nerves

Front 190

T or F the parietal pain sensation is localized to the area directly over the painful stimulus?

Back 190

True

Front 191

Name some NMDA receptor blockers

Back 191

-ketamine
-pre-emptive acetaminophen