(Set 8) Somatosensation And Spinal Cord

Front 1

General anatomy of the spinal cord has it that it is located in the ___ canal and formed by the ____

Back 1

vertebral canal
vertebrae

Front 2

The spinal cord is continuous with the brain and it starts at the foramen ___. Also the spinal cord ends at the ___ ___ vertebrae

Back 2

magnum
2nd lumbar

Front 3

The space b/t the end of the spinal cord at L2 and the end of the ___ sheath at S2 is filled with dorals and ventral roots referred to as the ____ ____

Back 3

dural sheath
cauda equina

Front 4

The size of the spinal cord is ___ in diameter superiority and ___ in diameter inferiority.

Back 4

larger
smaller

Front 5

The two enlargements occur where the nerves leave and enter the cord to supply what?
The name for these are ___ enlargement and ___ enlargement

Back 5

upper and lower limbs
cervical
lumbosacral

Front 6

The names of the regions of the spinal cord are:
1.
2.
3.
4.
5.

Back 6

1. Cervical (C)
2. Thoracic (T)
3. Lumbar (L)
4. Sacral (S)
5. Coccygeal (Co)

Front 7

The spinal nerves are numbered starting at the superior end of each region

Back 7

C1-C8
T1-T12
L1-L5
S1-S5
Co

Front 8

The spinal cord gives rise to ___ pairs of nerves

Back 8

31

Front 9

Dermatome: ___ ___ segments are related to areas of ___ and ___

Back 9

spinal cord
skin
muscle

Front 10

Dermatome: it is simply a ___ indicating the ___ distribution of each ___ ___

Back 10

map
sensory
spinal nerve

Front 11

The cross section of the spinal cord resembles an ___ and it is the location of ___ distribution.

Back 11

H
cell

Front 12

The central portion of the dermatome is composed of ___ matter, compose of ___ ___

Back 12

grey
cell bodies

Front 13

Clefts in the spinal cord (cross section) separate it into two 1/2's. The anterior ___ ___ (is what) and the posterior ___ ___

Back 13

median fissure
median sulcus

Front 14

There are 3 sections of white mater contained in the cross section of spinal cord
1.
2
3.

Back 14

Dorsal column
Ventral column
Lateral column

Front 15

Dorsal column (posterior) of spinal cord cross section contains what?

Back 15

cell processes of sensory neurons

Front 16

Ventral column (anterior) of spinal cord cross section contains what?

Back 16

Motor neurons

Front 17

Lateral column of spinal cord cross section contains what?

Back 17

sympathetic neurons of the ANS

Front 18

The three sections of gray matter in the cross section of the spinal cord are called?

Back 18

1. Dorsal horn
2. Anterior horn
3. Lateral horn

Front 19

The Dorsal horn of gray matter in the cross section of the spinal cord contains what?
What is it's function?

Back 19

It contains interneurons and projection neurons, dendrites, and cell bodies
-it is primarily sensory

Front 20

The Anterior horn of gray matter in the cross section of the spinal cord contains what?

Back 20

Cell bodies of skeletal motor neurons

Front 21

The lateral horn of gray matter in the cross section of the spinal cord contains what? Where is this located?
What else is contained in the lateral AREAS and where is it located?

Back 21

-cell bodies of the sympathetic system
-T1 and L3
-Lateral areas of the spinal cord b/t S2 and S4 contain parasympathetic fibers, but do NOT form a distinct lateral horn

Front 22

The dorsal roots of the nerves entering and exiting the spinal cord are ____, _____ axons
The nerves are composed of ___ cells

Back 22

Afferent, sensory
Unipolar

Front 23

In the dorsal root of the spinal cord contains cell bodies in what structure?

Back 23

Dorsal root ganglia

Front 24

The dorsal root of the spinal cord projects into where?

Back 24

into the posterior horn

Front 25

The dorsal root of the spinal cord synapse with what? and eventually do what?

Back 25

-synapse with interneurons
-ascend or descend in the spinal cord

Front 26

The ventral roots of the spinal cord contain ___, ____ axons

Back 26

efferent, motor

Front 27

Cell bodies that are located in the ventral roots of the anterior horn are called what?
-what type of cells are these?

Back 27

Somatic neurons
multipolar

Front 28

Cell bodies that are located in the ventral roots of the anterior horn are called what?

Back 28

Autonomic neurons

Front 29

The dorsal and ventral roots of the spinal cord combine to form what?

Back 29

spinal nerves (different amounts of fibers/type)

Front 30

In the structure of a nerve, each axon and its Schwann cell are surrounded by what?

Back 30

Endoneurium

Front 31

Groups of axons in the nerve are surrounded by what?

Back 31

Perineurium to form fascicles

Front 32

The nerve fascicles are surrounded by what? what does it form? what is unique about it?

Back 32

epineurium
forms the nerve
the epineurium is dense

Front 33

The (dense) epineurium of the nerve is continuous with what? What does it surround?

Back 33

continuous with the dura matter,
surrounding the CNS

Front 34

In the pathway of the nerves, the names of nerves usually indicates what?

Back 34

origin and termination

Front 35

Of the ascending pathways, what two main tracts are involved in conscious sensation?

Back 35

Lateral Spinothalamic tract and
Dorsal column

Front 36

How many neurons do the ascending Lateral Spinothalamic and Dorsal column

Back 36

Both tracts consist of 2-3 neurons

Front 37

Where does the ascending Lateral Spinothalamic tract terminate?

Back 37

Thalamus

Front 38

Where does the ascending Dorsal column terminate?

Back 38

Thalamus

Front 39

After both the ascending Lateral spinothalamic tract and dorsal column terminate in the thalamus, what happens?

Back 39

Then another nerve goes from the thalamus to the cerebral cortex

Front 40

*Why is the Lateral spinothalamic tract SO important?

Back 40

It helps doc. decide what the pt has

Front 41

The Lateral spinothalamic tract transmits information regarding what?

Back 41

the lateral spinothalamic tract transmits information regarding pain and temperature

Front 42

Almost immediately after entering the spinal cord, what will the ascending lateral spinothalamic tract do?
where does it head afterward?

Back 42

It will cross over to the opposite side of the spinal cord (heads up to the thalamus after crossing)

Front 43

The ascending Dorsal Column transmits information regarding what?

Back 43

The dorsal column transmits touch (2-pt-discrim), pressure and proprioception

Front 44

What is steriognosis?

Back 44

this is where you cannot tell the difference b/t the feeling of different objects touching you

Front 45

How do the ascending Dorsal Column fibers travel?

Back 45

the dorsal column fibers travel ipsilaterally up to the spinal cord then they cross the midline at the medulla

Front 46

What ascending nerve pathway is responsible for the sensation of light touch?

Back 46

Light touch is a combination of both the spinothalamic tract and the dorsal column

Front 47

What is the main 3 main ascending tracts involved in unconscious sensation?

Back 47

1. spinocerebellar
2. spinoreticular
3. spinomesencephalic

Front 48

What is the ascending spinocerebellar responsible for and how do its fibers travel?

Back 48

unconscious proprioception
its fibers remain ipsilateral

Front 49

what tract does the ascending spinoreticular tract follow?

Back 49

the spinothalamic

Front 50

how does the ascending spinoreticular tract transmit information?

Back 50

it crosses over to the opposite side of the spinal cord (sc) almost immediately after entering the sc (parallels the spinothalamic tract)

Front 51

The ascending spinoreticular tract caries ___ information to the reticular formation. What is the reticular formation responsible for?

Back 51

pain
arousal and focus

Front 52

how does the ascending spinomesencephalic tract transmit information? (what tract does it parallel?)

Back 52

It will cross over to the opposite side of the spinal cord almost immediately after entering the spinal cord (parallels the spinothalamic)

Front 53

What type of information does the ascending spinomesencephalic tract carry? where does it take it?

Back 53

pain information to the superior colliculus

Front 54

What is so IMPORTANT about the function of the superior colliculi (which receives information from the spinomesencephalic tract)

Back 54

it is the site that controls saccades

Front 55

The descending nerve pathways of the Somatic motor system are involved in what?
The descending pathways are considered what?

Back 55

motor control
corticospinal

Front 56

how does the Upper motor neuron of the descending pathway transmit information?

Back 56

it travels ipsilaterally and crosses at the medulla

Front 57

In the descending pathway of the upper motor neuron, were are the cell bodies located? (hint: 3 places)

Back 57

1. motor cortex
2. cerebellum
3. brainstem

Front 58

Fibers of the descending pathway of the upper motor neurons synapse with lower motor neurons where?

Back 58

in the spinal cord or brainstem

Front 59

in the Lower motor neurons of the descending pathway, where are the cell bodies

Back 59

the cell bodies are in the anterior horn of the spinal cord or the cranial nerve nuclei

Front 60

The axons of the descending pathway of the lower motor neurons extend where?

Back 60

to the skeletal muscle

Front 61

Spinal Cord Lession: Hemi-section

Back 61

-loss of pain/temp contralateral
-loss of steriognosis/conscious proprioception ipsilateral
-ipsilateral paralysis (left leg cannot move)

Front 62

Posterior Column Lesion

Back 62

-loss of steriogenesis and conscious proprioception ipsilaterally
-WONT have paralysis

Front 63

Anterior spinal cord (COMMON)

Back 63

-only thing spared is Dorsal column
-loss of pain, temp
-paralysis

Front 64

Central lesion at the level of the cervical cord

Back 64

-bilateral loss of pain/temp at the level of the lesion
-wont be able to tell diff. b/t cold and hot in arms but can move them

Front 65

Unilateral loss of all sensory modalities in an entire extremity

Back 65

-Lesion above the medulla
-in the brain

Front 66

A reflex is an automatic response to a stimulus through what?

Back 66

a reflex arc

Front 67

The reflex is designed to do what?

Back 67

to preserve homeostasis

Front 68

Some reflexes are what? while others are what?

Back 68

excitatory, inhibitory

Front 69

What are the 5 components of a reflex?

Back 69

1. sensory receptor
2. sensory neuron
3. interneuron
4. motor neuron
5. effector neuron

Front 70

info. does not need to go to the brain in what type of reflex?

Back 70

the stretch reflex

Front 71

Three things happen in a stretch reflex:
1. what detects sudden stretch of muscle?
2. what synapses and what is innervated?
3. what causes the muscle to contract?

Back 71

1. muscle spindles
2. sensory axons synapse directly with motor neurons which innervate the muscle
3. motor neurons cause the muscle to contract

Front 72

What would happen if there was a lesion (anywhere) along the stretch reflex pathway?

Back 72

you will observe a decrease in their reflex

Front 73

what does the function of the Golgi Tendon reflex prevent?

Back 73

it prevents muscles that are contracting from putting excessive tension on the tendon

Front 74

what are the sensory detectors for the Golgi Tendon reflex? where are they found?

Back 74

Golgi tendon organs are found w/in the tendon are the sensory receptors

Front 75

In a Golgi tendon reflex, when a muscle contracts, what happens?

Back 75

when a muscle contracts, the tendons are stretched stimulating sensory neurons

Front 76

in a Golgi tendon reflex, what do sensory neurons synapse with?

Back 76

sensory neurons synapse with inhibitory interneurons

Front 77

in a Golgi tendon reflex, why do the interneurons synapse with motor neurons?

Back 77

the interneurons synapse with motor neurons that cause the muscle to relax

Front 78

the Withdraw reflex functions to remove the body part from what?

Back 78

the withdraw reflex removes the body part from a painful stimulus

Front 79

what do withdraw reflex pain receptors cause?

Back 79

withdraw reflex pain receptors cause an action potential in sensory neurons

Front 80

withdraw reflex sensory neurons synapse with what?

Back 80

withdraw reflex sensory neurons synapse with excitatory neurons

Front 81

withdraw reflex interneurons synapse with what?

Back 81

withdraw reflex interneurons synapse with motor neurons

Front 82

How does the withdraw reflex stimulated to remove the limb from painful stimulus?

Back 82

Flexor muscles are stimulated to remove the limb from painful stimulus

Front 83

At the same time as the withdraw reflex, the inhibitory neurons send action potential where? to do what?

Back 83

at the same time inhibitory neurons send action potential to motor neurons to relax the extensor muscle

Front 84

in crossed extensor reflex, the ___ axons extend through the white commissure and synapse with the motor neurons where?

Back 84

-collateral
-on the opposite side of the spinal cord

Front 85

while the withdrawal reflex causes flexion IN on one limb, the CROSSED EXTENSOR reflex causes what?

Back 85

The crossed extensor reflex causes extension in the opposite lower limb when the withdrawal reflex causes flexion in one lower limb

Front 86

What does the crossed extensor reflex allow? while what is happening?

Back 86

The crossed extensor reflex allows support of the body weight during the withdrawal reflex

Front 87

Sensation: How does the brain perceive information about the environment?

Back 87

The brain perceives information about the environment by sensory receptors

Front 88

what are The two groups of senses?
1.
2.

Back 88

1. Special senses
2. General senses

Front 89

Special senses are located where?

Back 89

special senses are located in specific areas of the body

Front 90

special senses have specialized what?

Back 90

special senses have specialized nerve endings

Front 91

what 5 abilities do special senses includes?

Back 91

1. smell
2. sight
3. taste
4. hearing
5. balance

Front 92

general sense are located where?

Back 92

general senses are located throughout the body

Front 93

the two groups of general senses are called?

Back 93

somatic senses and visceral senses

Front 94

The general Somatic senses transmit information about what? 7 sub-items?

Back 94

Somatic senses transmit info. about the environment (touch, pressure, itch, vibration, temperature, proprioception, pain)

Front 95

The general Visceral senses transmit information about what? 2 syb-items?

Back 95

Visceral senses transmit information about the internal organs (pain and pressure)

Front 96

What are the three types of sensory receptors?

Back 96

1. Chemoreceptors
2. Photoreceptors
3. Somatosensory receptors

Front 97

Chemoreceptors function?

Back 97

chemoreceptors chemical change in to action potential

Front 98

Photoreceptors function?

Back 98

photoreceptors change light into action potential

Front 99

What three type of Somatosensory receptors are there?

Back 99

1. mechanoreceptors
2. thermoreceptors
3. nociceptors

Front 100

how does the somatosensory receptor called the mechanoreceptors function?

Back 100

it responds to deformation via pressure

Front 101

how does the somatosensory receptor called the thermoreceptor function?

Back 101

it responds to temp.

Front 102

how does the somatosensory receptor called the nociceptors function?

Back 102

it responds to pain

Front 103

the somatosensory receptors are what type of cells?

Back 103

unipolar neurons

Front 104

the somatosensory receptors' cell bodies reside where?

Back 104

cell bodies in the dorsal root ganglion

Front 105

sensory receptors respond to stimuli by doing what?

Back 105

sensory receptors respond to stimuli by generating an action potential

Front 106

After sensory receptors respond to stimuli by generating action potentials, the action potential is then propagated where?

Back 106

the action potential is then propagated along the nerve to the spinal cord and brain

Front 107

A lot of sensory information is NOT what?

Back 107

perceived

Front 108

Some information about body position and movement is sent where?

Back 108

some information about body position and movement is sent directly to the cerebellum

Front 109

sensory receptors monitor what 3 things?

Back 109

sensory receptors monitor blood pressure, blood oxygen, and pH levels unconsciously

Front 110

the cerebral cortex does what in regard to many action potentials

Back 110

the cerebral cortex ignores many action potentials

Front 111

what two neuromodulators decrease the frequency of action potentials in the sensory tract?

Back 111

endorphins and enkephalin

Front 112

a lot of the sensory information is not perceived due to what?

Back 112

adaptation

Front 113

sensory disorders: Hyperalgesia is what?

Back 113

observed when stimuli that is normally only mildly uncomfortable is extremely painful (ie. sunburn back)

Front 114

sensory disorders: Allodynia is what?

Back 114

observed when normally un-painful stimuli are perceived as painful (ie sore thought)

Front 115

sensory disorders: Ataxia is what?

Back 115

observed as the in-coordination that is not due to weakness

Front 116

people with sensory ataxia use ___ to compensate for decreased ___ information

Back 116

vision
somatosensory

Front 117

Romberg test is used if ataxia is observed to distinguish b/t what?

Back 117

sensory and cerebellar ataxia