Nervous System--Spinal Cord

Front 1

What is the purpose of the spinal cord?

Back 1

To carry messages to and from the brain (Ascending and descending)/ reflexes.

Front 2

How long is the spinal cord? Where does it end and begin?

Back 2

about 18 inches--extends from foramen magnum to L1 of lumbar vertebrae.

Front 3

The spinal cord runs vertically through which foramina of the spinal column?

Back 3

Vertebral foramen

Front 4

What are the three types of meninges covering the spinal cord?

Back 4

Dura mater, Pia mater, and Arachnoid.

Front 5

What is different about the spinal cord than brain (in terms of anatomy)?

Back 5

Spinal cord has large epidural space with fat.

Front 6

Where is the CSF located in spinal cord?

Back 6

The subarachnoid space (Between arachnoid and pia mater).

Front 7

Do the dura mater and arachnoid also end at L1 with the spinal cord? Why is that significant?

Back 7

No, the extend to the sacrum (S2)--This enables spinal cord to be anchored into coccyx.

Front 8

Conus medullaris

Back 8

Tapered end of spinal cord around L1 (cone shaped.)

Front 9

After the end of the spinal cord, the pia mater that extends is referred to as:

Back 9

Filum terminale.

Front 10

Are spinal nerves sensory, motor, or mixed? What is a mixed nerve?

Back 10

Mixed--carries both sensory and motor neurons.

Front 11

Where is the spinal cord wider in diameter, and why?

Back 11

In the cervical and lumbar regions because these areas provide many motor neurons to the arms and legs.

Front 12

What is the Cauda Equina ("Horses tail")?

Back 12

The nerve roots of the spinal cord that extend beyond the inferior end fo spinal cord into vertebral canal.

Front 13

What are the "horns" and "columns" of the spinal cord?

Back 13

The horns of the spinal cord are the areas where gray matter is located, and the columns contain white matter (myelinated axons of neurons).

Front 14

What is a ganglion?

Back 14

a group of cell bodies outside of the central nervous system (PNS).

Front 15

Where is the cell body of sensory unipolar neuron located?

Back 15

In between its two axons.

Front 16

Where is the cell body of the motor neuron located?

Back 16

In the gray horn.

Front 17

Where do sensory impulses enter in the spinal cord?

Back 17

The posterior (Dorsal) side.

Front 18

Where do motor impulses exit the spinal cord

Back 18

The ventral side of spinal cord.

Front 19

If a sensory impulse continues to brain, what path will it follow?

Back 19

Recptor--> afferent (sensory) nerves--> Spinal cord (dorsal side)--> Ascending tracts (traveling upward)--> Thalamus (for crude interpretation of sensory info)--> Post central gyrus

Front 20

A sensory neuron is _____ if it brings impulses to the spinal cord.

Back 20

Afferent

Front 21

Where does the cell body of a sensory neuron sit?

Back 21

In the dorsal root ganglion.

Front 22

If the sensory neuron synapses with a motor neuron, where is the cell body of the motor neuron?

Back 22

In Anterior gray horn.

Front 23

Which part of the spinal cord are tracts found?

Back 23

Columns

Front 24

How are tracts named?

Back 24

By location and position (posterior/anterior)

Front 25

Where does the spinothalamic tract begin and end?

Back 25

Begins @ spinal cord, ends @ thalamus.

Front 26

Where does the spinocerebellar tract end?

Back 26

Begins @ spinal cord, ends @ cerebellum (sensory tract)

Front 27

Are tracts in any special order inside spinal cord?

Back 27

Yes, sensory supplies dorsal side of spinal cord, motor supplies ventral side.

Front 28

How do motor impulses travel from brain to spinal cord?

Back 28

Motor impulse beigns in pyramidal cell in precentral gyrus and travels down tract to motor neuron in anterior gray horn, where it is then sent to effector.

Front 29

Are spinal nerves apart of PNS or CNS?

Back 29

PNS

Front 30

Which spinal nerves remain separate (supplying anterior and posterior trunks directly) and do not form a plexus?

Back 30

Thoracic nerves (From T1 to T12)

Front 31

What are the four different plexuses?

Back 31

Cervical, Lumbar, Sacral, and Brachial plexuses.

Front 32

Where does the cervical plexus start and end, and what and important nerve of the plexus (what does it innervate?)

Back 32

From C1-C5. Phrenic nerve supplies the diaphragm in this plexus.

Front 33

Where does the brachial plexus begin and end, and what are its important nerves?

Back 33

From C5-T1. Key nerves are axillary, median, ulnar, radial, and musculocutaneous nerves.

Front 34

Where does the lumbar plexus begin and end, and what is the key nerve of this plexus (What does it innervate?)

Back 34

From L1-L4. Femoral nerve supplies the anterior thigh (Quadriceps femoris).

Front 35

Where does the Sacral plexus begin and end, and what important nerve here innervates muscles of lower thigh/leg?

Back 35

From L4-S4. Sciatic nerve innervates hamstrings.

Front 36

Dermatome (Definition, significance, and role in shingles?)

Back 36

Area of skin supplied by a specific spinal nerve--can be a sign of spinal problems based on which corresponding area of skin is affected (shingles affects dermatomes and can lie dormant in ganglion--when nerves are affected by shingles, specific areas of skin are affected with shingles).

Front 37

Which nerve has no dermatome?

Back 37

C1 (of cervical plexus)

Front 38

What is a reflex?

Back 38

Automatic, involuntary response to stimulus--rapid and predictable, and help maintain homeostasis of body.

Front 39

What is the difference between autonomic and somatic reflexes?

Back 39

In somatic, the effector is skeletal muscle, autonomic, effector is smooth muscle, glands, or cardiac muscle.

Front 40

What does monosynaptic mean in terms of reflexes?

Back 40

Reflex only requires two neurons (one synapse).

Front 41

What does polysynaptic mean?

Back 41

Reflex has more than one synapse (integration neuron).

Front 42

What is ipsilateral refer to in reflexes?

Back 42

Receptor and effector of reflex arc on same side of body.

Front 43

What is bilateral refer to in terms of reflexes?

Back 43

Both sides of body respond when one side is stimulated.

Front 44

Which reflex is faster--monosynaptic/polysynaptic, and why?

Back 44

Monosynaptic, because it only requires one synapse, so takes less neurons to travel through.

Front 45

What is a muscle spindle?

Back 45

A receptor for stretch reflex (detects stretch in muscles.)

Front 46

How is muscle spindle stimulated in knee jerk reflex?

Back 46

By tapping on patellar tendon.

Front 47

What is the reflex arc for the stretch reflex?

Back 47

Receptor= muscle spindle
Afferent neuron= sensory neuron
Efferent neuron= motor neuron
Effector= muscle
Response= contraction

Front 48

Is the stretch reflex mono or polysynaptic? Ipsilateral or bilateral?

Back 48

Monosynaptic and ipsilateral

Front 49

Which muscle is involved in the knee jerk stretch reflex? Innervated by which nerve?

Back 49

Quadriceps femoris (Femoral nerve)

Front 50

Which muscle is involved in Achilles reflex? Innervated by which nerve?

Back 50

Gastrocnemius (Sciatic nerve)

Front 51

What is the receptor for the tendon reflex? What does it detect?

Back 51

Golgi tendon organ--detects contraction (relaxes muscle in response).

Front 52

What is the reflex arc for the tendon reflex? Does it have and integration neuron?

Back 52

Receptor= golgi tendon organ

Afferent neuron= Cell bodies in dorsal root ganglion

Integration neuron? Yes

Efferent neuron= Cell bodies in anterior gray horn

Effector=Skeletal muscle

Response? Skeletal muscle will relax

Front 53

Is the tendon reflex poly or monosynaptic? Bi or ipsilateral?

Back 53

polysynaptic and ipsilateral

Front 54

How do the tendon and stretch reflex work together to maintain homeostasis?

Back 54

They both prevent overstretching and contracting of the muscle to avoid injury (tendon reflex relaxes muscle when over contracted, stretch contracts when over stretched.)

Front 55

What is the receptor for the withdrawal reflex?

Back 55

Nociceptors

Front 56

What do nociceptors detect?

Back 56

Pain

Front 57

Reflex arc for the withdrawal reflex:

Back 57

Receptor= Nociceptor (pain receptor)

Sensory neuron= Unipolar neuron w/ cell body in dorsal root ganglion

Integration neuron? yes

Motor neuron= Cell body in anterior gray horn.

Effector= Skeletal muscle (somatic)

What is the response? Flexion

Front 58

Is the withdrawal reflex ipsi or bilateral? Mono or polysynaptic?

Back 58

Polysynaptic and ipsilateral

Front 59

Sensory pathway will always begin with a _____

Back 59

Receptor

Front 60

What do receptors initiate?

Back 60

Action potentials

Front 61

Stimulus

Back 61

Change in the environment that can produce a response.

Front 62

Examples of stimuli:

Back 62

Touch, pain, temperature, etc.

Front 63

Punctuate distribution

Back 63

Receptors are unequally distributed

Front 64

Adaptation

Back 64

Receptor no longer fires action potential when stimulated continuously.

Front 65

Which receptors adapt readily? Which do not?

Back 65

Touch and Chemoreceptors/ Nociceptors do no adapt readily.

Front 66

Exteroceptors

Back 66

Detect change outside of the body
Ex. Skin (cutaneous receptors--touch, pressure, etc.)

Front 67

Interoceptors

Back 67

Detects change inside the body.
Ex. Internal organs (pressure, pain receptors, etc.)

Front 68

Proprioceptors

Back 68

Detect changes in the position of the body.

Front 69

Proprioception

Back 69

Sense of body position/body orientation.

Front 70

Mechanoreceptors

Back 70

Responds to mechanical change (touch, pressure receptors)

Front 71

Thermoreceptors

Back 71

Responds to changes in temperature.

Front 72

Nociceptors

Back 72

Stimulated by pain--responds to tissue damage.

Front 73

Chemoreceptors

Back 73

Respond to chemicals (taste buds, olfactory, etc.)

Front 74

Photoreceptors

Back 74

Respond to light (special senses).

Front 75

What do all receptors have in common?

Back 75

They initiate action potentials.

Front 76

Types of mechanoreceptors:

Back 76

Merkel disc (touch receptor in epidermis)

Meissner corpuscle (dermal papilla)

Hair root plexus (free dendritic endings)

Pacinian corpuscle (pressure receptor in dermis)

Front 77

Muscle spindles

Back 77

Specialized muscle cells--detects change in length of muscle (detects stretch, info goes to postcentral gyrus)

Front 78

Joint receptors

Back 78

Located in capsule of synovial joints (joint receptors detect joint position).

Front 79

Internal ear receptors

Back 79

Tell brain about head position at all times.

Front 80

Anterior spinothalamic pathway

Back 80

Pathway for touch and pressure.

Front 81

Lateral spinothalamic pathway

Back 81

Pathway for pain and temperature

Front 82

If patient has spinal cord damage on the right side, what sensory would be lost on what side?

Back 82

Pain & Temp lost on left side. Pressure and touch lost on left side. Discriminative touch lost on same side.

Front 83

How many neurons does a motor pathway have?

Back 83

Two--upper and lower motor neuron.

Front 84

General Sensory pathway:

Back 84

Receptor= detects a stimulus
Afferent unipolar neuron= First order neuron
Neuron that will cross over to other side= second order neuron
Neuron with cell body in thalamus= third order neuron
Third order neuron ends in postcentral gyrus (axon in postcentral)

Front 85

Where is cell body of the first order neuron located?

Back 85

In dorsal root ganglion

Front 86

Where is the cell body of the second order neuron located?

Back 86

In posterior horn of spinal cord (crosses over to other side).

Front 87

Where is cell body of the third order neuron located? Where does the axon of this neuron end?

Back 87

In the thalamus--post central gyrus

Front 88

Which neuron is creating the anterior spinothalamic tract? Which is creating the lateral spinothalamic tract?

Back 88

The first order neuron/ second order neuron

Front 89

What impulses does the posterior column pathway carry?

Back 89

Impulses for discriminative touch (what part of body was touched).

Front 90

Parts of Posterior column pathway:

Back 90

First order neuron: Cell body in dorsal root ganglion

Second order neuron: Cell body in medulla oblongata and crosses over to opposite side

Third order neuron: Cell body in thalamus, axon ends in post central gyrus.

Front 91

Are motor pathways ascending or descending?

Back 91

descending

Front 92

Where is the cell body and axon of the upper neuron in the corticospinal pathway?

Back 92

cell body in precentral gyrus, axon extends through cerebellar peduncles.

Front 93

Another name for pyramidal (direct) motor pathway?

Back 93

Corticospinal pathway

Front 94

Where are the cell body and the axon of the lower motor neuron of the corticospinal tract located?

Back 94

Cell body in anterior gray horn, axon extends to skeletal muscle.

Front 95

Where do most of the axons of the motor corticospinal tract cross over, and what do they continue as?

Back 95

Decussation of periods, and continues as lateral corticospinal tract in spinal cord.

Front 96

What do the remainder of axons continue as?

Back 96

Continues as anterior corticospinal tract in spinal cord.

Front 97

Spastic paralysis

Back 97

damage to upper motor neuron

Front 98

Flaccid paralysis

Back 98

damage to lower motor neuron

Front 99

What is the role of the basal nuclei in neural integration?

Back 99

basal nuclei have influence over the upper motor neurons of both the indirect and direct motor pathways.

Front 100

What happens if there is damage to anterior gray horn or ventral root (motor nerve exiting spinal cord)?

Back 100

No action potentials will reach the skeletal muscle.

Front 101

A Positive Babinski sign indicates damage to which motor neuron?

Back 101

Upper motor neuron