Phys Ii: Neuro Sensory

Front 1

What is divergence?

Back 1

One neuron influences several other neurons.

Front 2

What is convergence?

Back 2

Several neurons work together to affect one neuron.

Front 3

Temporal arrangement refers to ____ and is measured in ___

Back 3

timing, impulses/min.
(the more the stronger)

Front 4

The spatial arrangement of input to neurons suggests that the ______ the impulse is, the ____ _it is.

Back 4

1. farther away from the axon
2. weaker

Front 5

At what location on a neuron is the most sensitive part, where an impulse would have the strongest effect?

Back 5

Axon hillock

Front 6

______ transmission describes how stimulation occurs between the axon terminal and the dendrite in the synaptic cleft.

Back 6

Electro-chemical transmission

Front 7

What factors affect the speed of an action potential conduction in neurons?

Back 7

1. Axon diameter (bigger = faster)
2. Whether it is myelinated (myelinated = faster)

Front 8

Pain, thermal, and autonomic axons are the _____ conduction because they are ___ and ___.

Back 8

slow, thin and unmyelinated

Front 9

Tactile and motor axons have ____ conduction.

Back 9

Fast (medium thickness, only lightly myelinated)

Front 10

Proprioception axons have _____ conductions.

Back 10

Very Fast (thick and myelinated)

Front 11

In the PNS, what cells produce and maintain myelin?

Back 11

Schwann cells

Front 12

In the CNS, what cells produce and maintain myelin?

Back 12

oligodendroglial

Front 13

Propogation of the axon potential relies on what two ions being shifted across the cell membrane?

Back 13

Potassium, Sodium

Front 14

At rest, the axon has a ___ charge on the outside and a ____ on the inside.

Back 14

Positive on the outside, negative at the inside

Front 15

_____ ion channels only open when the voltage changes.

Back 15

Voltage-gated

Front 16

What is saltatory conduction?

Back 16

Fast action potential propogation that jumps from one node to the next.

Front 17

Describe the process of neurotransmission (5 steps).

Back 17

1. nerve impulse arrives at azon terminal and causes calcium to bind to its receptor
2. Calcium causes synaptic esicles to release neurotransmitter into synaptic cleft.
3. Transmitter binds to receptor on membrane of dendrite.
4. new nerve impuls in the dendrite is generated, and is propogated to the neuron and its axon
5. transmitter is neutralized by re-uptake, re-use, or enxyme destruction

Front 18

Why do dendrites create destruction of neuroreceptors?

Back 18

To clean up after the process, so you can control stimulation.

Front 19

Sensory nerve fibers have _____ axon diameter and ____, to increase ______

Back 19

increased axon diameter and myelination to increase conduction velocity

Front 20

____ receptors are the largest of all in sensory nerve fibers.

Back 20

Proprioceptive

Front 21

In M.S. _____ degenerates resulting in weakness due to ____

Back 21

myelin sheath degenerates
weakness due to loss of proprioception!

Front 22

the ______ nerve innervates the skin of the face, but _____ innervates the back of the head, and _____ innervates the neck.

Back 22

Trigeminal nerve = face
C2 = back of head
C3 = neck

Front 23

Pain & Thermal pathways have _____ pathways but ______ axons.

Back 23

the same pathway, different axons

Front 24

When you feel pain or thermal input, it synapses at the _____.

Back 24

Substantia gelatinosa

Front 25

After synapse at the substantia gelatinosa, some neurons will go to _____, but the majority go to _____

Back 25

1. reflex neurons
2. cross over to contralateral side and ascend the opposite side of spinal tract to the thalamus

Front 26

The contralateral long tract is ____ in the sacral area, and ____ near the neck.

Back 26

1. thin near sacral
2. large near neck

Front 27

The pain and temperature conduction pathway occurs via the _____.

Back 27

Spinothalamic tract or anterolateral tract (LONG TRACT!!!)

Front 28

A lesion of a spinal nerve results in loss of sensation _____, where a lesion of the spinal cord (STT), the sensation is lost ____.

Back 28

1. spinal nerve = same side
2. spinal cord = contralateral side.

Front 29

The spinothalamic tract is located ________ and is specific to what functions?

Back 29

1. in the lateral white matter of the spinal cord
2. specific to pain and temperature only!!

Front 30

How do you figure out a lesion of a R spinal nerve vs L spinal cord?

Back 30

Look at the OTHER symptoms and put the puzzle pieces together.

Front 31

The diencephalon consists of what?

Back 31

Thalamus and Hypothalamus

Front 32

The spinothalamic tract is a ____ tract (long/ short)

Back 32

LONG!

Front 33

If you have loss of pain and temperature sensation of the right side, but loss of vagus nerve function on the left side, what condition would you suspect?

Back 33

Lesion of the Left side medulla

Front 34

Whne pain singals enter the pons, what happens next?

Back 34

They travel (without synapse) lateral side downward to caudal medulla and then back upto the pons before synapsing.

Front 35

What is significant about the trigeminal pathway?

Back 35

the pain sensation works on the same side in the head most of the time, because lesions are rare in ascending pathway from medulla back to midpons

Front 36

Which gyrus is the sensory receptor in cerebral cortex?

Back 36

Postcentral gyrus

Front 37

The _____ artery supplies the medial surface of the brain.

Back 37

anterior cerebral

Front 38

The ___ artery suplies the lateral surface of the brain?

Back 38

Middle cerebral artery

Front 39

If a stroke occured within the anterior cerebral artery, where would sensory be lost ?

Back 39

Lower extremity of Contralateral side.

Front 40

The fast conducted neuron fibers carry pain to the ____.

Back 40

cortex

Front 41

What is the function of the slow pain fibers?

Back 41

Bring behavioral responses to the pain up to the cortex

Front 42

Why does referred pain occur at a different place than the source of pain?

Back 42

Because skin and organ developed in the same area in the embryo, but then organs migrate to other sites with growth.

Front 43

Cardiac pain is typically referred where?

Back 43

Chest, neck, L arm, jaw

Front 44

Biliary (liver) pain is referred where?

Back 44

R chest, R posterior shoulder

Front 45

Fasciculus gracilis and facilis cuneatus can collectively be called the ____

Back 45

dorsal columns

Front 46

The fascuculus gracilis serves the _____ half of the body.

Back 46

Lower

Front 47

The fasciculus cuneatus serves the _____ half of the body

Back 47

upper

Front 48

The dorsal column medial lemniscus pathway serves what senations?

Back 48

descrimnative tactile, vibratory, and position sense (conscious proprioception)

Front 49

If a patient is unable to hold a coin and identify it as a coin, there is a lesion of what pathway?

Back 49

Dorsal columns pathway.

Front 50

An exam procedure in which you blindly move the patient's big toe and they cannot sense the direction of movement, suggests lesion of ____

Back 50

dorsal columns

Front 51

Once axons from dorsal columns cross over, they form the ____

Back 51

contralateral medial emniscus

Front 52

What is the Rhomberg sign?

Back 52

Pt loses sense of balance wiht feet together with eyes closed. It indicates dysfunction of dorsal column-medial lemniscus system

Front 53

The non-conscious proprioception pathway is a ____ tract to the ___.

Back 53

Cerebellum - LONG tract!!!

Front 54

The non-conscious proprioception pathway conveys what type of information?

Back 54

muscle tension, movement, body posiiton.

Front 55

Injury in the cerebellar and vestibular path results in _

Back 55

- diminished strength
- poor timing and accuracy of movement
- tremors when initiating movement
- diminished balance
- DOES NOT result in paralysis (just severe weakness)

Front 56

WHat are the 4 long tracts?

Back 56

1. pain & temp
2 dorsal column medial lemniscus
3. spinocerebellar
4. voluntary motor

Front 57

The volutary motor tract crosses over to the contralateral side where?

Back 57

Motor ecussation in lower brainstem.

Front 58

dorsal columnar tract crosses to the contralateral side at ____

Back 58

sensory decussation in lower brainstem.

Front 59

The -______ regulates visceral and endocrine functions

Back 59

Hypothalamus

Front 60

The hypothalamus exerts control by _____

Back 60

meeting up with sympathetic and parasympathetic axons

Front 61

What are Raphe nuclei?

Back 61

groups of interconnected neurons in the brain stem, especially at the midline of the brain stem

Front 62

What reticular formations modulate pain

Back 62

Periaquaductal gray, and Raphe nuclei

Front 63

What part of the brain stem are the respiratory centers in?

Back 63

Pons and medulla

Front 64

The Raphe nuclei are most prominent in what part of the brain stem?

Back 64

pons and medulla

Front 65

Cardiovascular centers lie within the ___

Back 65

medulla

Front 66

As pain comes up through STT, it gives off some neurons to ___, ___, and ___ which in turn send projections of ____ to the body.

Back 66

gives off to Raphe nuclei, periaqueductal grey, and hypothalamus..... projections of Seratonin

Front 67

The enkephalin neuron does what?

Back 67

inhibits the pain fiber from transmitting to brain

Front 68

Tactile fibers help activate ______ to help reduce pain.

Back 68

enkephalin inhibitory neurons.

Front 69

What is nocioception?

Back 69

Pain perception

Front 70

Where do fast pain fibers transmit to?

Back 70

conductied via A-delta lightly myelinated axons to thalamus and sensory cortex (location and character of pain/temp)

Front 71

Where to slow pain fibers transmit to?

Back 71

Conducted via C unmyelinated axons to the thalamus and limbic structures (affective, behavioral, responses to pain)

Front 72

What is the only descending long tract?

Back 72

Voluntary motor

Front 73

Where do visceral pain fibers transmit to?

Back 73

from organs and vessels they follow autonomic nerves to the spinal cord (irritants, ischemia, muscle spasms, organ distension)

Front 74

Warm and cold sensations are conveyed by _____ fibers and ____ pain fibers.

Back 74

1. separate fibers
2. separate from painf ibers

Front 75

Below and above which range does temperature become most painful? They are sensitive to about ____ degree.

Back 75

1. 15-45 deg C
2. 1 deg C sensitivity

Front 76

How does pain protect tissue from damage?

Back 76

By evoking avoidance behaviors

Front 77

Patients are constantly aware of pain because ____

Back 77

Pain receptors do not adapt

Front 78

What does neuropathic pain refer to?

Back 78

pain caused by injury to a nerve as in sciatica, pinched nerve, etc.

Front 79

Why are muscle spasms painful?

Back 79

They evoke muscle ischemia

Front 80

Where to viruses migrate to in order to cause skin pain, inflammation, as in shingles?

Back 80

Shingles is a viral invasion of peripheral sensory neurons that migrate to dendritic terminal causing these problems.

Front 81

When the enkephlin neuron is doing it's job, the gate for pain reception is _____.

Back 81

CLOSED! (pain can't get through)

Front 82

Where does each long tract cross over?

Back 82

1. STT = in spinal column at level of spinal nerve input
2. Dorsal columns = medulla
3. Spinocerebellar = most do not cross
4. voluntary motor = medulla