L12: Pain and Vestibular Control

Question 1

the translation of a noxious stimulus into neural activity

Answer 1

transduction

Question 2

propogation of nerve impulses from receptors into the CNS

Answer 2

transmission

Question 3

facilitation of inhibition of neurons and interneurons in the spinal cord

Answer 3

modulation

Question 4

what is nociception

Answer 4

perception of pain

Question 5

what is mechanical deformation

Answer 5

stretch or damage to the receptor membrane that opens ion channels

Question 6

the application of chemicals opens ______ in chemoreceptors

Answer 6

ion channels

Question 7

changes in _____ alters the permeability of the membrane thermoreceptors

Answer 7

temperature

Question 8

pain is detected through

Answer 8

free nerve endings

Question 9

what type of pain do A-delta fibers detect

Answer 9

immediate, sharp pain

Question 10

what type of pain do C fibers detect

Answer 10

dull, burning pain

Question 11

what does free nerve ending mean

Answer 11

non myelinated endings

Question 12

does pain occur in the brain

Answer 12

no

Question 13

where are nociceptors located

Answer 13

skin, joints, internal organs and bones

Question 14

T/F: temperature extremes and pain can be perceived as pain

Answer 14

True
Transient Receptor Potential channels (TRP)

Question 15

_____ receptors increase AP frequency with increase in temperature

Answer 15

Warm

Question 16

_____ receptors increase AP frequency with decreases in temp

Answer 16

cold

Question 17

in what nerve fibers are warm receptors located

Answer 17

C

Question 18

in what nerve fibers are cold receptors located

Answer 18

Aẟ with non-mylenated endings

Question 19

Aẟ fibers have what 2 types of nociceptors

Answer 19

mechanical & Noxoius thermal nociceptors

Question 20

_____ nociceptors respond to mechanical damage: cutting, crushing, pinching

Answer 20

Mechanical

Question 21

_______ nociceptors respond to extreme heat and cold

Answer 21

noxious thermal

Question 22

C Fibers have what two types of nociceptors

Answer 22

Thermal & Polymodal

Question 23

thermal nociceptors respond to …

Answer 23

thermal gradients

Question 24

what do polymodal nociceptors respond to

Answer 24

various novious damaging stimuli : thermal, mechanical, chemical

Question 25

____ nociceptors are peripheral and mostly found in _____

Answer 25

polymodal, skin

Question 26

pathways that convey **somatic sensation** require how many neurons

Answer 26

3 1st, 2nd and 3rd order sensory neurons

Question 27

what sensory neuron has a cell body in the dorsal root ganglion, is an afferent neuron, and has peripheral receptors that detect stimuli

Answer 27

First order sensory neuron

Question 28

what sensory neuron has a soma in the spinal cord or brainstem and synapses with a 3rd order neuron

Answer 28

2nd

Question 29

what sensory neuron is located in the thalamus and synapses in the cortex layers (2-6)

Answer 29

3rd order

Question 30

what is the only sensory neuron in the pain pathway with receptors in the PNS

Answer 30

first order sensory neuron

Question 31

the spinothalamic pathways transmit information on ______, ________ and light touch

Answer 31

pain, temp

Question 32

where do first order pain neurons synapse

Answer 32

onto 2nd order neurons in the spinal cord

Question 33

where do 2nd order pain neurons synapse

Answer 33

in the thalamus - perception of pain

Question 34

where do 3rd order pain neurons synapse

Answer 34

somatosensory cortex - location of pain

Question 35

what is a non-adpating receptor

Answer 35

nociceptors that are activated as long as a lesion is present

Question 36

hyperalgesia

Answer 36

increases sensitivity to pain

Question 37

what causes hyperalgesia

Answer 37

tissue damage

Question 38

initial injury only stimulates _____ pain sensation through what fibers

Answer 38

acute A-delta

Question 39

over time, dull pain sensations increase in intensity, stimulating ___ fibers

Answer 39

C

Question 40

what things are released by the inflammatory response to pain

Answer 40

* bradykinins * prostaglandins * substance P (causes mast cells to release histamine which activates nociceptor endings) * K+, H+

Question 41

_______ in the ECF stimulate polymodal nociceptors and contribute to tissue inflammation

Answer 41

Bradykinins

Question 42

Substance __ stimulates mast cells to release histamine

Answer 42

P

Question 43

repeated sitmulation of ___ fibers enhances pain

Answer 43

C

Question 44

Substance P binds ______ receptors in neurons and initiates vasodilation and inflammation

Answer 44

neurokinin 1

Question 45

repeated stimulation of dorsal horn neurons causes ___________

Answer 45

central sensitization ---> recruitment of glutamate receptors to make C fibers more senstiive

Question 46

what inhibits the release of substance P, therefore alleviating pain

Answer 46

Enkephalin which is released from activation of opiate receptors

Question 47

what are the analgesia endogenous opioid substances

Answer 47

* endorphins * enkephalins * dynorphins

Question 48

what drug blocks the action of opioids

Answer 48

Naloxone has high affinity for the μ opioid receptor, where it acts as a competitive antagonist.

Question 49

where are μ opioid receptors concentrated

Answer 49

dorsal horns of spinal cord

Question 50

how are serotonin and NE involved in modulating pain

Answer 50

they stimulate enkephalin releasing interneurons or pain modulating nucli in the brainstem *NE and 5-HT can be manipulated by a variety of pharmacological agents*

Question 51

NSAIDS block ______, a critical enzyme in the synthesis of _______

Answer 51

COX2 prostaglandins this decreases sensitization to pain

Question 52

exogenous opioids are good at agonizing ______ receptors

Answer 52

endogenous opioid

Question 53

endocannabinoids help modulate ______ and increase following sustained physcial acvitiy

Answer 53

pain

Question 54

located in the inner ear, informs CNS about head position and movement

Answer 54

vestibular system

Question 55

what does the vestibular system measure

Answer 55

* static tilt of head * linear acceleration * rotary acceleration

Question 56

the vestibular system is composed of _____ and _____

Answer 56

3 semicircular canals and 2 ampullae

Question 57

what are the sensory receptor cells of the vestibular system

Answer 57

hair cells

Question 58

clinical signs of vestibular syndrome

Answer 58

* head tilt * nystagmus * ataxia * loss of balance

Question 59

why do middle ear infections cause head tilt

Answer 59

infections cause pressure on the round/oval window of the cochlea the pressure difference causes unbalanced AP frequency bw the affected and normal ear

Question 60

at the base of each semicircular canal sit 3 _______ that contain a ridge within hair cells called _________

Answer 60

ampulla crista ampullaris

Question 61

2 of the 3 ampulla in the semicircular canals are connected to a _____ and ______

Answer 61

utricle & saccule

Question 62

inside the 3 ampulla, the saccule and utricle are hair cells bathed in _____

Answer 62

endolymph

Question 63

what 5 things do hair cells consist of

Answer 63

* cilia at luminal membrane * synapse with sensory neuron * vestibulochochlear nerve * other hair cells along the crista ampullaris * cupula (gelatinous mass)

Question 64

bending of hair cells towards the cilia causes ____ channels to open

Answer 64

K+ --> depolarization

Question 65

moving of the head in one direction will cause the endolymph to move across hair cells in the _____ direction

Answer 65

opposite = deceleration

Question 67

hair cells are on the _____

Answer 67

macula

Question 68

the utricle has a ______ oriented macula and the saccule has a _______ oriented macula

Answer 68

horizontally vertically

Question 69

mass of calcium carbonate crystals that sit atop the cilia and gelatinous cupula

Answer 69

otoliths

Question 70

otoliths and _________ cause cilia to bend in the opposite direction of head movement

Answer 70

endolymph

Question 71

what are the 3 targets of CN VIII via vestibular nuclei

Answer 71

* vestibulospinal tracts * medial longitudinal fasciculus * flocculondular node of the cerebellum

Question 72

what is the goal of the vestibuloocular reflex

Answer 72

move extraocular eye muscles to maintain contact with the target as the head/body is in motion

Question 73

what is the goal of the vestibulospinal reflex (VSR)

Answer 73

stabilize the body

Question 74

what is the vestibulo-collic reflex

Answer 74

head and neck muscles adjusting to **maintain head position**

Question 75

what is affected in **peripheral** vestibular syndrome

Answer 75

labyrinth within the petrosal bone associated w/ head tilt

Question 76

in central disease type vestibular syndrome, the _____ is affected

Answer 76

brain stem associated w/ paresis/hemiparesis, gait and posture