Lecture 13+14 and DLA 15+16+17

Question 1

phasic receptor vs tonic receptor

Answer 1

phasic or rapidly adapting:
respond at the beginning and end of a stimulus
most sensitive to change

tonic or slowly adapting:
stimulus duration is signaled by persistent depolarization
best for monitoring

Question 2

The three types of cutaneous receptors?

Answer 2

1. mechanoreceptors (can be tonic or phasic)
2. thermoreceptors
3. nociceptors (polymodal)

Question 3

Merkel disks?

Answer 3

touch

smaller RF

Question 4

ruffini endings?

Answer 4

skin stretch

larger RF

Question 5

Meissner corpuscle and Pacinian corpuscle

Answer 5

both are involved in vibration

Meissner: best at lower frequencies (smaller RF)
changes in shape

Pacinian: better at higher frequencies (larger RF)
tapping

Question 6

Dorsal column/ medial lemniscus (sensation)

Answer 6

touch
vibration
proprioception (responds to muscular stretch)

Question 7

anterolateral system (sensation)

Answer 7

temperature

Nociception

Question 8

A alpha fiber (I): modality?

Answer 8

largest diameter

Proprioception
discriminative touch
vibration

Question 9

A beta (II): modality?

Answer 9

larger diameter

Proprioception
discriminative touch
vibration

Question 10

A delta (III): modality

Answer 10

smaller diameter

pain and temp

Question 11

C (IV): Modality?

Answer 11

smallest diameter

pain and temperature

Question 12

Nociceptive vs neuropathic pain

Answer 12

Nociceptive:
pain that arises from damage from a non-neural tissue
(first pain, second pain, referred (visceral) pain)

neuropathic:
pain caused by a lesion of disease of the CNS or PNS \

acute pain:
often nociceptive and has a cause

chronic pain:
long duration and usually neuropathic

Question 13

first pain

Answer 13

carried by the A delta fiber

reaches the brain first

Question 14

second pain

Answer 14

carried by the C fiber

experienced later than first pain

Question 15

visceral pain or referred pain

Answer 15

carried along the visceral afferents (C-fibers)

Question 16

primary vs secondary vs tertiary sensory neuron

Answer 16

primary:
axon in the periphery, cell body in periphery

secondary:
cell body in CNS, axon crosses the midline, synaptic terminal in thalamus

tertiary:
cell body in the thalamus; synaptic terminal in parietal lobe

Question 17

chemical activation of nociceptors?

Answer 17

histamine from mast cells

K from damaged cells

bradykinin from blood vessels

Question 18

chemicals that are used for sensitization of nociceptors

Answer 18

increased prostaglandins
substance P

both of these increase pain sensitivity

Question 19

sensitization may only be inferred indirectly from what??

Answer 19

hyperalgesia: increased pain stimulus
allodynia: pain from a stimulus that does not usually cause pain
mechanism:

hyper: Increase of suprathreshold response of
nociceptors

allo: Lowering of pain threshold of nociceptors