Lecture 13+14 and DLA 15+16+17 Flashcards
phasic receptor vs tonic receptor
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
The three types of cutaneous receptors?
- mechanoreceptors (can be tonic or phasic)
- thermoreceptors
- nociceptors (polymodal)
Merkel disks?
touch
smaller RF
ruffini endings?
skin stretch
larger RF
Meissner corpuscle and Pacinian corpuscle
both are involved in vibration
Meissner: best at lower frequencies (smaller RF)
changes in shape
Pacinian: better at higher frequencies (larger RF)
tapping
Dorsal column/ medial lemniscus (sensation)
touch
vibration
proprioception (responds to muscular stretch)
anterolateral system (sensation)
temperature
Nociception
A alpha fiber (I): modality?
largest diameter
Proprioception
discriminative touch
vibration
A beta (II): modality?
larger diameter
Proprioception
discriminative touch
vibration
A delta (III): modality
smaller diameter
pain and temp
C (IV): Modality?
smallest diameter
pain and temperature
Nociceptive vs neuropathic pain
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
first pain
carried by the A delta fiber
reaches the brain first
second pain
carried by the C fiber
experienced later than first pain
visceral pain or referred pain
carried along the visceral afferents (C-fibers)
primary vs secondary vs tertiary sensory neuron
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
chemical activation of nociceptors?
histamine from mast cells
K from damaged cells
bradykinin from blood vessels
chemicals that are used for sensitization of nociceptors
increased prostaglandins
substance P
both of these increase pain sensitivity
sensitization may only be inferred indirectly from what??
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
