What are the three types of axons?
A- beta
A-delta
C axons
What is the conductance times for the 3 types of axons?
A beta: 35-75 m/s
A delta: 5-30 m/s
C: 0.5-2 m/s, unmyelinated
What are each of the axons responsible for?
A beta: touch
A delta: pain temperature
C: pain, temperature
What is the diameter of each of the axons?
A beta: 6-12 um
A delta: 1-5 um
C: 0.2 -1.5 um
What is the DCML responsible for and where does it synapse?
- responsible for touch, a beta axons
- synapse in the brainstem (medulla)
What is the STT responsible for and what is the main difference between the STT and the DCML?
- pain and temperature from C axons and a delta
- decussates
What are the four part of the spinal cord?
Cervical
Thoracic
Lumbar
Sacral
What are dermatomes?
areas of the skin that is mainly supplied by a single nerve cell
What are the four types of receptor endings?
- Meissner Corpuscle
- Merkel Cell
- Ruffini Ending
- Panician Corpuscle
What are the benefits of adaptation?
- helps us to ignore constant stimuli reducing distractions
- allows us to detect changes in stimulus intensities over a larger range of intensities
What is the cost of adaptation?
we can’t tell stimulus strength from firing rate
- adaptation eliminates the baseline so you can identify change better but then you don’t know the baseline
ex. putting a cup on a scale and clearing the weight of the cup so you get the weight of whats inside
What part of the spinal cord does the DCML refer to?
dorsal
What part of the spinal cord does the STT refer to?
ventral
If the left side of the body’s sense of pain and temperature is affected, what system is affected, and what side of the spinal cord?
STT
right side because it decussates
ventral part
What is a cold receptor?
a receptor that fires more action potentials in the cold
What is a warm receptor?
a receptor that fires more action potentials in the warm
how thick is the cortical column?
2 mm thick
What percentage of the column is excitatory neurons and what percentage is inhibitory neurons? what are the other names for these neurons?
70 % excitatory or pyramidal
30% inhibitory or non pyramidal
What do each of the individual layers do?
2-3: send axons to and receives axons from other cortical areas
4: receives axons from the thalamus
5: sends axons to the brainstem and spinal cord
6: sends axons to thalamus
What is the TRPV1 receptor and how is it gated?
receptor is permeable to Na and Ca
heat gated, the warmer it is the easier it will open
also permeable to acids