Neurophysiology - L9

Question 1

Chorda Tympanic

Answer 1

Where the taste receptors synapse on to at cranial nerve VII

Question 2

Where are Taste buds

Answer 2

In the papillae

Question 3

What are the four types of taste buds

Answer 3

1 and 2 are support cells
3 is the actual sensory cells
4 is the basil cell which will replace number three every 10 days

Question 4

Transduction of Salt Taste

Answer 4

Passive influx of sodium. The gate being open at rest.

Salt is pumped out by Na/K pump

Question 5

Sour1

Answer 5

Proton Regulated. As you increase the protons it will block on a potassium gated channel
depols and releases calcium

Question 6

Bitter2

Answer 6

Bitter receptor goes through a g protein called Gastducin!

It is a Gq meaning int goes through the PLC and IP3 path to increase calcium.

Question 7

Sweet (Two Pathways)

Answer 7

Both Pathways are G proteins

1) Is also Gastducin but it is Gs so it activated AC which goes to cyclic AMP goin gto a protein kinase. This will close a k channel causing depol
2) a Gq Pathway - so it will go through the PLC and IP3 to open up calcium to send over NT

Question 8

Umami

Answer 8

Binds metabotropic glutamate receptor. Activates Gi which decreases cyclic GMP and somewhoe leads to depolarization

Question 9

Spicy pathway

Answer 9

Comes from Capsaicin. and activates warm receptor ionotropic. Goes through VR1 channel and lets sodium and calcium in

Question 10

Olfactory Receptors (where are they and how long do they last)

Answer 10

Cilia are absorbed in mucus. Cells last 60 days. they have so much surface area and such a small volume so depolarize super quick

Question 11

Transduction of a smell

Answer 11

Odorin hits a cell activating Gs (Golf) going through AC and cAMP and then opens the sodium channel and Na comes in also letting in Calcium. Calcium ENTERING causes Vm to stay near the same (note that distribution of ions is different in nose).
Calcium Entering will result in Chlorine channel opening.
Chlorine EXITS in olfactor
causing a depolarization

Question 12

Primary and Secondary Current in the smell

Answer 12

Primary - the open of the Na and Calcium channels bringing them in
Secondary Current - Chlorine channel opening and them leaving

Question 13

Recognizing Odors

Answer 13

Cilia are not odor specific. So what happens is that the odorin receptors are very different and will actually form a pattern that the brain can read to have a reaction