Human Phys 2.6

Question 1

Neuromuscular junction steps

Answer 1

1. Nerve impulse is going to allow calcium to move into Presynaptic terminal
2. Calcium will signal for exocytosis of ACh into the synaptic cleft
3. ACh with travel and bind to nicotinic receptors on the muscle fiber and opens the receptor
4. Na+ rushes into the cell and generates an end plate potential which will generate an end plate potential
5. If end plate potential is strong enough to cause an action potential then the AP travels down t tubules and this causes DHPR receptor to open
6. DHPR receptor opening stimulates calcium release for RYR receptor and leads to muscle contraction

Question 2

What happens once the DHPR receptor opens?

Answer 2

It interacts with RYR receptor due to protein interaction (once RYR opens calcium moves from Sarcoplasmic reticulum to cell membrane causing muscle contraction)

Question 3

T tubule

Answer 3

Action potential travels down

Question 4

SERCA 2 pump

Answer 4

Picks up calcium and moves it back into the sarcoplasmic reticulum using ATP (active transport)

Question 5

Botulinum toxin

Answer 5

Blocks ACh release from nerve terminal (causes paralysis and eventually death via respiratory failure)

Question 6

Curare

Answer 6

Competes with ACh for its receptor but max doses can cause paralysis and death (used in anesthesia)

Question 7

Tetrodotoxin

Answer 7

Inhibits Na+ channels (found in Japanese puffer fish)

Question 8

Neostigmine

Answer 8

ACh esterase inhibitor (used to treat myasthania gravis)

Question 9

Hemicholinium

Answer 9

Blocks choline reuptake and depleted ACh stores

Question 10

What do excitatory neurotransmitters do?

Answer 10

Depolarize the postsynaptic cell producing EPSP (ACh, epinephrine, dopamine)

Question 11

What do inhibitory neurotransmitters do?

Answer 11

Hyperpolarize via opening Cl- and K+ channels producing IPSP (GABA and glycine)