Lecture 5: Neuromuscular Junction

Question 1

Which of the following are anchored to the presynaptic membrane and associated with synaptic vesicles to which they are tethered by short filaments?

A. synaptic vesicles
B. Calcium channels
C. Dense bars
D. DHP channels

Answer 1

C. Dense bars

Question 2

In order for Ach-gated channels to open, how many Ach molecules are necessary to attach to its alpha subunits?

A. One
B. Two
C. Three
D. Four

Answer 2

B. Two

Question 3

Which of the following represents the first thing that happens after Ach binds to the ligand-gated channels on the sarcolemma?

A. An action potential is created on the sarcolemma
B. DHP channels allow entry of calcium ions
C. An end plate potential is created on the muscle fiber
D. Ryanodine signaling channels allow calcium to escape into the myoplasm

Answer 3

C. An end plate potential is created on the muscle fiber

Question 4

Vesicles for Ach are transported to the axon terminal from where?

A. Rough ER
B. Smooth ER
C. Axon terminal membrane
D. Golgi

Answer 4

D. Golgi

Question 5

Which of the following can be used to inactivate acetylcholinesterase?

A. Methacholine
B. Curare
C. Physostigmine
D. Carbachol

Answer 5

C. Physostigmine