Muscles -- Lecture 21 (exam 3)

Question 1

structure of a nerve:

nerves are a collection of ___

Answer 1

axon bundles (fascicles)

Question 2

structure of a nerve:

nerves are surrounded by a ___

Answer 2

nerve sheath

Question 3

neuromuscular junction (definition)

Answer 3

connection b/n neurons and muscles

Question 4

normal pathway of a nerve signal:

Answer 4

action potential reaches axon termini

vesicles containing neurotransmitters

vesicles fuse to pre-synaptic membrane

release of neurotransmitters across synaptic cleft –> neurotransmitter receptors on post-synaptic membrane

muscle contraction

Question 5

synapse (definition)

Answer 5

pre and post synaptic membranes + synaptic cleft

Question 6

how does botulinum toxin (botox) paralyze muscles?

what exactly does botox do

Answer 6

botox – blocks fusion of the vesicles w/ the pre-synaptic membrane

neurotransmitter is not released

Question 7

how does botulinum toxin (botox) paralyze muscles?

describe the pathway

Answer 7

action potential reaches axon termini

vesicles containing neurotransmitters receive the signal to fuse w/ the pre-synaptic membrane

botox – blocks the fusion of the vesicles w/ the pre-synaptic membrane

neurotransmitter is not released –> neurotransmitters don’t cross the synaptic cleft to reach neurotransmitter receptors on post-synaptic membrane

communication b/n neuron and muscle is cut off

Question 8

dynamic wrinkles (what are they)

Answer 8

wrinkles that appear when facial muscles contract

Question 9

what does botox do to facial muscles?

Answer 9

botox injections paralyze the facial muscles

Question 10

caution: if botox is not injected properly, it can cause a condition called ___

Answer 10

frozen face