Exam 2 Lecture - Neuromuscular junction

Question 1

Where are somatic motor innervations located?

Answer 1

in the ventral horn

Question 2

What is the neurotransmitter associated with somatic motor innervations?

Answer 2

acetylcholine

Question 3

What is the structure of the neuromuscular junction?

Answer 3

motor end plate and a junctional fold of sarcolemma

Question 4

What are the steps involved in neuromuscular transmission?

Answer 4

• action potential opens voltage gated Ca channels
• synaptic vesicles release Ach by exocytosis
• Ach opens ligand gated ion channels for Na
• Na influx and membrane depolarize
• Voltage gated Na and K channels open when the membrane voltage is greater than the threshold voltage of the muscle cell

Question 5

How does tic paralysis occur?

Answer 5

the neurotoxin is secreted by feeding female wood ticks interferes with the release of Ach

Question 6

What is a symptom of tic paralysis?

Answer 6

generalized muscle weakness

Question 7

What type of deficit is tic paralysis?

Answer 7

presynaptic deficit

Question 8

What does myasthenia gravis do?

Answer 8

the antibody blocks, alters, or destroys AChR, decreasing the numbers of available AChR

Question 9

What is a symptom of myasthenia gravis?

Answer 9

progressive loss of muscle strength

Question 10

What is myasthenia gravis typically seen as?

Answer 10

exercise induced motor weakness that improves following rest