Physiology

Question 1

Does sodium rush into the cell during an AP?

Answer 1

NO!

There is few sodium ions with lots of charge entering the cells. It isn’t enough that it changes the gradient, ions are just moving.

There is still much more Na outside the cell than in the cell.

Question 2

What does hypercholemia do to the membrane potential?

Which gate would always be shut or open?

Answer 2

Hypercholemia: more potassium outside the cell than normal will make the potential more positive.

This hypercholemia will close the inactivation gate, probably for good.

Question 3

What are two diseases of the neuromuscular junction.

Answer 3

Myasthenia Gravis: (MG)
Antibodies attack postsynaptic ACh receptors
Associated with thymoma
Muscles are weaker with repetition
Manifests with ptosis, diploid, muscle weakness at the end of the day.

Lambert-Eaton Syndrome:
Antibodies attack presynaptic Ca channels
Associated with small-cell lung cancer
Muscles are stronger with repetition
Manifests with difficulty rising from a chair and weakness of large muscles especially in the morning. Respiratory and ocular muscle involvement not as severe as in MG