Cell Polarization, Depolarization, and Insulin Release

Flashcards about cell polarization, depolarization, and repolarization, as well as insulin release.

What does it mean for a cell to be polarized?

Negative on the inside and positive on the outside; the state of resting cells.

How does a cell depolarize?

Sodium moving into a cell or calcium moving into a cell.

What processes are facilitated by a depolarized cell?

Muscle cell contraction, neuron neurotransmitter release, and pancreatic beta cell insulin release.

What causes repolarization?

Efflux of potassium, or potassium leaving the cell.

What is the role of secretory vesicles?

Secretory vesicles contain molecules that will eventually be released from the cell.

What is insulin?

A hormone that regulates glucose levels released from the pancreas.

What are the islets of Langerhans?

Regions within the pancreas that contain beta and alpha cells.

What do beta and alpha cells release?

Beta cells release insulin, and alpha cells release glucagon.

What is the role of Insulin when released?

It allows our downstream cells to utilize that glucose.

Describe a glucose leakage channel.

It has no gate and is always open, allowing glucose to move into the cell.

Describe a sodium leakage channel

It's not a gated channel; it allows sodium to move in whenever there's a higher concentration of sodium outside the cell.

What happens when the potassium ATPase channel is open?

If the potassium ATPase channel is open, potassium will leave the cell down its chemical gradient.

What happens when the voltage-gated calcium channel opens?

If this gate opens, calcium is going to move in down its electrochemical gradient.

What happens when glucose reacts with oxygen inside the beta cell?

Glucose reacts with oxygen to create ATP plus heat, water, and carbon dioxide.

What happens when ATP binds to the potassium ATPase channel?

ATP binds to the potassium ATPase channel and closes it which causes the cell to depolarize.

What causes the cell to depolarize when glucose levels are high?

The movement of sodium into the cell through leakage channels and the inability of potassium to leave the cell.

What is the result of the opening of the voltage-gated calcium channel?

Calcium moves into the cell and facilitates calcium-induced exocytosis, which releases insulin.