Physiology Quiz: Endocrine Pancreas - Part 2

Physiology Quiz -
Endocrine Pancreas - Part 2

The pancreas is a compound gland. It is both an endocrine gland, and an exocrine gland. The exocrine pancreas plays a crucial role in food digestion by secreting digesting enzymes and bicarbonate into the duodenum portion of the small intestine. The endocrine part of the pancreas is responsible for secreting at least four important hormones, two of which, insulin and glucagon, play an important role in plasma glucose homeostasis. Test your basic knowledge of the endocrine pancreas by taking this simple quiz.

(1) The endocrine portion of the pancreas is composed of clusters of cells organized into structures referred to as the __________.

(2) An increase in glucose concentration in the extracellular fluid of pancreatic insulin-secreting cells results in the generation of action potentials in these cells. The action potentials ultimately lead to insulin secretion. Which of the following channels are responsible for the initial depolarization of these endocrine cells to threshold?

	(A) Voltage-gated K⁺ channels similar to those found in neurons
	(B) Voltage-gated Na⁺ channels similar to those found in neurons
	(C) K_ATP channels
	(D) Ca²⁺-activated K⁺ channels (also referred to as maxi K channels)
	(E) Voltage-gated Ca²⁺ channels similar to those found in neurons

(3) An increase in glucose concentration in the extracellular fluid of pancreatic insulin-secreting cells results in the generation of action potentials in these cells. The action potentials ultimately lead to insulin secretion. Which of the following channels are responsible for the spike phase of the action potential in these endocrine cells?

	(A) Voltage-gated K⁺ channels similar to those found in neurons
	(B) Voltage-gated Na⁺ channels similar to those found in neurons
	(C) K_ATP channels
	(D) Ca²⁺-activated K⁺ channels (also referred to as maxi K channels)
	(E) Voltage-gated Ca²⁺ channels similar to those found in neurons

(4) An increase in glucose concentration in the extracellular fluid of pancreatic insulin-secreting cells results in the generation of action potentials in these cells. The action potentials ultimately lead to insulin secretion. Which of the following channels are responsible for membrane repolarization back to the resting potential in these endocrine cells?

	(A) Voltage-gated K⁺ channels similar to those found in neurons
	(B) Voltage-gated Na⁺ channels similar to those found in neurons
	(C) K_ATP channels
	(D) Ca²⁺-activated K⁺ channels (also referred to as maxi K channels)
	(E) Voltage-gated Ca²⁺ channels similar to those found in neurons

(5) The facilitative glucose transporter isoform that is regulated by insulin in its target tissues is:

	(A) GLUT1
	(B) GLUT2
	(C) GLUT3
	(D) GLUT4
	(E) GLUT5