Glucose Homeostasis and DM

Question 1

What is the most important source of energy for cellular respiration?

Answer 1

Glucose

Question 2

Glucose is regulated at two levels, what are they?

Answer 2

Cellular and systemic

Question 3

List two reasons why glucose homeostasis is important.

Answer 3

Some organs rely solely on glucose for energy, dietary glucose supply is irregular

Question 4

Define glycolysis

Answer 4

the conversion of glucose into pyruvate and ATP

Question 5

Define glycogenolysis

Answer 5

release of stored glycogen into glucose

Question 6

Define gluconeogenesis

Answer 6

making glucose from other stores when BGL low

Question 7

What is the optimal BGL range?

Answer 7

4.-5-5.5mmo/L

Question 8

What are the main target tissues of insulin?

Answer 8

liver, muscle and adipose tissue

Question 9

What hormones oppose insulin?

Answer 9

glucagon, epi, GH and cortisol (stress hormones cause increase in BGL)

Question 10

Differentiate between the two types of glucose transporters.

Answer 10

GLUTs: membrane bound facilitated glucose transporters, 4 types
SGLTs: sodium glucose cotransporters, 2 types, glucose uptake in gut and kidneys

Question 11

List the major hormone producing cell types of the pancreas and what they each produce.

Answer 11

alpha cell produce glucagon, beta cells produce insulin

Question 12

Where are endocrine cells located in the pancreas?

Answer 12

In the islets of Langerhans

Question 13

What are the functions of beta cells?

Answer 13

Beta cells detect BGL levels, release stored insulin granules into systemic circulation to act on target tissue when BGL too high

Question 14

List the main actions of insulin

Answer 14

Insulin clears glucose from the blood by binding to receptor, stimulating second messenger system = GLUT4 translocates to cell membrane and deposits glucose into tissues, prevents body making new glucose

Question 15

List the main actions of glucagon

Answer 15

Glucagon stimulates conversion of stored glycogen to be released as glucose, breaks down fats for other cells to use so glucose saved for brain

Question 16

Differentiate between T1DM, T2DM and GDM

Answer 16

T1DM involves genetic predisposition and environmental trigger, most common in 9-14y/o, involves damage to beta cells in pancreas, insulin dependent for life.
T2DM involves release and synthesis of insulin however sensitivity of insulin dependent peripheral tissues is altered.
GDM involves an elevated BGL during pregnancy.

Question 17

What are the main functions of the key glucose transporters?

Answer 17

regulate intestinal and renal absorption and cellular uptake

Question 18

Differentiate between location of actions of GLUT1, GLUT2, GLUT3 and GLUT4

Answer 18

GLUT2: pancreatic glucose transporter, GI main glucose transporter
GLUT3 and GLUT1: brain
GLUT4: muscle, fat and insulin sensitive, directly regulated by insulin