Midterm

Question 1

What are the different types of cells found in the anterior pituitary? What do they release?

Answer 1

1. Somatotrophs - growth hormone
2. Lactotrophs - prolactin releasing hormone
3. Thyrotrophs - thyroid stimulating hormone
4. Corticotrophs - adrenocorticotropic hormone
5. Gonadotrophs -

Question 2

What is the function of Insulin-like Growth Factor 1 (IGF-1)?

Answer 2

Mediates growth promoting effects of growth hormone

Question 3

What promotes the synthesis of Insulin-like Growth Factor 1 (IGF-1)?

Answer 3

Stimulated by growth hormone through hepatocytes (in the liver)

Question 4

What it the function of Janus Kinase 2 (JAK2)?

Answer 4

Auto-phosphorylates and phosphorylates growth hormone receptors to provide a docking site for STAT

Question 5

What is Acromegaly?

Answer 5

Excess growth hormone after puberty - the body keeps growing after growth plates close

Question 6

What is Laron Syndrome?

Answer 6

Resistance to growth hormone leading to elevated growth hormone levels and low IGF-1 levels

Question 7

What is Cushing Syndrome?

Answer 7

High levels of glucocorticoids suppressing growth by increasing somatostatin secretion

Question 8

What are the growth factors that use receptor tyrosine kinases?

Answer 8

1. IGF-1/IGF-2
2. Epidermal (EGF)
3. Fibroblast (FGF)
4. Nerve (NGF)

Question 9

What are the hormones that affect growth?

Answer 9

Thyroid, gonadal, glucocorticoid, growth and IGF-1/2

Question 10

What is the role of the placenta?

Answer 10

It is an endocrine organ that is critical for fetal growth - supplied nutrients and oxygen - produces/release many hormones

Question 11

What are the four cells in the Islet of Langerhans?

Answer 11

Glucagon (α cells)
Insulin (β cells)
Somatostatin (δ cells)
Pancreatic polypeptide

Question 12

What is the difference between hypoglycemia and hyperglycemia?

Answer 12

Hypo = low glucose levels
Hyper = high glucose levels (affects osmotic balance of blood)

Question 13

How is insulin secreted?

Answer 13

1. β cells sense glucoses levels
2. Glucose enters β cells via GLUT2
3. Glycolysis and oxidative phosphorylation occurs to increase ATP/ADP
4. ATP dependent K channels close leading to depolarization
5. Ca channels are activated causing the release of insulin

Question 14

What is the function of GLUT4?

Answer 14

Translocated to the cell surface to facilitate glucose uptake into that cell

Question 15

What inhibits glucagon secretion?

Answer 15

Insulin (β cells) and somatostatin (δ cells)

Question 16

What causes Type 1 Diabetes?

Answer 16

β cells destruction by T-cell lymphocytes

Question 17

What happens with Type 1 Diabetes?

Answer 17

The body acts as though it is in a fasted state even though there is high glucose in the blood.

Question 18

What risk factor gene is Type 1 Diabetes associated with?

Answer 18

Major histocompatibility complex

Question 19

What happens with insulin resistance during pregnancy?

Answer 19

β cell mass doubles and insulin sensitivity declines leading to increase insulin levels

Question 20

What is Gestational Diabetes?

Answer 20

Elevated glucose levels develop during pregnancy due to insulin resistance - increases risk of Type 2 diabetes

Question 21

What causes Type 2 Diabetes?

Answer 21

β cells can no longer compensate for increased demand
Constantly high glucose leads to high insulin secretion, but there is insulin resistance

Question 22

What happens to adiposity with an increase in insulin resistance?

Answer 22

An increase in adiposity (visceral/central fat depots)

Question 23

What are adipocytes?