Endocrine System

Question 1

What are the two classes of hormones?

Answer 1

lipid and water soluble

Question 2

Name a lipid-soluble hormone

Answer 2

steroids

Question 3

Name a water-soluble hormone

Answer 3

amines eg epinephrine

Question 4

How are lipid-soluble hormones are transported in the blood?

Answer 4

they circulate in the blood by binding to transport proteins (synthesised by liver)

Question 5

How are water-soluble hormones are transported in the blood?

Answer 5

circulate free in the blood stream

Question 6

Outline the mechanism of action of water-soluble hormones

Answer 6

1. hormone (1st receptor) binds with receptor on cell membrane which activates G protein to turn on adenylate cyclase
2. this converts ATP into cAMP (2nd messenger) which activates protein kinases.
3. PKs phosphorylate cellular proteins which catalyse reactions to produce specific physiological responses. (Cell signalling)

Question 7

Name the 2 types of receptors that hormones attach to and identify which class of hormone attaches to each receptor.

Answer 7

• Transmembrane receptors (water-soluble)

* Nuclear receptors (lipid-soluble)

Question 8

List any 3 hypothalamic hormones that regulate release of hormones from the anterior pituitary gland. (Note: full names required)

Answer 8

• GnRH (Gonadotropin-releasing hormone
• (TRH) Thyrotropin-releasing hormone
• (PIF) Prolactin-inhibiting factor

Question 9

How does the hypothalamus regulate the anterior pituitary gland using Thyrotropin Releasing Hormone?

Answer 9

• LOW T3/T4 concentration in blood
• hypothalamus releases TRH
• triggers the release of TSH by the anterior pituitary.
• triggers the release of T3 and T4 by Thyroid Follicle Cells.

(increase basal metabolic rate & body temp)

• HIGH T3 or T4 concentration
• Hypothalamus stops TRH release
• Stops the anterior pituitary from releasing TSH

Question 10

List the 2 hypothalamic hormones that are secreted to the posterior pituitary gland.

Answer 10

• antidiuretic hormone

* oxytocin