Lecture 32: Hormones

Question 1

What do endocrine gland cells do?

Answer 1

Secrete hormones

Question 2

Which organ links the nervous system to the endocrine system?

Answer 2

The hypothalamus links the two systems and controls the secretion of many endocrine glands.

Question 3

A hormone can only affect cells with ________ _______ for that hormone.

Answer 3

A hormone can only affect cells with SPECIFIC RECEPTORS for that hormone.

Question 4

Where do hormones move into the ISF?

Answer 4

At capillaries.

Question 5

What are the 2 types of hormones?

Answer 5

Lipid and water soluble.

Question 6

What are the 2 types of water soluble hormones?

Answer 6

Peptides and Catecholamines

Question 7

What is an example of catecholamines?

Answer 7

Adrenaline, noradrenaline…

Question 8

What are the 2 types of lipid soluble hormones?

Answer 8

Steroids and Thyroid Hormones (inc. T3 & T4)

Question 9

Explain the production and storage of the different types of hormones.

Answer 9

Water soluble hormones are made and stored until required, then released by exocytosis.

Steroids are made from cholesterol as required (NOT stored), and Thyroid hormones are made in thyroid cells and stored until required.

Question 10

How do lipid soluble hormones travel in the blood?

Answer 10

Bound to a carrier protein.

Question 11

Where are hormone receptors located?

Answer 11

Water soluble hormone receptors are located in the cell membrane, as the hormones can’t pass through.

Lipid soluble hormone receptors are located in the cytoplasm or nucleus as they can diffuse across the membrane.

Question 12

Explain the steps in cellular response to water soluble hormone receptor activation.

Answer 12

1. WS hormone binds to cell surface receptor.
2. Binding activates protein.
3. Protein activates adenylyl cyclase.
4. SECOND MESSENGER PRODUCTION.
5. Messenger activates protein.
6. Protein activates enzyme.
7. Enzyme converts substrate into PRODUCT.

Question 13

Explain the steps in cellular response to lipid soluble hormone receptor activation.

Answer 13

1. LP hormone dissociates from carrier protein.
2. Hormones diffuses through membrane.
3. Binds to INTRACELLULAR receptor.
4. Hormone receptor complex acts as transcription factor.
5. New mRNA is generated.
6. New protein is created by translation.
7. New protein mediates cell’s RESPONSE (slow process)

Question 14

How fast are LS and WS hormones?

Answer 14

WS: ms -mins
LS: hrs - days

Question 15

What 2 things determine the amount of hormone in the bloodstream?

Answer 15

Rate of secretion and rate of removal.

Question 16

What type of control loop do most hormones use?

Answer 16

Negative feedback control. (eg. change detected -> mechanism activated -> back to homeostatic set point)

A few use positive feedback at specific times.