13. Endocrinology - Pam Hagan

Question 1

1. Define the word homeostasis
2. Define the word hormones
3. What is the difference between an exocrine gland and an endocrine gland?

Answer 1

1. Maintenance of a constant environment within and around living cells
2. Collection of glands that secrete chemical messages. Trigger actions in specific target cells
3. Exocrine gland: pour secretions into a duct .e.g. Sweat glands and tear glands
   Endocrine gland: pour secretions into blood vessels then to target

Question 2

Name the 5 types of hormone communication and describe how they work

Answer 2

1. Endocrine: transport in blood to distant site
2. Intracrine: within cell
3. Paracrine: on a nearby cell
4. Autocrine: back on the producing cell
5. Juxtacrine: connecting cells (needs physical contact)

Question 3

What are the 3 types of influences exerted by other hormones and how do they work?

Answer 3

1. Permissive effect: one strengthens effect of another
2. Synergistic effect: both needed together
3. Antagonistic effect: one has an opposite effect to the other

Question 4

What are the 4 classes of hormones? State their solubility and give an example.

Answer 4

1. Peptide hormones: water soluble
   Insulin/ glucagon/ GH/ FSH
2. Derivatives of phenylalanine: water soluble
   Adrenaline/ noradrenaline
3. Derivatives of arachidonic acid: water soluble
   PGs/ thromboxanes/ LTs
4. Steroid hormones: lipid soluble
   Glucocorticoids/ aldosterone/ sex hormones

Question 5

Describe the 4 steps of peptide hormone biosynthesis

Answer 5

1. Peptide hormone translated on RER as pre-prohormone
2. Co-translationally cleaved into prohormone
3. Post-translationally cleaved into parent hormone
4. Stored in secretory vesicles of endocrine gland

Question 6

What is produced when the POMC gene is cleaved?

Answer 6

8 different peptide hormones

Question 7

Steroid hormones

1. What is the precursor?
2. What are the 4 families?
3. What stimulates steroid hormone production?
4. What does the adrenal cortex secrete?
5. What do the ovaries secrete?
6. What does the placenta secrete?
7. What do the testes secrete?

Answer 7

1. Cholesterol
2. Corticoids/ progestins/ androgens/ oestrogens
3. Peptide hormones