Lecture 16

Question 1

What is a regulatory (tropic) hormone?

Answer 1

A hormone that acts to alter the secretion of another hormone

Question 2

What is an effector hormone (non-tropic)

Answer 2

A hormone that has direct physiological effects on its target cells

Question 3

What are the 8 hormones released by the anterior and posterior lobes of the pituitary?

Answer 3

1. Thyroid stimulating hormone (TSH)
2. Adrenocorticotropic hormone (ACTH)
3. Growth hormone (GH)
4. Prolactin
5. LH
6. FSH
7. Vasopressin (ADH)
8. Oxytocin (OT)

Question 4

What is the difference between the role of the hypothalamus in the release of posterior vs anterior pituitary hormones??

Answer 4

• The posterior pituitary hormones are secreted in the hypothalamus and released by the pituitary
• the anterior pituitary hormones are secreted after the hypothalamus secretes a different hormone

Question 5

What are the three main causes of hormone hyposecretion?

Answer 5

Metabolic: lack of iodine
physical damage: stroke, tumour brain damage, target organ damage
congenital disorders: mutation in gene coding for peptide hormones/enzyme that synthesizes non-peptide hormones, or hormone insensitivity

Question 6

What is the most common cause of hormone hypersecretion?

Answer 6

Endocrine tumours

Question 7

What are some functions of the hypothalamus?

Answer 7

• controlling survival behaviours
• regulating circadian rhythm
• secreting hormones through the pituitary gland
• regulating alertness and limbic system

Question 8

Where is ADH secreted ?

Answer 8

neurons in the supra-optic nuclei

Question 9

Where is OT secreted?

Answer 9

Neurons in the paraventricular nuclei

Question 10

What is the function of ADH? What is the function of OXT?

Answer 10

• Water reabsorption by the kidneys

- uterine contraction during labour, milk letdown in lactating mammary glands

Question 11

What is a hormone axis? How are they regulated?

Answer 11

• A set of hormones and organs that influence each other through a complex set of interactions (hypothalamic neurons, anterior pituitary cells and target organ)
• negative feedback

Question 12

What is the difference between tropic and trophic? Which pituitary hormones are both?

Answer 12

Tropic: alters the secretion of another hormone
Trophic: a hormone that stimulates cell division in its target cells
- ACTH, TH, LH, FSH

Question 13

Each axis involves three types of hormones:

Answer 13

Releasing, pituitary and effector

Question 14

Which hormone regulates the overall activity of the axis and how does it do this?

Answer 14

Effector hormone, by inhibiting the release of releasing hormones and pituitary hormones

Question 15

What is the HPA axis?

Answer 15

CRH— ACTH—Adrenal cortex—glucocorticoids

Question 16

What is the HPG axis?

Answer 16

GnRH—FSH/LH—testes: inhibin and androgens, ovaries: inhibin estrogens and progesterone estrogens

Question 17

What is the growth hormone axis?

Answer 17

• GH-IH/GH-RH—GH (acts on epithelia, adipose and liver)— liver—somatomedins stimulate growth of skeletal muscle, cartilage, other tissues
• both GH and somatomedin act on the hypothalamus for negative feedback