Wk 4

Question 1

What are the two components of the pituitary gland?

Answer 1

Adenohypophysis (anterior pituitary)

Neurohypophysis (posterior pituitary, release oxytocin & ADH)

Question 2

How many cell types make up the anterior pituitary?

Answer 2

5 cell types

Question 3

What are the secretory cell types?

Answer 3

1. Somatotropes
2. Lactotropes
3. Corticotropes
4. Thyrotropes
5. Gonadotropes

Question 4

How many hormones do the cell types secrete?

Answer 4

6 hormones

Question 5

What is adenohypophysis composed of?

Answer 5

1. Pars Distalis (90%)
2. Pars Tuberalis
3. Pars Intermedia

Question 6

What are the two groups of cell types?

Answer 6

1. Acidophils (somatotropes, lactotropes)
2. Basophils (corticotropes, thyrotropes, gonadotropes)

Question 7

What are somatotropes?

Answer 7

• Release GH
• Target liver and other growing tissues
• Function is growth and stimulation of IGF-1

Question 8

What are lactotropes?

Answer 8

• Release prolactin (PRL)
• Target the mammary gland
• Function is milk production

Question 9

What are corticotropes?

Answer 9

• Release ACTH
• Target the adrenal cortex
• Function is cortisol and adrenal androgens

Question 10

What are thyrotropes?

Answer 10

• Release TSH
• Target the thyroid gland
• Function is the control of thyroid hormones

Question 11

What are gonadotropes?

Answer 11

• Release LH & FSH
• Target the gonads
• Function is to control Estrogen, testosterone, progesterone

Question 12

Define tropic hormones

Answer 12

Hormones that are released by an endocrine gland and act upon another endocrine gland.

Question 13

What are tropic hormones?

Answer 13

• ACTH
• TSH
• LH & FSH

Question 14

Define trophic hormones

Answer 14

Stimulate growth in target tissues.

Question 15

What are trophic hormones?

Answer 15

• GH
• Prolactin

Question 16

What is the difference between peptide and glycoprotein?

Answer 16

Peptide - smaller unit of a protein

Glycoprotein - many proteins joined

Question 17

Which hormones are proteins?

Answer 17

ACTH (peptide), GH, Prolactin

Question 18

Which hormones are glycoproteins?

Answer 18

TSH, LH, FSH

Question 19

What are the ACTH receptors?

Answer 19

MC2R –> increased cortisol and androgens in adrenal cortex.

MC1R –> hyperpigmentation (excess ACTH)

Question 20

What is the ACTH biosynthetic pathway?

Answer 20

Gs-cAMP-PKA signalling pathway

Question 21

What is the ACTH axis (negative feedback loop)?

Answer 21

Hypothalamic
Pituitary
Adrenal

Question 22

What is the action of ACTH?

Answer 22

Diurnal variation (fluctuations in 24hr cycle) in secretion; regulated by CRH; ADH with CRH stimulates ACTH.

Question 23

What are TSH receptors?

Answer 23

Thyroid gland cells

Question 24

What is the TSH biosynthetic signalling pathway?

Answer 24

Gs-cAMP-PKA signalling pathway

Question 25

What is the TSH axis (negative feedback loop)?

Answer 25

Hypothalamic Pituitary Thyroid

Question 26

What is the action of TSH?

Answer 26

Stimulates all steps in thyroid hormone synthesis.

Question 27

What are LH & FSH receptors?

Answer 27

Gonads (testis and ovary)

Question 28

What is the biosynthetic pathway for LH & FSH?

Answer 28

Gs-cAMP-PKA signalling pathway

Question 29

What is the axis for LH & FSH (negative feedback loop?

Answer 29

Hypothalamic Pituitary Gonads

Question 30

What is the action for LH & FSH?

Answer 30

Glycoprotein hormones have alpha and beta subunits, alpha subunit common for glycoprotein hormones.

Question 31

What are GH receptors?

Answer 31

Growth hormone receptors

Question 32

What is the biosynthetic signalling pathway for GH?

Answer 32

JAK-STAT signalling pathway

Question 33

What is the axis for GH (negative feedback loop?

Answer 33

Hypothalamic Pituitary Growth

Question 34

What is the action for GH?

Answer 34

Two regulatory hormones from hypothalamus, GHRH & GHIH.

Question 35

What is the prolactin biosynthetic synthesis pathway?

Answer 35

JAK-STAT signalling pathway

Question 35

What are prolactin receptors?

Answer 35

Breast tissue - Causes milk production, breast growth & development, duct proliferation, milk protein synthesis

Question 36

What is the action of prolactin?

Answer 36

Inhibitory signal from hypothalamus: - Dopamine inhibits prolactin --> increases GnRH --> increases FSH, LH --> ovulation - TRH stimulates prolactin --> inhibits GnRH --> inhibits FSH, LH --> no ovulation

Question 37

What is prolactinoma?

Answer 37

Hypersecretion of prolactin (most frequent pituitary hyper secretion). - Causes infertility in males - Causes amenorrhea, galactorrhoea, menstrual irregularities in females