HIST Pituitary, Thyroid & Adrenal Glands Workshop - Week 11

Question 1

Describe process of ant pit hormone secretion

Answer 1

For anterior pit. hormones, stimulating hormones are synthesised in the hypothalamus & secreted into capillaries -> travels via veins into ant. pituitary -> stimulate cells to synthesise & secrete hormones -> enter bloodstream.

Question 2

Describe process of post pit hormone secretion.

Answer 2

For posterior pit. hormones, hormones are synthesised in the hypothalamus -> travel via axons of the neurons which create them -> stored in ends of the axons in the post. pituitary - > later released into capillaries to travel to post. pituitary.

Question 3

Somatotrophs are found in what endocrine organ, release what hormone, are under what hypothalamic control & have what action?

Answer 3

Ant pit. GH. GHRH (releasing) & SRIF (somatostatin inhibiting). Growth promotion.

Question 4

Thyrotrophs are found in what endocrine organ, release what hormone, are under what hypothalamic control & have what action?

Answer 4

Ant pit. TSH. TRH, SRIF. Secretion of thyroid hormones.

Question 5

Corticotrophs are found in what endocrine organ, release what hormone, are under what hypothalamic control & have what action?

Answer 5

Ant pit. ACTH. CRH, AVP. Secretion of cortisol.

Question 6

Lactotrophs are found in what endocrine organ, release what hormone, are under what hypothalamic control & have what action?

Answer 6

Ant pit. Prolactin. TRH (Thytrophin-releasing hormone), dopamine - inhibitory. Milk secretion.

Question 7

Gonadotrophs are found in what endocrine organ, release what hormone, are under what hypothalamic control & have what action?

Answer 7

Ant pit. FSH, LH. GnRH. Production of gametes, secretion of sex steroids.

Question 8

Post pit synthesises & secretes what hormones?

Answer 8

ADH & oxytocin.

Question 9

What 2 classes of hormones does the adrenal cortex synthesise?

Answer 9

Protein & steroid hormones.

Question 10

Adenohypophysis

Answer 10

Ant pit.

Question 11

Pars distalis

Answer 11

Ant pit.

Question 12

Pars nervosa

Answer 12

Post pit.

Question 13

Neurohypophysis

Answer 13

Post pit.

Question 14

How do hormones produced in the hypothalamus travel to the ant pit?

Answer 14

Hormones produced in hypothalamus pass through capillaries -> portal venous system -> capillaries @ ant pit where hormone will finally be released into the bloodstream.

Question 15

How do hormones produced in the hypothalamus travel to the post pit?

Answer 15

Post pit consists of nerve fibres from the hypothalamus, their terminals, being in close association with capillaries. Post pit hormones are peptides, which are synthesised in the hypothalamus, then bound to carrier proteins and stored in granules in the axon terminals until discharged by exocytosis.

Question 16

What tissue is the ant pit derived from?

Answer 16

Oral ectoderm (epithelial organ).

Question 17

What tissue is the post pit derived from?

Answer 17

Nervous tissue.

Question 18

What are the main cells composing the ant pit gland? How are these cells arranged?

Answer 18

Secretory cells. Often arranged in clumps/cords.

Question 19

What hormones does the thyroid gland synthesise and how are these created - what critical mineral/element is required and from where is this sourced?

Answer 19

Makes & stores hormones - T3 & T4. These hormones can be stored for months in colloid tissue (which also includes iodinated glycoprotein, thyroglobulin), until release post signal.

Question 20

What epithelial cells surround follicular cells?

Answer 20

Simple cuboidal/simple squamous cells.

Question 21

What is the inner layer of stromal cells surrounding a follicle called? What is their function?

Answer 21

Thecal cells. Secrete steroid precursors.

Question 22

What receptors do thecal cells have?

Answer 22

LH receptors.

Question 23

What is an immature follicle termed?

Answer 23

Primordial follicle.

Question 24

What cells are the main steroid producing cells of the testis? Where are they found? What hormones do they respond to? What steroids do they mainly synthesise? Where are these steroids secreted?

Answer 24

Leydig cells. Interstitial tissue (space btw seminiferous tubules). Respond to LH from the ant pit. Smooth ER characteristic of these cells to support testosterone synthesis. Testosterone secreted into lymphatics.

Question 25

2 x regions of the adrenal gland

Answer 25

Inner medulla & outer cortex.

Question 26

What are the main cells of the inner adrenal medulla? What is their main function? What cells are they derived from? How are they usually arranged?

Answer 26

Chromaffin cells - modified symp post-ganglionic neurons. Derived from neural crest cells. Synthesise & store A & NA. Nests & cords.

Question 27

What 2 x classifications of hormones does the adrenal cortex synthesise?

Answer 27

Protein & steroid hormones.

Question 28

What are the 3 x layers of the adrenal cortex?

Answer 28

• Zonula glomerulosa – synthesises & secretes mineralcorticoids (e.g., aldosterone) to regulate fluid.
• Zonula fasiculata – synthesise glucocorticoids (e.g., cortisol) w foamy appearance histologically due to high presence of lipid droplets required to synthesise these hormones.
• Zonula reticularis – synthesise weak androgens (e.g., DHEA – precursor of testosterone).
  Remember: GFR & salt, sugar, sex.

Question 29

What hormones are produced by the endocrine pancreas?

Answer 29

Insulin & glucagon.

Question 30

How many parathyroid glands are there usually? What is the function of these glands?

Answer 30

4. Secretes parathyroid hormones strongly regulating Ca2+ homeostasis.

Question 31

What kind of hormone is Vit D classified as?

Answer 31

Steroid.

Question 32

What kind of hormone is insulin classified as?

Answer 32

Peptide hormone.