Endocrinology 1 - Hormonal Axis

Question 1

6 hormones released by the anterior pituitary

2 hormones released by the posterior pituitary

Answer 1

6 anterior =
TSH, ACTH, GH, FSH+LH, prolactin

2 posterior =
ADH, oxytocin

Question 2

describe the thyroid axis

Answer 2

hypothalamus - TRH
A pituitary - TSH
thyroid - T3, T4
as T3,4 increase, TRH + TSH are repressed

Question 3

describe the adrenal axis

Answer 3

hypothalamus - CRH
A pituitary - ACTH
adrenal zona fasciculata - cortisol
cortisol suppresses CRH+ACTH

(NB outermost layer glomerulosa does aldosterone)

Question 4

5 actions of cortisol in the body

Answer 4

diurnal variation, morning peak, stress triggers

• inhibits immune system
• inhibits bone formation
• raises blood glucose
• increases metabolism
• increases alertness

Question 5

growth hormone axis

Answer 5

hypothalamus - GnRH
A pituitary - GH
liver - IGF-1
muscles/bones/cells/organs stimulated

Question 6

parathyroid axis

Answer 6

PTH secreted if calcium low or magnesium low or phosphate high

PTH - increases bone resorption + renal reabsorption of calcium, increases phosphateexcretion, triggers Vit D active form

calcitriol - active vit D increases gut calcium reabs,

Question 7

renin angiotensin system

Answer 7

renin secreted by JGA in afferent arterioles in kidney

more released if BP low

renin converts angiotensinogen (liver made) to angiotensin I

converted in lungs to Ang II by ACE

Ang II stimulates aldosterone secretion and vasoconstricts

Question 8

aldosterone actions x3

Answer 8

increased distal tubule sodium reabsorption
increased distal tubule potassium secretion
increased collecting duct hyrdogen secretion