Endocrinology- anterior and posterior pituitary glands

Question 1

Pituitary gland also known as? Lies where in the brain? Connected to hypothalamus via what? Anterior sometimes called what? Posterior lobe sometimes called?

Answer 1

Hypophysis 
In a pocket of the sphenoid bone at base of the brain just below hypothalamus 
Infundibulum/ pituitary stalk
Adenohypophysis 
Neurohypophysis

Question 2

What does the hypothalamus do via the hypothalamus-hypophyseal portal vessels? Stimulated to release these by what?

Answer 2

Secrete hypophysiotropic hormones which reach the anterior pituitary- further stimulate anterior to release 6 hormones
CNS receptors that detect outside environment

Question 3

Action potentials in hypothalamus neurones causes to do what?

Answer 3

Secrete hormones via exocytosis similar to other neurones releasing NTs

Question 4

Hypophysiotropic hormones released from hypothalamus to anterior pituitary?

Answer 4

Corticotropin-releasing hormone(CRH)
Growth-hormone-releasing hormone (GHRH)
Somatostatin (SST)
Thyrotropin-releasing hormone (TRH)
Gonadotropin-releasing hormone (GnRH) 
Dopamine

Question 5

CRH stimulates release of what from anterior?
GHRH stimulates release of what? Somatostatin inhibits the release of what?
TRH stimulates release of what? GnRH stimulates the release of what? Dopamine inhibits the release of what?

Answer 5

Adrenocorticotropic hormone (ACTH) 
Growth hormone (GH) 
GHRH
TSH
LH and FSH
Prolactin

Question 6

What doesn’t the anterior pituitary have? Receives blood from where? Contains how many types of hormone producing cell and produces how many hormones?

Answer 6

Arterial blood supply and neural connections to the hypothalamus
Hypothalamo-hypophyseal portal vessels
5 types of hormone producing cell and produces 6 hormones

Question 7

Benefit of 3 step sequence of hypothalamus–anterior pituitary– hormone from other endocrine gland acting on target cells?

Answer 7

Permit variety of hormonal feedback and allow amplification of small number of hypothalamic neurones–> large peripheral hormonal signal

Question 8

6 peptide hormones released from anterior pituitary? Mnemonic to remember?

Answer 8

FSH- produced in gonadotrophs 
LH- in gonadotrophs 
ACTH- in corticotrophs 
TSH- in thyrotrophs 
Prolactin- in lactotrophs 
GH- in somatotropin 
FLATPIG- ignore I

Question 9

FSH and LH do what? GH does what? ACTH does what? TSH does what? Prolactin does what?

Answer 9

Stimulate germ cell development and release of hormone (females= estradiol and progesterone, males= testosterone)
Growth and protein synthesis
Stimulates adrenal cortex to secrete cortisol
Stimulates thyroid to secrete T3 and T4–> increased metabolism
Stimulates breasts to produce milk and breast development

Question 10

TRH stimulates what….?

Answer 10

TSH from anterior–> T3 and T4 from thyroid–> increased metabolism

Question 11

GnRH stimulates what….?

Answer 11

LH and FSH–> gonads produce oestrogen, progesterone and testosterone

Question 12

GHRH stimulates what…?

Answer 12

GH from anterior–> growth and protein synthesis

Question 13

Somatostatin does what?

Answer 13

Inhibits GH–> less growth and protein synthesis

Question 14

CRH stimulates what…?

Answer 14

ACTH release–> increase cortisol production in adrenal cortex from zona fasiculata

Question 15

Dopamine stimulates what….?

Answer 15

Inhibits prolactin—> inhibits growth and milk production

Question 16

What is a long-loop negative feedback? Hormones doing this? What hormone doesn’t?

Answer 16

The hormone secreted by a 3rd endocrine gland exerts a negative feedback effect over the anterior pituitary and/ or hypothalamus.
FSH, LH and TSH
Prolactin and GH

Question 17

Influence of an anterior pituitary gland hormone on the hypothalamus known as what? Symptoms of anterior pituitary gland tumour?

Answer 17

A short- loop negative feedback
Pressure on optic nerves–> bitemporal hemianopia
Pressure on normal pituitary–> hypo/ hyper-pituitarism

Question 18

2 peptide hormones released by posterior pituitary gland? Axons of supraoptic and paraventricular nuclei pass down where?

Answer 18

ADH (in cell body of supraoptic nucleus) and oxytocin (in cell body of paraventricular nucleus)
Pituitary stalk and terminate in posterior pituitary

Question 19

Hormones from hypo—> posterior enclosed in what? What triggers the release via exocytosis? Hormones then enter where?

Answer 19

Vesicles that accumulate at axon terminal in posterior pituitary
Various stimuli activate inputs to neurones causing action potentials to propagate to axon terminals and trigger release
Capillaries to be carried away by blood returning to heart

Question 20

ADH does what?

Answer 20

Decreases water secretion in kidneys and acts on smooth muscle cells around blood vessels to cause vasoconstriction to increase BP- may occur due to decrease from blood blood due to injury

Question 21

ADH released in response to what?

Answer 21

Decreased blood volume, trauma, stress, increase blood CO2, decreased blood O2 or increased osmotic pressure of blood

Question 22

Oxytocin stimulates what?

Answer 22

Contraction of smooth muscles of breasts resulting in milk ejection during lactation- due to stimulation of nipples during nursing of infant
Contraction of uterine smooth muscles until baby is born
Promotes onset of labour

Question 23

Oxytocin and ADH have what half-life?

Answer 23

Very short half-life- regulated frequently once released on a minute-to-minute basis

Question 24

All pituitary and hypothalamic hormones act on what receptors?

Answer 24

G-protein coupled receptors