2.5 Hypothalamic-Pituitary Axis

Question 1

What are the other names of the anterior and posterior pituitary?

Answer 1

Adenohypophysis and Neurohypophysis respectively

Question 2

Where is vasopressin released and what is its function?

Answer 2

Posterior pituitary from the suproptic nucleus, function is to conserve water by reabsorption in the collecting tube

Question 3

What is the result of deficient vasopressin?

Answer 3

Diabetes Insipidus - extreme thirst and polyuria, increased plasma sodium and osmolarity

Question 4

What two hormones are released from the posterior pituitary?

Answer 4

Vasopressin and oxytocin

Question 5

What hormones are released from the anterior pituitary?

Answer 5

TSH, ACTH, LH, FSH, Prolactin, GH

Question 6

What stimulates an inhibits TSH release?

Answer 6

Stimulated by TSH and inhibited by T3 and T4 feedback

Question 7

What stimulates and inhibits ACTH (adrenocorticotrophic hormone)?

Answer 7

Stimulated by CRF and inhibited by feedback from cortisol levels

Question 8

What is ACTH released as?

Answer 8

pro hormone: pro-opio-melanocorticin

Question 9

What inhibits LH in males and females

Answer 9

Testosterone and oestrogen

Question 10

What cells do LH work on in males and females?

Answer 10

Leydig cells in males and interstitial cells in females

Question 11

Where does FSH work in males and females and what inhibits it?

Answer 11

Males: sertoli cells, inhibited by inhibin
Females: Granulosa cells of ovarian follicle and inhibited by inhibition complex

Question 12

What is the role of prolactin and what stimulates and inhibits it?

Answer 12

Role is in lactation, stimulated by nipple-aroelar complex during suckling and is inhibited by dopamine prolactin inhibitory factor

Question 13

What stimulates and inhibits release of GH?

Answer 13

Stimulated by GHRH and inhibited by somatostatin

Question 14

What are the pituitary releasing hormones from the hypothalamus?

Answer 14

CRH: ACTH
TRH: TSH
GHRH: GH
GnRH: LH and FSH

Question 15

What is acrogmegaly and what is it called in children?

Answer 15

excess of GH in adults and in children this is gigantism

Question 16

What are the clinical features of acromegaly?

Answer 16

Increased ring, shoe, glove, hat size
increased lips, nose, soft tissue of face, tongue and jaw
Deep cavernous voice
Fleshy, enlarged hands and feet
Increased metabolic rate: sweating and warm skin
Skin tags
Joint problems

Question 17

What are the metabolic/visceral features of acromegaly

Answer 17

Hypertension
Glucose intolerance
Cardiac enlargement/failure
Enlargement of spleen, liver, kidneys, thyroid, adrenal

Question 18

Treatment of acromegaly

Answer 18

Surgery: trans-spenoidal and trans-frontal
Somatostatin agonists
Radiotherapy
Dopamine agonists (not very effective)

Question 19

What is the blood and nerve supply for the anterior pituitary?

Answer 19

median eminence from the hypothalamus and sympathetic/parasympathetic nerves

Question 20

What is the blood and nerve supply for the posterior pituitary?

Answer 20

supraoptic and paraventricular nuclei in hypothalamus