37: Hypothalamic/Pituitary Relations

Question 1

Neurohypophysis vs adenohypophysis

Answer 1

Neuro: posterior pituitary
Adeno: anterior pituitary

Question 2

How is the posterior pituitary connected to the hypothalamus?

Answer 2

Post pit is a collection of axons whose cell bodies are in the hypothalamus

Question 3

Two nuclei of the posterior pituitary

Answer 3

SON (supraoptic nulcei) and PVN (paraventricular nuclei)

Question 4

Two neuropeptides secreted by the posterior pituitary

Answer 4

ADH, oxytocin

Question 5

How does ant pit communicate with hypothalamus

Answer 5

Neurally and hormonally

Question 6

Connection between hypothalamus and pituitary gland and what’s inside it

Answer 6

Hypophyseal stalk, holds the hypothalamic-hypophyseal portal blood vessels

Question 7

What can pituitary tumors cause?

Answer 7

Pressure on optic nerves -> visual issues and dizziness

Question 8

Primary, secondary, and tertiary endocrine disorders regarding the HPA axis

Answer 8

Primary: targets peripheral gland
Secondary: targets pituitary
Tertiary: targets hypothalamus

Question 9

GH fluctuation during the day

Answer 9

Peaks with exercise and sleep

Question 10

GH fluctuation throughout lifetime

Answer 10

Peak at puberty, moderate amount as an adult, almost none in senescence

Question 11

Things that stimulate GH production

Answer 11

1. Fasting/hunger/starvation
2. Hypoglycemia
3. Puberty hormones
4. Exercise
5. Sleep
6. Stress

Question 12

Fed state influence on GH

Answer 12

Carbs and proteins -> GH produced -> liver produces IGF-1

Question 13

What is stimulated by GH in fed state?

Answer 13

Lipolysis, mitogenesis, differentiation of cells, synthesis of DNA/RNA/proteins

Question 14

GH action in low protein state

Answer 14

GH is inhibited -> no IGF-1 from liver

Question 15

What happens in low protein state?

Answer 15

Lipogenesis, carb storage, weight gain

Question 16

What happens with GH in a low carb state?

Answer 16

GH levels increase -> IGF-1 is produced

Question 17

What is stimulated by a low carb state?

Answer 17

Lipolysis, ketogenic metabolism, diabetogenic state

Question 18

Diabetogenic state

Answer 18

Insulin sensitivity - increased blood glucose causes insulin resistance, so there is decreased glucose uptake and utilization by target tissues -> increased blood insulin levels

Question 19

Causes of gigantism vs acromegaly

Answer 19

Gigantism: excess GH before closure of bone epiphyses
Acromegaly: excess GH after closure of bone epiphyses

Question 20

What occurs in acromegaly?

Answer 20

Promotion of growth of deep organs, bones, and cartilage

Question 21

Hormonal cause of gigantism

Answer 21

IGF-1 stimulates long bone growth

Question 22

GH insensitivity

Answer 22

GH receptors on liver are non-functional -> less IGF-1 -> less negative feedback on GH -> lots of GH produced

Question 23

Secondary deficiency of the HPGH axis: levels of GH and IGF-1

Answer 23

Low GH and low IGF-1

Question 24

Tertiary deficiency of the HPGH axis: GHRH, GH, and IGF-1 amounts

Answer 24

All three are low

Question 25

What hormone is inhibited by prolactin?

Answer 25

GnRH

Question 26

Two major actions of oxytocin

Answer 26

Milk ejection, uterine contraction

Question 27

Major stimulus of milk ejection besides oxytocin

Answer 27

Suckling, signs/sounds/smells of an infant