Hypothalamus/Pituitary Relationships and Biofeedback

Question 1

Pituitary tumors

Answer 1

Often put pressure on the optic nerves causing visual problems, dizziness

Question 2

Posterior pituitary

Answer 2

Supraoptic nucleus SON - ADH

Paraventricular nucleus PVN - Oxytocin

Question 3

Anterior pituitary secretions

Answer 3

ACTH
TSH
FSH
LH
GH
Prolactin
girls like acting trashy for prom

Question 4

Hypothalamus direct/indirect control of pituitary

Answer 4

Directly releases hormones to the anterior pituitary via portal system - both neural and endocrine connection
Releases hormones on posterior pituitary solely via neural connection

Question 5

Primary, secondary, tertiary endocrine disorders

Answer 5

Primary- low/high hormone levels due to defect in peripheral endocrine organ
Secondary- low/high hormone levels due to defect in pituitary
Tertiary- low/high hormone levels due to defect in hypothalamus

Question 6

Anterior pituitary targets what organs

Answer 6

Gonads (hypothalamic-pituitary-gonad HPG axes etc..)
Liver
Thyroid
Adrenal
(also a hypothalamic-pituitary-prolactin axes)

Question 7

Acromegaly

Answer 7

Excessive soft tissue, cartilage and bone in face
Prolonged and excessive secretion of growth hormone
Before puberty-causes gigantism (long bone growth) before closure of bone epiphysis
After puberty- causes acromegaly (deep organ/cartilage growth) after close of bone epiphysis

Question 8

Growth hormone

Answer 8

Produced by somatotropes–> somatotropin (GH)
Somatostatin is growth hormone inhibiting factor GHIH
GH receptor GHR linked to JAK-STAT
Signals liver to produce IGF-1 (somatomedin)
Inhibited by somatostatin and IGF-1
Stimulated by fasting/hunger (grehlin) and hypoglycemia

Question 9

Regulation of GH release

Answer 9

Increased GH leads to decreased GHRH

Increased IGF-1 leads to decreased GH and increased GHIH

Question 10

High carb/low protein effect on GH release

Answer 10

High carb stimulates GH production but low protein will inhibit it
Lower carb intake and blood glucose + higher protein intake will lead to GH/IGF production and peripheral metabolism shifts to lipids for energy, hepatic gluconeogenesis is stimulated

Question 11

Diagnosing gigantism/acromegaly

Answer 11

Elevated serum GH and IGF-1
AND failure to suppress GH production in response to an oral load of glucose (very high sensitivity test)
Pituitary enlargement on MRI

Question 12

GH/IGF secretion timing

Answer 12

GH levels fluctuate throughout day, while IGF levels remain constant
High during sleep, peaks with exercise
Sleep disturbances can perturb GH secretion
GH is secreted throughout life

Question 13

GH deficiency

Answer 13

Lower secretion of GHRH (due to hypothalamic dysfunction)
Lower GH secretion
Failure to generate somatomedins
GH or somatomedin resistance

Question 14

Prolactin (PRL) release

Answer 14

Synthesized by lactotropes
Secretion begins 5th week of pregnancy
PRL UNDER TONIC INHIBITION BY HYPOTHALAMIC DOPAMINE
Primary action is to stimulate/maintain lactation
Suppresses LH and FSH to decrease reproductive function and suppress sexual drive

Question 15

Prolactin regulation

Answer 15

PRL inhibits dopamine release from hypothalamus so that pituitary cannot be inhibited from making prolactin
Estrogen from pregnancy stimulates prolactin

Question 16

Prolactinoma

Answer 16

Pituitary adenoma secreting prolactin (most common type)

Question 17

Decreased FSH/LH due to hypopituitarism causes what

Answer 17

Women- hypogonadism, menstrual irregularity

Men- Infertility, hypogonadism, reduced sperm count

Question 18

Hypopituitarism

Answer 18

Decreased:
GH
FSH/LH
TSH
ACTH
ADH

Question 19

Oxytocin actions

Answer 19

Milk ejection, stimulated by suckling, but also sight, sound or smell of infant
Production stimulated by dilation of cervix or orgasm, causes uterine contractions
Pitocin induces labor

Question 20

Zona glomerulosa (adrenal gland) releases

Answer 20

Mineralcorticoid- Aldosterone

Question 21

Zona reticularis and zona fasciculata release

Answer 21

Glucocorticoids and Androgens

Question 22

Epinephrine vs norepinephrine area of action

Answer 22

NE- at target cell near point of release

E- at distant target cell

Question 23

PNMT upregulated by what

Answer 23

Cortisol

Question 24

Pheochromocytoma

Answer 24

Benign, unilateral adrenal tumor

Catecholamines secreted by these tumors stimulate both alpha and beta adrenergic receptors

Question 25

17a enzyme deficiency

Answer 25

Increased ACTH, BP
Decreased cortisol, K+
Decreased androstenedione in labwork
Undescended testes, lack of secondary sexual characteristics

Question 26

21b enzyme deficiency

Answer 26

Decreased ACTH, cortisol, BP
Increased K+
Increased renin activity and 17-hydroxy-progesterone in labs

Question 27

11b enzyme deficiency

Answer 27

Decreased aldosterone, cortisol and K+
Increased BP
Decreased renin activity

Question 28

Addisons disease

Answer 28

Primary adrenal insufficiency
Primary deficiency of cortisol and aldosterone
Hypotension, hyponatremia, decreased blood Na
Weakness, weight loss, hyperpigmentation

Question 29

Primary hyperaldosteronism

Answer 29

Excess secretion of aldosterone

Hypertension, hypokalemia, low plasma renin, low K+

Question 30

CRH and hyperpigmentation

Answer 30

CRH–>ACTH–> activates melanocytes to produce melanin

Question 31

Cushings syndrome vs disease

Answer 31

Cushings syndrome is high levels of cortisol caused by adrenal tumor
Cushings disease is high levels of ACTH and cortisol caused by pituitary tumor/ectopic ACTH secreting tumor
Dexamethasone high dose distinguishes if increased cortisol is caused by pituitary tumor or ACTH secreting ectopic tumor.
Low dose dexa just tells you if you have CS or not
Dexamethasone causes feedback inhibition of pituitary to inhibit ACTH release