Endo - Hypothalamus-Pituitary

Question 1

things ant pituitary regulates

Answer 1

thyroid
adrenals
repro glands
somatic growth
lactation

Question 2

things post pituitary regulates

Answer 2

water metabolism

Question 3

ant pit aka

Answer 3

adenohypophysis

Question 4

post pit aka

Answer 4

neurohypophysis

Question 5

hypothalamus fxn

Answer 5

collect and integrate signals from diverse sources

relay to pituitary

Question 6

pituitary tumor –> blindness how

Answer 6

optic chiasm right above pit

swelling/tumor in pit compress optic nerve –> loss of visual fields/acuity

Question 7

pit embryology

Answer 7

floor of diencephalon grows downward (infundibulum)
secretes factors to induce upgrowth of oral ectoderm (–> Rathke’s pouch)
rathke’s pouch –> adenohypophysis and detaches from oral ectoderm
infandibulum –> neurohypophysis - stays connected by median eminence?

Question 8

neurons of PP

Answer 8

cell bodies in hypothalamus:
suproptic nucleu (ADH)
paraventricular nuclei (oxytocin)
all are magnocellular

Question 9

ADH fxns

Answer 9

maintain ECF osmolarity

maintain blood volume

Question 10

ADH mech

Answer 10

open aquoporin channels in CD of kidneys –> reabsorb water

Question 11

ADH stimulation mech

Answer 11

1. up ECF osmolarity: sensed by osmoreceptors in hypo –> target V2 receptor in renal cells
2. down blood vol or BP: sensed by baroreceptors in atria –> target V1 recepors in vascular SM

Question 12

oxytocin fxns

Answer 12

uterine motility

milk release

Question 13

oxytocin stim + action steps

Answer 13

1. stretch vagina and cervix –> target uterine myometrium

2. suckling –> target myoepithelial cells aroound mammary glands

Question 14

PP hormones

Answer 14

oxytocin

ADH

Question 15

AP hormones

Answer 15

prolactin (PRL)
growth hormone (GH)
thyroid stimulating hormone (TSH)
adenocorticotropic hormone (ACTH)
follicle stimulating hormone (FSH)
lutenizing hormone (LH)

Question 16

AP cell types (+hormones)

Answer 16

corticotroph (ACTH)
thyrotroph (TSH)
gonadotroph (LH, FSH)
somatotroph (GH)
lactotroph (PRL)

Question 17

hypo hormones to AP path

Answer 17

parvocellular neurons stim
secreted from terminals in median eminence
hormones into hypophyseal-portal system to AP

Question 18

PRL inhibition

Answer 18

tonically inhibited

dopamine binds to D2 receptors on lactotrophs

Question 19

things that cause hyperprolactinemia

Answer 19

drugs that block dopamine
lesions that interfere w/ portal blood flow
primary hyperthyroidism (high TRH)
lactotroph adenomas (prolactinomas)

Question 20

PRL actions

Answer 20

enhance breast development in pregnancy

induce milk production

Question 21

PRL during preg

Answer 21

estrogen stim proliferation of pit lactotroph cells

but lactation is inhibited by high est and progest

Question 22

PRL post partum

Answer 22

rapid decline of est and progest allows lactation to start

ovulation may be suppressed due to PRL suppressing gonadotropins

Question 23

GH direct effects

Answer 23

action on tissues

lipolysis in adipocytes

Question 24

GH indirect effects

Answer 24

anything done by IGF-1

liver/tissue release IGF-1 in response to GH

Question 25

GH feedback loop

Answer 25

GHRH --> GH (AP) --> IGF GHRH inhibit GHRH release, IGF inhibit GH release IGF and GH --> SS

Question 26

GH receptor

Answer 26

cytokine receptor intracellular domain or receptor has protein tyrosine kinase (JAK) Jak cascade protein phosphorylation --> STAT proteins go into nucleus and alter DNA transcription

Question 27

GH effects

Answer 27

``` postnatal growth of bones* (proliferate cart @ epi plates) up lean body mass down fat cell size (lipolysis) up blood gluc up organ size/fxn ```

Question 28

GH stimulating factors

Answer 28

``` down glucose down FAs fasting puberty hormones (est, test) exercise stress alpha-adrenergic agonists ```

Question 29

GH inhibitory factors

Answer 29

``` up glucose up FAs obesity SS beta adrenergic agonists pregnancy ```

Question 30

GH pulses

Answer 30

10 pulses daily peak 1 hr after stage 3 or 4 sleep most in puberty low in elderly/obese

Question 31

GH deficiency (children)

Answer 31

dwarfism retarded skeletal growth poorly developed muscles excessive subcutaneous fat

Question 32

GH deficiency (adults)

Answer 32

``` reduced well-being increased fat mass (central obesity) dyslipidemia up CV disease down bone density ```

Question 33

GH excess (before puberty)

Answer 33

``` gigantism glucose intolerance and hyperinsulinism CV problems (hypertrophy) up infections usually from pit tumors ```

Question 34

GH excess (adults)

Answer 34

acromegaly insidious onset overgrowth of bone/CT --> course features decreased subcutanous fat metabolic derangements (glucose intolerance/diabetes)