Hypothalamic-pituitary relationship (L3)

Question 1

Relative anatomical location of the hypothalamus

Answer 1

Between the lamina terminalis and the mammillary bodies

Question 2

Median eminence

Answer 2

Forms a base at the base of the third ventricle; convergence point for hypothalamic hormone release to the pituitary

Question 3

What regulates sleep?

Answer 3

Suprachiasmatic nucleus

Question 4

What regulates feeding behavior/satiety?

Answer 4

Arcuate nucleus

Question 5

What regulates thirst?

Answer 5

Paraventricular nucleus

Question 6

What regulates reproduction?

Answer 6

Preoptic nucleus

Question 7

What regulates circadian rhythms?

Answer 7

The suprachiasmatic nucleus

Question 8

What regulates mood/stress?

Answer 8

Paraventricular and arcuate nuclei

Question 9

What regulates body temperature?

Answer 9

Preoptic nucleus

Question 10

What regulates blood pressure?

Answer 10

Paraventricular nucleus

Question 11

Location for cell bodies for gonadotropin releasing hormone (GnRH)

Answer 11

Scattered throughout brain, but mostly concentrated in the preoptic nucleus

Question 12

How many GnRH neurons do humans have?

Answer 12

Only 1500-2000, which is relatively few

Question 13

How are downstream effects mediated by GnRH?

Answer 13

Through GPCRs

Question 14

How long is GnRH?

Answer 14

10 amino acids

Question 15

In what manner is GnRH released?

Answer 15

Pulsatile; OBLIGATORY

Question 16

Incidence of Kallmann syndrome

Answer 16

Rare; 1/8,000 men, 1/40,000 women

Question 17

Clinical manifestations and causes of Kallmann syndrome

Answer 17

Anosmia and reproductive failure; failure of GnRH neurons to enter the CNS

Question 18

Heritability of Kallmann syndrome

Answer 18

X-linked: Kal1

Autosomal: Kal2

Question 19

From where do GnRH neurons migrate during fetal development?

Answer 19

From olfactory placode through cribriform plate into forebrain

Question 20

Downstream effects of GnRH binding to its GPCRs

Answer 20

Activation of PLC cleaving PIP2 to IP3 and DAG, leading to increased intracellular Ca2+ and PKC activation.

Question 21

GAP

Answer 21

GnRH-associated peptide: part of prohormone for GnRH

Question 22

High pulse frequency with GnRH

Answer 22

Preferentially releases leutinizing hormone (1 pulse every 30-60 minutes)

Question 23

Slow pulse frequency with GnRH

Answer 23

Preferentially releases FSH (once every 2-3 hours)

Question 24

Superior hypophysial artery

Answer 24

Gives rise to the capillary plexus - “portal plexus” of the anterior pituitary

Question 25

Inferior hypophysial artery

Answer 25

Supplies the posterior pituitary

Question 26

Course of the superiorhypophysial artery

Answer 26

Breaks into primary capillary plexus that supplies the median eminence, then drains into the hypophyseal portal veins and secondary capillary plexus that supplies the pars distalis

Question 27

Tuberoinfundibular system

Answer 27

All neurons that send neurons to the median eminence, and hormones then target the anterior pituitary through the capillary system

Question 28

Neurohypophysial tract

Answer 28

Neurons whose axons terminate in the posterior pituitary

Question 29

Parts of the anterior pituitary

Answer 29

``` Pars distalis (90%) Pars intermedia Pars tuberalis ```

Question 30

Parts of the posterior pituitary

Answer 30

Pars nervosa | Infundibulum (stalk)

Question 31

Derivations of the anterior pituitary

Answer 31

Glandular tissue derived from embryonic foregut

Question 32

Derivations of the posterior pituitary

Answer 32

Neural tissue from neuroectoderm

Question 33

Axons from the __ __ terminate in the neurohypophysis

Answer 33

magnocellular neurons

Question 34

Herring bodies

Answer 34

Dilations of unmyelinated axons near the terminals; site of hormone release in the posterior pituitary

Question 35

Herring bodies are in close proximity to what structures

Answer 35

Fenestrated capillaries

Question 36

Pituicytes

Answer 36

Small, darkly stained cells; glial-like cells of the posterior pituitary

Question 37

Acidophils

Answer 37

Somatotrophs and lactotrophs

Question 38

Basophils

Answer 38

Corticotrophs, gonadotrophs, and thyrotrophs

Question 39

Chromotrophs

Answer 39

Appear clear on stain; have paracrine actions

Question 40

Topographical distrubution of cell types in the anterior pituitary

Answer 40

TSH near top ACTH in middle GH/PRL on the sides FSH/LH throughout