Pituitary Gland

Question 1

Pituitary anatomy

Answer 1

Aka hypophysis Composed of neuro and adenohypophysis.
A small apendage below the brain intimately associated with the hypot
Exert control over many repro and metab fxs

Question 2

Pit location

Answer 2

Ventral to brain
Caudal to optic chiasm
Attached to brain by pars tuberalis (thin stalk)
Floor of cran cavity
Dura surrounds the stalk so removing brain with the pit is dufficult
Varied size (incr in preg and lactation)

Question 3

Anterior Pit dev (adenohyp)

Answer 3

Epi origin
From roof of mouth
Pars distalis (main) and pars intermedia
Pars tuberalis
Rathkes pouch remnant space from embr dev between two pars

Question 4

Post pit dev (neurohyp)

Answer 4

Down growth from brain tissue
Aka pars nervosa
Neural origin

Question 5

Circle of willis

Answer 5

Paired carotid aa supply pit
Circle formed by int car aa amd vertebral aa. They anastomose around the optic chiasm and infundilbulum of pit stalk. Allows for equalisation of blood flow between 2 sides of brain if part of circle is occluded

Question 6

Blood supply posterior pit

Answer 6

Direct from inferior hypophysial a (branch of int car a)
Capillary bed (1o plexus) around the infundibulum and median eminence supplied direct from the superior hypophysial a

Question 7

Blood supply anterir pit

Answer 7

Supplied by hypophysial vv (run into 2o cap plexus of hypothalmohypophysial portal syst)

Question 8

Pit drainage

Answer 8

Blood drains into hypoph vv to syst circ via carotid vv

Question 9

Post pit anatomy

Answer 9

Extension of hypot
Comp of mostly axons with large cell bodies originating from supraoptic nucleus and PVN. Axons terminate in close assoc with the cap network in the post pit. When act pot travels down an axon the h is released onto caps and diffuse into periph circ

Question 10

Oxytocin

Answer 10

Milk let down, parturition, sexual behaviour. In M acts on smth m of prostate and is responsible for ejaculation. Has a role in sexual partner bonding and controls maternal behaviour

Question 11

Vasopressin

Answer 11

ADH
H2o and electrolyte balance
Acts on kid tonpromote h2o rabs and centrally to effect social behaviour

Question 12

Anterior anatomy

Answer 12

No direct neural connection between hypot and ant pit. Neuroendocr cell bodies in hypot have axons terminating in the median eminence cap bed.

Question 13

Median eminence

Answer 13

Base of hypot. Serves as an interface between neural and peripheral endocr system. Site where hypot releasing hs are released intoncap bed to be transported to ant pit cells, act on spec recs which provide further signals to target endocr syst

Question 14

CRH

Answer 14

Corticotrophin rh

Question 15

TRH

Answer 15

Thyrotrophin rh

Question 16

GnRH

Answer 16

Gonadotrophin rh

Question 17

GRH

Answer 17

GH rh

Question 18

GIH

Answer 18

GH ih

Aka somatostatin

Question 19

PIH

Answer 19

Prolactin ih

Aka dopamine

Question 20

GnIH

Answer 20

Gonadotrophin ih

Question 21

Cell classifications

Answer 21

Cromaphobes and phils (split into acidophils - acid stain orange, and basophils - basic stain blue)

Question 22

Ways to visualise cells other than dye

Answer 22

Immunohistochem- chromogen or dye linked to antibody stains for a specific antigen
Can also be used to locate h recs.
In situ hybridisation- locate h mrna expression in ant pit cells
E- microscopy- reveals granule density in ant pit cells

Question 23

Somatotrophs

Answer 23

PD
40-50
Acidophilic
Secr GH
Stim growth via effects on liver that prod somatomedins

Question 24

Lactotrophs

Answer 24

PD
20
Acidophilic
Secr prolactin - milk prod and mam tissue dev
No and size incr in preg due to oestrogen stim effect

Question 25

Corticotrophs

Answer 25

``` PD 20 Basophilic Synth POMC goes to ACTH Control adrenal cortex activity and GC secr ```

Question 26

Thyrotrophs

Answer 26

PD 5 Basophilic Secr TSH control thyr h secr

Question 27

Gonadotrophs

Answer 27

``` PD 5 Basophilic FSH and LH Concerned with gern cell dev and control of gonads ```

Question 28

Melanotrophs

Answer 28

PI Main type Basophilic Synth POMC goes to ACTH GOES TO MSGa and CLIP aMSH secr into circ important for control of hair/skin/feather colour

Question 29

Diabetes insipidus

Answer 29

Cause polydipsia and uria (dilute). red fluid intake doesn't alter urine conc Caused by Vp deficiency, insens of kid to Vp or iatrogenic drug use. Central DI treated with desmopressin (mimic Vp)