Endocrinology- pituitary gland Flashcards
What is a hormone? How do they travel to targeted organ?
Messenger Travels via blood stream
2 Types of hormones?
peptide and steroid
How are each one synthesised?
Peptide- pro-hormone + requires further processing to activate Steroid- from cholesterol
How are each one stored? And how do they bind to receptors
Peptide- in vesicles ( regulatory secretion) Bind rec on CM + 2nd signal using messaging system Steroid- released immediately (constitutive) Bind intra cel rep + change gene expression directly
Annotate diagram of Pituitary gland
What neurone regulated anterior pituaitary function?
hypothalamic parvocellular
Release hypothalamic releasing/inhibt factors into capillary eminence in m
How do they work to reg function?
hypothalamic releasing/inhibt factor—> cappliary plexus (in median eminence)—–>portal ciculation—-> pit gland
What cells in anterior pituarity?
How are regulated?
5-Somatrophs, lactorophys, cortiocptrpohy, thyrotrophs, gondatrophs
by hypothalamic releasing factors into hypophsyeal-pit portal system.
explain example throid hormone production pathway from hypo thalamus to pit gland
hypothalamic cells TRH into hypothalamo-hypophsysialportal system—->
TRH stimulate thyrotrophs produce TSH (thyrotrophin) —–>
to thyroid gland produce throxine
For each of somatrophy, lactotrophs thyrotrophs, gonadotrophs and corticotrophs cells:
What releasing hormones stimulate it?
What hormones release
Where is target for each anterior pituitary gland hormone?
Growth hormone- genereal tissues (liver)
Prolactin- Breasts
TSH- T gland
LH and FSH- Testes and ovaries
ACTH- adrenal cortex
How does a tumour in Pituarity tumour affect eye sight?
What is the condition called?
Bitemporal hemianopia
Fibres from medial retinae, info from lateral visual field, cross at optic chiasm.
Tumour compress optic chiasm + prevent info transmittion.
explain steps of Reflect arc of milk production from hypo to breast?
Stimulation nipples activate afferent path—–> decrease dopamine from dopaminergic neurone in hypo
——–> less dop in portal system less inhibtion of lactotrophs
—–> increased prolactin so increased milk secretion
How do growth hormones have effect on body tissue?
(how does it involve liver)
Directly- Somatotrophin on tissues
Indirectly- GP effect on liver
produced IGF-1 AND 2 (2 mainly for feutus)
What is condition that causes excessive growth?
Acromegaly- excessive Growth hormone
NO increase in height as post-puberty so end bones fused
what are features of Acromegaly?
coaresning of facial featues
large jaw
sweatiness
headache
macroglossia- big tounge
proganthism- extension of jaw
what hormones does posterior produce?
Arginine vasopression (anti-diuretic hormone)
Oxytocin
What is difference between posterior and anterior pituarity gland in structure?
- Anterior is anatomically contiounus with hypothalamus (nerve cells). Posterior is endochrine cells
- Cells nuceli located in supraoptic(AVP) and paraventricular (oxytocin) in hypo. Extend stalk to posterior where realease content into blood. Posterior has pit gland stimulate hormones from hypo.
What is function/action of vasopressin?
stimulation water reabsoprtion in renal collecting ducts
concentrates urine through V2 receptor
ALSO vascocontrsictor via V1 reeptor and STIMULATE ACTH
How does vasopression concentrate urine?
AVP bind to V2 receptor.
cascade rxns lead to aquaporin 2 migrate to tubular side
more reabsoprtion of water
What are 2 actions of oxytocin?
1. Uterus contraction
Of myometrial cells at labour push baby, deilvery
2. Milk ejection
Contraction of mypoepithelial cells to expell milk during lactation
