endocrine AFP regision session Flashcards
hormone
a chemical substance which is secreted into the bloodstream and acts at specific target organs on specific receptors, regulating processes and maintaining homeostasis
endocrine
a hormone is secreted directly into the blood and acts at a distant site
paracrine
hormone which has effect only in the vicinity of the gland secreting it
autocrine
cell-produced substance that has an effect on the cell by which it is secreted
molecules that act as hormones
catecholamines - water soluble, e.g. adrenaline, noradrenaline, melatonin
peptides - water soluble, e.g. insulin, PTH
steroids - lipid soluble e.g. cortisol, sex steroids, vitamin D
thyroid hormone - lipid soluble, e.g, T3 and T4
gases - e.g. NO
HPA axis - cortisol
hypothalamus secrets CRH, acts on ant. pituitary to secrete adrenocorticotropic hormone
stimulates the adrenal gland to release cortisol from the zona fasciculata
layers of the adrenal cortex
zona glomerulosa - mineralcorticoids e.g. aldosterone
zona fasciculata - glucocorticoids e.g. cortisol
zona reticularis - androgens e.g. DHEA, precursors to sex hormones
GFR = salt, sugar, sex
angiotensin II effects
potent vasoconstrictor - increases blood pressure
stimulates aldosterone release from adrenal cortex
stimulates thirst and secretion of ADH
contributes to cardiovascular regulation
hypothyroidism symptoms
weight gain, hoarse voice, cold sensitivity, goitre (potentially), weakness, fatigue
hyperthyroidism symptoms
weight loss despite increased appetite, increased HR, heat intolerance, insomnia, goitre (not always)
testosterone production
produced by leydig cells in males and theta interna cells of the ovaries in response to LH
oestrogen types and production
types: oestradiol, oestrone, estriol
produced in ovaries by granulosa cells in response to LH and FSH
regulates GnRH secretion, responsible for ovulation and important in bone density
progesterone production
secreted by corpus luteum and placenta and maintains pregnancy
what is adipose tissue composed of
adipocytes and stromavascular cells
what does adipose tissue do
releases adiponectin, enhances peripheral insulin sensitivity
