Endicrinology Flashcards
what is a hormone?
chemical signal secreted by specialised endocrine cells directly into the blood to exert an effect on distant target cells.
what are autocrines?
effect on itself
what are paracrines?
same local environment
what is a humoural stimulus?
caused by altered levels of certain critical ions or nutrients
what is a neural stimulus?
hormone release caused by neural input
what is a hormonal stimulus?
hormone release caused by another hormone
what does the pineal gland do?
secretes melatonin at night which makes you drowsy
where does the hypothalamus receive input from?
- higher brain centers
- also receive input from visceral and somatic sense via brain stem.
what does the posterior lobe secrete?
- secretes oxytocin and vasopressin
- hormones are secreted from paraventricular nucleus and supreoptic nerve.
how do signals in the hypothalmic nuclei travel to the anterior pituitary?
- neroendocrine signals such as TRH and GnRH are released.
- travel down portal vein
- act on specific cells in anterior pituitary to release hormone such as TSH, PRL, LH, FSH
what does GnRH secrete?
LH and FSH
what is the role of LH in females?
-acts on the ovarian follicle and induces ovulation
what is the role of FSH in females?
causes development on the ovarian follicle and stimulates secretion of oestradiol and progesterone.
what is the role of LH in males?
acts on testes to produce testosterone
What is the role of FSH in males?
acts on testes to maintain spermatogenesis
how does the negative feedback of TSH work?
- Increased T4 and T3 stimulates anterior lobe of pituitary gland to reduce TSH secretion
- T4 and T3 reduces in circulation ,removing the block on TSH secretion.
what does ACTH hormone secretion result in?
cortisol
which hormone released from posterior pituitary increase water retention?
ADH
When is Oxytocin released?
- when giving birth
- socialisation
- orgasm
what is the function of parathyroid hormone (PTH)?
PTH retains calcium
ACTH has an effect on the cortex and releases corticosteroids. What are mineralcorticoids released for?
increases NA+ retention by kidney and thus H20
maintains BP and blood volume.
what are glucocorticoids used for?
- increases metabolism of fats
- increases blood glucose levels through gluconeogenesis
what is ACTH secretion regulated by?
CRH
Negative feedback
what are androgens used for?
precursors to testosterone
