Endocrine system Flashcards
exocrine
ducts
endocrine
directly into blood
where does the NS integrate with the endocrine system
hypothalamus (within the diencephalon)
3 mechanisms of hormone release
humoral - release in response to ECF changes
neural
hormonal
what are trophic hormones
causes another gland to release hormones
peptide/lipid based hormone
e. g. salbutamol
- usually uses 2nd messengers → binds to R associated with nuclear DNA
- e.g. T4, T3
Steroid hormone
lipid based (made cholesterol)
- lipid soluble → binds DNA/modify transcription
- slow acting
parathyroid hormone (PTH) and Ca feedback
decrease Ca due to lactation → sensed by PT cells → increase PTH → stimulate osteoclast → increase Ca release from bone storage → increase blood [Ca]
PGA
decrease BP and increase coronary BF
PGE
regulation of RBC and platelet aggregation
regulation of HCl secretion
PGF
causes uterine contractions
POS pituitary gland (neurohypophysos)
- ADH/oxytocin
- directly innervated by hypothalamus
- storage and release site
ANT pituitary gland (adenohypophysis)
- ACTH→secretes cortisol
- GH, TSH, prolactin, LH, FSH
- activated by secretion of hormones
pineal gland
manufactures melatonin (involved in sleep/wake) - part of NS and endocrine system
thyroid gland
-thyroid hormones
- promotes metabolic activity, cell growth and tissue diff
- secretes T3/4
secretes calcitonin by
- parafollicular cells (increase Ca uptake into bones)
abnormalities of thyroid glands
hypersecretion (from TSH over-stimulation) → graves disease (increase metabolic activity)
hyposecretion (low secretion of TSH or inflam) → cretinism (decreases metabolic activity)
parathyroid gland
control Ca levels
- decrease of [ca] in bones → stimulate PTH release → increases [ca] internal absorption
adrenal glands
medulla (neurosecretory): secretes N/NA
cortex (endocrine): secretes aldosterone, cortisol, androgen
3 layers of cortex
zona glomerulosa → secretes mineralocorticoids
zona fasciculata → secretes glucocorticoids
zona reticularis → secretes gonadcorticoids
cushing’s syndrome
increased cortisol
redistribution of body fat, HT, decrease lymphocyte and plasma cells
aldosteronism
increase aldosterone
increase water retention, muscle weakness due to k loss
tumours in adrenal cortex
increased androgens
addision’s disease
decreased aldosterone/cortisol
decrease appetite and weight loss
decrease Na and glucose
increase K
Dehydration
islet a
glucagon
islet b
insulin
islet delta
somatostatin
- released in response to food, pH, stretch in gut
islet epsilon
ghrelin
- stimulates hypothalamus to boost appetite
islet pancreatic polypeptide cells (F or PP cells)
pancreatic polypeptides
-influences digestion and distribution of food molecules
Acini (cluster of cells) exocrine portion
secretes serous fluid containing digestive enz
testes
produces testosterone → growth and maintenance of male sexual char
ovaries
produce estrogen and progesterone
placenta
temporary endocrine gland secreting hCG, estrogen, and progesterone
thymus
thymosin and thymopoietin
- stimulates development of T cells
gut and heart
CCK, gastrin, ghrelin
- for digestion and appetite
ANP prod in heart → decrease Na → decrease BV and BP
paracrine hormone
has activity on cells immediately surrounding it (i.e. PG)
5 secretory cells in adenohypophysis
somatotrophs → GH Corticotrophs → ACTH Thyrotrophs → TSH Lactotrophs → PRL gonadotrophs → LH and FSH
4 trophic hormones
TSH
ACTH
FSH
LH
Aldosterone
released in response to renin
increase Na reabs in kidneys, controlled by RAS
glucocorticoids
cortisols → released in response to stress
- cooperates with SNS → increase breakdown of tissues →ensure enoguh nutrients
ageing
atrophy of endocrine organs/loss of cells → decrease secretion of hormones
decrease clearance by liver → increase level of hormones
