Unit 5 - Endocrine Physiology Flashcards
steroid hormone
lipid soluble (lipophilic) - can dissolve through plasma membrane & enter cell
- bind to receptors in the nucleus of their target cells.
- cortisol
non-steroid hormones
water soluble (hydrophilic) - cannot dissolve through plasma membrane
attach to a receptor on the membrane
- insulin, FSH
Target cell activation depends on 3 things:
- blood levels of the hormone
- relative number of receptors on target cell
- affinity of those receptors for the hormone
Up regulation
- target cells form more receptors in response to hormone
- ex. oxytocin (promotes contractions of uterine smooth muscle) receptors increase during the 3rd trimester of pregnancy
Down regulation
target cells lose receptors in response to the hormone
Name 6 anterior pituitary hormones that are well known:
- FSH - follicle stimulating
- LH - leutinizing
- prolactin
- TSH - thyroid stimulating
- ACTH - adrenocorticotropic
- growth hormone
adrenal gland
outer part - cortex
inner part - medulla
posterior pituitary hormones
vasopressin
oxytocin
anterior pituitary hormones
follicle stimulating hormone (FSH) leutinizing hormone (LH) growth hormone (GH) thyroid stimulating hormone (TSH) adrenocorticotropin hormone (ACTH) prolactin
Which gland produces iodine containing hormones? What are they called?
Thyroid
Triiodothyronine (T3)
Thyroxine (T4)
Both are non-steroid hormones
bone resorption
dissolves bones / removal puts more Ca2+ in blood plasma from the parathyroid parathyroid hormone (PTH) osteoclasts
High Ca2+ in plasma
thyroid C cells release Calcitonin
they trigger osteoBLASTS to take up Ca2+ & form new bone
What hormones & vitamin are involved in calcium homeostasis?
- Calcitonin - thyroid / if Ca2+ is too high
- Parathyroid hormone - parathyroid / if Ca2+ is too low
- Vitamin D -
bone deposition
formation of bone
osteoblasts involved
humoral stimuli
hormones secreted in direct response to changing blood levels of ions & nutrients
hormonal stimuli
release of hormones in response to hormones produced by other endocrine organs
neural stimuli
ANS efferent nerve fibers stimulate hormone release
- preganglionic sympathetic NS fibers stimulate the adrenal medulla
Thyroid hormones
Both produced by thyroglobulin & iodine
- T3
- T4
- calcitonin (produced by C Cells)
Adrenal gland
Cortex has 3 layers:
- zona glomerulosa (outer most part) - mineral corticoids
- – mainly aldosterone - zona fasciculata (middle layer) - glucocorticoids
- – cortisol - zona reticularis (inner layer) - gonadocorticoids
- — androgens
zona fasciculata
middle part of adrenal cortex
secretes glucocorticoids – cortisol
glucocorticoids
zona fasciculata
- cortisol - help resist stress
- stimulate gluconeogenesis
- inhibits glucose uptake by many tissues, making it available for the brain
- stimulates protein degradation
- facilitates lipolysis
- anti-inflammatory agent
gonadocorticoids
zona reticularis
- source of testosterone for men/ estrogen for women
mineralcorticoids
zona glomerulosa
- aldosterone
Pancreas
alpha cells secrete glucagons
beta cells secrete insulin
diabetes insidious caused by:
deficiency in vasopressin/ADH
The term used to describe the presence of glucose in the urine is
glycosuria
catecholamines
released by adrenal medulla
- epinephrine
- norepinechrine
How does Vit D help with Ca2+ levels?
- promotes absorption in intestine
- decrease Ca2+ loss in urine
Pancreas - what is exocrine & what is endocrine?
Exocrine - secretes watery, alkaline solution & digestive enzymes thru pancreatic duct into digestive tract lumen
Endocrine - 1-2% of mass; islets of Langerhans
- beta cells - (60% of islet mass) synthesize & secrete hormone INSULIN
- alpha cells - (25% of islet mass) produce hormone GLUCAGON
- D (delta) cells - (1% of islet mass) synthesize SOMATOSTATIN
- F cells - produce pancreatic polypeptide (not very well understood)
