endocrine II Flashcards
what is the thyroid gland made up of and what are the 2 hormones it produces?
-made up of follicular and areolar connective tissue
-produces TH and calcitonin
what does TH synthesis require?
iodine
what si the function of TH?
-it acts on the cells to increase metabolism
-increases heat
(thyroxine, T3, T4)
what is Grave’s disease?
HYPERthyroidism
-an autoimmune condition
-excessive thyroxine
when are from where is calcitonin secreted?
-secreted from the thyroid gland
-released if blood calcium is high and increases absorption of calcium into the bones and kindeys
-decreased absorption of calcium in gut
what is PTH?
Parathyroid hormone is the antagonist to calcitonin
-releases calcium into blood
-increases gut absorption
-decreases absorption from kidney and bones release the calcium
how is vitamin D activated/synthesized?
-activated by PTH
-stimulates calcium and phosphate absorption from intestine
-can be synthesized from cholesterol derivative when there is sun exposure (liver/kidney)
what is vitamin D deficiency in adults and children?
-children=rickets
-adults=osteomalacia
-decalcification of bones leading to muscle weakness, weight loss, and bone pain
what is secreted from the adrenal medulla
epinephrine
-longer sympathetic effect
-increased breathing, metabolic rate, and heart rate (fight/flight)
what is secreted from the adrenal cortex
-steroids
-mineralcorticoids; aldosterone
-glucocorticoids; cortisol
-androgens
when is aldosterone released and from where?
released from the adrenal cortex
-released if blood volume or sodium level is low; acts on renal tubules to speed up Na/K pump
-increases sodium reabsorption (water follows)
-also plays a role in BP control?
what are androgens?
-secretes both male and female sex hormones in both sexes (males produce estrogen, females produce testosterone)
what is DHEA?
-it is overpowered by testicular testosterone in males
-in females, it causes growth spurt, pubic hair, and female libedo
why is estrogen important in men?
-bone health
-cholesterol levels
-low estrogen=increased belly fat and poor bone health
-high estrogen=developing breasts, erectile dysfunction, infertility
what is the function of glucocorticoid?
-plays a role in glucose balance (increases it)
-stimulates hepatic gluconeogenesis
-inhibits glucose uptake by cells
-stimulates protein break-down in muscles
-facilitates lipolysis
what is the ‘stress hormone’ and how does it work?
-high BP and fatty acids
-key role in adaptation to stress
-anti-inflammatory and immunosuppressive effects that can result in sickness if cortisol levels get too high
what are the 3 phases of the stress response?
- alarm (fight/flight)
- resistance (cortisol response)
- exhaustion (abnormal body function and organ system failure)
what hormones are involved in the stress response?
-cortisol
-hGH
-TH
what are the immediate effects of stress?
-nor/epinephrine in the sympathetic NS (2-3 secs)
-adrenal response: epi/norepinephrine from adrenal medulla (20-30 secs)
-increase heart rate, breathing, and blood pressure
what is the second stage of the stress response ?
-cortisol is the primary hormone but hGH and TH are also involved
-lasts longer than original fight/flight phase
-stress adaptation leading to higher blood sugar and fatty acids
what is Cushing’s syndrome?
when there is too high level of cortisol
-hyperabsorption in the gut
-hyperglycemia and hyperlipidemia
-poor immune function
-weight gain
-sweating
function of the exocrine cells of the pancreas?
have acinar cells that secrete digestive enzymes
function of endocrine cells of pancreas?
Islets of Langerhans
Pancreatic islets
what do alpha and beta and delta cells of the pancreas secrete?
alpha cells = glucagon
beta cells = insulin
delta = somatostatin (which inhibits the secretion of both insulin and glucagon)
when is insulin released and how does it function?
-released when blood glucose is high
-causes glucose to move into cells and form glycogen
-also promotes cellular uptake of fatty acids and amino acids (enhances conversion of these into triglycerides and proteins)
when is glucagon released and how does it act?
-released if blood glucose is low
-increases blood glucose by gluconeogenesis, glycogenolysis (breakdown of glycogen), and ketogenesis
what is the absorptive and post-absorptibve feeding state?
absorptive= 3-4 hours after eating insulin is the main controller to move nutrients into cells and storage
POST-absorptive is more than 4 hour after eating glucagon is the main controller to move nutrients out of storage and cells
what is diabetes mellitus?
insufficient (HYPOsecretion) secretion on insulin
-leads to high blood glucose
-traceable glucose in urine and high urine volume
-frequent urination, thirst, and hunger
Type I vs. II Diabetes mellitus?
TYPE I= low insulin, autoimmune disorder, daily injections or insulin and monitoring is needed
TYPE II= low insulin response, gradually onset with lifestyle habits, islets of Langerhans are ‘worn out;
early vs. late TYPE II diabetes mellitus
early= a poor response to insulin as insulin levels are too high; CANNOT be given insulin injections as this would further desensitize them
late= beta cells are fully dysfunctional and insulin levels dropped; now may need insulin injections
what are possible complications with diabetes mellitus?
-long term tissue damage
-atherosclerosis
-diabetic retinopathy
-kidney damage
-heart disease
-neuropathies
what are the 3 reproductive hormones?
estrogen , testosterone, progesterone
what do the testes secrete and when?
testosterone from puberty to death
-develop secondary sex characteristics
-sperm production (motility/number)
what do the ovaries secrete and what does it control?
-estrogen and progesterone effects the cyclic cycle (follicles/corpus luteum)
what are the effects of estrogen?
-menstrual cycle, increased fat, increased water, breasts, bone deposition, mucous
