Endocrine physiology Flashcards
In vitamin D intoxication what are the phosphate levels?
elevated
Testosterone converts to DHT via which enzyme?
5 alpha reductase
Which pancreatic cells produce glucagon?
alpha-cells
In renal insufficiency what are the Ca levels?
low- not vitamin D means less absorption
How do steroids circulate if they are lipophilic?
bound to binding globulins. This increases their solubility and allows for increased delivery to the target organ
What triggers the release of calcitonin?
Increases serum calcium and calcium secretion
In Hyperparathyroidism, what are the phosphate levels?
decreased. PTH increases its secretion in the kidney to keep serum Ca high
How does peripheral tissue help regulate thyroid hormones?
interconversion between rT3 (weakest), T4 (weak), T3 (strongest)
What are the four Bs that describe T3s function?
brain maturation, bone growth, beta adrenergic effects, basal metabolic rate increased
Sort form strongest to weakest: reverse-T3, T3, T4
T3, then T4 then r-T3
Name five steroid hormones.
progesterone, estrogen, testosterone, cortisol, aldosterone
Zona ____ makes cortisol?
zona fasciculata (remember GFR-salt, sugar, sex)
What prevents there from being too much thyroid hormone?
negative feedback of T3 to the anterior pituitary, decreases sensitivity to TRH from hypothalamus
What is the main secretory product of the medulla?
catecholamines
What effect does PTH have on Vitamin D?
increases its formation
Which cells synthesize thyroxine?
follicular/principle cells of thyroid
What is the mechanism by which metabolic rate is increased?
increased Na+/K+ ATPase activity, increased O2 consumption, increased body temperature
Zona glomerulosa makes ____?
aldosterone
What are some common causes of Hypercalcemia?
malignancy, intxication with vit d, sacroidosis, hyperparathyroidism, pagets (bone)
Which two hormones are the primary regulators of the zona fasciculata?
ACTH (direct) and CRH (indirect)
In hyperparathyroidism, what are the Ca levels?
increased. remember, PTH acts to increase Ca2+ in the serum
zona reticularis manufactures?
sex hormones
How do iodine levels affect T3 an dT4 concentrations?
low levels of iodine= more T3
high levels of iodine= more T4
What effect would high does vitamin D consumption have on endogenous vitamin D production?
decrease in active 1, 25 synthesis in the kidney. Negative feedback loop
Where is calcitonin made?
parafollicular or c cells in the thyroid gland
Which cells of the adrenal glands produce catacholamines?
chromaffin cells
Which pancreatic cells produce somatostatin?
delta-cells
What happens to glucose and lipid balance under T3s effect?
increased glycogenolysis, gluconeogenesis and lipolysis
What kind of receptor do thyroid hormones binds to?
intracellular receptor- become transcription factors to alter gene transcription
If you lack vitamin D as a child you get_____?
rickets
Which hormone is the primary regulator of the zona glomerulosa?
renin-angiotensin
In renal insufficiency what are the phosphate levels?
high-kidney can’t excrete
Calcitonin are secreted by which cells?
parafollicular cells (c cells)
What are two main functions of vitamin D?
- increases calcium phosphate absorption from the gut
2. increases bone resorption of calcium and phosphate.
In Osteoporosis what are the Phosphate levels?
normal
What does the kidney convert vitamin D into?
1, 25-OH-vitamin D (biologically active form)
Testosterone can be converted to estrogen via which enzyme?
aromatase
If you lack vitamin D as an adult you get ___?
osteomalacia
What are the main effects of thyroid hormones? (6)
- increase protein synthesis
- increase cell growth and maturating
- increase cellular respiration
- increase oxygen consumption and metabolic rate
- increase food intake
- increase cardiac output and thermogenesis
Which pancreatic cells produce insulin?
beta-cells
