Endocrine phys part 2 Flashcards
Parathyroid hormone function
Mobilize Ca from bone, Increase Ca reabsorbtion in kidney, increase Ca absorbtion in GI tract, increase phosphate excretion
1, 25 dihydroxycholeaclciferol function
- increase Ca absorbtion in GI tract
- Stimulates Ca reabsorption in kidneys
- Causes bone remodeling
Calcitonin function
inhibit ca resorbtion (Keeps Ca in bone)
What are the 2 types of calcium in the bone
Stable (28,000 mmol) or readily exchangable (100 mmol)
Function of calbindin-D9k
Prevents cell signaling from calcium while transporting Ca (has high affinity for Ca)
Phosphourous key roles in body
ATP, Modify proteins, DNA/RNA, cAMP (cell signaling), Intracellular buffering
How is phosphorous filtered and reabsorbed
Filtered in kidneys, reabsorbed via Na cotransporters (NaPi-2a/2b)
What activates phosphorous
1,25, dihydroxycholecalciferol (calcitrol)
Magnesium roles
protein/DNA synthesis, oxidative phosphorylation, cardiovascular tone, neuromuscular excitability, bone formation
Where is magnesium absorbed
In GI trat
Where is magnesium reabsorbed
Kidneys (PTH increases reabsorbtion)
What is the key role of vitamin D in intestines
Increase transport of calcium and phosphate in intestines
What do high calcium and phosphate inhibit the formation of
calcitrol
What stimulates the production and release of vitamin D
Low calcium, low phosphate, High PTH
What stimulates PTH release
Low calcium levels
What does vitamin D deficiency cause in children
Rickets
- Weakness, bowing of legs, tooth defects, hypocalcemia
What does vitamin D deficiency cause in adults
Osteomalacia
What type of cells produce and secrete PTH
Chief cells (inside parathyroid gland)
Hypoparathyroidism symptoms
Hyperexcitability of nerves, tetany, Chvostek sign (contraction of facial muscles with tapping on facial nerve), Trousseau sign (flexion of wrist and thumb)
Hyperparathyroidism symptoms
Usually asymptomatic (usally caused by parathyroid tumor, high Ca and Low Phosphate)
What is hypercalcemia cosed by often
bone, breast, kidney, ovary, skin cancer
Where are the calcitonin cells made
parafollicular cells of thyroid
Actions of calcitonin
decrease blood ca and p, block resorbtion of Ca from bone, increase Ca excretion in urine
What are bones made of
Collagen and crystallized ca p salts
Structure of bone
Outside strength (cortical, compact) and spongy (trabecular) inside (bone marrow).
What kind of connective tissue is on the outside of a bone
periosteum connective tissue
Osteopetrosis MOA
Ineffective osteoclasts- over abundance of bone being added all the time, lead to too thick of bones (blood vessils close and cause pain)
Osteoporosis MOA
Too much osteoclast activity- bones become thin and weak
What do thecal cells release
Androgens
What do granulosa cells release
estrogens
What cells release estrogens
granulosa cells
What cells release androgens
thecal cells
What cells secrete estrogens
Granulosa cells, corpus luteum, placenta
What is estrogen formation dependent on
Aromatase
What does aromatase convert
Testosterone to estradiol and androtendione to estrone
What happens to thecal cells when LH rises
LH causes thecal cells to release androstenedione–> send to granulosa cells–> convert to estrone–> estradiol–> release to follicular fluid in antrum
What causes to mature granulosa cells when LH increases
they release estradiol and produce it
What does P450 do
helps form steroids- acts as a mitochondrial enzyme
What secretes progesterone
Corpus luteum and placenta
What stimulates corpus luteum to release progesterone
LH binds to corpus luteum
Where does sperm development occur
Sperm development
Where does sperm maturation occur
Epididymis
Vas deferens function
Connect testis to urethra
What are the pancreatic exocrine cells
acini cells (secrete pancreatic juice for digestion)
What are the endocrine cells of the pancreas
Islets of langerhans
What organ is Vitamin D3 made in
Kidney
