Week 4 Review Q's Flashcards
Anatomy of parathyroid (1-52) Regulation of Ca and Pi (53-90) bone and Ca biochem (91-122) hormones and negative feedback (123-138) D3 regulated gene expression seminar (139-170) pharma agents that affect bone homeostasis (171-196) clinical medicine osteoporosis (197-220) Radiology endocine imaging (221-235) Investigation of bone disorders (236-264) Genetics of the endocrine system (265-281)
What is the Chvostek sign? What does it indicate?
It refers to an abnormal reaction to the stimulation of the facial nerve. (existing nerve hyperexcitability/tetany). Seen in patients with hypocalcemia.
What percent of people don’t have all 4 parathyroid glands?
20%
Which is also called parathyroid 4? a. superior parathyroid glands b. inferior parathyroid glands
a. superior parathyroid glands
Which is more variable in location? a. superior parathyroid glands b. inferior parathyroid glands
b. inferior parathyroid glands
Which is ventral to the recurrent laryngeal nerve? a. superior parathyroid glands b. inferior parathyroid glands
b. inferior parathyroid glands
Which is more constantly found within the false capsule? a. superior parathyroid glands b. inferior parathyroid glands
a. superior parathyroid glands
What’s the branch of the superior thyroid artery that anastomosis with the inferior thyroid artery?
the posterior branch
What artery gives rise to the superior thyroid artery?
external carotid artery
What three things are in the carotid sheath when it near the area of the parathyroid?
Inferior vena cava Vagus nerve Common carotid artery
When do the oxyphil cells of the parathyroid develop?
differentiate later at puperty
Which are more acidophilic? a. principal cells b. oxyphil cells
b. oxyphil cells
Which have a secretory role? a. principal cells b. oxyphil cells
a. principal cells
Which are more numerous? a. principal cells b. oxyphil cells
a. principal cells
When do the principal cells of the parathyroid develop?
during embryonic development
Which has more mitochondria? a. principal cells b. oxyphil cells
b. oxyphil cells
What TWO of the following does PTH do? a. increase calcium b. decrease calcium c. increase phosphate d. decrease phosphate
a. increase calcium & d. decrease phosphorus
What three organs does PTH have an effect on?
bone gut kidney
How does the PTH help calcium absorption in the gut?
by activating the enzyme that activates vitamin D (1-alpha-hydroxylase). Vitamin D helps absorb calcium in the blood.
Where does 1-alpha-hydroxylase function?
in the kidney
Using which mechanism does PTH activate osteoclasts?
PTH activates osteoblasts to make RANKL, which then binds to RANK receptor of osteoclasts and activates it
Why would PTH be used for the treatment of osteoporosis?
because intermittent treatment with the hormone has an anabolic action of bone via the cAMP/IGF-I pathway
What occurs after prolonged treatment with PTH?
catabolic effect on bone (causes low bone mass)
How does PTH control phosphate levels?
increases the excretion of phosphate in the kidney
Which of the following form the superior parathyroid? a. pouch 1 b. pouch 2 c. pouch 3 d. pouch 4
d. pouch 4 (dorsal wing of the fourth pouch) (the ventral wing of the fourth pouch makes the ultimobranchial body -> parafollicular cells/C cells)
Which of the following forms an overgrowth that makes the neck smooth? a. pouch 1 b. pouch 2 c. pouch 3 d. pouch 4
b. pouch 2
Which of the following forms the thymus? a. pouch 1 b. pouch 2 c. pouch 3 d. pouch 4
c. pouch 3 (ventral wing of third pouch)
Digeorge syndrome is caused by a failure of which pharyngeal arch(es)?
3rd and 4th pouch
Nezelof’s syndrome is caused by a failure of which pharyngeal arch(es)?
3rd pouch
Which of the following causes an absence/underdevelopment of the thymus? a. Nezelof’s syndrome b. Digeorge syndrome c. both
c. both
Which of the following causes cleft lip? a. Nezelof’s syndrome b. Digeorge syndrome c. both
b. Digeorge syndrome
Which of the following causes diarrhea and pyoderma? a. Nezelof’s syndrome b. Digeorge syndrome c. both
a. Nezelof’s syndrome
Which of the following causes cardiac defects? a. Nezelof’s syndrome b. Digeorge syndrome c. both
b. Digeorge syndrome
Which of the following is caused by the deletion of the long arm of chromosome 22? a. Nezelof’s syndrome b. Digeorge syndrome c. both
b. Digeorge syndrome
What happens to the parathyroid glands during most thyroidectomy procedures?
the posterior part of the thyroid is kept to safe keep the parathyroid glands
What happens to the parathyroid glands when the entire thyroid needs to be removed?
they are transplanted to the forearm or SCM muscle
What are the symptoms of low calcium levels?
tingling (often in the lips, tongue, fingers, and feet), muscle aches, spasms of the muscles in the throat (leading to difficulty breathing), stiffening and spasms of muscles (tetany), seizures, and abnormal heart rhythms.
What is hungry bone syndrome? When does it occur?
Calcium uptake by bone increases and calcium levels falls. It occurs after parathyroid surgery.
What’s the most common etiology of primary hyperparathyroidism?
parathyroid adenomas (85%)
How can small cell lung cancer raise calcium levels?
the cells of the tumor make analogs of PTH that causes the raise in calcium
T/F: about 20% of patients with parathyroid adenomas are asymptomatic
false, its 85%
How does estrogen and testosterone affect bone resorption?
estrogen and testosterone both inhibit bone breakdown (resorption) by inhibiting osteoclast activity and increasing its apoptosis
Which of the following describes sex hormone function? a. bone resorption b. bone formation c. both
b. bone formation
Which of the following describes PTH function? a. bone resorption b. bone formation c. both
c. both (depends on dose and duration)
Which describes Calcitriol function? a. inhibit bone breakdown b. conserve calcium c. stimulates bone resorption d. stimulate bone formation e. increase calcium absorption
e. increase calcium absorption (and phosphorous absorption)
T/F: bone resorption exceeding bone formation is pathological
false, it’s a normal process of aging
Which describes Calcitonin function? a. inhibit bone breakdown b. conserve calcium c. stimulates bone resorption d. stimulate bone formation e. increase calcium absorption
a. inhibit bone breakdown (by inactivating osteoclasts)
How do excess glucocorticoids affect bones of kids/adults?
stop bone growth in children + cause marked thinning of the bone in adults (both lead to fractures)
Which describes PTH effect on gut? a. inhibit bone breakdown b. conserve calcium c. stimulates bone resorption d. stimulate bone formation e. stimulate calcitriol f. increase calcium absorption
f. increase calcium absorption
What is Osteitis fibrosa cystica? What does it lead to?
characteristic, but rare, manifestation of primary hyperparathyroidism. Cystic changes in the bone occur due to osteoclastic resorption. fibrous replacement of resorbed bone may lead to the formation of non-neoplastic tumor-like masses (brown tumor) on x-ray films.
Which describes PTH effect on kidneys? (two answers) a. inhibit bone breakdown b. conserve calcium c. stimulates bone resorption d. stimulate bone formation e. stimulate calcitriol f. increase calcium absorption
b. conserve calcium & e. stimulate calcitriol
How are kidney stones related to high PTH?
PTH increases calcium and the high calcium leads to stone formation
Which describes PTH effect on bone? (two answers) a. inhibit bone breakdown b. conserve calcium c. stimulates bone resorption d. stimulate bone formation e. stimulate calcitriol f. increase calcium absorption
c. stimulates bone resorption & d. stimulate bone formation (depending on if its intermittent or prolonged treatment)
How does calcium aid in hormone secretion?
be acting as a second messenger
Which of the following decreases calcium levels? a. Parathyroid hormone b. Calcitonin c. Calcitriol d. Fibroblast growth factor 23
b. Calcitonin
Which of the following is stimulated by high calcium levels? a. Parathyroid hormone b. Calcitonin c. Calcitriol d. Fibroblast growth factor 23
b. Calcitonin
Which two of the following are stimulated by high phosphate levels? a. Parathyroid hormone b. Calcitonin c. Calcitriol d. Fibroblast growth factor 23
a. Parathyroid hormone & d. Fibroblast growth factor 23 (they both decrease phosphate levels)
How does calcium help nerves function?
maintaining membrane stability and helping in membrane depolarization
How do high phosphate levels indirectly stimulate parathyroid levels?
by binding to/decreasing calcium levels which then increases PTH
Which of the following does the PTH work on indirectly? a. bone b. intestine c. kidney
b. intestine
How does 1,25-Vitamin D (calcitriol) inhibit PTH genes directly and indirectly?
directly by inhibiting the PTH gene transcription indirectly by activating CaSR gene transcription-> increase CaSR synthesis (when CaSR is activated it inhibits the PTH gene transcription and decreases PTH secretion)
Where is Cholecalciferol synthesized?
made by the skin when exposed to sunlight
What two methods does Ca sensing receptor (CaSR) use to decrease PTH in blood?
inhibit PTH secretion inhibit PTH gene transcription
What’s the dietary source of vitamin D2?
plants
What’s the dietary source of vitamin D3?
animals
Whats (two things) transport vitamin D from the gut to the liver?
chylomicrons DBP (vitamin D Binding Protein)
What hormone stimulates 1-alpha-hydroxylase function?
PTH
Which of the following is a rapid response when PTH is high? a. higher Ca absorption in gut b. higher bone turnover
b. higher bone turnover
What are the three ways vitamin D acts to increase calcium?
- increase Ca absorption in gut - increase bone turnover - increase Ca reabsorption and Pi excretion
Whats the main effect of vitamin D?
increase Ca absorption in gut
How does PTH & Fibroblast growth factor 23 (FGF23) decrease phosphate levels?
by inhibiting Pi reabsorption
How does renal failure lead to osteoporosis?
renal failure→Pi retention→high Pi→low Ca→high PTH→bone resorption
What regulates calcitonin?
CaSR
What stimulates calcitonin release?
high Ca & Pi
What makes and releases calcitonin?
Parafollicular cells (C cells) of the thyroid
Compare and contrast PTH & FGF23. What do they do similarly/differently?
both inhibit Pi reabsorption (decrease Pi) PTH stimulates 1-alpha-hydroxylase activity while FGF23 inhibits it. (PTH increases vit D, FGF23 decreases vit D)
Which causes corneal/ectopic calcification? a. hypoparathyroidism b. hyperparathyroidism
b. hyperparathyroidism
Which can be caused by low magnesium levels? a. hypoparathyroidism b. hyperparathyroidism
a. hypoparathyroidism
What do chvostek sign and trousseau sign indicate?
low calcium and high phosphate concentrations
High PTH levels in a fiver year old caused major bone resorption. What is the result? a. osteomalacia b. rickets
b. rickets
How do sex hormones protect against bone loss?
by promoting osteoblast survival and osteoclast apoptosis
T/F: swimming and walking are the best exercises for building bone
false, weight-bearing exercises are the best for building bone
T/F: Ca and vit D supplements are always useful methods of preventing osteoporosis
false, they’re not useful after menopause
What are four causes of osteoporosis?
- estrogen loss - bed rest - loss of gravity - high glucocorticoids
What do you give postmenopausal women who have bone resorption?
hormone replacement therapy (estrogen to slow down bone resorption, but it doesn’t rebuild)
Which drug would you give women who have family history of breast cancer?
Selective estrogen receptor modulators (SERM)
Which of the following can be given as a nasal spray? a. Calcitonin b. Bisphosphonates c. Raloxifen d. Tamoxifen
a. Calcitonin
Which of the following has to be taken while standing or sitting upright? Why? a. Calcitonin b. Bisphosphonates c. Raloxifen d. Tamoxifen
b. Bisphosphonates (because it damages the esophagus)
Which of the following doesn’t have estrogen stimulation on breast and uterus? a. Raloxifen b. Tamoxifen
a. Raloxifen
Which of the following can we extracted by salmon? a. Calcitonin b. Bisphosphonates c. Raloxifen d. Tamoxifen
a. Calcitonin
Which of the following is used to treat certain breast cancers? a. Raloxifen b. Tamoxifen
b. Tamoxifen
Which of the following makes extracellular ePi-Pi? a. ANKP b. NPP-1 c. TNAP d. ALKP
b. NPP-1
Carbonic anhydrase deficiency leads to which disease formation?
Osteopetrosis
Which of the following hydrolyze phosphate groups? a. ANKP b. NPP-1 c. TNAP d. ALKP
c. TNAP
What transports H+ into the ruffled surface area of osteoclasts?
H+-ATPase
Mutations in what two proteins will cause osteopetrosis?
H+-ATPase (proton pump) Carbonic anhydrase
How does denosumab treat osteopetrosis?
it binds to RANKL and prevents it from activating the RANK receptors which activate osteoclasts (denosumab= anti RANKL antibody)
Which of the following transports Intracellular Pi-Pi to Extracellular (ePi-Pi)? a. ANKP b. NPP-1 c. TNAP d. ALKP
a. ANKP
How does estrogen protect from osteoporosis?
through induction of osteoprotegerin (OPG), which acts like a RANK receptor and competitively inhibits the (RANK) receptor activation
How does collagen help bone ossification?
it provides nucleation for hydroxyapatite formation
Which initiates hydroxyapatite crystallization along the collagen fibers? a. Osteopontin b. Osteonectin c. Osteocalcin d. Bone sialoprotein
d. Bone sialoprotein (BSP)
Which TWO of the following have binding sites for Arginylglycylaspartic acid (RGD)? a. Osteopontin b. Osteonectin c. Osteocalcin d. Bone sialoprotein
a. Osteopontin & d. Bone sialoprotein
Which of the following has a greater negative charge due to post-transcriptional modification? a. Osteopontin b. Osteonectin c. Osteocalcin d. Bone sialoprotein
c. Osteocalcin (γ-Glutamyl carboxylation added the negative charge)
Which of the following may serve as a target for the treatment of osteoporosis in menopausal women? a. Osteopontin b. Osteonectin c. Osteocalcin d. Bone sialoprotein
a. Osteopontin (when its gene is mutated, there’s a reduction in the ruffled surface area)
A defect in which of the following causes osteopenia? a. Osteopontin b. Osteonectin c. Osteocalcin d. Bone sialoprotein
b. Osteonectin
Which of the following is regulated by PTH? a. Osteopontin b. Osteonectin c. Osteocalcin d. Bone sialoprotein
b. Osteonectin
Which of the following is the most abundant osteoblast-specific ECM protein? a. Osteopontin b. Osteonectin c. Osteocalcin d. Bone sialoprotein
c. Osteocalcin
A mutation of which of the following results is a short person? a. Osteopontin b. Osteonectin c. Osteocalcin d. Bone sialoprotein
d. Bone sialoprotein (controls femur bone growth)
Which of the following regulates bone resorption through ruffled border area? a. Osteopontin b. Osteonectin c. Osteocalcin d. Bone sialoprotein
a. Osteopontin
What are bone morphogenetic proteins? What family do they belong to? What are they also known as?
Signaling molecules that serve as growth factors. They belong to TGF-beta super family. Also known as Osteogenin
Which of the following releases Pi from the extracellular ePi-Pi? a. ANKP b. NPP-1 c. TNAP d. ALKP
d. ALKP (alkaline phosphatase)
What does a high concentration of ePi-Pi do?
inhibits bone formation (he said that high pyrophosphate inhibits mineralization due to competition. the pyrophosphate competes with the phosphate to form defective crystallization instead of hydroxyapatite)
What TWO enzymes increase ePi-Pi?
ANKP & NPP-1 (so when you over-activate them it increases ePi-Pi and that suppresses bone formation)
What regulates ALKP? What happens to bones if ALKP gene got mutated? Why?
ALKP is regulated by BMP (bone morphogenic proteins) Mutations in ALKP lead to soft bone, thats because ALKP decreases ePi-Pi by transforming it to Pi. If ALKP is defective, ePi-Pi would be increased and Pi would decrease, both of those inhibit bone formation.
Which location is Ca concentration less? a. serum b. ER c. cytosol
c. cytosol
Which three pumps remover Ca from the cytoplasm?
PMCA SERCA NCX
Which of the following cannot release Ca in bulk due to the its high affinity? a. PMCA b. SERCA c. NCX
a. PMCA
Which of the following is the most important for bone miniralization? why? a. PMCA b. SERCA c. NCX
c. NCX (it has low affinity so it’s able to release Ca in bulk)