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)
1
Q
What is the Chvostek sign? What does it indicate?
A
It refers to an abnormal reaction to the stimulation of the facial nerve. (existing nerve hyperexcitability/tetany). Seen in patients with hypocalcemia.
2
Q
What percent of people don’t have all 4 parathyroid glands?
A
20%
3
Q
Which is also called parathyroid 4? a. superior parathyroid glands b. inferior parathyroid glands
A
a. superior parathyroid glands
4
Q
Which is more variable in location? a. superior parathyroid glands b. inferior parathyroid glands
A
b. inferior parathyroid glands
5
Q
Which is ventral to the recurrent laryngeal nerve? a. superior parathyroid glands b. inferior parathyroid glands
A
b. inferior parathyroid glands
6
Q
Which is more constantly found within the false capsule? a. superior parathyroid glands b. inferior parathyroid glands
A
a. superior parathyroid glands
7
Q
What’s the branch of the superior thyroid artery that anastomosis with the inferior thyroid artery?
A
the posterior branch
8
Q
What artery gives rise to the superior thyroid artery?
A
external carotid artery
9
Q
What three things are in the carotid sheath when it near the area of the parathyroid?
A
Inferior vena cava Vagus nerve Common carotid artery
10
Q
When do the oxyphil cells of the parathyroid develop?
A
differentiate later at puperty
11
Q
Which are more acidophilic? a. principal cells b. oxyphil cells
A
b. oxyphil cells
12
Q
Which have a secretory role? a. principal cells b. oxyphil cells
A
a. principal cells
13
Q
Which are more numerous? a. principal cells b. oxyphil cells
A
a. principal cells
14
Q
When do the principal cells of the parathyroid develop?
A
during embryonic development
15
Q
Which has more mitochondria? a. principal cells b. oxyphil cells
A
b. oxyphil cells
16
Q
What TWO of the following does PTH do? a. increase calcium b. decrease calcium c. increase phosphate d. decrease phosphate
A
a. increase calcium & d. decrease phosphorus
17
Q
What three organs does PTH have an effect on?
A
bone gut kidney
18
Q
How does the PTH help calcium absorption in the gut?
A
by activating the enzyme that activates vitamin D (1-alpha-hydroxylase). Vitamin D helps absorb calcium in the blood.
19
Q
Where does 1-alpha-hydroxylase function?
A
in the kidney
20
Q
Using which mechanism does PTH activate osteoclasts?
A
PTH activates osteoblasts to make RANKL, which then binds to RANK receptor of osteoclasts and activates it
21
Q
Why would PTH be used for the treatment of osteoporosis?
A
because intermittent treatment with the hormone has an anabolic action of bone via the cAMP/IGF-I pathway
22
Q
What occurs after prolonged treatment with PTH?
A
catabolic effect on bone (causes low bone mass)
23
Q
How does PTH control phosphate levels?
A
increases the excretion of phosphate in the kidney
24
Q
Which of the following form the superior parathyroid? a. pouch 1 b. pouch 2 c. pouch 3 d. pouch 4
A
d. pouch 4 (dorsal wing of the fourth pouch) (the ventral wing of the fourth pouch makes the ultimobranchial body -> parafollicular cells/C cells)
25
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
26
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)
27
Digeorge syndrome is caused by a failure of which pharyngeal arch(es)?
3rd and 4th pouch
28
Nezelof's syndrome is caused by a failure of which pharyngeal arch(es)?
3rd pouch
29
Which of the following causes an absence/underdevelopment of the thymus? a. Nezelof's syndrome b. Digeorge syndrome c. both
c. both
30
Which of the following causes cleft lip? a. Nezelof's syndrome b. Digeorge syndrome c. both
b. Digeorge syndrome
31
Which of the following causes diarrhea and pyoderma? a. Nezelof's syndrome b. Digeorge syndrome c. both
a. Nezelof's syndrome
32
Which of the following causes cardiac defects? a. Nezelof's syndrome b. Digeorge syndrome c. both
b. Digeorge syndrome
33
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
34
What happens to the parathyroid glands during most thyroidectomy procedures?
the posterior part of the thyroid is kept to safe keep the parathyroid glands
35
What happens to the parathyroid glands when the entire thyroid needs to be removed?
they are transplanted to the forearm or SCM muscle
36
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.
37
What is hungry bone syndrome? When does it occur?
Calcium uptake by bone increases and calcium levels falls. It occurs after parathyroid surgery.
38
What's the most common etiology of primary hyperparathyroidism?
parathyroid adenomas (85%)
39
How can small cell lung cancer raise calcium levels?
the cells of the tumor make analogs of PTH that causes the raise in calcium
40
T/F: about 20% of patients with parathyroid adenomas are asymptomatic
false, its 85%
41
How does estrogen and testosterone affect bone resorption?
estrogen and testosterone both inhibit bone breakdown (resorption) by inhibiting osteoclast activity and increasing its apoptosis
42
Which of the following describes sex hormone function? a. bone resorption b. bone formation c. both
b. bone formation
43
Which of the following describes PTH function? a. bone resorption b. bone formation c. both
c. both (depends on dose and duration)
44
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)
45
T/F: bone resorption exceeding bone formation is pathological
false, it's a normal process of aging
46
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)
47
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)
48
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
49
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.
50
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
51
How are kidney stones related to high PTH?
PTH increases calcium and the high calcium leads to stone formation
52
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)
53
How does calcium aid in hormone secretion?
be acting as a second messenger
54
Which of the following decreases calcium levels? a. Parathyroid hormone b. Calcitonin c. Calcitriol d. Fibroblast growth factor 23
b. Calcitonin
55
Which of the following is stimulated by high calcium levels? a. Parathyroid hormone b. Calcitonin c. Calcitriol d. Fibroblast growth factor 23
b. Calcitonin
56
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)
57
How does calcium help nerves function?
maintaining membrane stability and helping in membrane depolarization
58
How do high phosphate levels indirectly stimulate parathyroid levels?
by binding to/decreasing calcium levels which then increases PTH
59
Which of the following does the PTH work on indirectly? a. bone b. intestine c. kidney
b. intestine
60
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)
61
Where is Cholecalciferol synthesized?
made by the skin when exposed to sunlight
62
What two methods does Ca sensing receptor (CaSR) use to decrease PTH in blood?
inhibit PTH secretion inhibit PTH gene transcription
63
What's the dietary source of vitamin D2?
plants
64
What's the dietary source of vitamin D3?
animals
65
Whats (two things) transport vitamin D from the gut to the liver?
chylomicrons DBP (vitamin D Binding Protein)
66
What hormone stimulates 1-alpha-hydroxylase function?
PTH
67
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
68
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
69
Whats the main effect of vitamin D?
increase Ca absorption in gut
70
How does PTH & Fibroblast growth factor 23 (FGF23) decrease phosphate levels?
by inhibiting Pi reabsorption
71
How does renal failure lead to osteoporosis?
renal failure→Pi retention→high Pi→low Ca→high PTH→bone resorption
72
What regulates calcitonin?
CaSR
73
What stimulates calcitonin release?
high Ca & Pi
74
What makes and releases calcitonin?
Parafollicular cells (C cells) of the thyroid
75
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)
76
Which causes corneal/ectopic calcification? a. hypoparathyroidism b. hyperparathyroidism
b. hyperparathyroidism
77
Which can be caused by low magnesium levels? a. hypoparathyroidism b. hyperparathyroidism
a. hypoparathyroidism
78
What do chvostek sign and trousseau sign indicate?
low calcium and high phosphate concentrations
79
High PTH levels in a fiver year old caused major bone resorption. What is the result? a. osteomalacia b. rickets
b. rickets
80
How do sex hormones protect against bone loss?
by promoting osteoblast survival and osteoclast apoptosis
81
T/F: swimming and walking are the best exercises for building bone
false, weight-bearing exercises are the best for building bone
82
T/F: Ca and vit D supplements are always useful methods of preventing osteoporosis
false, they're not useful after menopause
83
What are four causes of osteoporosis?
- estrogen loss - bed rest - loss of gravity - high glucocorticoids
84
What do you give postmenopausal women who have bone resorption?
hormone replacement therapy (estrogen to slow down bone resorption, but it doesn't rebuild)
85
Which drug would you give women who have family history of breast cancer?
Selective estrogen receptor modulators (SERM)
86
Which of the following can be given as a nasal spray? a. Calcitonin b. Bisphosphonates c. Raloxifen d. Tamoxifen
a. Calcitonin
87
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)
88
Which of the following doesn’t have estrogen stimulation on breast and uterus? a. Raloxifen b. Tamoxifen
a. Raloxifen
89
Which of the following can we extracted by salmon? a. Calcitonin b. Bisphosphonates c. Raloxifen d. Tamoxifen
a. Calcitonin
90
Which of the following is used to treat certain breast cancers? a. Raloxifen b. Tamoxifen
b. Tamoxifen
91
Which of the following makes extracellular ePi-Pi? a. ANKP b. NPP-1 c. TNAP d. ALKP
b. NPP-1
92
Carbonic anhydrase deficiency leads to which disease formation?
Osteopetrosis
93
Which of the following hydrolyze phosphate groups? a. ANKP b. NPP-1 c. TNAP d. ALKP
c. TNAP
94
What transports H+ into the ruffled surface area of osteoclasts?
H+-ATPase
95
Mutations in what two proteins will cause osteopetrosis?
H+-ATPase (proton pump) Carbonic anhydrase
96
How does denosumab treat osteopetrosis?
it binds to RANKL and prevents it from activating the RANK receptors which activate osteoclasts (denosumab= anti RANKL antibody)
97
Which of the following transports Intracellular Pi-Pi to Extracellular (ePi-Pi)? a. ANKP b. NPP-1 c. TNAP d. ALKP
a. ANKP
98
How does estrogen protect from osteoporosis?
through induction of osteoprotegerin (OPG), which acts like a RANK receptor and competitively inhibits the (RANK) receptor activation
99
How does collagen help bone ossification?
it provides nucleation for hydroxyapatite formation
100
Which initiates hydroxyapatite crystallization along the collagen fibers? a. Osteopontin b. Osteonectin c. Osteocalcin d. Bone sialoprotein
d. Bone sialoprotein (BSP)
101
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
102
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)
103
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)
104
A defect in which of the following causes osteopenia? a. Osteopontin b. Osteonectin c. Osteocalcin d. Bone sialoprotein
b. Osteonectin
105
Which of the following is regulated by PTH? a. Osteopontin b. Osteonectin c. Osteocalcin d. Bone sialoprotein
b. Osteonectin
106
Which of the following is the most abundant osteoblast-specific ECM protein? a. Osteopontin b. Osteonectin c. Osteocalcin d. Bone sialoprotein
c. Osteocalcin
107
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)
108
Which of the following regulates bone resorption through ruffled border area? a. Osteopontin b. Osteonectin c. Osteocalcin d. Bone sialoprotein
a. Osteopontin
109
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
110
Which of the following releases Pi from the extracellular ePi-Pi? a. ANKP b. NPP-1 c. TNAP d. ALKP
d. ALKP (alkaline phosphatase)
111
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)
112
What TWO enzymes increase ePi-Pi?
ANKP & NPP-1 (so when you over-activate them it increases ePi-Pi and that suppresses bone formation)
113
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.
114
Which location is Ca concentration less? a. serum b. ER c. cytosol
c. cytosol
115
Which three pumps remover Ca from the cytoplasm?
PMCA SERCA NCX
116
Which of the following cannot release Ca in bulk due to the its high affinity? a. PMCA b. SERCA c. NCX
a. PMCA
117
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)
118
How many aa's of PTH are removed in the liver?
2
119
How many aa's of PTH are removed in the ER?
25
120
How many aa's of PTH are removed in the golgi?
6
121
Which aa's of PTH peptide are active? What does it serve as?
1-34 PTH's 25-34 amino acid serves as receptor binding region
122
During PTH release, what initiates the increase in calcium? (which allows the release of the PTH filled vesicles?)
IP3 is the second messenger molecule that releases the Ca
123
Which is responsible for 90% of plasma osmolarity? a. Na b. K
a. Na
124
Whats the most abundant intracellular cation?
K+
125
What are the four causes of thirst?
high osmolarity low volume high angiotensin 2 dry mouth
126
Whats the most abundant extracellular cation?
Na+
127
Where is osmolarity sensed? By what?
osmoreceptors in the anterior pituitary
128
Where is volume sensed? By what?
via volume receptor in the venae cava and atrium
129
Whats the primary effect of aldosterone?
Sodium levels, but it also has a secondary effect on water reabsorption
130
Whats the primary effect of ADH?
Water reabsorption is the primary effect
131
Where does ADH act on?
late distal convoluted tubule and collecting duct (increase water absorption in the areas)
132
Renin helps the secretion of which of the following? a. ADH b. aldosterone
b. aldosterone
133
T/F: all amino acid derivatives are lipid-soluble
false, they can be both
134
polypeptides are a. lipophilic b. lipophobic
a. lipophilic
135
What are the 6 hypothalamic hormones?
The. TRH: Thyroid-releasing Hormone. Drunk. DA: Dopamine. Girl. GHRH: Growth hormone-releasing hormone. Got. GnRH: Gonadotropin-releasing hormone. Some. Somatostatin. Courage. CRF: Corticotropin-releasing Factor.
136
What is the indirect function of growth hormone?
stimulate insulin-like growth factor (IGF) via the liver (this stimulates bone growth, lipolysis, protein synthesis of muscles)
137
Growth hormone is also called...
Somatotropin
138
How are thyroid hormones transported?
bound by Thyroxine-binding globulin (70%), albumin (20%) and transthyretin (5%)
139
What is the biologically active form of vitamin D?
1,25-dihydroxycholecalciferol AKA calcitriol
140
Which enzyme is used in the hydroxylation of vitamin D in the liver?
25 hydroxylase enzyme
141
Which enzyme is used in the hydroxylation of vitamin D in the Kidney?
1‐alpha‐hydroxylase enzyme
142
What does 1,25-dihydroxy Vit-D3 target?
• Gastro intestinal tract • Renaltubules
143
Where does Vitamin D / VDR complex bind to Retinoic X receptor (RXR)?
In nucleus
144
Where does Vitamin D binds to its receptor (Vitamin D receptor)?
In the cytosol
145
Which transports Ca2+ from the apical membrane to the basolateral membrane? a. PMCA1b b. TRPV6 c. Calbindin
c. Calbindin
146
Which responds to oral calcium treatment? a. Vitamin D-Dependent Rickets (VDDR) - Type I b. Hereditary Vitamin D Resistant Rickets (HVDRR) - Type II c. both
a. Vitamin D-Dependent Rickets (VDDR) - Type I
147
Which commonly causes alopecia? a. Vitamin D-Dependent Rickets (VDDR) - Type I b. Hereditary Vitamin D Resistant Rickets (HVDRR) - Type II c. both
b. Hereditary Vitamin D Resistant Rickets (HVDRR) - Type II
148
Which facilitates the uptake of Ca2+ across the brush border apical membrane into the enterocyte? a. PMCA1b b. TRPV6 c. Calbindin
b. TRPV6
149
Which has an earlier onset? a. Vitamin D-Dependent Rickets (VDDR) - Type I b. Hereditary Vitamin D Resistant Rickets (HVDRR) - Type II
b. Hereditary Vitamin D Resistant Rickets (HVDRR) - Type II
150
Which is autosomal recessive? a. Vitamin D-Dependent Rickets (VDDR) - Type I b. Hereditary Vitamin D Resistant Rickets (HVDRR) - Type II c. both
c. both
151
Which facilitates the transport of calcium from the enterocyte into the circulation? a. PMCA1b b. TRPV6 c. Calbindin
a. PMCA1b
152
Most rickets cases is due to mutations in which TWO of the following domains? a. DNA binding domain b. AF-2 domain c. Multifunctional ligand binding domain d. Hinge domain
a. DNA binding domain & c. Multifunctional ligand binding domain
153
T/F: only 65 different mutations of the VDR gene were found
false, these are only the ones that cause functional changes. There are many other mutations.
154
A mutation of which of the following prevents the interaction of VDR and VDRE of target genes? a. DNA binding domain b. AF-2 domain c. Multifunctional ligand binding domain d. Hinge domain
a. DNA binding domain
155
What occurs if there's a mutation in the Vitamin D receptor (VDR)? How do you treat it?
patient is unable to absorb calcium from the gastrointestinal tract. You treat with vit D injections.
156
A mutation of which of the following affects the binding of Vitamin D3 or RXR? a. DNA binding domain b. AF-2 domain c. Multifunctional ligand binding domain d. Hinge domain
c. Multifunctional ligand binding domain
157
What can you conclude when Alkaline phosphatase (ALP) concentration is high?
high osteoblastic acitivity
158
Which is due to a mutation in vitamin D receptor? a. Vitamin D-Dependent Rickets (VDDR) - Type I b. Hereditary Vitamin D Resistant Rickets (HVDRR) - Type II
b. Hereditary Vitamin D Resistant Rickets (HVDRR) - Type II
159
What can you conclude about a patient with rickets that has low Calcidiol and high Calcitriol levels?
they do not have a 1-alpha-hydroxylase deficiency (not type 1 rickets)
160
Why would a patient with rickets have low Calcidiol and high Calcitriol?
the low calcium levels cause high PTH, which stimulates 1-a-hydroxylase, thus transforming calcidiol to cacitriol
161
"Hereditary Vitamin D Resistant Ricket” (HVDRR) is also known as
type 2 rickets
162
Describe Alkaline phosphatase (ALP) concentration in rickets?
high due to compensatory mechanisms
163
Whats the best indicator of Vitamin D3 status in a patient? What do you test to determine D3 levels?
25-hydroxy-Vit D3 (Calcidiol) is the best indicator because its not modulated by PTH activity
164
If a mutation occurs in DNA binding domain, what occurs?
Complete loss of function & alopecia w/ serum calcium (Rickets)
165
If a mutation occurs in vitamin D3 ligand domain of VDR, what occurs?
Complete loss of function & alopecia w/ serum calcium (Rickets)
166
Which type of rickets does a patient with deficient 1-a-hydroxylase have?
type 1 rickets
167
Do mutations in the DNA binding domain of VDR cause alopecia?
yes, mutations in the DNA binding domain of VDR cause complete loss of function & alopecia
168
If a mutation occurs in RXR ligand binding domain of VDR, what occurs?
Partial loss of function & \*\*No alopecia\*\* w/ serum calcium (Rickets) Arg(274)Leu His(305)Gln Ile(314)Ser
169
Why do keratinocytes need vitamin D?
hair follicle cycling is dependent on the interaction of VDR / RXR.
170
How does vitamin D non-genomically activates different cell types?
by activating intracellular cellular calcium release
171
T/F: bone is made up of 75% inorganic components
true
172
If a patient was given a dose of calcium, about what percent would be absorbed?
30%. If a 100mg is given, 30mg gets absorbed
173
How does alkaline phosphatase effect phosphate levels?
It hydrolyzes phosphate esters and liberates inorganic phosphates, thus increasing phosphate
174
How long does the bone resorption cycle take?
3 weeks
175
Which of the following causes secondary osteoporosis? a. osteoarthritis b. rheumatoid arthritis
b. rheumatoid arthritis
176
How does kidney failure cause secondary hyperparathyroidism?
1-alpha-hydroxylase acts in the kidney to activate vitamin D. Kidney failure stops this, causing low vitamin D. Vitamin D is needed for calcium absorption from the GI. When the calcium is decreased PTH is increased to compensate.
177
How do Selective estrogen receptor modulators (SERM) help osteoporosis? a. increase bone formation b. stop bone resorption
b. stop bone resorption
178
How do high glucocorticoids lead to secondary hyperparathyroidism?
they inhibit calcium absorption and induce its excretion, PTH compensates
179
Whats the difference between Calcitonin and Calcimer?
Calcimer is a synthetic analog of Calcitonin. So it has a higher receptor affinity and duration.
180
Which of the following best describes Estrogen? a. increases bone mass b. decreases bone mass c. none of them
c. none of them it maintains the bone mass
181
Why are progestational agents used alongside estrogen to treat osteoporosis?
because estrogen may cause endometrial cancer, and progesterone like compounds prevent that
182
Patient comes in with osteoporosis. Which of the following options is preferable? a. Estrogen b. Raloxifene c. both the same
b. Raloxifene (it acts as an agonist or antagonist based on the tissue. Estrogen acts as an agonist for all)
183
Which of the following increases High-density lipoproteins and lowers Low-density lipoproteins? a. Estrogen b. Raloxifene c. both
c. both
184
Which TWO of the following must the patient stay in an upright position for 30 minutes after taking? Why? a. Estrogen b. Alendronate c. Risedronate d. Raloxifene
b. Alendronate & c. Risedronate (they're both bisphosphonates that may cause esophagitis)
185
Which of the following has a side effect of uterine bleeding and venous thromboembolism? a. Estrogen b. Alendronate c. Risedronate d. Raloxifene
a. Estrogen
186
Describe the activity of Raloxifene on the breast?
antagonistic
187
How do Bisphosphonates work to treat osteoporosis?
they have the P-C-P structure, which is similar to the P-O-P structure of native pyrophosphate. The difference is that the new P-C-P structure is resistant to hydrolysis by alkaline phosphatase, so it stays in the bone matrix longer. They're anti-resorptive pyrophosphate analogs.
188
Which pyrophosphate bond is stronger? a. ester bond b. carbon bond
b. carbon bond resistant to hydrolysis by alkaline phosphatase
189
How is Miacalcin and Calcimer administered?
Iv or subcutaneous (NOT orally)
190
What occurs after long term use of calcitonin analogs?
(Miacalcin and Calcimer) long term use causes tachyphylaxis (a decrease in response due to subsensitivity of calcitonin receptors cause this side effect. that basically means the receptor number is low or the post signaling receptor pathway is reduced-\> reaction not strong)
191
Which of the following decreases IL-6? a. Estrogen b. Alendronate c. Raloxifene
b. Alendronate (Bisphosphonates decrease interleukins)
192
Which TWO of the following are markers of bone resorption? a. alkaline phosphatase b. osteocalcin c. n-telopeptide d. hydroxyproline
c. n-telopeptide & d. hydroxyproline A&B are markers for bone formation
193
How does Sevelamer treat hyperparathyroidism?
by binding to phosphate in the GI and inhibiting it's absorption. Pi decreases and Ca increases, causing inhibition of PTH
194
How does Calcitriol treat hyperparathyroidism?
by suppressing the PTH hormone gene expression
195
How does Cinacalcet treat hyperparathyroidism?
by increasing receptor sensitivity to Ca, causing more negative inhibition to lower PTH
196
What are two markers for bone formation?
alkaline phosphatase & osteocalcin
197
The quality of bone depends on a. bone mass b. bone architecture
b. bone architecture
198
Which one factor mostly determines peak bone mass?
genetics 70-80%
199
Which physiological changes causes accelerated bone mass in the remodeling phase?
menopause
200
Compare the peak bone mass of white versus black people
black people have a higher peak bone mass
201
The quantity of bone depends on a. bone mass b. bone architecture
a. bone mass
202
Which is a risk factor for osteoporosis? a. osteoarthritis b. rheumatoid arthritis
b. rheumatoid arthritis
203
Whats the most important drug that's associated with osteoporosis?
glucocorticoids
204
osteomalacia versus osteoporosis
Osteoporosis is reduction of mass of the bones. On the other hand osteomalacia is the softening of the bones. Osteoporosis can be cause due to deficiency of vitamin D, while osteomalacia is caused by a deficiency in calcium and phosphorus.
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How do glucocorticoids induce osteoporosis?
- increases bone resorption by stimulating osteoclasts - decreased Ca inhibiting its reabsorption - suppressing bone formation by inhibiting osteoblasts and antagonizing PTH
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Whats a risk factor for fractures?
osteoporosis
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Whats the most serious osteoporotic fractures?
hip fractures (many complications, can lead to death)
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What does the FRAX tool measure?
calculates a ten-year probability of a major osteoporotic fracture
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Primary vs secondary osteoporosis prevention
primary = prevent first fractures secondary = prevent furthet fractures
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DXA scan spine checks for a. bone quality b. bone mass
b. bone mass (DXA scan = bone mineral density scan)
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What do you do when a patient is too obese to fit in the DXA scan?
measure bone density of radius (1/3 of it)
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Which of the following measurements of bone mineral density compares the patients bone mass to a population that is age, sex, race matched? a. T score b. Z score
b. Z score
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Patient comes in with a hip fracture due to a minor fall. Can you assume they have osteoporosis without further testing?
yes, if they have a fragitlity fracture its enough to diagnose
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Patient's T-score is -1.5, what does he have?
osteopenia (-1 to -2.5)
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What percent of calcium is bound to albumin?
40%
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Which of the following measurements of bone mineral density compares the patients bone mass to a population that at the peak bone mass? a. T score b. Z score
a. T score (NOT age, race, sex matched)
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Whats true? a. higher albumin levels increase corrected calcium levels b. higher albumin levels decrease corrected calcium levels
b. higher albumin levels decrease corrected calcium levels (inverse relationship)
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65 y/o patient with high Ca, low Pi, and high PTH. What's the diagnosis?
primary hyperparathyroidism (the high Ca isn't suppressing the PTH)
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The T score of a 55 y/o women is -2.2 in the spine and -3.2 in the hip. Whats the diagnosis? a. osteopenia b. osteoporosis
b. osteoporosis (you only need one location to be osteoporotic for the diagnosis)
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WHats the gold standard for diagnosing osteoporosis?
bone mineral density measurement (DEXA scan)
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What is the best imaging modality for the pituitary gland?
MRI
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What is the best imaging modality for seeing pituitary gland calcifications/bony destruction?
CT scan
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What are the tracheal rings that the thyroid gland sits on top of?
second to the fourth tracheal ring
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The thyroid extends from a. C4 to T2 b. C3 to T1 c. C5 to T1 d. C5 to T2
c. C5 to T1
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What are the two cartilages that the thyroid gland sits on top of?
thyroid and cricoid cartilage
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What is the best imaging modality for the thyroid gland?
ultrasound
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What tests do you use during the retrosternal extension of the thyroid?
CT/MRI (to asses the extent of expansion)
228
Give me 5 reasons why ultrasound are awesome
- widely available - cheap - easy to use - no ionizing radiation - good for procedures like fine needle aspiration
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Where is the head of the pancreas located
C loop of duodenum
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What is the best imaging modality for the pancreas?
CT scan
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What do you use to test a patient you suspect of having a common bile duct blockage?
Magnetic resonance cholangiopancreatography (MRCP) (use to do it with an endoscope, but now just the MRI)
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What test do you use to test for pancreatic calcifications?
CT scan
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Which adrenal gland is (usually) larger?
left
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A tumor of the medulla of the adrenal gland is called
Pheochromocytoma
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High amylase enzyme indicates
pancreatitis
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Which (one or two) of the following causes bone loss?
a. coupled and balanced bone remodeling
b. coupled and unbalance bone remodeling
c. uncoupled bone remodeling
b. coupled and unbalance bone remodeling & c. uncoupled bone remodeling
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What are two functions of bone in the extracellular fluid?
excite nerves and muscle blood clotting
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What percent of calcium is bound to phosphate?
10% (so 40% with albumin, 10% with phosphate, and the rest is free)
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Whats the predominant form of vitamin D in blood?
25 hydroxycholecalciferol (Calcifediol)
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What is the only hypocalcemic hormone?
calcitonin
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How can sarcoidosis lead to hypercalcemia?
(granulomatous diseases) can cause an extra-renal hydroxylation of vitamin D leading to high vitamin D which then leads to high calcium absorption and hypercalcemia
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A patient has malabsorption issues, due to that, high PTH levels get high. Which is more accurate? a. primary hyperparathyroidism b. secondary hyperparathyroidism c. tertiary hyperparathyroidism
b. secondary hyperparathyroidism
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Whats the main storage form of vitamin D in the body?
25 hydroxycholecalciferol (Calcifediol)
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Which has poor calcification? a. rickets b. osteomalacia c. both
c. both
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Which is caused by incomplete mineralization? a. rickets b. osteomalacia c. both
a. rickets
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A patient has high PTH levels due to hyperplasia in a long-standing disease. Which is more accurate? a. primary hyperparathyroidism b. secondary hyperparathyroidism c. tertiary hyperparathyroidism
c. tertiary hyperparathyroidism
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Which causes bone deformity? a. rickets b. osteomalacia c. both
a. rickets
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Which is cause by demineralization? a. rickets b. osteomalacia c. both
b. osteomalacia
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Describe calcium levels in rickets
low
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Describe alkaline phosphatase (ALP) levels in rickets
high
251
Describe 25 hydroxycholecalciferol (Calcifediol) levels in rickets
low
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A lady with dowager's hump most probably has...
osteoporosis
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How do you determine the cause of rickets?
renal function tests Calcifediol levels PTH in blood
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T/F: excess caffeine intake may lead to osteoporosis
true, its one of the minor risk factors (along with smoking)
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What byproduct of muscle metabolism is used to determine kidney function
creatinine
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Which bone disorders does high Alkaline Phosphatase indicate?
Paget disease or rickets/osteomalacia (disorders with high osteoblastic acitivty)
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A 45 y/o man comes in with osteoporosis, what additional test must be done?
testosterone
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A patient with moon face and abdominal striae has osteoporosis, what additional test must be done?
24 hour urine cortisol (because crushing syndrome is associates with osteoporosis!)
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A patient comes in with osteoporosis and suspected paraproteinemia, what additional test must be done?
serum protein electrophoresis (SPEP) test OR Urine protein electrophoresis (UPEP) (the patient may have multiple myeloma, which causes deposits in the bone leading to bone loss)
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Patient has mosaic bone pattern. What's more likely?
Paget's disease
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How is Paget's disease linked to deafness and nerve entrapment?
bone growth causes compression to surroundings leading to deafness + compression of nerves
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Whats the complication of an immobilized patient with Paget's disease?
hypercalcemia
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Whats a marker of bone resorption? give an example where you'll find high levels of it.
hydroxyproline; Paget's disease
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Patient has patchy and thick looking X-ray images. What's more likely?
Paget's disease
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What percent of DNA is different between each human?
0.5%
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low-frequency SNPs are also known as
germline mutations
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Give me examples of two syndromic obesity-related to chromosomal abnormalities
Prader-Willi (PWS) syndrome Bardet-Biedl (BBS) syndrome
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Which of the following mostly depends on genetics and very little on environment? a. Monogenic obesity b. Polygenic obesity
a. Monogenic obesity
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Give an example of one gene directly related to body mass
FTO gene
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Which of the following phenotypes of the FTO gene would have a higher body weight on average? a. AA b. AT c. TT
a. AA
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Why do kids with AA FTO gene phenotype eat more when exposed to advertisements about food?
The FTO gene is involved in regulating the dopamine reward pathway, so kids with AA phenotype would experience a higher dopamine activation than kids w/TT (thus would eat more)
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Which of the following phenotypes of the FTO gene would the ketogenic diet work best for? a. AA b. AT c. TT
c. TT (AA phenotype doesn't metabolize fat as well as the TT)
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Which is amplified by an obesogenic lifestyle? a. Monogenic obesity b. Polygenic obesity
b. Polygenic obesity
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What are the two most common monogenic mutations that may lead to obesity
Melanocortin 4 receptor (MC4R) and Leptin (LEP) genes
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How many defective copies of the LEP gene do you have to have to get the leptin deficiency?
two, its homozygous
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How can how can knowing the genetic phenotype of the patient help in medicine?
it can help us chose the appropriate treatment. (ex/ if patient is likely to become diabetic again after the bariatric surgery, we can continue giving him the treatment in lower doses instead of stopping it completely)
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Whats the number one treatment for morbid obesity?
bariatric surgery (many studies show individuals losing weight via lifestyle modifications and then regaining the weight)
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A morbidly obese patient comes in with almost no leptin in the blood. She explains that she has a normal weight when born but started gaining weight afterwards, whats a likely diagnosis?
Congenital Leptin Deficiency (CLD)
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Congenital Leptin Deficiency (CLD) is caused by the defect of which gene?
LEP gene
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T/F: we are able to accurately predict the sustainability of bariatric surgery via genetic testing
true
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LEP gene defect affects which of the following a. leptin ligand b. leptin receptor
a. leptin ligand
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Which of the following is true regarding superior parathyroid glands?
A. They developed from the third pharyngeal pouch
B. They are located at the posterior border of the lateral lobe of the thyroid
C. They are located at the first tracheal ring behind the isthmus
D. Their position is highly variable
B. They are located at the posterior border of the lateral lobe of the thyroid
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Which of the following cells does not have a parathormone receptor?
A. Osteoclasts
B. Osteoblasts
C. Osteocytes
D. Osteoprogenitor cells
A. Osteoclasts
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Which of the following is a function of parathormone?
A. Increases serum phosphate
B. Increases serum calcium
C. Increases calcium absorption in the gut directly
D. Secreted by parafollicular cells of thyroid gland
B. Increases serum calcium
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Patient who previously underwent a thyroidectomy presented with numbness
around her mouth and carpal spasm. What is the most likely clinical finding?
A. High albumin
B. Low albumin
C. High intact PTH
D. Low intact PTH
D. Low intact PTH
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Patient presents with renal failure. What is the most likely clinical finding?
A. Decreased secretion of parathyroid hormone
B. Decreased phosphate retention
C. Decreased calcitriol formation
C. Decreased calcitriol formation
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Which osteoblast-specific protein that, when mutated, causes short body size?
A. Bone sialoprotein
B. Osteocalcin
C. Osteopontin
D. Osteonectin
A. Bone sialoprotein
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Which osteoblast-specific protein that, if inhibited, can prevent post-menopausal
osteoporosis?
A. Bone sialoprotein
B. Osteocalcin
C. Osteopontin
D. Osteonectin
C. Osteopontin
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Vitamin D Dependent Rickets is characterized by a mutation in which of the
following?
A. 1 α hydroxylase
B. Vitamin D receptor
C. 21 hydroxylase
D. 24 hydroxylase
A. 1 α hydroxylase
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What is a benefit of taking teriparatide (1-34 PTH) at low intermittent doses?
A. Decreases protein kinase activity
B. Increases osteocalcin
C. Increases osteoblast apoptosis
D. Decreases lifespan of mature osteoblasts
E. Decreases bone mass
B. Increases osteocalcin
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Which of the following is the best imaging modality for the pituitary gland?
A. MRI
B. CT scan
C. Intracranial ultrasonography
D. Plain radiology
E. Nuclear scan
A. MRI
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Which of the following is the best imaging technique for the thyroid gland?
A. MRI
B. CT scan
C. Ultrasound
D. Plain x-ray
C. Ultrasound
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Polygenic obesity is the more common form of obesity. However, there are some
cases of monogenic obesity. What is the most common gene causing monogenic
obesity?
A. LPL
B. LEP
C. FTO
D. APOC3
B. LEP
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