Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Therapeutics Exam 3 > Calcium Homeostasis > Flashcards

Calcium Homeostasis Flashcards

1
Q

What is cystalline form, phosphate and calcium is found in complexed form in bones

A

Hydroxyapatite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What cells causes bone resorption

A

Osteoclasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the bone sensing cell that maintains balance between osteoblastic and osteoclastic activites

A

Osteocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the bone forming cells

A

Osteoblasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When the load is high what factors does the osteocytes recruit to increase BMD

A

Osteonectin, nitric oxide and dentin matrix protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

When the load is low, what does the osteocytes recruit to decrease bone mineral density

A

Sclerostin , DKK-1, RANKL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is Ecac1/TrpV5

A

They are calcium channels in the kidney that open up and cause calcium reabsorption in the kidneys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the four ways PTH increase serum calcium levels

A
  1. Increase calcium reabsorption from collecting tubules in the kidneys through ECAC 1 and TRPV 5. 2. Increase osteoclastic activity and numbers/increase calcium resorption. 3. Increase phosphate loss in the urine. 4. Increase production of vitamin D3 in the kidney
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Through what receptor does the body sense low serum calcium level

A

Through the GPCR calcium level sensor. When calcium is bound to the receptor, it will secrete PLC that will inhibit PTH. But when calcium is not bound, it will not inhibit PTH. The sensor acts like a negative feedback loop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the active form of vitamin D3

A

1,25 dihydroxyl Vitamin D3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does cholecalcifeoral look like

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

In the presences of 1 alpha hydroxylase and PTH, what form of vitamin D do we have

A

We have the active form, which is 1,25 dihydroxylvitamin D3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Under the enzyme 24-hydroxylase and no PTH, what do we have

A

24,25 dihydroxy vitamin D3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Apart from high calcium level having a negative feedback through GPCR on PTH, what other substances can inhibit PTH secretion

A

High levels of 1,25 dihydroxy vitamin D3, high levels of calcium and high levels of FGF 23

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does calbidin-D9k do

A

It binds to calcium and prevents it from beinf sequestered into intracellular organelles. It also presents the calcium to the calcium ATPase which pumps it out of the cell into the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the factors vitamin D3 upregultes

A

Calbidin-D9k, Trp v6, calcium ATPase, and NPt2B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Why is the regulation of PTH secretion dysregulated in people with kidney disease

A

Because they can not make 1,25 dijydroxy vitamin D3 an important inhibitor of PTH

18
Q

What does calcitonin do

A

Decreases osteoclastic activity, blocks renal reabsorption of phosphate and calcium

19
Q

How does calcitonin reduce calcium serum level

A

Inhibit osteoclastic bone resorption, taking away the ability to bring calcium out of the bone into the serum It also increases calcium and phosphate loss in the urine

20
Q

Explain the pathophysiology of pagets disease

A

It is caused by uncontrolled osteoclastic and osteoblastic activity It is caused by a slow acting virus

21
Q

What are the symptoms of pagets disease

A

Hearing loss secondary to hypercalcemia Bone deformities Bone pain

22
Q

What are the risk factors of osteoprosis

A

Age. Physical inactivity Low calcium intake in early years Long term glucocorticoid use

23
Q

What is cholecaiferol, who can get it as a drug

A

An unhydroxylated form of 1,25 dihydroxy vitamin D3. A person with a functioning kidney and liver

24
Q

What is the mechanism of action of active form of vitamin D3

A

Increased calcium and phosphate absorption from the gut Increased calcium and phosphate reabsorption in the renal tubules

25
Q

What is the mechansim of action of bisphosphonates

A

Inhibits bone resorption and increase bone building capacity through this means. 1. Serves as phosphate analog that can replenish hydroxyapatite in bone minerals increasinf osteoblastic activity. 2. Induce apoptosis of osteoclasts reducing their numbers. 3. Block farnesyl pp an important intermidate in the synthesis of osteoclasts

26
Q

What are the two bisphosphonates used only for cancer and pagets disease

A

Pamidronate and etidronate

27
Q

What are the second line treatment to treat osteoprosis

A

Estrogens and SERMS Calcitonin

28
Q

What is teriparatide(forteo) and abaloparatide(tymos)

A

They are parathyroid hormone analogs that are used for severe osteoprosis

29
Q

What important ligand bind to their receptors for osteoclasts to be made

A

Rank L binding to Rank induce the synthesis of osteoclasts

30
Q

What does continuous release/high dose of PTH do

A

Increase RANK L, decrease OPG. Increase bone resorption and serum calcium level

31
Q

What are the pros for teriparatide treatment for osteoprosis

A

Builds bone mass at higher rate than bisphosphonates

32
Q

What is the con for teriparatide

A

You have to inject daily. Not recommended for more than 2 years cos of the black box warning of causing bone cancer

33
Q

What is the mechanism of action for denosumab

A

It binds to rank L and prevents it from binding to rank on osteoclast precursors preventing the making and differentiation of osteoclasts

34
Q

What is the mechanism of action for Romosozumab

A

It inhibits sclerostin which is released by osteoclasts when there is no load or estrogen present. Sclerostin inhibits osteoblasts but increases osteoclasts

35
Q

What is the ADR for romosozumab

A

MACE( major adverse cardiovascular events). People with myocardial infraction or stroke within one year should not take it

36
Q

How does cincalet work

A

It is a positive allosteric modulator that increases the calcium sensing ability of the calcium sensing receptors in people with Chronic kidney disease to decrease PTH secretion

37
Q

What does etelcalcetide do

A

It is a peptide that works the same way as cincalet. It is a PAM that inhibits PTH secretion by increasing the responsiveness of the calcium sensing receptor in people with CKD

38
Q

What are zemplar and hectorol

A

Viramin D analogs that inhibits secretion of PTH with less effects on calcium resorption in the gut compared to vitamin D3

39
Q

What are the two phosphate binders drugs we have

A

Lanthanum carbonate(fosrenol). Sevelamer(renagel)

40
Q

What is the MOA for phosphate binders

A

They stay in the gut and bind up phosphate preventing it from getting absorbed in the intestine leading to decreased serum phosphate level

41
Q

What are the three functions of fibroblast growth factor

A

Inhibit vitamin D synthesis. Inhibits PTH secretion. Stimulates phosphates excretion

Therapeutics Exam 3 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions