L75: Parathyroid & Ca regulation Flashcards Preview

FHB - Endocrinology (by Richie) > L75: Parathyroid & Ca regulation > Flashcards

Flashcards in L75: Parathyroid & Ca regulation Deck (44)
1

Osteoprotegerin (OPG)

decoy for RANKL. It binds RANKL.

2

Osteoprotegerin

?

3

RANKL

?

4

M-CSF

?

5

What is the normal range of calcium (normal)?

2.2-2.5mM (tightly regulated)

6

Albumin levels

good indicator of free Ca2+ availability

7

2 regulators of Ca2+

Vitamin D PTH

8

What cells secrete PTH

Chief cells

9

These cells increase with age and chronic kidney disease. No known function.

Oxyphil cells

10

PTHrP

?

11

PTH1R

?

12

PTH2R

?

13

PTH targets

bone and kidney

14

Net effect of PTH

increase plasma Ca, decrease plasma Pi

15

Nucleation

Process of mineralizing/hardening bone...via osteoblasts

16

PTH receptors are located on osteoblasts or osteoclasts?

Osteoblasts

17

PTH stimulates osteoblasts to make

M-CSF. Causes stem cells to differentiate into osteoclasts

18

What ligand activates mature osteoclasts?

RANKL

19

What makes RANKL?

Osteoblasts

20

What does cortisol do to OPG?

Inhibits it. This allows excess RANKL to stimulate osteoclasts, making more bone breakdown than normal.

21

2 effects of PTH on kidney

?

22

Calcium sensing receptor

?

23

Where is CaSR located?

Kidney, Chief cells, C-cells

24

Direct and indirect actions of CaSR

?

25

Direct and indirect actions of 1,25 Vitamin D

?

26

Does D3 have a high affinity for vitamin D receptor?

No

27

3 targets of VitD

Bone gut kidney

28

Calbindin

?

29

Primary vs. secondary hyperparathyroidism

?

30

Chvostek sign

Twitching of facial muscles in response to tapping CNVII

31

Rickets/Osteomalacia

softening of bone (not due to density but mineralization problems)....osteoblasts are not mineralizing bone...

32

Pseudohypoparathyroidism

Genetic defect in GPCR that associates with PTHR1...associates broadly with PTH, TSH, LH, and FSH....

33

Normal phosphate range

0.8-1.45mM

34

Urinary hydroxyproline is indicative of

enhanced bone resorption

35

Paget disease

localized areas of bone resorption. Causes reactive sclerosis. Treatment: calcitonin

36

Calcitonin used to treat

Paget's disease. Not long-term because of escape phenomenon.

37

Does PTHrP bind PTH1R or PTH2R?

PTH1R (found in osteoblasts and kidney)

38

Does PTH bind osteoclasts?

No. There are 2 indirect effects of PTH:

1. PTH binds osteoblasts-->secrete RANKL--> stimulates maturation of osteoclasts

2. PTH binds osteoblatss --> secretes M-CSF --> formation of osteoclast differentiation from stem cells

39

What are osteocytes?

Terminally differentiated osteoBLASTS resident in bone matrix

40

What cells export Ca2+ and Pi into the EC for bone mineralization?

OsteoBLASTS

41

What does estrogen do to OPG?

Stimulates OPG, thus decreasing bone resorption

42

What does cortisol do to OPG?

It suppresses the synthesis of OPG, thus promoting RANKL-mediated bone resorption via osteoclast activity

43

What gene encodes for 1-alpha-Hydroxylase?

CYP1-alpha gene

44

To be continued

handout page 36 endo