Lecture 51

Question 1

PTH responds to ____ levels of calium

Answer 1

LOW

Question 2

_____ is a monoclonal antibody that blocks RANKL to prevent osteoporosis.

Answer 2

PROLIA

Question 3

PTH acts directly on kidneys to _____ reabsorption of Ca in DCT and ______ Phosphate reabsorbtion at DCT and PCT

Answer 3

INCREASE reabsorption of Ca in DCT and INHIBIT reabsorption of phosphate at DCT and PCT

Question 4

PTH does not have a direct effect on _______ (no receptors there,) but it increases synthesis of _____ in kidneys which increase Ca absorption in the ________.

Answer 4

Does NOT have a direct effect on the INTESTINES, but increases synth of Vit D3 in kidneys which increases Ca absorption in the __________.

Question 5

______ causes hypercalcemia of malignancy (usually secreted from tumors in Lung and Kidney.) It acts at PTH receptors in ____ and Kidney.

Answer 5

PTHrP

Bone

Question 6

Calcitonin is synthesized in the C-cells of the _____ and responds to ______ levels of Ca. It acts on bone by shrinking _____ to decrease release of Ca from bone resorption. It does not act on ______, and only acts on kidneys at super-physiological levels (which helps in tumor identification.)

Answer 6

THYROID

HIGH

OSTEOCLASTS

INTESTINES

Question 7

Vit D works to _____ Ca levels. UV radiation forms cholecalciferol from 7-_______ in skin. Cholecalciferol goes to liver where it becomes ______ (the most stable form, so this is the one that’s measure in blood tests). Next it moves to kidneys where it becomes either _______ (the active form) or ______ (the mostly inactive form.)

Answer 7

Vit D works to INCREASE Ca levels. UV forms Cholecalciferol from 7-DEHYDROCHOLESTEROL. Cholecalciferol goes to liver to become 25-HYDROXY D3. Then it moves to kidneys to become either 1,25-DIHYDROXY D3 (active) or 24,25-DIHYDROXY D3 (inactive.)

Question 8

1,25 D3’s main effect on Ca regulation is to _____ Ca absorption in the intestine by activating/increasing transcription of _______ (a calcium channel) and ______ (a Ca++ binding protein). It also acts on bone in the same way PTH does (keep in mind it binds INTRAcellular receptors in osteoblasts, while PTH binds membrane-bound receptors), and acts in the kidney by ______ PTH activity at the DCT.

Answer 8

INCREASE

TRPV6

Calbindin

BINDING

INCREASING

Question 9

Normal serum concentration of Ca++ is ____mg/dL. 51% is ionized, 46% bound to protein, and 3% complexed to other ions.

Answer 9

10mg/dL

Question 10

PTH receptors are present on _____ (type of bone cells). These cells produce _____ in response to PTH binding, which causes pre-_____ to mature into _____.

Answer 10

Osteoblasts

RANKL

pre-osteoclasts

Osteoclasts