Calcium & Phosphate Handling Flashcards
1
Q
Extracellular Matrix Calcium
A
- calcified matrix of bone and teeth
2
Q
Extracellular Fluid Calcium
A
- nt release at synapse
- myocardial and smooth muscle contraction
- “cement” for tight junctions
- cofactor in coagulation cascade
3
Q
Intracellular Calcium
A
- muscle contraction
- signal in 2nd messenger pathways
- SR
4
Q
Hydroxyapatite
A
calcified extracellular matrix, major ECM of bone
5
Q
Osteoblasts
A
- synthesize new bone
- create calcium phosphate crystals to replace cartilage
6
Q
Osteoclasts
A
- reabsorb bone
- secrete acid & enzymes that dissolve calcium phosphate in bone
7
Q
Chondocytes
A
produce cartilage
8
Q
Calcium Intake
A
ingested in the diet and absorbed across the wall of the SI
9
Q
Calcium Output
A
loss from the body via the kidneys (reabsorbed when needed)
10
Q
Calcium Homeostasis Mechanisms
A
- Parathyroid hormone (PTH)
- Calcitriol (Vit D3)
- Calcitonin
11
Q
Parathyroid Hormone
A
- originates at the parathyroid glands
-continous production, little stored - released on decreased plasma calcium
- dissolves in plasma
- increases plasma calcium
INCREASES calcium resorption from bone, kidney, GI
12
Q
Calcitriol (Vitamin D3)
A
- steroid hormone
- ingested in food / sunlight activated synthess
- bound to plasma proteins
- synthesizes by decreases calcium
- increases plasma calcium by absorption (GI)
13
Q
Calcitonin
A
- 32 aa peptide
- dissolved in plasma
- releases on increased plasma calcium
- targets bone & kidney, on a GPCR
- prevents bone resorption, enhances kidney secretion
INHIBITS OSTEOCLASTS
14
Q
Phosphate and Calcium
A
phosphate handling mirrors calcium handling
