CALCIUM Flashcards
- DIVALENT CATION; 5TH MOST COMMON ELEMENT in the body
- For muscle contraction
- For blood coagulation
CALCIUM
Ca is evaluated with phosphorus for
bone metabolism
T/F. Ca is MAJOR INORGANIC COMPONENT of the osseous tissues (bone)
True
T/F. Presence of calcium cannot activate enzymes in coagulation cascade
False, can activate enzymes in coagulation cascade
Absorbed in the upper Small Intestine in the presence of
Vitamin D (Active Form)
Percentage of Ca that found in bones and teeth
99%
Percentage of Ca that found in blood and ECF
1%
Ca DISTRIBUTION IN BLOOD through:
IONIZED
PROTEIN BOUND
COMPLEX
Physiological ACTIVE form of calcium (UNBOUND/FREE FORM)
45% of total Calcium in the plasma
IONIZED
Attached to a protein (Albumin – protein transporter)
40% of Total Calcium
PROTEIN BOUND
Bound to ANIONS (opposite charge)
Ex: Bicarbonate, Phosphate, & Lactate
15% of Total Calcium
COMPLEX
What are the FACTORS AFFECTING CALCIUM LEVEL IN THE BLOOD?
BONE RESORPTION
BONE DEPOSITION
INTESTINAL ABSORPTION
Bone matrix destruction by the Osteoclast → calcium release in blood
Promoted by PTH, which mobilizes calcium from the bone to the blood
BONE RESORPTION
Also known as Bone Mineralization (Bone formation)
Cause ↓ blood calcium level
Promoted by calcitonin (inhibits PTH and vitamin D activity)
BONE DEPOSITION
Promoted by Vitamin D in the active form
Can INCREASE BONE RESORPTION
INTESTINAL ABSORPTION
will result to the inhibition of PTH release
Presence of HYPERCALCEMIA
will induce PTH secretion by the parathyroid gland to act on the bone & kidney, stimulating bone resorption and calcium absorption in the kidneys
Presence of HYPOCALCEMIA
promotes:
PTH stimulates osteoclastic activity which releases Ca++ and HPO4-
In Bone
promotes:
Absorption of Ca2+
Excretion of HPO4-
Activation of renal 1-a-hydroxylas
In the Kidney, PTH
coverts 25-OH Vitamin D to 1,25 (OH)2 Vit D (active form)
1-α-hydroxylase
T/F. 1,25 (OH)2 Vit D, promotes Intestinal Absorption and Renal Reabsorption of Ca2+ and HPO4-
True
T/F. The UV rays from the early morning sunlight (best time) accelerates and hastens the activation of Vitamin D in the blood or biologic system. However, prolonged exposure to UV rays is damaging. Melanin cannot PROTECT us from it.
First sentence is correct, Second sentence is incorrect
*Melanin can PROTECT us from it.
protection is low and is prone to skin disorders
Too low melanin
excess melanin can block UV rays which leads to poor activation of available Vitamin D → prone to bone disorders
Too high melanin
