Lecture: Calcium Flashcards
Functions of calcium in the body (8)
Structural role Activator Blood caogulation Skeletal and cardiac muscle contraction Nerve impulse transmission Milk production Regulation of membrane ion transport Cellular secretion
Major sources of dietary calcium
Milk and milk products
Factors affecting the variability in absorption of calcium from the SI
Concentration in the diet pH Presence of activated vitamin D Parathyroid hormone High protein Diet Steatorrhea Age
Storage of calcium in the body
Gut
ECF
Kidney
Bone (highest conc)
What 3 forms is calcium present in serum in
Ionised/free (active)
Complexed
Protein bound (inactive)
What are blood calcium levels influenced by
Parathyroid hormone
Calcitonin
Vitamin D
How many amino acids compose the PTH
84
When is PTH released
When ECF calcium is decreased
What organs/tissues does PTH act on
Bone, kidney and intestine
Describe calcitonin molecule
32 amino acid peptide with one disulphide bond
What secretes calcitonin
C cells of the thyroid in response to an increase in ionised calcium
Three target tissues for activated vitamin D
Intestine, bone and kidney
How much calcium is bound to albumin
50%
Non diseases state total serum calcium level
2.4 mmol/L
When is binding of calcium to protein decreased/increased
Decreased in acidosis states
Increased in alkalosis states
What is normal calcium level required for
Nerve function, membrane permeability and glandular secretion