Skeletal system Flashcards
(8 cards)
1
Q
What does vitamin D deficiency cause?
A
Rickets (children)
Ostemomalacia (adults)
2
Q
What enzyme is bone mineralisation dependent om?
A
Alkaline phosphatase
3
Q
What 2 things regulates the [Calcium] and [Phosphate] in blood and bone?
A
- Parathyroid hormone
- Vitamin D
4
Q
The active form of vitamin D is calcitriol. What functions does it perform?
A
- increased renal tubular reabsorption of Calcium ions
- increased intestinal absorption of calcium and phosphate
5
Q
Parathyroid hormone is secreted in response to low blood ___ levels
A
calcium
6
Q
What does inadequate bone mineralisation do in adults vs children?
A
children:
- softening of bones
- impaired growth
- malformations
adults:
- weakening of bones
- softening of bones
Difference is due to the fact that growth plates in adults have closed vs. still open in children
7
Q
What causes vitamin D deficiency?
A
- lack of UVA exposure
- phenytoin (anticonvulsant) steals liver enzymes involved in vitamin D synthesis
- intestinal malabsorption (coeliac disease, Crohn’s disease)
8
Q
What are the clinical manifestations of rickets?
A
- bald nape
- sweating
- late dentition
- O or X-shaped curvature of lower extremities (saber shins)
- craniotabes (thin, soft skull bone)
- muscular hypotonia
- late closing of fontannels
- ## prominent frontal bone
