Physiology of hypocalaemia Flashcards
1
Q
Describe the effects of hypocalcaemia
A
- Increased neuromuscular irritability
- Decreased smooth muscle contraction
- Decreased skeletal muscle contraction
- Reduced cardiac muscle contractility
2
Q
Why does a high concentration of calcium help to stabilise neurones?
A
It decreases sodium permeability
3
Q
What are the symptoms of milk fever (hypocalcaemia)?
A
- Reduce muscle contraction (skeletal/ smooth and cardiac)
- Effect posture/ gait
- Effect repro tract (expulsion of foetal membranes)
- Effect GI tract (bloat)
- Effect heart/ circulation)
4
Q
Describe the lag time and how it contributes to milk fever problems
A
- Lag time= 48 hours for PTH to up-regulate osteoclasts
- This means that the increasing calcium demand isn’t met fast enough
5
Q
What other aspects affect a cow’s calcium control?
A
- Metabolic alkalosis at calving reduces its response to PTH
- Low magnesium reduces PTH secretion and effect
6
Q
List examples of hypocalcaemia in other species
A
- Tetany (thumps) in race horses
- Eclampsia in dogs
- Metabolic bone disease in reptiles/birds
