Calcium homeostasis

Functions of Calcium 

1. Nerve and muscle functions 

-Decreased extracellular calcium - increase excitability of excitable cells and lowers the threshold potential - less inward current is required to depolarize the threshold potential - less inward current is required to fire AP

- Hence causing tingling and numbness (sensory) and spontaneous muscle twitches (motor neurons and muscles) 

2. Homeostasis 

-Activation of clotting enzyme is the plasma

3. Preserving bone density

4. Neurotransmitter release 

*Pathathyroid Hormone (PTH)

-Increase in extracellular calcium concentration -> inhibit PTH secretion 

- extracellular Ca2+ is decreased -> decreased Ca2+ binding to the receptor -> stimulates PTH secretion 

<PTH>

-bone

 : bone resorption , and increase calcium concentration 

- kidney

  : inhibits PO4 reabsorption  - less complexed Ca-PO4  ->increase plasma calcium 

-actions on small intestine (indirect)

 : stimulates Ca2+ reabsorption via activation of vitamin D 

http://www.slideshare.net/PrakashPokhrel1/calcium-homeostasis-63864498