Information about Cayenne Pepper.

Cayenne is nature's wonder.  Cayenne contains capsaicin - the potent substance that gives them their "fiery" character. 
Almost 80% of the capsaicin in a Cayenne is in its seeds and membranes. 

Cayenne are a very good source of Vitamin C and Vitamin A.
Chili is the dried ripe fruit of the genus Capsicum annum.
This plant is a short-lived perennial herb approx. 1 meter in height.
Leaves are oblong and glabrous.
The flowers are solitary; color pure white to bluish white.
The Cayenne berries are green, maturing into yellow, orange to red and then to brown or purple.
Fruits are pendent and sometimes bi lobed. Seeds are white, thin having long placental connections.

Why is Chili 'HOT"?  'Hot' Cayenne peppers contain more capsaicin, the source of their warm, and stimulant properties.
The way capsaicin seems to act is by homing on the surface of the membranes of nerve cells.
Here it fits smugly on a receptor protein, quite like a key fits into a lock. The so activated receptor protein opens up a channel in the membrane through which calcium ions rush inside the nerve cells. This triggers off an electrical impulse that is registered in the brain as "hot".

Information gathered from Indus Organics