Question

when our heartbeat goes up when we r afraid ?

Answer 1

What actually happens is we get signal to our brain through sensory organs and the pituitary gland orders the adrenaline gland also known as kidney hats to produce adrenaline. this adrenaline this produced by endocrine glands which don't have specific transport system are directly released into blood stream and hence reaches every part of the body as blood is present in every part of the body. It is due to this harmone that we feel afraid and our heartrate goes up.
The effect of Harmones released by endocrine glands last longer than that of neuro signals.


Hope It helps you out mate!!