HORMONES

Action Of Protein Hormones

on a signal-transduction pathway

First, the protein hormone is reconized by the receptor and binds to it (signal). Then a secondary messenger system, and transduction (to transfer a message from one form to another) occurs. And finally a response from a cell is produced.

This all takes place on a signal transduction pathway. This requires the use of energy and different messengers.

Action Of Epinephrine

(adrenalin)

First the epinephrine binds to receptor than a message is sent to second receptor. It goes through a secondary messenger system and eventually sends a response to release glucose to blood.

2° Messenger System

has benefits
A 2° messenger system is a chain reaction, allowing for amplication and a very fast response.

Maintaing Homeostasis
negative feedback

When a specific body condition gets to high, a glad is signaled to produce a hormone, which lowers body condition. When condition gets too low, gland is signaled to produce a different hormone to raise body coondidtion.

An example of this is the Nervous System controlling Body temperature. When body temperature gets too high, brain sends nerve signals which make body sweat and dilate survace blood vessels, lowering temperature. When body temperature gets too low, brain sends nerve signals to make body shiver and constrict surface blood vessels bringing temperature back up.