ANATOMY

Detailed explanation-1: -A hormone will only act on a part of the body if it ‘fits’. A hormone can be thought of as a key, and its target site (such as an organ) has specially shaped locks on the cell walls. If the hormone fits the cell wall, then it will work.

Detailed explanation-2: -Endocrine glands release hormones into the bloodstream. This lets the hormones travel to cells in other parts of the body.

Detailed explanation-3: -Once hormones find a target cell, they bind with specific protein receptors inside or on the surface of the cell and specifically change the cell’s activities. The protein receptor reads the hormone’s message and carries out the instructions by either influencing gene expression or altering cellular protein activity.

Detailed explanation-4: -Hormones are recognised by their target receptors in a “lock and key” system. Each hormone (key) fits exactly into its receptor (lock). Only those parts of the body that have the receptor (lock) can respond to the hormone (key). This is why hormones affect some parts of the body, but have no effect on others.

Detailed explanation-5: -The glands that make up the endocrine system produce chemical messengers called hormones that travel through the blood to other parts of the body.