its used for communication around the body

uses the blood circulatory system to transport its signals

hormones

protein and peptide hormones and derivatives of amino acids as well as steroid hormones

adrenaline, insulin and glucagon

Proteins are not soluble in the phospholipid membrane and do not enter the cell. Instead they bind to the cell surface membrane and release a second messenger into the cell

they can pass through the membrane and enter the cell and the nucleus and have a direct effect on the DNA in the nucleus.

They are ductless glands. They release hormones directly into the blood.

non steroid hormones such as adrenaline, insulin and glucagon

They are signalling molecules outside the cell that bind to the cell surface membrane and initiate a second messenger which stimulates a change inside the cell.

G protein is activated when the hormone binds to the receptor, G protein activates adenyl cyclase which converts ATP into cAMP which initiates a cascade of enzyme controlled reactions

Adrenal gland which is located just above the kidneys

Outer adrenal cortex and inner adrenal medulla

secretes adrenaline and noradrenaline

The steroid hormone passes through the cell membrane of a target cell, the steroid hormone binds with a specific receptor in the cytoplasm, the receptor steroid hormone complex enters the nucleus of the target cell and binds on the to another receptor on the chromosomal material, binding stimulates the production of MRNA which code for the production of proteins