What are the adrenal glands and what do they do?
The adrenal glands are two small, triangular-shaped endocrine glands located on top of the kidneys. They are orange in color and covered in a connective tissue capsule that is hidden in a layer of fat. These glands are made up of two parts – the adrenal cortex (outside) and the adrenal medulla (inside).
The adrenal glands work together with the pituitary gland and hypothalamus in the brain to produce a number of different hormones essential for the overall health and functioning of your dog. The process commences when the hypothalamus produces corticotrophin hormones which stimulate the pituitary gland. The pituitary gland, in turn also produces ACTH (Adrenocortico-trophic hormone) which then stimulates the adrenal glands to produce corticosteroid hormones.
These hormones are key components for your dog’s health and vitality - they are responsible for the functioning of every tissue, organ and gland in the body. Adrenal glands maintain metabolic processes by managing blood sugar levels, regulating inflammation as well the balance of salt and water, and controlling the “fight or flight” response to stress.
The adrenal medulla and the adrenal cortex each have a separate but specific role.
Adrenal medulla
The adrenal medulla is the inner region of the gland which is responsible for producing hormones called epinephrine and norepinephrine (adrenaline and noradrenaline). These hormones play an important role in the way the body responds to stress and regulate a number of different body functions.
Epinephrine (also called adrenaline)
- Facilitates the flow of blood to the brain and muscles
- Increases the heart rate and encourages heart contractions
- Helps muscles to relax
- Helps to convert glycogen to glucose in the liver
Norepinephrine (also called noradrenaline)
- Has strong vasoconstrictive effects thereby increasing blood pressure.
Adrenal cortex
The adrenal cortex is the outer region of the gland and produces corticosteroid hormones, androgens and aldosterone
Corticosteroid hormones
- Consists of hydrocortisone and corticosterone hormones.
- The hydrocortisone hormone controls how the body uses fats, proteins and carbohydrates, while the corticosterone hormone represses inflammatory responses in the body and affects the immune system.
Aldosterone hormone
- By controlling the amount of sodium excreted into the urine Aldosterone is the main hormone responsible for fluid and electrolyte balance which in turn is an integral part of maintaining blood pressure and blood volume.