Adrenal glands are also known as the kidney hats. As the name suggests these glands are located just above the kidneys. The size of the adrenal gland varies throughout our life. A seven-month fetus will have the size of adrenal glands same as that of kidneys. When the baby is born, these glands shrink slightly and then continue to shrink throughout the life. At an old age, the adrenal glands are so small that we cannot see them. Adrenal glands have two kinds of tissues: Medulla and cortex.
Some of the functions of adrenal glands are as follows:
- Maintaining salt level in the kidney: Adrenal gland plays a crucial role in the maintenance of the salt level in the kidneys. The adrenal cortex tissue secretes aldosterone hormone which is responsible for maintaining the body’s salt and fluid balance. Sodium and potassium act as an electrolyte in the body which controls the fluid balance. The aldosterone hormone retains water level in the body. If the body has too much of sodium and fluid, then it may cause high blood pressure. Similarly, if the potassium content decreases, it can cause muscle cramps. So if the body does not secrete enough aldosterone, sodium content in the body will be low, resulting in brain swelling and low Blood pressure.
- Secretion of adrenaline: The adrenal medulla tissue secretes two hormones:
- Epinephrine: This hormone is known by its other name: This hormone is rapidly released into the blood during a stressful condition, sending impulses to the organ to respond back to the situation, by increasing the heart rate, the flow rate of blood from muscles and brain. It also increases the blood sugar level by converting glycogen to glucose in the liver.
- Norepinephrine: Norepinephrine is also termed as noradrenaline. This hormone also responds to stress with the help of adrenaline. It can result in vasoconstriction (narrowing of blood vessels).
This is the reason that whenever we are chased by a street dog or any other animal of which we are scared, we experience an increase in the heart rate, faster breathing, and high blood pressure.