State location and types of adrenal gland. 

Location : Our body has one pair of adrenal glands, one at the anterior part of each kidney. The gland is composed of two types of tissues. The centrally located tissue is called the adrenal medulla and outside this lies the adrenal cortex.

The adrenal medulla secretes two hormones called adrenaline or epinephrine and nor-adrenaline or norepinephrine.

These are commonly called as catecholamines.

Adrenaline and nor-adrenaline are rapidly secreted in response to stress of any kind and during emergency situations.

They are called emergency hormones or hormones of fight or flight.

These hormones increase alertness, pupillary dilation, piloerection (raising of hairs), sweating etc.

Both the hormones increase the heart beat, the strength of heart contraction and the rate of respiration.

- Catecholamines also stimulate the breakdown of glycogen resulting in an increased concentration of glucose in blood.

They also stimulate the break down of lipids and proteins.

The adrenal cortex can be divided into $3$ layers, called zona glomerulose (outer layer), zona fasciculate (middle layer) and zona reticularis (inner layer).

The adrenal cortex secretes many hormones, commonly called as corticoids.

$\alpha$ - glucocorticoids - involved in carbohydrate metabolism.

- $\beta$ - mineralocorticoids - regulate the balance of water and electrolytes in our body.

Aldosterone is the main mineral corticoid in our body.

$\rightarrow$ Glucocorticoids stimulate, gluconeogenesis, lipolysis and proteolysis; and inhibit cellular uptake and utilisation of amino acids.

Cortisol is also involved in maintaining the cardiovascular system as well as the kidney functions.

Glucocorticoids, particularly cortisol, produces anti-inflammatory reactions and suppresses theimmune response.

Cortisol stimulates the $RBC$ production.

Aldosterone acts mainly at the renal tubules and stimulates the reabsorption of $\mathrm{Na}^{+} \mathrm{H}_{2} \mathrm{O}$ and water and excretion of $\mathrm{K}^{+}$and phosphate ions.

Thus, aldosterone helps in the maintenance of electrolytes, body fluid volume, osmotic pressure and blood pressure.

Small amounts of androgenic steroids are also secreted by the adrenal cortex which play a role in the growth of axial hair, pubic hair and facial hair during puberty.

Less production of hormones by adrenal cortex changes carbohydrate metabolism due to which weakness and fatigueness is observed.

It leads to adison's disease.