Organ Histology of "Adrenal Gland"

by:

Marianne Bird

The adrenal glands, or suprarenal glands, are a part of the endocrine system located above the kidneys and below the diaphragm. There are two adrenal glands, the one on the right is slightly larger and shaped like a pyramid and the one on the left is shaped more like a crescent moon. They are separated from the kidneys by connective tissue and connected to the diaphragm by renal fascia. In the average human the adrenal glands are 5cm long, 3cm wide and 1cm thick. Each adrenal gland has 2 parts, an outer cortex and an inner medulla, and is divided into 3 zones; zona glomerulosa, zona fasciculata and zona reticularis.The adrenal glands produce steroid hormones which can be metabolized in the gland or other parts of the body. The adrenal glands are highly connected to the blood stream and have one of the greatest blood supply rates of any organ, as much as 60 small blood vessels can be connected to the glands.

The adrenal cortex is the outermost layer of the gland and produces the hormones cortisol, androgens and aldosterone, this helps regulate stress in the body and blood pressure.  Zona Glomerulosa is the main producer of aldosterone which regulates blood pressure, this zone is the outermost zone, the cells are oval and separated by fibrous connective tissue and capilaries. The largest is the middle zone, Zona Fasciculata, which makes up 80% of the cortex; it is columnar and contains mitochondria, a smooth endoplasmic reticulum and lipids and produces the hormone cortisol. Zona Redicularis is closest to the medulla, has a cytoplasm and lipids, and produces the precursor to testosterone, and other androgens. The cells are found in clusters separated by capillaries and connective tissue. The medulla is in the center of the gland and is effected by the sympathetic nervous system and the adrenaline and noradrenaline it produces directly flows into the blood. This is the body's main source of adrenaline and noradrenaline.

Works Cited:

https://www.hopkinsmedicine.org/health/conditions-and-diseases/adrenal-glands

https://en.wikipedia.org/wiki/Adrenal_gland

https://www.endocrineweb.com/endocrinology/overview-adrenal-glands