Apocrine vs merocrine

Difference between Apocrine and Merocrine Sweat Glands

Our body comprises of many natural factors that involve the secretion of energy in the form of sweat while performing any high-level activity. There are two types of sweat glands present in our body that secrete this sweat; merocrine sweat gland and apocrine sweat gland.

Apocrine and merocrine, both are different types of exocrine glands. These types of glands secrete their substances through ducts on the surface of our body. These substances can be sweat, tears, saliva, milk or digestive juices.

What are Apocrine Sweat Glands?

Apocrine glands are such glands that release parts of cells along with the substances they secrete in the form of vesicles. The apocrine glands of the skin and eyelid are sweat glands. Apocrine glands are mostly found in the armpits, the groin and around the nipples of the breast.

An example of apocrine gland is mammary glands that produce milk in women and other female mammals. The apocrine glands of breast secrete fat droplets of breast milk and the glands of ear help in the formation of earwax. The main function of these glands is considered as scent glands that are involved in the production of pheromones, even though this function is fundamental in case of humans.

These apocrine sweat glands are tubular, coiled, secretory glands surrounding a large lumen, lined up by a cuboidal epithelium. They comprise of myoepithelial cells that help in the movement of secretory products upwards and outwards. They develop in those areas that have many hair follicles, like scalp and armpits. The two primary parts of apocrine glands are- a coiled secretory structure, the gland itself and a straight duct. Gland has numerous large granules. These glands are non-functional prior to puberty. After hitting puberty, they start growing and secreting.

What are Merocrine Sweat Glands?

Merocrine sweat glands are the most common type of sweat glands found in human body. These simple tubular glands secrete sweat onto the body’s surface directly.

Merocrine glands are mostly found in the superficial hypodermis. Thus, these glands do not extend to the dermis of our skin. Such glands secrete sweat by a process called exocytosis. The sweat is mostly water and also contains sodium chloride, urea, and potassium. These glands secrete more sweat when we fear or take stress. These glands are also known as eccrine sweat glands.

Merocrine glands are small in size and have a small secretory part. They carry out some of the most important functions in human body like thermoregulation, protection and excretion. These glands are more concentrated on palms and soles. It comprises of a straight section and a secretory coiled section.

Similarities between Apocrine and Merocrine Sweat Glands

Both the glands are a type of exocrine gland. Both glands produce clear and odourless sweat. Both the glands are multicellular. Both the glands are found in our skin.

Difference between Apocrine and Merocrine Sweat Glands

The following table highlights the major differences between Apocrine and Merocrine sweat glands −

These are the most common type of sweat glands and secrete sweat to skin’s surface directly.

These are a type of sweat glands that secrete sweat into the sac of hair follicles and do not open directly in to our skin.

They are distributed all over our body.

They are distributed in armpits, breast, public and perianal area.

These glands are located superficially.

These glands are located deep in our skin.

Merocrine glands are about ten times smaller in size than apocrine glands.

These glands are much larger in comparison to merocrine glands.

Merocrine glands have small secretory portions.

Apocrine glands have large secretory portions.

These glands open on to the skin directly.

They do not open onto the skin directly.

Merocrine glands secret though the process of exocytosis of a vesicle that contains sweat.

Some parts of the cell that contains the secretion pinches of wholly.

These glands start their activity when a person is born.

The glands start acting at puberty, even though these glands are present in our body since birth.

These glands secrete sweat that mostly contains water, along with sodium chloride.

These glands secrete substances that are thick and rich in nutrients for bacteria on the skin.

The primary difference between these two glands is that the merocrine glands are present all over the body, while apocrine glands are present in genital areas only. In merocrine secretion, the cells secrete through exocytosis and remain intact even after secretion. In apocrine secretion, cells secrete by destroying their apex membrane so that the secretion flows out of the cells into the excretion duct and after secretion the cell regenerates its apex membranes.

Conclusion

Both, merocrine and apocrine, are two types of sweat glands. Merocrine glands produce clear, thin sweat but apocrine glands produce thick substance which provides nutrients to the bacteria on the skin. The significance of merocrine glands in our body is that it helps in thermal regulation and protects our body against any infection.

So, now we have summed up all the differences between merocrine glands and apocrine glands along with what they are and what are the similarities between them.

Autor: Kress (Efimova) Elena Viktorovna Candidate of Medical Sciences, Chief Physician of the Tomsk Research Institute of Cardiology