Question

How do apocrine, exocrine, merocrine, and holocrine glands differ?

Answer 1

Hint: Apocrine, merocrine and holocrine glands are all different types of exocrine glands. There are many exocrine glands in our body such as sweat, salivary, mammary, liver, and pancreas. The pancreas is both exocrine as well as endocrine hence it is known as a mixed gland.

Complete Answer:

Apocrine	Exocrine	Mesocrine	Holocrine
Apocrine glands are glands that release some part of the cell along with their secretions in the form of vesicles.	Exocrine glands are said to be glands that pour their secretions into a duct instead of releasing it directly into the blood.	Mesocrine glands are said to be glands that release their secretions without causing any harm to the cells.	Holocrine glands are said to be glands that contain disintegrated cells due to the rupture of the plasma membrane, as part of their secretions.
Examples include the mammary glands	The liver and pancreas are two such exocrine glands that produce secretions for the gastrointestinal tract.	Examples include the pancreas and salivary gland.	Examples include the oil glands of the skin.

Additional information:
-The ciliary glands present in the eyelids, mammary glands, and ceruminous glands (ear wax producing glands) are all examples of modified apocrine glands.
-Apocrine sweat glands are present in fewer numbers as compared to merocrine or eccrine sweat glands that are present on the rest of the body.
-The most damaging type of secretion to cells is holocrine, whereas merocrine is the least damaging, and apocrine is in between them.

Note:
-Endocrine glands are the glands that release their secretions directly into the blood and hence they are known as ductless glands. Their secretions are specifically known as hormones.
-Hormones can be defined as non-nutrient substances whose purpose is to act as intracellular messengers.
-Exocrine glands are further divided into a glandular part and duct part. The glandular part may be in the form of tubes or acini and the duct part can be branched or unbranched.