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Difference between Endocrine and Exocrine Glands

Biology is a branch of science that focuses on several body parts like the glands, intestines, and various other systems that help in the efficient functioning of the body. So today, we will be discussing about the most commonly used glands, i.e., the endocrine glands and the exocrine glands. Now, what are endocrine and exocrine glands? Well, let us see the basic meaning of these two terms.

Endocrine Glands

The endocrine gland is a part of the endocrine system. The endocrine system is commonly known as the messenger system that includes providing feedbacks regarding the hormones and the circulatory system of an organism. The endocrine gland is the hormone-making gland. These hormones are dispersed into the blood, and they travel all over the body. Endocrine glands are very helpful in controlling several functions of the body like growth, fertility, metabolism, etc. Some examples of endocrine glands are the adrenal gland, thyroid gland, pituitary gland, etc. Well, it is interesting to note that the pancreas is the largest endocrine gland as well as an exocrine gland. This is because the pancreas comprises of 95% of exocrine tissue and 5% of endocrine tissue. That is why the pancreas comes under both categories.

Exocrine Glands

The exocrine gland is part of the exocrine system. The exocrine gland is defined as the gland that is used for making substances like tears, sweat, saliva, etc., in the body. These substances are released through a tube/ duct on the body surface. There are three significant kinds of exocrine glands, namely Merocrine glands, Apocrine glands, and Holocrine glands. Some of the examples of exocrine glands include salivary glands, sweat glands, mammary glands, digestive glands (intestine, pancreas, and stomach), etc. Now, let us look at some of the differences between endocrine and exocrine glands.

S.NO.	ENDOCRINE GLANDS	EXOCRINE GLANDS
1.	The endocrine gland is defined as the gland that produces and releases hormones in the body.	On the other hand, exocrine glands are defined as the glands that make several substances in the body like sweat, tears, saliva, etc.
2.	Endocrine glands do not have ducts/ tubes.	Exocrine glands have ducts/ tubes.
3.	Endocrine glands secrete into the bloodstream.	Exocrine glands secrete directly on the body’s surface.
4.	Endocrine glands secrete hormones.	Exocrine glands secrete enzymes.
5.	The responsive action of the endocrine gland is delayed because the secretion takes place slowly.	The response of the exocrine gland is very fast as the secretion takes place in a rapid manner.
6.	Endocrine glands are helpful in controlling activities like growth, development, fertility, etc.	Exocrine glands control short-term activities.
7.	There are two kinds of endocrine glands. They are: Primary Endocrine Gland Secondary Endocrine Gland	There are different types of exocrine glands like: Merocrine Gland Apocrine Gland Holocrine Gland Serous Gland Mixed Glands Mucous Glands Unicellular Exocrine Glands Multi-cellular Exocrine Glands
8.	Endocrine glands secrete hormones in the blood.	The exocrine gland releases the secretion on the body surface.
9.	Examples: Thyroid Gland Pituitary Gland Adrenal Gland	Examples: Gastric Gland Salivary Glands Mammary Glands Digestive Gland

So, these are some of the major differences between the endocrine gland and the exocrine gland. Both these glands are essential for the efficient functioning of the body. Now, there are several types of endocrine and exocrine glands that help in keeping the body aligned. So, let us take a look at them.

Types of Endocrine Glands

There are several types of endocrine glands in the body. They are:

1. Pineal Gland: The pineal gland is located in the interbrain (part of the forebrain). Melatonin is released by the pineal gland that affects the daily routine of people.
2. Gonads: Gonads are defined as the ovaries of females that release two hormones, i.e., estrogens and progesterone. Estrogens are responsible for the maturation of the female body, while progesterone is responsible for starting the menstrual cycle in females.
3. Pancreas: Pancreas is the largest gland in the human body, located below the stomach. The alpha and beta cells in the body release glucose and insulin that increases the blood sugar levels in the body. The pancreas controls these levels in the body.
4. Adrenal Glands: Adrenal glands are the glands that produce several hormones and steroids in the body like adrenaline, aldosterone, cortisol, etc. Adrenal glands control the behaviour in emotional situations.
5. Parathyroid Glands: Parathyroid glands are located behind the thyroid glands, which increases the blood calcium level in the body. Parathyroid hormone is often released in situations of the rise and fall of blood calcium levels.
6. Thyroid Gland: The thyroid gland is located in a shape of a butterfly connected by thyroid tissues. The thyroid increases thyroxine and triiodothyronine in the blood. One more hormone is released by the thyroid gland called calcitonin that is responsible for the increased level of blood calcium levels in the body. Excessive secretion in the thyroid gland causes hyperthyroidism, and the deficiency for the same causes hypothyroidism in the body.
7. Pituitary gland: The pituitary gland is in the shape of a pea. This gland is responsible for the overall wellbeing of the body. The pituitary gland is called as the master gland, as it controls the activities of other glands as well.

Types of Exocrine Glands

1. Holocrine Glands: Holocrine glands are a result of a break in the plasma membrane. These glands are produced in the cells containing cytoplasm. These glands are used for destroying the cells and secrete substances in the lumen.
2. Merocrine Glands: Merocrine glands are also called eccrine glands. The substances released by these glands secrete through a duct/ tube. The cell wall is not broken in these glands.
3. Apocrine Glands: Apocrine glands are responsible for releasing several substances in the ductal systems through cytoplasm and membrane.
4. Lacrimal Glands: Lacrimal glands are situated in the eye that secretes fluid in the cornea and conjunctiva.
5. Pancreas: The pancreas is the largest gland in the body which secretes pancreatic juice along with digestive enzymes in the body.
6. Salivary Glands: These glands help in the secretion of saliva along with digestive enzymes.
7. Mammary Glands: These glands are responsible for the secretion of breast milk.
8. Sweat Glands: These glands are responsible for producing sweat through the process of perspiration.

So, these are some of the types of endocrine and exocrine glands. It is essential to note that both these glands are required for the smooth functioning of the human body. Both endocrine and exocrine glands are different in several aspects, but both are responsible for protecting the body. Thus, both endocrine and exocrine glands are essential for the human body.

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