What are Glands? Types and Functions

Glands are small organs that secrete chemicals directly into a body cavity or onto the surface of an organ. Most glands have ducts, lined with one or more membranes, that carry the gland’s secretions to their targets.  Learn more about some of the most common glands.

Classification of Glands By Their Shape

Glands can be classified by their shape.

1. Tubular Gland
2. Alveolar Or Saccular Gland

If a gland retains its shape as a tube, it’s called a tubular gland. Alternatively, if the secretory portion of the gland is enlarged and the lumens are increased in size, it is called an alveolar or saccular gland.

Types of Glands

Glands can be divided into two main types:

1. Endocrine Glands
2. Endocrine Glands

Endocrine Glands

Endocrine glands are responsible for secreting substances that circulate in the bloodstream. These glands secrete their products through the basal lamina into the bloodstream.

Examples Of Endocrine Glands

1. Testies
2. Ovary
3. Pancreas
4. Adrenal gland
5. Thymus
6. Thyroid gland
7. Pituitary gland
8. Pineal gland

Functions Of Endocrine Glands

Endocrine glands help control many body functions, including growth and development, metabolism, and fertility.

Exocrine Gland

Exocrine glands produce and release substances through a duct and onto either the inner or outer surface of the body. For example, this could be on the skin or gastrointestinal tract. The secretion process occurs directly on the apical surface.

Types of Exocrine Glands

There are three types of exocrine glands, that are:

• Holocrine Glands.
• Merocrine Glands.
• Apocrine Glands.

Secretions Of Exocrine Glands

Exocrine glands secrete sweat, tears, saliva, milk, and digestive juices.

Functions Of Exocrine Glands

It assists in;

• Food digestion

• Mucosal protection

• Thermoregulation

• Lubrication

• Nutrition

• Regulate body temperature

• Lactation

• Helps in reproduction

Examples of Exocrine Glands

It includes a number of glands. Some are enlisted here.

1. Sweat glands
2. Lacrimal glands
3. Salivary glands
4. Mammary glands
5. Digestive glands in the stomach, intestines, and pancreas.

Difference Between Endocrine And Exocrine Glands

Endocrine Glands	Endocrine Glands
Endocrine glands do not have ducts.	They Have ducts.
Secretory products are released directly into the bloodstream.	Secretory products are released to an internal organ or sometimes the external surface through a duct.

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