A gland is an organ which produces and releases substances that perform a specific function in the body. There are two types of gland. Endocrine glands are ductless glands and release the substances that they make (hormones) directly into the bloodstream. These glands form part of the endocrine system and information on them is included in this website. There is another type of gland called an exocrine gland (e.g. sweat glands, lymph nodes). These are not considered part of the endocrine system as they do not produce hormones and they release their product through a duct.
What Are Endocrine Glands?
Endocrine glands are ductless glands of the endocrine system that secrete their products, hormones, directly into the blood. The major glands of the endocrine system include the pineal gland, pituitary gland, pancreas, ovaries, testes, thyroid gland, parathyroid gland, hypothalamus and adrenal glands.
The adrenal glands are small structures attached to the top of each kidney. The human body has two adrenal glands that release chemicals called hormones into the bloodstream. These hormones affect many parts of the human body.
Endocrine glands, such as the pancreas and thyroid gland, use the bloodstream to monitor the body’s internal environment and to communicate with each other through substances called hormones, which are released into the bloodstream. The hypothalamus and the pituitary gland are the command and control centers, directing hormones to other glands and throughout the body. Other primary endocrine glands, including the thyroid and parathyroid glands, the adrenal glands and the pineal gland, adjust the levels of various substances in the blood and regulate metabolism, growth, the sleep cycle and other processes. Organs such as the pancreas also secrete hormones as part of the endocrine system. Secondary endocrine organs include the gonads, kidneys and thymus.
What You Need To Know About Endocrine Glands
- Endocrine glands are ductless gland. No ducts are attached to the glands.
- The secretions are directly poured into the circulating bloodstream eventually reaching the target organ.
- They secrete hormones.
- Endocrine glands are complex in nature.
- The transportation of the hormones is slower than that of exocrine system.
- These glands have slower response time as hormones have to travel through blood before reaching the target organs.
What Are Exocrine Glands?
Exocrine glands are glands that secrete substances onto an epithelial surface by way of a duct. Examples of exocrine glands include sweat, salivary, mammary, ceruminous, lacrimal, sebaceous, prostate and mucus. Exocrine glands are one of two types of glands in the human body, the other being endocrine glands, which secrete their products directly into the bloodstream. The liver and pancreas are both exocrine and endocrine glands; they are exocrine glands because they secrete products—bile and pancreatic juice—into the gastrointestinal tract through a series of ducts, and endocrine because they secrete other substances directly into the bloodstream.
Exocrine gland structure is broken down into the ductal portion and the glandular portion. The glandular portion is either a round (also called acinus or acini (plural)) or elongated cluster of cells that produce the secreted substance. There are different types of cells found in the glandular portion depending on the substance secreted. Some common cell types include serous cells (protein excretion) and mucous cells (mucus/fluid excretion).
The tubular portion is often a single, cuboidal cell thick wall that aids in movement of the secretion. The tubular duct can be simple in structure (unbranched) or complex with many duct branches. The tubular duct can also be observed in a simple coiled structure.
What You Need To Know About Exocrine Glands
- Exocrine glands have duct glands. They are attached with a specific duct.
- The secretions are released to the outer surface of the body or to some internal organ through a duct.
- They secrete enzymes, mucous, sebum, sweat and other substances.
- Exocrine glands are complex in nature.
- The transportation of secretions is faster than that of the endocrine.
- These glands have faster response time as transportation occurs through ducts.
Also Read: Difference Between Hormones And Enzymes
Difference Between Endocrine And Exocrine Glands In Tabular Form
|BASIS OF COMPARISON||ENDOCRINE GLANDS||EXOCRINE GLANDS|
|Description||Endocrine glands are ductless gland. No ducts are attached to the glands.||Exocrine glands have duct glands. They are attached with a specific duct.|
|Secretions||The secretions are directly poured into the circulating bloodstream eventually reaching the target organ.||The secretions are released to the outer surface of the body or to some internal organ through a duct.|
|Main Secretion||They secrete hormones.||They secrete enzymes, mucous, sebum, sweat and other substances.|
|Nature||Endocrine glands are complex in nature.||Exocrine glands are complex in nature.|
|Transportation Of Hormones||The transportation of the hormones is slower than that of exocrine system.||The transportation of secretions is faster than that of the endocrine.|
|Response Time||These glands have slower response time as hormones have to travel through blood before reaching the target organs.||These glands have faster response time as transportation occurs through ducts.|
|Examples||Thyroid gland, pineal gland, thalamus gland, pituitary glands, adrenal, pancrease, sex-glands etc.||Liver, pancrease, sebaceous glands, lacrimal, Brunner’s glandsmammary glands and salivary glands.|