What is a Gland?
Gland is the name given to an organ, the function of which is to produce and release chemicals which help the human body in some way or the other. Basically, there are two types of glands in human body which are then further subdivided into various other glands. These two main glands found in the human body are Exocrine Glands and Endocrine Glands. The Exocrine Glands are glands which have a duct which connects them to the surface of the body and the products produced by them are released through these ducts. Some of the examples of these types of glands are the Sweat Glands, Salivary Glands, Mammary Glands etc. The second type of gland is the Endocrine Glands. These glands form a part of the endocrine system of the body. They are not attached to the surface of the body as they do not have ducts in them. They release the products they form directly into the bloodstream. Some of the examples of the Endocrine Glands are the Pineal Glands, Thyroid Glands, Adrenal Glands etc.
Glands in the Human Body and their Functions
As stated, there are two types of glands in our body which are the Exocrine Glands and the Endocrine Glands. The function of these glands is to secrete substances like enzymes and hormones which help in the growth and development of the body. Below mentioned are the glands present in the body and their specific functions related to the body.
Exocrine Glands: These glands have ducts which connect them to the surface of the body and the products produced by these glands get collected in these ducts and are released to the surface of the body like sweat or tears.
Some of the glands which come under the category of Exocrine Glands are:
Sweat Gland and its Function: These glands are also known by the name of Sudoriferous Glands. These glands are present over the entire surface of the body. The primary function of these glands is to regulate the function of the body. Citing an example, if the weather is too hot outside, the body temperature increases, then the sweat glands release sweat from the body which cools down the body. The Sweat Glands are further divided into two types which are the Eccrine Sweat Glands and Apocrine Sweat Glands. The Eccrine Sweat Glands are quite small and they do not extend to the surface of the body. These glands are coiled and are tubular in shape and they discharge their secretions directly into the surface of the skin. Apocrine Sweat Glands are also coiled and tubular in shape and release a cloudy and secretion with an odor. These secretions when acted on by bacteria present in the atmosphere result in an odor. This is the cause of a foul odor noticed especially in the armpits or the sole of the foot in extremely hot conditions.
Salivary Gland and its Function: The primary function of this gland is to produce saliva which begins the process of digestion of food in the body. These glands are again subdivided into three categories knows as the Parotid Glands, Submandibular Glands, and Sublingual Glands. The Parotid glands are present underneath and in front of the ears. These glands are the largest of all salivary glands. The Submandibular Glands are located just under the mandible. The Sublingual Glands are present in the floor of the mouth between the tongue and mandible. They release their secretions directly into the mouth. Saliva that we have in our mouth is digestive secretions which are produced by these glands. The functions of the saliva are to keep the mouth and tongue, moistening the food so that it is easily swallowed and passes smoothly through the esophagus into the stomach. Saliva also dissolves some part of food thus stimulating the taste buds. It also does the function of keeping the mouth clean.
Mammary Gland & its Functions: This gland is present in the breasts of females and its primary function is lactation or producing milk. This glandular tissue is present in both males and females but in females this tissue starts to develop after attaining puberty as a result of release of estrogen. Mammary Glands produce milk only after the birth of a baby. At the time when a female is pregnant, the hormones progesterone and prolactin are released. The progesterone reacts with prolactin and thus preventing these glands from producing milk. During this period, very small amount of a substance called colostrum is produced. This substance is extremely rich in antibodies and nutrients and is helpful for the infant in the first few days of life. Post child birth, the progesterone level in the body start to go down whereas the prolactin levels remain increased thus allowing the mammary glands to produce milk. After every feeding the milk in the breast is finished only to be refilled again. Once a woman passes the reproductive age and reaches menopause there is degeneration of this gland and thus the gland loses its ability to produce milk.
Lacrimal Gland & its Functions: The function of this gland is to produce tears and keep the surface of the eyes moist. They also act as a lubricant for the eyelids and are helpful in eliminating or washing out any foreign bodies which may enter the eye from the outside atmosphere like dust. These glands act up and release tears when an individual is emotionally charged up, either very happy or very sad resulting in tears rolling down from the eyes.
Sebaceous Gland & its Functions: The function of the Sebaceous Glands is to produce an oily substance called as sebum which keeps the skin moist. Sebaceous Glands are situated neighboring the hairs in sebaceous follicles. The hormones resulting in physical changes after puberty cause these glands to produce more oil. This oil which is released by the gland sometimes reacts with the dead cells on the surface of the body causing a block over the skin pore resulting in what is known as a pimple.
Endocrine Glands: Now coming to the endocrine glands, as stated these glands produce hormones which are directly released into the blood stream. They do not have any ducts which connect them to the surface of the body. Below mentioned are the glands which form the Endocrine Glands and their functions in detail.
Pineal Gland & its Functions: This gland is situated in a small cavity just above the back portion of the pituitary gland right in the middle of the brain. It is sometimes also referred to as the controller gland. This function of the pineal gland is to promote growth of the body and controlling the sex glands. The reason why it is sometimes referred to as the controller gland is because it controls the functioning of the other glands. It also helps in neutralizing the affect of light on the color of the skin.
Pituitary Gland & its Functions: This gland is located right at the base of the brain and is joined to the hypothalamus. This gland requires help from other glands to function and becomes active when other glands undergo a malfunction and when there are increased secretions from other glands then this gland reduces secretions. The function of pituitary gland is promote grown and development of bones and muscles of the body. An increase or decrease in the functioning this gland decides the height and weight of an individual. Pineal gland also activates the seminal cells in males and ovary in females. Pineal gland also helps in production of milk in the mammary glands after the birth of a child. This gland also functions by signaling the kidneys to absorb more fluids.
Thyroid Gland & its Functions: The location of thyroid gland is at the upper end of bronchial tube neighboring the vocal cords. This gland absorbs iodine which is required by the body. Since this gland absorbs iodine it utilizes this iodine for metabolism of fats, carbs, and proteins thus helping with digestion of food. Iron is also released through this gland and is very useful for the body. Phosphorus release is used by the nerves.
Parathyroid Gland & its Functions: The location of parathyroid gland is above and below the thyroid gland adjacent to the vocal cords. Parathyroid gland is protected by the thyroid gland but they are in no way same as the thyroid gland whether it be structure or function. The function of parathyroid gland is to control the amount of calcium in the blood and play a vital role in activation of muscles and the nervous system. A defect in secretion from this gland may lead to may disease conditions.
Thymus Glands & its Functions: This gland is situated just behind the junction of the collarbone and the neck right in the middle of the chest. The main function of the thymus gland is to control development until the individual attains puberty. This gland also does not allow sex glands to grow till the individual attains puberty. This gland also plays a vital role in the development of brain and also facilitates removal of waster products from the body.
Adrenal Glands & its Functions: These glands are present above the kidneys and are attached to the diaphragm. The secretions of adrenal glands are extremely essential for sustaining life. The hormones it releases are helpful in curing many illnesses like gout, blood circulation problems, colon defects, asthma and the like. Adrenal gland also facilitates emotional changes in an individual. Adrenal gland is so important that without it, it is impossible to imagine life. Another function of the adrenal gland is to help in metabolism. This gland promotes contraction and expansion of different muscles and arteries of the heart. In a crisis situation, this gland acts up and sends an emergency signal in the body thus preparing the body to face the situation and making us emotionally strong to face the situation.
- Exocrine Glands – https://en.wikipedia.org/wiki/Exocrine_gland
- Endocrine Glands – https://en.wikipedia.org/wiki/Endocrine_gland
- Hormones and Their Functions – https://www.ncbi.nlm.nih.gov/books/NBK539698/
- Glandular Disorders – https://www.merckmanuals.com/home/hormonal-and-metabolic-disorders/glandular-disorders/introduction-to-glandular-disorders
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