Endocrine Gland – An overview
Animals including humans have a complex living system. In the case of animals, they have the
nervous system and endocrine system for control and coordination. The Endocrine System is
responsible for chemical coordination. Numerous involuntary physiological activities are under
the control of the endocrine system. It consists of glands which release hormones. Endocrine
glands are also called ductless glands. Hormones play a vital role in various activities in the body
including growth and development. They also support the nervous system.
Endocrine glands in animals are the hypothalamus, the pituitary gland, the pineal gland, the
thyroid, the parathyroid, the thymus, the pancreas, the adrenal gland and the gonads.
Different endocrine glands along with the hormone they release are given below:
Hypothalamus
This gland is a part of the brain that consists of neurosecretory cells. They connect both the
nervous and the endocrine system. The hypothalamus secretes various releasing hormones like
gonadotropin-releasing hormones and growth hormone-releasing hormones. These hormones
act on the pituitary gland to stimulate other glands.
Pituitary Gland
The pituitary gland is the master gland. It is a pea-sized gland that is located at the bottom of the
brain. It controls and regulates other glands in the body. Hormones released by this gland are
growth hormone, thyroid-stimulating hormone, LH, FSH etc.
Pineal Gland
This gland is also located in the brain. It releases the hormone called melatonin which regulates
the wake-up and sleep clock and helps in immunity etc.
Thyroid gland
This is a butterfly-shaped paired gland located in the neck region. It releases the hormones
triiodothyronine (T3) and thyroxine (T4). These hormones regulate body metabolism. Iodine is
vital for thyroxine synthesis. Its deficiency leads to a disease called goitre.
Parathyroid Gland
This gland is located near the Thyroid gland in the neck region. The hormone released by this
gland is called Parathyroid hormone, which regulates calcium and phosphorus level in bones.
Pancreas
The pancreas is an endocrine as well as an exocrine gland. That is why the Pancreas is also
known as a mixed gland. The pancreas secretes hormones like glucagon and insulin; these two
hormones balance the blood sugar level in the body. Other hormones secreted are somatostatin
and pancreatic polypeptide.
Adrenal Glands
Adrenal glands have two regions known as the adrenal cortex and adrenal medulla.
The cortex region of the adrenal gland secretes the hormones cortisol, aldosterone, and
androgens while the medulla region secretes the hormones adrenaline and noradrenaline.
Adrenaline is the hormone responsible for the fight or flight response of the body in times of
emergency.
Gonads
Gonads are reproductive glands present in males and females. The male gonad is the pair of
testes which secretes the hormone testosterone. This is responsible for the secondary sexual
characteristics in males. The female gonad consists of a pair of ovaries. They secrete two
hormones estrogen and progesterone. Both of these regulate secondary sexual characteristics in
females.
Q1.Where are the endocrine glands located?
The endocrine system is comprised of several glands. The human brain contains the
hypothalamus, pituitary, and pineal glands. The neck includes the parathyroid and thyroid
glands. The pancreas is beneath our stomach, the adrenals are on top of the kidneys, and the
thymus is between our lungs. The pelvic area contains either male testes or female ovaries,
depending upon gender.
Q2.What is the most important endocrine gland?
The pituitary gland, a tiny gland around the size of a pea, is essential for controlling
important functions of the body and overall well-being. Because it manages the function of
most other hormone-secreting glands, it is known as the “master gland” of the body.
Q3.Mention the functions of the gonads.
Steroid hormone synthesis and gametogenesis are the two primary functions of the gonads. In
addition, reproductive hormones are essential for foetal growth, development, sexual
maturation, and sexual differentiation.
Q4.Which endocrine gland plays important role in improving
immunity?
The dorsal side of the heart contains the thymus gland, linked to immune system development.
Thymosin hormone is secreted by it, which is essential for developing T-lymphocyte
differentiation.
Q5.What is the endocrine gland?
The endocrine system comprises endocrine glands that create hormones and chemical
messengers that flow via the blood to various body regions. The hypothalamus, pituitary,
parathyroid, thyroid, and adrenal glands are significant endocrine glands.
Q6.What are exocrine glands and endocrine glands?
The human endocrine system has endocrine glands that release hormones. Exocrine glands
release their materials onto the surfaces of the body through ducts. Endocrine glands, in
contrast, discharge their chemicals readily into the circulatory system. We refer to them as
ductless glands.
