Endocrine Glands And Hormones

An ecosystem is all about the interaction and dependency between living and non-living components. This interaction ensures the existence and survival of each organism. For better interaction, they need a well-defined coordinating system. Animals and plants have their own control and coordination mechanism. Let us see how endocrine glands help in chemical coordination in animals.

Animals including humans have a complex system of living. In the case of animals, they have the nervous system and endocrine system for control and coordination. The endocrine system is responsible for the 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

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:

Endocrine Gland and Hormones

Endocrine System


This gland is a part of the brain that consists of neurosecretory cells. They connect both nervous and endocrine systems. The hypothalamus secretes various releasing hormones like gonadotropin-releasing hormones, growth hormone releasing hormones. These hormones act on pituitary glands to stimulate other glands.

Pituitary gland

The pituitary gland is the master gland. This is pea-sized and is located at the bottom of the brain. They control and regulate other glands in the body. Hormones released by this gland are growth hormone, thyroid stimulating hormone, LH, FSH etc.

Pineal gland:

This is also a gland 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 present in front of the neck. It releases the hormones triiodothyronine (T3) and thyroxine (T4). They regulate the body metabolism. Iodine is vital for thyroxine synthesis. Its deficiency leads to a disease called goiter.

Parathyroid gland

This is a butterfly-shaped paired gland. Hormone released by this gland is called parathormone which regulates calcium and phosphorus level in bones.

This is a butterfly-shaped paired gland. Hormone released by this gland is called parathormone which regulates calcium and phosphorus level in bones.


The pancreas is endocrine as well as an exocrine gland. The pancreas secretes hormones like glucagon, insulin; these two 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 adrenal cortex and adrenal medulla.

Cortex region secretes the hormones cortisol, aldosterone, and androgens while medulla region secretes the hormones adrenaline and noradrenaline.  Adrenaline is the “hormone of fight or flight”.


Gonads are reproductive glands present in male and female. Male gonad is the pair of testes which secretes the hormone testosterone. This is responsible for the secondary sexual characteristics in males. Female gonad consists of a pair of ovaries. They secrete two hormones estrogen and progesterone. Both of these regulate the secondary sexual characteristics in females.

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Practise This Question

Which of the following statements is correct in relation to the endocrine system?