Control and Coordination
Endocrine Glands And Their Functions
We salivate when we see delicious food; we feel tense or anxious while making important decisions; we digest different types of food that we ingest; children grow taller during the early years of their life; voices of boys crack during puberty; lactation begins during motherhood. Do you know why these changes occur? How does the body control these functions? Is there another system governing these complex functions? Let us explore.
A hormone is a chemical messenger that regulates physiological processes in living organisms. It is secreted by a gland.
The regulation of the physiological processes, control and coordination by hormones is governed by the endocrine system. The nervous system, along with the endocrine system in our body, controls and coordinates the physiological processes.
Characteristics of hormones:
Hormones act as chemical messengers.
They are secreted by living cells/tissues or organs called glands.
They are secreted in very small quantities by glands.
They act upon specific cells, tissues, or organs called the target sites.
They are generally slow in action, but have long lasting effects.
They either accelerate or inhibit a reaction.
A cell, tissue, or an organ that secretes hormones required for a specific function is called a gland. You are familiar with the pancreas, pituitary gland, and thyroid gland. Glands are mainly divided into two broad categories -endocrine and exocrine.
These glands possess ducts for discharging their secretions into the body surface. The sebaceous glands present in the skin, salivary glands present in the buccal cavity, and gastric glands present in the walls of the stomach etc. are a few examples of exocrine glands.
These glands do not discharge their secretions through ducts. Hence, they are also known as ductless glands. They discharge their secretions directly into the bloodstream. Their secretions are known as hormones. The pituitary gland, thyroid gland, adrenal gland etc. are a few examples endocrine glands.
Do you know that the term ‘hormone’ was first introduced by Ernest Starling? Secretin was the first hormone to be discovered. Ernest Starling and William Bayliss are credited for its discovery.
Importance of hormones
We have often heard people complaining that they suffer from sugar. Do you know which condition they are referring to? How do we treat this condition?
They are referring to the condition called diabetes. It is a chronic condition characterized by high levels of sugar (glucose) in the blood.
What is the reason for the increase of sugar in the blood? How are other activities such as sleep, hunger, stress, body temperature etc. regulated? Let us explore.
Hormones in the human body
There are different kinds of hormones found in the human body. However, we will discuss only a few.
It is a tiny pea sized gland located near the hypothalamus of the brain. It is known as master gland as functions of many other endocrine glands are regulated by the pituitary gland. The gland is divided into two lobes- anterior lobe also called adenohypophysis and posterior lobe also called neurohypophysis.
Functions of the pituitary Gland
- It influences the secretion of other glan...
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