Question

Explain chemical co-ordination in humans and give the names and functions of some hormones.

Answer 1

This is coordination is brought about through chemical messages called hormones. Hormones are realesed into blood to provide you extra energy and strength to run

Answer 2

Answer:

Coordination in humans occurs in two levels i.e. nervous coordination and chemical coordination. The

coordination which occurs with the help of hormones is called chemical coordination. Hormones are the organic

chemicals produced by the body, which are released into the blood. The key feature of the hormones is that they

are secreted by the ductless glands. The glands that secrete hormones do not have ducts. Hormones are released

directly into the bloodstream and reach the target organ. The endocrine system works in association with nervous

system to control and coordinate our bodies.

Characteristics of Hormones

Hormones are the organic chemicals that are secreted in response to environmental changes in or outside the

body.

Hormones are secreted by ductless glands and transported along with the blood stream to the site of their

action. The site of their production and the organ of their influence are different.

They can be amino-acid derivatives, proteins, or steroids.

Being low molecular weight substances, they can easily diffuse through the cell membrane.

They are produced in small quantities and are effective in extremely lower concentrations.

Abnormal production of hormones (be it less or more) affects the body in a negative manner.

i. Some of the hormones produced by pituitary are:

Prolactin- Growth of mammary glands and formation of milk in them.

TSH- Synthesis and release of thyroid hormones.

Adrenocorticotrophic hormone (ACTH)- Stimulates synthesis and secretion of steroid hormones called

glucocorticoids from the adrenal cortex.

Vasopressin- Stimulates reabsorption of water from the distal tubules, and hence, prevents loss of water

through urine (diuresis); therefore, also called anti-diuretic hormone (ADH).

ii. Thyroxine hormone is produced by thyroid gland and its functions are:

Control of BMR (Basal metabolism rate)

Control of working of kidney and urine formation

Regulation of physical, mental, and sexual growth