10th Class Science Control and Coordination Coordination in Animals

       Coordination in Animals

The coordination in animals is brought by hormones and nervous system. The hormones are the chemical substance which controls the various growth activities in the animals and plants. The hormones are secreted by the endocrine system in the animals. The endocrine system consists of ductless glands which generates the hormones. The various endocrine glands in human being are as follows:

            Pituitary Gland

This gland is attached to the central part of the brain and secrets the pituitary hormones also called growth hormones. It controls the functioning of other endocrine glands. It also regulates the growth and development of body. If excess of hormones is stored then it cause gigantism and if insufficient of hormones is secreted, it cause dwarfism.

            Pineal Gland

It is a small gland attached to the dorsal part of the brain. It controls the time mechanism of the organism, which regulates the sleeping of man.

           Thymus Gland

This gland is found in small babies which produce WBC to protect babies from diseases and disappears with the age.

            Thyroid Gland

This gland is found behind larynx and secrets thyroxine hormones which contains iodine. It controls the metabolism of carbohydrates, fats and proteins. Excessive secretion of this hormones cause hyperthyroidism and insufficient secretion cause goiter.

           Parathyroid Gland

This gland is inside the thyroid gland and secrets parathormone which increase the level of calcium in blood.

             Adrenal Gland

It is located on kidney and secrets the hormones called adrenaline. When a person is fighting or running or get frightened this hormones is secreted in large amount.

             Testis

It secrets male sex hormones called testrone which begins at the onset of puberty. It helps in development of sperm, beard, moustache, hard voice etc.

             Ovaries

It secrets female sex hormones called oestrogen and progesterone. It produces egg cells in female. It leads to fertilization in female and production of baby in female.

       Which tropism is responsible for the movement of plants in response to the chemicals?

(a) Phototropism

(b) Geotropism

(c) Chemotropism

(d) Hydrotropism

(e) None of these

Answer: (c)

       Which plant hormones is responsible for elongation in plants?

(a) Auxins

(b) Cytokinins  

(c) Gibberellins

(d) Abscisic Acid

(e) None of these

Answer: (a)

         The functional unit of nerve cells is called:

(a) Axons

(b) Dencfrites     

(c) Neurons

(d) Cytons

(e) None of these

Answer: (c)

• The functions of the brain were found by the ancient Egyptians and Greeks in 400 BC.
• There are no pain receptors in the brain, so the brain can feel no pain.
• The human brain is the fattest organ in the body and may consists of at least 60% fat.
• Humans continue to make new neurons throughout life in response to mental activity.

• In human and animals; the control and coordination is carried out by nervous system and hormones.
• The massage is transmitted in the form of electrical impulse.
• Human brain is divided into three parts, fore brain, mid brain and hind brains.
• The main thinking work is done by fore brain.
• In plant, the control and coordination is carried out by specialized tissue, called xylem and phloem.
• A feedback mechanism regulates the action of the hormones.