give description of plant and animal hormone?

Plant Hormones: Plant hormones control some aspects of the growth of plants such as cell division, cell enlargement and cell differentiation.

Phytohormones	Description
1. Auxins	Promote growth of plants. They are secreted by the cells present at the tip of stems and roots. Therefore, auxins control the phototropic and geotropic movements of plants. Auxins accelerate growth of stems but reduce the growth in roots. Synthetic auxins are used in horticulture.
2. Gibberellins	Promote cell differentiation in the presence of auxins. They break seed dormancy. They also break dormancy in buds. Stimulate elongation of shoots.
3. Cytokinins	Promote cell division in plants. Delay ageing of leaves. Promote opening of stomata. Promote fruit growth.
4. Abscisic Acid	Acts as a growth inhibitor. It promotes dormancy in seeds and buds. Promotes closing of stomata. Promotes abscission, i.e. wilting and falling of leaves. Detachment of flowers and fruits from the plants is due to abscisic acid.

 

 

Hormones in Animals: They are secreted by different endocrine glands.

 

Hormones	Functions	Disorders
1. Adrenaline Produced by the adrenal glands.	Adrenaline prepares the body for the fight and flight mechanism. When excited or in anger, the adrenal glands produce a lot of adrenaline. It speeds up heart beat and breathing. It raises the blood pressure. Blood supply to the digestive system and skin is reduced, and the blood supply to the skeletal muscles is increased.
2. Thyroxine Secreted by the thyroid gland.	Regulates carbohydrate, protein and fat metabolism. It increases the basal metabolic rate (BMR). It regulates body growth such as ossification of bones and mental development.	Simple goitre: It is caused by iodine deficiency. Iodine is necessary for the synthesis of thyroxine. In this disorder, the gland is enlarged which is prominent due to swelling in the neck.
3. Growth Hormone (Somatotropin) Secreted by the anterior lobe of the pituitary gland.	It is essential for normal growth.	Dwarfism: Due to the deficiency of growth hormone. The growth of bones and other body organs is slow. Gigantism: Due to the oversecretion of growth hormone. The bones grow long. Such a person giants up to 2.7 metre in height.
4. Insulin Secreted by pancreas	Regulates the blood glucose (sugar) level.	Diabetes Mellitus Symptoms: High concentration of sugar in blood (hyperglycemia). Excretes large amount of urine containing more concentration of sugar. A person feels thirsty due to constant loss of water through urination. The person loses weight and becomes weaker. Sometimes, the person may lose vision. Treatment: It cannot be cured, but sugar levels can be maintained by the administration of insulin.
5. Testosterone Secreted by the testes in males.	Controls the development of sex organs in males. Controls the development of secondary sexual characters during puberty.
6. Oestrogen Secreted by the ovaries in females.	Controls the development of female sex organs. Controls the development of secondary sexual characters during puberty in females.