 are the chemical messengers (regulators) which control, co-ordinate and integrate the functi...){kind=link}
Hormones are synthesized and secreted by the endocrine glands. Hormones are released into the bloodstream and travel elsewhere in the body to the target organs, upon which they act. The general properties of hormones are as follows:
i. Hormones act as chemical messengers to control and regulate metabolic activity growth and development of a body.
ii. Hormones are specific in function.
iii. They act only on target organs, tissues and Hormones are produced by the endocrine glands.
iv. Hormones are required in small amounts, and their effects are long-lasting. They are chemically proteins, steroids or amino acids.
Functions of Hormones
i. Hormones stimulate and control various physiological and metabolic activities of the body
ii. They regulate growth and reproduction.
iii. They synthesize, store and utilize various substances like glucose,
iv. They conserve water and minerals in the body.
Fact: Hormones are called chemical messengers, why?
Ans: Hormones are the chemicals carried to all parts of the body through blood circulation to bring about the harmonious working of the body. So hormones are called chemical messengers.
There are a large number of glands present in the human body. Among them, some are exocrine (having ducts) and some are endocrine (ductless) glands.
The exocrine gland product enzymes and secretes its product into a duct, e.g, salivary gland, gastric gland, etc. Similarly. the endocrine gland produces hormones and it secretes its product directly into the bloodstream eg pituitary gland, thyroid gland, etc.
Pituitary gland
The pituitary gland is a small (about lcm in diameter) oval gland of the size of a pea. It is located just below the mid-brain and attached to the lower surface of the brain by a short slender stalk called the infundibulum.
The anterior lobe of the pituitary gland secretes six hormones. These hormones are Growth hormone (GH), Thyroid-stimulating hormone (TSH), Follicle-stimulating hormone (FSH), Trophic hormone (TH), Prolactin hormone (PRL) and Luteinizing hormone (LH).
Similarly, the posterior lobe of the pituitary gland secretes two hormones: Oxytocin hormone and Vasopressin or Antidiuretic hormone (ADH).
Fact 2:. The pituitary gland is called the master gland, why?
Ans: The pituitary gland controls and stimulates many activities of the body, and the secretion of other endocrine glands. So it is also called the master gland.
The pituitary gland is a small (about lcm in diameter) oval gland of the size of a pea. It is located just below the mid-brain and attached to the lower surface of the brain by a short slender stalk called the infundibulum.
The anterior lobe of the pituitary gland secretes six hormones. These hormones are Growth hormone (GH), Thyroid-stimulating hormone (TSH), Follicle-stimulating hormone (FSH), Trophic hormone (TH), Prolactin hormone (PRL) and Luteinizing hormone (LH).
Similarly, the posterior lobe of the pituitary gland secretes two hormones: Oxytocin hormone and Vasopressin or Antidiuretic hormone (ADH).
Fact 2:. The pituitary gland is called the master gland, why?
Ans: The pituitary gland controls and stimulates many activities of the body, and the secretion of other endocrine glands. So it is also called the master gland.
Thyroid gland
The thyroid gland is located in the neck region in front of the trachea just below the larynx. It has two lateral lobes, one on either side of the trachea. The two lobes are connected by a narrow mass of tissue called the isthmus. The thyroid gland secretes two hormones, viz. Thyroxine and Calcitonin.
The thyroid gland is located in the neck region in front of the trachea just below the larynx. It has two lateral lobes, one on either side of the trachea. The two lobes are connected by a narrow mass of tissue called the isthmus. The thyroid gland secretes two hormones, viz. Thyroxine and Calcitonin.
Functions of thyroxine
i. It stimulates the rate of cellular oxidation and metabolism.
ii. It regulates the growth and development of the body, ossification of the bones and mental development.
iii. It regulates the activities of the nervous system.
iv. Lack of iodine in the diet, or hyposecretion of thyroxin, causes simple goiters) In such a condition the thyroid gland enlarges and becomes visible as a swelling in the neck similarly. hyposecretion of thyroxin causes roughness or puffiness of the skin, falling of hairs, obesity, stammering and physical and mental weakness.
Hypersecretion of thyroxine causes mental imbalance, bulging eyes, digestive disorders, loss of weight and excessive excitement.
Functions of calcitonin
i. This hormone regulates the level of calcium and phosphate in the blood.
ii. It facilitates calcium absorption and releases by the bones.
i. It stimulates the rate of cellular oxidation and metabolism.
ii. It regulates the growth and development of the body, ossification of the bones and mental development.
iii. It regulates the activities of the nervous system.
iv. Lack of iodine in the diet, or hyposecretion of thyroxin, causes simple goiters) In such a condition the thyroid gland enlarges and becomes visible as a swelling in the neck similarly. hyposecretion of thyroxin causes roughness or puffiness of the skin, falling of hairs, obesity, stammering and physical and mental weakness.
Hypersecretion of thyroxine causes mental imbalance, bulging eyes, digestive disorders, loss of weight and excessive excitement.
Functions of calcitonin
i. This hormone regulates the level of calcium and phosphate in the blood.
ii. It facilitates calcium absorption and releases by the bones.
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