Multicellular organisms communicate with, and control their various parts by means of two major systems- the nervous system (absent in plant) and the endocrine system. The two systems, through diverse in their functions, coordinate their activities so that internal body harmony and balance is maintained. The hypothalamus, a major nerve center in t . . .
Homeostasis is a state of equilibrium produced by a balance of functions and of chemical composition within an organism. Example: The body produces more red blood cells to cope with the lack of oxygen at high altitudes. In other words, the internal system of the body adjusted to the change in external environment for the survival of the organism. . . .
1.Cretinism: it is caused due to undersecretion during growth years. It two main effects are: Dwarfism: due to failure of the skeleton to grow and mature. Mental retardation: due to failure of the brain to develop fully Cretins also show retarded sexual development, yellowish skin colour, round face, large thick producing to . . .
Regulation of organic metabolism and energy balance: All protein, fat and carbohydrate metabolism is influenced by thyroxine. Since the overall effect is to increase catabolism, they increase the basal metabolic rate (BMR). The energy produced raises the body temperature. Regulation of growth and development: They regulates tissue (especially . . .
The nervous system controls and maintain the body’s internal environment within physiological limits by impulses passing through neurons. The nervous system sends message to specific sets of cells like muscles fibers, glands and other neurons etc. The nervous system causes muscles to contract and relax, glands to secrete more or less of their prod . . .
The endocrine system affects bodily activities by releasing chemical messengers called hormones into the blood stream. The endocrine system as a whole sends messages to cells in any part of the body. The endocrine system brings about changes in the metabolic activities of all body tissue. Hence, affects growth. Action is slow. Hormones can take hours or . . .
Hormones are secretions of the endocrine glands (or tissues) which enter directly into the blood, without passing through ducts. They are secreted in extremely minute quantities. The amount of hormone released is determined by the body’s needs. Chemically, hormones may be polypeptides and proteins, amino acids and their derivatives or stero . . .
The pituitary gland is a round, pea-sized structure measuring about 1.3 cm in diameter. it lies in the brain, attached to the hypothalamus by a stalk-like structure called the infundibulum. The pituitary gland is divided structurally and functionally into the anterior lobe and the posterior lobe. Between these lobes lie the intermediate lobe. . . .
Undersecretion of Hgh: Results in dwarfism if the human growth hormones are insufficient during growth years. Bone growth is slow, and other body organs also fail to grow. Undersecretion of Vasopressin: Results in diabetes insipidus. Symptoms include excretion of large amounts of urine and subsequent dehydration and thirst. No sugar or albumin is p . . .
The thyroid gland is a lobular structure. The two lobes are located on either side of the trachea in front of the larynx. The lobes are connected by a mass of tissue called the isthmus. The thyroid gland looks like a butterfly straddled on the wind-pipe. The tissue of each lobe is made up of a multitude of glandular sacs called follicles. I . . .
Iodine containing hormones exert a marked effect on the central nervous system, growth and development of all types of metabolism, especially the energy releasing oxidation process in body cells. An excess accelerates bodily activity, speeding up the heart and making the brain restless, while too &n . . .