GENERAL PHYSIOLOGY

Physiology is the science of the function of living systems. It is a study of the function of the systems of the body in health and exercise. This includes how organisms, organ systems, organs, cells and bio-molecules carry out the chemical or physical functions that exist in a living system. Since this course entails the study function of living systems, we will focus on the osmotic regulation in animals, excretory mechanism and transport systems. Also, homeostatic mechanism, coordination in animals and plant -water relations will be treated.
The behaviour of an animal in its environment to maintain itself depends on the coordination of its organs systems. Without coordination of various organ systems, various physiological processes would work in a haphazard way, without linking together activities. The linking together in time and space of various activities of an animal is called coordination. Coordination is brought about by the nervous system and sense organs, and by means of chemical substances (hormones) secreted by the endocrine glands. During the course of evolution, nervous systems have become more complex. This is largely because animals have become larger and more mobile, requiring more neurons than a sedentary animal. The most fundamental function of a nervous system is (1) to receive a stimulus (2) transmission of a stimulus to a central "brain", (3) interpretation and analysis of the stimulus and (4) proper response by an effector. With the evolution of a complex nervous system and bilateral symmetry, cephalis Ation (formation of a head) has taken place, and the ganglia in the head became large enough to be called a brain, which is the main nervous control centre of the body.
Water is vital to plant life and well being. It forms 80-90% of fresh weight of plants. Plants grow in soil and absorb water and minerals which is available in soil. Therefore water has great importance for plants. Water functions as a reactant as well as a product. Water and dissolved substances are transported within and outside the cell through the process of diffusion and osmosis. An understanding of plant water relations depends upon an understanding of the principle of diffusion and osmosis. Different regions of the plant body maintain varying concentrations of both solute and water molecules. The varying concentrations create gradients through substances must travel. Hence, this unit will focus on the principle of diffusion and osmosis.