3. STRUCTURE AND FUNCTIONS OF HUMAN BODY-ORGAN SYTEMS
BIOLOGY
ERVOUS SYSTEM – N INTRODUCTION Two or more people when gather together, each one is set with an interest and aptitude and performs his works in his own way. But when it is the question of maintenance of an order, a systematic working among them, there is a need for someone to control and co-ordinate them so that a harmony prevails. Similarly the functions of organs and organ system in our body cannot go on in their own way but must be coordinated to maintain the harmonius steady state of body functioning called Homeostasis. Coordination is the process through which two or more organs interact and compliment the functions of one or the other. In our body the neural or nervous system and the endocrine system do the function of coordinating and integrating all the activities of the organs so that the body works efficiently by synchronizing the functions.
through hormones. In this chapter, we will learn the structure and functioning of the nervous system and the endocrine system in man.
The nervous system provides an organized network of point to point connections for a quicker coordination. The endocrine system provides chemical integration 34
Dendrite Nissle’s granule Nucleus Cell body Nodes of Ranvier Cytoplasm
Terminal branches
Neurilemma Axon Myelin sheath
Neuron
Dendrite Nucleus
Axon Bipolar Unipolar
Axon Multipolar
Fig. 3.1 structure of neuron and types