VPB 121: Veterinary Physiology - II (2+1)

INTRODUCTION

•  Pioneering discoveries of LUGI GALVANI’S explanation of animal electricity which he showed as a muscle twitch in a dead frog on application of electrical current led away to the modern study of neurophysiology.From his work, a clue was spread about the functions of nervous system, as a unit of control of activities of the body. Based on this revolutionary idea, nerves were thought to be similar to water carrying pipes. Much of such discussion on neuronal communications and cellular cross talk find its way for discoveries and updates theories in modern neurophysiology.
• Nervous system is a structural and functional mechanism involved in the co-ordination of an animal’s response to internal and external environment.Nervous system collect information from outside and inside the body, as well as integrate the information. It comprises of collection of neurons to specialize to covey information with the great speed and accuracy. Nerve cells are designated to respond to stimuli and transmit information to various parts of the body. It provides effective responses to stimuli.Nervous system is composed of millions of discrete structural, functional and genetic unit called neurons.

Nervous system can be subdivided into different parts for the convenience of study but they function together.

• Central nervous system( CNS): brain & spinal cord
• Peripheral nervous system(PNS): cranial nerves and spinal nerves.
• Autonomic nervous system (ANS): sympathetic and parasympathetic divisions.

• Brain is the major area of central nervous system, is a large structure with the cluster of neurons viz SUPERGANGLION integrates and dictates other systems according to the external and internal stimuli.
• PNS is the communication network that connects CNS with the other parts of the body. Their neural tissue lie outside the CNS they have afferent division (towards) brings sensory information from receptor (centripetal) and efferent division (from/ exit) carries motor commands to effectors. Effectors can be skeletal muscles, smooth muscles or cardiac muscles. Efferent division includes somatic nervous system (skeletal muscle) and autonomic nervous system(smooth muscles, cardiac muscles, glands, brown fat and immune organs).
• Both central and peripheral nervous systems are made up of NEURONS and supporting tissues known as GLIAL CELLS.