22-11-2012, 11:41 AM
NEURAL CONTROL AND COORDINATION
NEURAL networks.pptx (Size: 994.61 KB / Downloads: 68)
Neural Control and Coordination
Coordination is the process through which two or more organs interact and complement the functions of one another.
In our body the neural system and the endocrine system jointly coordinate and integrate all the activities of the organs so that they function in a synchronized fashion.
The endocrine system provides chemical integration through hormones.
NEURAL SYSTEM
The neural system of all animals is composed of highly specialised cells called neurons which can detect, receive and transmit different kinds of stimuli.
The neural organisation is very simple in lower invertebrates.
For example, in Hydra it is composed of a network of neurons.
The neural system is better organised in insects, where a brain is present along with a number of ganglia and neural tissues.
The vertebrates have a more developed neural system.
NEURON AS STRUCTURAL AND FUNCTIONAL UNIT OF NEURAL SYSTEM
A neuron is a microscopic structure composed of three major parts, namely, cell body, dendrites and axon.
The cell body contains cytoplasm with typical cell organelles and certain granular bodies called Nissl’s granules.
Short fibers which branch repeatedly and project out of the cell body also contain Nissl’s granules and are called dendrites.
These fibres transmit impulses towards the cell body. The axon is a long fiber, the distal end of which is branched.
The axons transmit nerve impulses away from the cell body to a synapse or to a neuro-muscular junction.
Based on the number of axon and dendrites, the neurons are divided into three types, i.e.,multipolar (with one axon and two or more dendrites; found in the cerebral cortex),
bipolar (with one axon and one dendrite, found in the retina of eye)
unipolar (cell body with one axon only; found usually in the embryonic stage).
CENTRAL NEURAL SYSTEM
The brain is the central information processing organ of our body, and acts as the ‘command and control system’.
It controls the voluntary movements, balance of the body, functioning of vital involuntary organs
thermoregulation, hunger and thirst,
rhythms of our body, activities of several endocrine glands and human behavior.
It is also the site for processing of vision, hearing, speech, memory, intelligence, emotions and thoughts.