The Nervous System
Control and coordination
- Working together of various integrated body systems in response to changes in the surrounding for the maintenance of bodily functions is known as control and coordination
- Nervous system and endocrine system provide control and coordination in animals.
- Neurons -functional units of the nervous system, conduct messages in the form of electrical and chemical impulses
- Neuron composed of cell body and dendrite, axon and nerve endings.
- Types of neuron:-
- Sensory neuron
- Motor neuron
- Relaying or intermediate neuron
- Nerve: A nerve is a collection of nerve fibres (or axons) enclosed in a tubular medullary sheath. This sheath acts as an insulation and prevents mixing of impulses in the adjacent fibres.
- Transmission of nerve impulse:
Under normal conditions, the outer side of the nerve fibre consists of positive charge as more Na+ ions are present outside axon membrane. The neuron is then said to be in polarised state. On stimulation, the membrane becomes more permeable and Na+ ions move inside causing depolarisation. Such a region is known as excited region. The point of depolarisation behaves as stimulus for the neighbouring area and this goes on. In the mean time, the pre…
To view the complete topic, please