Q1..) Describe the conduction of nerve impulse through a neuron
Q2..) Describe the conduction of impulse through a synapse
(1) POLARISED MEMBRANE / RESTING POTENTIAL
In resting phase when neuron is not conducting an impulse , the axonal membrane is called polarised. this is due to concentration of ions across the axonal membrane .
AT REST
Action potential : when a nerve fibre is stimulated , the permeability of membrane to Na+ is greatly increased at the point of stimulus (rapid infiux of Na+ ) and hence polarity of membrane is reversed and now membrane is said to be depolarised . The electric potential difference across the plasma membrane at that site is called action potential , which infact termed as nerve impulse.
depolarisation is very rapid , so that conduction of nerve impulse along the entire length of axon occures in fractions of second.
(2). TRANSMISSION OF IMPULSES AT SYNAPSE
In resting phase when neuron is not conducting an impulse , the axonal membrane is called polarised. this is due to concentration of ions across the axonal membrane .
AT REST
- Axoplasm inside the axon contain high conc. of K+ and low conc. ofNa+.
- the fluid outside the axon contain low conc. of K + and high conc. of Na+ .
Action potential : when a nerve fibre is stimulated , the permeability of membrane to Na+ is greatly increased at the point of stimulus (rapid infiux of Na+ ) and hence polarity of membrane is reversed and now membrane is said to be depolarised . The electric potential difference across the plasma membrane at that site is called action potential , which infact termed as nerve impulse.
depolarisation is very rapid , so that conduction of nerve impulse along the entire length of axon occures in fractions of second.
(2). TRANSMISSION OF IMPULSES AT SYNAPSE
- At electrical synapses: here the membrane of pre and post -syneptic neuronare invery close proximity. Electric current can flow directly from one neuron into other across these synapses, like impulse conduction along a single axon.
- AT CHEMICAL SYNAPSES:Here the membrane of pre and post -synaptic neuron are separated by fluid filled space called synaptic cleft. Neurotransmitter are involved here .