Summarize and explain the events that occur during theconduction of nerve impulses in electrical and chemicalsynapses.
Summarize and explain the events that occur during the
conduction of nerve impulses in electrical and chemical
synapses.
Neurons are the basic cells of the nervous system and our brain. They are held responsible for every signal received from the external world in the form of stimulation. These then send motor commands to our muscular organs and parts for transforming the electrical signals at every step. A neuron has 3 parts , the cell body , an axon and dendrites. Cell body is known to contain the genetic DNA in the nucleus. Dendrites are responsible for receiving information in the form of signals.
NERVE IMPULSE CONDUCTION
Nerve impulse is an overall psychological change that occurs in the neuron due to disturbances created by a stimulus. It runs through acon, synapse and a neuromuscular junction.
- Polarisation : Resting potential
- Depolarisation : action potential
- Repolarisation
Resting potential
When a neuron is electrically charged but not conducting, it is called at resting. The charge of the plasma membrane is negative whereas the interstitial fluid is positively charged. The potential at this stage is resting potential and is ar -70mV. Interstitial Fluid has a high amount of Na+ ions and this concentration is higher outside the neuron. Also, the axoplasm has a high concentration of K+ ions which is higher inside. Due to this difference, the sodium ions diffuse into the axoplasm and the potassium ions diffuse out of the axoplasm. Since the membrane is more permeable to potassium ions than the sodium, potassium leaves faster than sodium enters.
There is a high concentration of cations outside the neuron. This state of resting neurons is called Polarized state.
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