BY4.7 Nerve Impulses

Nerve Impulses

• electrical charge associated with an impulse is very small: 50mv
• impulses can eb recorded and measured
• impuses are picked up from the nerves through a pair of microelectrodes and are fed into a cathode ray oscilloscope
• measures the magnitude and speed of transmission of an impulse
• can analyse patterns of impulses generated in different parts of the nervous system

Transmission of nerve impulses:

• neurones transmit electrical impulses along cell surface membrane surrounding the axon
• inside of the membrane had a more negative elctrical charge comapred to the outside

resting potential: the potential difference between the inside and outside of the membrane when a nerve impulse is not being conducted

- usually a minus value

Action potential:

• the membrane is at resting potential of -70mv
• voltage gated sodium and potassium channels are closed, the sodium potassium pump is open
• potassium flows in and sodium flows out by active transport, the potential difference is negative inside the membrane
• stimulus is appplied at the threshold (-50mv) is reached and action potential occurs
• voltage gated sodium channels open quicker than the voltage gated potassium ones so sodium rushes in along an electrochemical gradient and concentration gradient
• inside potential difference becomes more…