Task 1 questions Flashcards
Describe how the myelin sheath speeds up nerve impulse transmission.
The myelin sheath allows saltatory conduction, where impulses “jump” between nodes of Ranvier, speeding up transmission
Describe transmission of a nerve impulse along a neuron
-Transmission of a nerve impulse is conducted along a neuron due to the neuron having a resting membrane potential (RMP) at -70mV.
-First step is neurotransmitters binding to receptors at the end of the nerve cell and they open the receptors which allow Na+ to enter the first part of the neuron.
-If enough Na+ enters the neuron, it will reach a threshold, which is at -55mV, and depolarisation will continue.
-If the threshold is not met, action potential will not continue.
-When the threshold is met, it acts as a key for the voltage-gated Na+ channels to open which allows for an influx of Na+ inside the neuron.
-This causes the inside of the cell to be more positive than the outside; the voltage is now at +30mV.
-At +30mV, repolarisation will start occurring by voltage-gated K+ channels opening and they start leaving the neuron and voltage-gated Na+ channels closing which causes the neuron to be at -90mV, which is called hyperpolarisation.
-Since the neuron wants to go back to RMP, Na+ K+ pumps open and start pumping out 3 Na+ for every K+ pumped in until it has reached RMP (-55mV).
-The cell has a refractory period in which a new neuron impulse can not be transmitted.
Discuss the process of synaptic transmission
