Neuron Function

Question 1

what is a nerve impulse

Answer 1

A nerve impulse is a wave of chemical and electronical charges that is conducted along a neuron. When stimulated, a neuron can change from its resting state to an active state, and back again.

Question 2

what are the processes involved in a nerve transmittion

Answer 2

1. Generation of a nerve impulses or action potential in a sensory neuron as a result of a stimulus.
2. Conduction of an impulse along a neuron from the dendrites to the cell body, to the axon.
3. Transmission of a signal to another neuron across a synapse. A chemical transmitter substance is released across the synapse to allow the electrical impulses to pass from one neuron to another.

Question 3

what is action potential

Answer 3

An action potential occurs when a neuron sends information down an axon, away from the cell body.

Question 4

how are action potentials caused

Answer 4

They are caused by an exchange of ions across the semi-permeable neuron membrane. The action potential is an explosion of electrical activity. When the threshold level is reached, an action potential of a fixed size will fire (for any given neurons, the action potential is always the same). If the neuron does not meet the threshold, it will not fire. If it is reached a full action potential is fired (this is the all or nothing principle). Reached = all, Not reached = nothing.

Question 5

what is a synapse

Answer 5

Is the ‘gap’ between the axon of one nerve and the dendrite of the next one. The average neuron has 1,000 synapses with other neurons.

Question 6

what is synapse transmission

Answer 6

t the synaptic, an electrical impulse will trigger the migration of vesicles containing neurotransmitters towards the presynaptic membrane. Neurotransmitters are released into the synaptic cleft. Neurons can contain and release more than one transmitter.
The neurotransmitter molecules then diffuse across the synaptic cleft and bind with receptor sites on the postsynaptic ending to influence the electrical response in the postsynaptic neuron. Once bound to a receptor, the neurotransmitter makes the postsynaptic cell either more or less likely to fire an action potential. If the number of excitatory postsynaptic events is large enough, they cause an action potential in the postsynaptic cell and a continuation of the ‘message’.