Neurons and Synaptic Transmission

Question 1

Sensory Neuron

Answer 1

This tells the rest of the brain about the external and internal environment by processing information from the 5 senses.

Question 2

Motor Neuron

Answer 2

axon projects outside the spinal cord to control effector organs, mainly muscles and glands. This is based on messages sent from the CNS.

Question 3

Relay Neuron

Answer 3

They connect motor and sensory neurons. and are found in the spinal cord

Question 4

Outline the structures and processes involved in synaptic transmission.

Answer 4

Information from the environment that is received from our senses trigger an electrical impulse. (1) Electrical impulses (action potentials) reach the presynaptic terminal (1) These electrical impulses (action potentials) trigger release of neurotransmitters such as dopamine (1) These neurotransmitters cross the synapse once they have been released from vesicles (1). The neurotransmitters then combine with receptors on the postsynaptic membrane (1). The stimulation of postsynaptic receptors by neurotransmitters result in either excitation or inhibition of the postsynaptic membrane. (1)

Question 5

outline the structures and processes of the reflex arc

Answer 5

sensation detected by sensory neurons sends the information from the postsynaptic neuron to the presynaptic neuron. electrical signals cross the synapse and reach the dendrites on the relay neuron and sends the information towards the brain (CNS) motor neuron receives this information and transmits it towards the effector. this causes the limb to react or move as a result

Question 6

How are excitation and inhibition involved in synaptic transmission:

Answer 6

Neurotransmitters can be excitatory or inhibitory
If the neurotransmitter is excitatory then the postsynaptic neuron is more likely to fire an impulse.
If the neurotransmitter is inhibitory then the postsynaptic neuron is less likely to fire an impulse.
The excitatory and inhibitory influences are summed, if the net effect on the postsynaptic neuron is inhibitory, the neuron will be less likely to ‘fire’ and if the net effect is excitatory, the neuron will be more likely to fire.