Neurons and Synaptic Transmission Flashcards
What is the function of a sensory neuron?
To carry nerve impulses from sensory receptors in the PNS to the spinal cord and the brain.
Where are sensory neurons found?
In receptors such as the eye, skin and tongue.
Are sensory neurons unipolar?
Yes as they only send messages.
Outline the structure of a sensory neuron.
-Long dendrites, short axons.
-Cell body always sticks out.
What is the function of a relay neuron?
To connect sensory neurons to motor neurons and other relay neurons.
To send messages back and forth.
Where are relay neurons found?
Between sensory and motor neurons.
Only in the brain and spinal cord.
Are relay neurons unipolar?
No, they are multipolar as they send messages back and forth
Outline the structure of a relay neuron.
Short dendrites, short axons.
No myelin sheath.
What is the function of a motor neuron?
Carries messages from the CNS to effectors - connects the CNS to effectors.
Control muscle movement
Where are motor neurons found?
In the brain and spinal cord.
Are motor neurons unipolar?
No they are multipolar as they receive and pass messages on.
Outline the structure of a motor neuron.
Short dendrites, long axons.
What is meant by synaptic transmission?
The process of a neuron sending a chemical message across the synaptic cleft to communicate with another neuron.
Describe the process of synaptic transmission.
1- impulse arrives at presynaptic neuron.
2- neurotransmitters released from vesicles.
3- neurotransmitters diffuse across synaptic cleft.
4- neurotransmitter bind to receptor sites.
5- electrical impulse travels down axon.
6- neurotransmitters then broken down ad reabsorbed into presynaptic neuron.
During synaptic transmission, why is the direction of travel only one way?
Neurotransmitters are released from the presynaptic neuron and received at the postsynaptic neuron.
