Neurons and Synaptic Transmission

Question 1

What is a Neuron?

Answer 1

• Nerve Cells
• Basic building blocks of the nervous system.
• Process and transmit electrical and chemical signs.

Question 2

What is a Sensory Neuron?

Answer 2

• In the PNS
• Function is to carry messages from sensory receptors in the PNS to the CNS. Convert information from receptors to impulses which are then translated into sensations once they reach the brain. Some terminate in the spinal cord and do not make it to the brain.

Question 3

What does a sensory neuron look like?

Answer 3

• Cell body is separate.
• Short axons.
• Long Dendrites.

Question 4

What is a Motor Neuron?

Answer 4

• Located in CNS with axons in PNS.
• Function is to connect CNS to effectors such as muscles and glands. Controls muscle movement.
• Form synapses with muscles and control contractions. Once stimulated, releases neurotransmitters that bind to receptors on muscle, triggers a response causing movement.
• When axon fires, muscle that has form synapeses contracts. Strength depends on rate of firing.

Question 5

What does a motor Neuron look like?

Answer 5

• Long Axons
• Short dendrites

Question 6

Whar is a Relay Neuron?

Answer 6

• In the CNS
• Function - connects sensory to motor neurons or other relay neurons. Allow sensory and motor neurons to communicate.

Question 7

What does a Relay Neuron look like?

Answer 7

• Short axons
• Short dendrites

Question 8

Structure of a Neuron

Answer 8

• Cell body contains a nucleus which contains genetic material of a cell.
• Dendrites branch out from cell body, receiving signals from nearby cells.
• Axon Is thin body of neuron, carries impulses away from cell body down the length of a neuron.
• Axon is covered by a fatty, insulating substance known as the myelin sheath that protects axon and speeds up electrical transmission of the impulse.
• Myelin sheath is segmented by gaps called nodes of Ranvier. Speed up transmission of impulse by forcing it to jump across the gaps of the axon.

Question 9

What are terminal buttons?

Answer 9

• Located at the end of the axon.
• Communicate with the next nerve cell across the synapse.

Question 10

What is a neurotransmitter?

Answer 10

• Chemicals that diffuse across synapse to next neuron in the chain.

Question 11

Synaptic transmission

Answer 11

• Process by which neighboring nerve cells communicate messages to one another.
• Neurotransmitters in the vesicles exit the axon terminals through the transporters.
• Neurons travel across the synapse which is the small space between the end of the presynaptic neuron and the start of the post synaptic neuron. Chemical transmission.
• Dendrites receive the neurotransmitters through the receptors.
• When an impulse is sent through a neuron it is called electrical transmission.

Question 12

Excitation and Inhibition

Answer 12

• If there are more inhibitory neurotransmitters then the neuron will become negatively charged and less likely to fire.
• IF there are more excitatory neurotransmitters then the neuron will become positively charged and more likely to fire.

Question 13

Effects of psychoactive drugs

Answer 13

• Allow us to alter levels of neurotransmitters in the brain and treat mental illnesses e.g. agonist causes a neuron to fire as it has more excitatory neurotransmitters and an antagonist stops a neuron from firing as it has more inhibitory neurotransmitters.