Neurons and Synaptic Transmission

Question 1

What are neurons?

Answer 1

They transmit information using electrical and chemical signals. There are billions in the human nervous system with the majority found in the brain. They’re the main communication source for the nervous system.

Question 2

What are the 8 parts of neurons?

Answer 2

cell body
nucleus
dendrites
axon
myelin sheath
schwann cell
node of ranvier
axon terminal

Question 3

What’s the cell body?

Answer 3

The main part of the cell, containing the nucleus

Question 4

What’s the nucleus?

Answer 4

In the cell body, contains all genetic information of the cell

Question 5

What are the dendrites?

Answer 5

Parts coming off the cell body that receive messages from other neurons

Question 6

What’s the axon?

Answer 6

Transmits an electrical impulse away from the cell body down the length of the neuron

Question 7

What’s the Myelin sheath?

Answer 7

Fatty cells which act as insulation for the axon to help speed up electrical transmission

Question 8

What are Schwann cells?

Answer 8

They form the Myelin sheath

Question 9

What are the nodes of Ranvier?

Answer 9

Breaks in the Myelin sheath which encourage the impulse to speed up as it ‘jumps’ over the gap

Question 10

What are axon terminals?

Answer 10

The electrical impulse that has travelled along the axon is converted into a chemical message (neurotransmitter) to be passed on to the next neuron

Question 11

What are sensory neurons?

Answer 11

Neurons found in the peripheral nervous system. They transmit information taken in by sensory receptors (typically on the skin). The information is sent to the CNS where it can interpret the information

Question 12

What are relay neurons?

Answer 12

Neurons found mostly in the CNS. They transmit or relay information to and from other neurons. they go between and communicate with other relay, sensory and motor neurons. They analyse a message and prepare to relay what to do with this message to the relevant neuron

Question 13

What are motor neurons?

Answer 13

Their cell body is in the spinal cord but their long axons are part of the PNS. This is so that the message can travel down the axon and instruct the relevant muscles to move. They take information away from the CNS

Question 14

What’s the process of synaptic transmission?

Answer 14

Neurons communicate with one another in their neural network group. Chemical messages are transmitted across the synapse.
1. A neuron becomes positively charged after a stimulus activates it
2. An action potential travels down the axon of a neuron
3. At the pre-synaptic terminal, the neurotransmitter is fired from synaptic vesicles and sent across the synapse
4. They then bind to receptor sites on the dendrites of the postsynaptic neuron
Chemical messages can only travel in one direction and can only bind to a specific receptor site

Question 15

What is summation?

Answer 15

The process that determines whether or how frequently the neuron will fire by the combined effects of excitatory and inhibitory neurotransmitters.

Question 16

What’s excitation?

Answer 16

If the net is more excitatory then it’s more likely to fire and the action potential will then travel down the axon e.g. adrenaline

Question 17

What’s inhibition?

Answer 17

If the net is more inhibitory then its less likely to fire the action potential e.g. seratonin