Nuerons, synaptic transmission and nuerotransmitters

Question 1

Define what is a neuron

Answer 1

nerve cells that process and transmit messages through electrical and chemical signals

Question 2

Structure of neuron:

What’s the size variation of neurons

Answer 2

from less than a millimeter up to a metre

Question 3

Structure of neuron:

Describe the structure of a neuron

Answer 3

• Cell body has nucleus that contains genetic material
• dendrites stick out of the cell body (carry impulses from neighbouring neurons towards cell body)
• mylein sheath wrapped around axon, speeds up electrical transmission of impulse.

Question 4

Types of nuerons:

What are the 3 different types of neurons

Answer 4

sensory neuron

motor neuron

relay neuron

Question 5

Types of neurons

Role and structure of sensory neurons

Answer 5

role - carry messages from sensory receptors, across peripheral nervous system (PNS) to central nervous system (CNS).

structure - long dendrites, short axons

Question 6

Types of neurons

Role and structure of motor neuron

Answer 6

Role: carry messages from CNS, along PNS to effectors in the body

Structure: Short dendrites long axon

Question 7

Types of neurons

Role and structure of relay neurons

Answer 7

Role: connect sensory and motor neuron together, connect to other relay neurons aswell.

Structure: short dendrites, short axons and only found in the CNS.

Question 8

Function of neurons:

What charge is a neuron in a resting state

Answer 8

Negative

Question 9

Function of neurons:

What causes the neuron to become positively charged

Answer 9

Being activated by a stimulus

Question 10

Function of neurons:

Define depolarisation

Answer 10

Rapid change from negative to positive charge in neurons.
- creates an electrical impulse called action potential (AP)
- to create AP depolarisation has to reach certain threshold

Question 11

Synaptic transmission:

Define synaptic transmission

Answer 11

where neurons communicate with eachother via biochemical messangers called neurotransmitters via the synapse

Question 12

Synaptic transmission:

Define neurotransmitters

Answer 12

brain chemicals that diffuse across the synapse to the next neuron.
- released from synaptic vesicles

Question 13

Synaptic transmission:

outline the process of synaptic transmission

Answer 13

When AP reaches the end of the neuron, it triggers the release of neurotransmitters.

Neurotransmitters released from tiny sacs called synaptic vesicles

Diffuse across the synapse to matching receptors on post synaptic neuron.

Neurotransmitters that remain in the synapse and broken down and reabsorved (reuptake).

Question 14

Excitation and Inhibition:

What factor depends on whether a neurotransmitter falls into excitation category or inhibition category?

Answer 14

The function of the neurotransmitters on the neighbouring neuron

Question 15

Excitation and Inhibition:

Define inhibition with an example

Answer 15

where a neurotransmitter is negatively charged making it less likely to fire (serotonin)

Question 16

Excitation and Inhibition:

Define excitation with an example

Answer 16

Where a neurotransmitter is positively charged making it more likely to fire (dopamine)