Booklets 4,5 and 6

Question 1

What are neurons?

Answer 1

Cells that are responsible for transmitting electrical and chemical messages across the nervous system.

Question 2

What is the synapse?

Answer 2

The conjunction of the end of the axon of one neuron and the dendrites of the next.

Question 3

What is a synaptic transmission?

Answer 3

The process by which a nerve impulse passes across the synaptic cleft from one to the next.

Question 4

What are neurotransmitters?

Answer 4

These are chemical substances that transmit nerve impulses across the synapse.

Question 5

What does sensory neurons do?

Answer 5

Carry messages from the PNS to the CNS.

Question 6

What do relay neurons do?

Answer 6

Relay messages between the sensory and motor neurons

Question 7

What are mutton neurons?

Answer 7

These connect the CNS to effectors such as muscles and glands.

Question 8

Where are sensory neurons found?

Answer 8

In clusters known as ganglia in receptor cells of the CNS

Question 9

What are nerve impulses translated to?

Answer 9

Sensations such as vision and touch.

Question 10

What are the axon and dendrite lengths for sensory neurons?

Answer 10

They have longer dendrites and shorter axons.

Question 11

What is the most common neuron?

Answer 11

Really neurons make up around 97% of all neurons.

Question 12

What are the lengths of dendrites and axons of relay neurons?

Answer 12

They have short dendrites and short axons

Question 13

Where are motor neurons found?

Answer 13

The central nervous system

Question 14

What do motor neurons control?

Answer 14

Muscle movements

Question 15

What happens when motor neurons are stimulated?

Answer 15

They release neurotransmitters that bind to the receptors and muscles to trigger a response.

Question 16

What are the lengths of dendrites and axons in motor neurons?

Answer 16

They have short dendrites and long axons

Question 17

What are the different parts of a neuron?

Answer 17

Dendrite
Axon
Myelin sheath
Nodes of Ranvier
Axon terminal

Question 18

What is the dendrite?

Answer 18

They receive signals from other neurons or from sensory receptor cells. The dendrites are connected to the cell body and carry nerve impulses from neighbouring neurons towards the cell body.

Question 19

What is the axon?

Answer 19

Long slender fibre that carries nerve impulses, in the form of action potentials. The action carries nerve impulses away from the cell body down the length of the neuron.

Question 20

What is the myelin sheath?

Answer 20

This surrounds most axons and protects and insulates it so that electrical impulses travel faster along the axon.

Question 21

What are the nodes of ranvier?

Answer 21

The gaps that segment the myelin sheath which forces the impulse to jump across the gaps along the axon making it quicker.

Question 22

What are axon terminals?

Answer 22

These connect neurons to each other through synaptic transmission

Question 23

What is the firing of a neuron (electrical transmission)?

Answer 23

When in the neuron is at resting potential the inside of the cell is negatively charged compared to the outside. When it is activated by stimulus the inside of the cell becomes positively charged causing an action potential. This causes an electrical impulse to travel down the axon towards the end of the neuron

Question 24

What are neurotransmitters?

Answer 24

Chemicals that diffuse across the synapse to the next neuron in the chain. Once it crosses the gap it is taken up by the post synaptic receptor site of the next neuron

Question 25

What happens when neurotransmitters binds to the receptor sites on the postsynaptic cell?

Answer 25

The receptors become activated and either produce an excitory or inhibitory effect.

Question 26

What is the process of summation?

Answer 26

This is when the excitatory and inhibitory influences are summed. If the net effect on the postsynaptic neuron is inhibitory than the post synaptic neuron is less likely to fire and vice versa.

Question 27

What is hemispheric lateralisation?

Answer 27

The idea that the two halves of the brain are functionally different and each hemisphere has functional specialisations.

Question 28

What is the left visual field of both eyes connected to?

Answer 28

Right hemisphere, and the right visual field in both eyes is connected to the left hemisphere.

Question 29

What is the evaluation for hemispheric lateralisation?

Answer 29

It increases neural processing capacity, one study found that brain naturalisation is associated with an enhanced stability to form two tasks simultaneously.

Research support showing even in connected brains the two hemispheres process information differently. Pet scan used, right hemisphere more active when looking at a whole picture but left more active when focusing on finer detail.

Research going against the idea of people having a dominant side of the brain creating a different personality. There is no artists or mathematicians brain.

Question 30

What happens during an epileptic seizure?

Answer 30

The brain experiences excessive electrical activity which travels from one hemisphere to the other. To solve this doctors would cut the corpus colossal to separate the two hemispheres.

Question 31

What was Sperry’s research?

Answer 31

He conducted a quasi experiment with 11 participants who had had their corpus callosum severed.
An image or word was projected into a patient right visual field and then onto the left visual field. He had different tasks such as describe what you see, recognition by touch and drawing tasks.

Question 32

In Sperry’s research why could the participants not describe what they could see?

Answer 32

Because if it was shown to the left visual field which is governed by the right hemisphere, language is not present and so the participants could not report seeing anything. In the right visual field, governed by the left hemisphere the participants could describe what they saw because this hemisphere is dominant for language.

Question 33

In Sperry’s drawing task, why could participants draw or not draw a picture?

Answer 33

When drawing with the left hand and in the left visual field, control by the right hemisphere, the drawings were clearer and better than the right hand even if the participants were right-handed. This demonstrates the superiority of the right hemisphere when it comes to visual tasks. However, they would report seeing nothing when asked.

Question 34

What is the evaluation of split brain research?

Answer 34

Sperry’s research may have caused ethical issues. Although he only took advantage of a naturally occurring situation participants may not have fully understood what they were giving consent to.

Causal relationships are hard to establish as the epilepsy of the 11 participants may have caused unique features in cognitive abilities.

Research support from Gazzaniga finding that split brain participants actually perform better in certain tasks where the left hemispheres better cognitive strategies are down by the inferior right hemisphere in normal people.