🟢 Biopsychology - Neurons

Question 1

Function of dendrites

Answer 1

Receives messages from other cells

Question 2

Function of terminal branches of axon

Answer 2

Form junctions with other cells

Question 3

Function of myelin sheaf

Answer 3

Covers the axon of neurons and helps speed neural impulses

Question 4

Function of Axon

Answer 4

Passes messages away from cell body to other neurons muscles or glands

Question 5

Sensory neurons

Answer 5

Carry impulses from the sensory receptors to the CNS

LONG DENDRITES AND SHORT AXONS

Question 6

Relay neurons

Answer 6

Found in the brain and spinal cord and allow sensory and motor neurons to communicate

Question 7

Motor neurons

Answer 7

Responsible for directly or indirectly controlling muscles. They carry impulses from CNS to effector

SHORT DENDRITES AND LONG AXONS

Question 8

Neurotransmitters

Answer 8

• allow transfer of signalling messages between brain cells
• located in axon terminal and stored within thin walled sacs called synaptic vesicles

Question 9

Synaptic transmission

Answer 9

1. Information passed through electrical impulses down the pre synaptic axon
2. Once reached axon terminal, this stimulates release of neurotransmitters from vesicles
3. Neurotransmitters then diffuse across the synapse and bind to receptors on post synaptic axon
4. This stimulates release of electrical impulses to pass down post synaptic axon with same messages e

Question 10

What is reuptake

Answer 10

Any neurotransmitter molecules that have not been absorbed by the receptors will be destroyed by enzymes in the synaptic gap or absorbed by the presenaptic neuron

Question 11

What is the difference between excitatory NT and inhibitory NT

Answer 11

Excitory neurotransmitters binding make a neuron more likely to fire and inhibitory ones make it less likely to fire

Question 12

What are inhibitory NT responsibile for

Answer 12

Calming the mind, inducting sleep

Question 13

What is depolarisation

Answer 13

Depolarisation is the process where the inside of a neuron becomes less negative due to the inflow of positive ions, making an action potential more likely.

For example you touch something hot

Question 14

Why can the signal only go in 1 direction

Answer 14

The signal can only go in one direction as it is only the pre synaptic neuron that contains vesicles containing the NTs and it is only the post synaptic neuron that has receptors for the NTs to bind to.

Question 15

What is a synaptic cleft

Answer 15

Tiny gap between 2 neurons (synapse)

Question 16

Briefly outline how excitation and inhibition are involved in synaptic transmission

(4marks)

Answer 16

When a neurotransmitter is released across the synaptic cleft, it has
either an excitatory or inhibitory effect on the post synaptic neuron.
An excitatory effect increases the positive charge in the post-
synaptic neuron, making it more likely to fire. An inhibitory effect
results in the neuron becoming more negatively charged and less
likely to fire. Whether the signal fires or not depends on
summation; the summed total of number of excitory or inhibitory