5.1.3 Neuronal communication

Question 1

What are the 3 main types of neurons?

Answer 1

1- Sensory
2- Relay
3- Motor

Question 2

What do sensory neurons do?

Answer 2

transmit nerve impulses from receptors to the CNS - (the brain and the spinal cord)

Question 3

What do motor neurons do?

Answer 3

Transmit nerve impulses from the CNS to the effectors

Question 4

What do relay neurons do?

Answer 4

Transmit nerve impulses between sensory neurons and motor neurons

Question 5

What happens when a stimulus is detected by receptor cells?

Answer 5

A stimulus is detected by receptor cells and a nerve impulse is sent along a sensory neuron

When a nerve impulse reaches the end of the neuron, chemicals called neurotransmitters take the information across to the next neuron which then send a nerve impulse

The CNS then processes the information , decides what to do about it and sends impulses along motor neurons to an effector

Question 6

Order of this neuronal system

Answer 6

Stimulus , receptor, sensory neuron, CNS, motor neurons , effectors , response

Question 7

What role does the CNS play?

Answer 7

CNS processes information and decides what to do with it

Question 8

What do sensory receptors do?

Answer 8

Convert stimulus energy into nerve impulses

Question 9

What do sensory receptors act as ?

Answer 9

Transducers

Question 10

What is a transducer?

Answer 10

Something that converts one form of energy into another.

Question 11

Why are sensory neurons known as transducers?

Answer 11

Different stimuli have different forms of energy EG: light energy or chemical energy

BUT your nervous system only sends information in the form of nerve impulses (electrical impulses)

Sensory neurons convert the energy of a stimulus into electrical energy

so , sensory receptors act as transducers

Question 12

What is a resting potential?

Answer 12

The potential difference when a cell is at rest

Question 13

What is a generator potential?

Answer 13

The change in potential difference due to a stimulus

Question 14

What potential do we need for a neve impulse o take place?

Answer 14

We need our generator potential to be big enough to reach the threshold so that the action potential (nerve impulse ) can be triggered , if the stimulus is too weak, the generator potential wont reach the threshold so there will be no action potential

Question 15

What is potential difference also known as ?

Answer 15

Voltage

Question 16

Is there a potential difference / voltage across a cell membrane when the nervous system receptor is at rest (not being stimulated)?

Answer 16

There is a difference in charge between the inside and the outside of the cell, this is generated by ion pumps and ion channels . This means that there is a voltage/ potential difference across the membrane

Question 17

What happens to a potential difference when a stimulus is detected?

Answer 17

When a stimulus is detected, the cell membrane is “excited” and becomes more permeable allowing more ions to move in and out of the cell altering the potential difference , The change in the potential difference is called generator potential

Question 18

What happens to the membrane when there is an even bigger stimulus?

Answer 18

A bigger stimulus excited the membrane more meaning the membrane gets more permeable . This causes a bigger movement of ions and a bigger change in potential difference so a bigger generator potential is made / produced

Question 19

Example of a sensory receptor and what type of receptor it is

Answer 19

Pacinian corpuscle, it is an example of a mechanoreceptor

Question 20

What does mechanoreceptors mean?

Answer 20

They detect mechanical stimuli EG: pressure and vibrations

Question 21

Where are Pacinian corpuscles found?

Answer 21

in your skin

Question 22

What do Pacinian corpuscles contain?

Answer 22

The end of a sensory neuron

Question 23

What is the end of a sensory neurone called?

Answer 23

A sensory nerve ending

Question 24

What are the sensory nerve endings surrounded by?

Answer 24

The sensory nerve ending is wrapped in lots of layers of connective tissue

Question 25

What are they layers of connective tissue surrounding the sensory nerve endings called?

Answer 25

lamellae

Question 26

Example of how a Pacinian corpuscle can be stimulated?

Answer 26

EG: By a tap on the arm

Question 27

What happens when a Pacinian corpuscle is stimulated?

Answer 27

the lamellae gets deformed and press on the sensory nerve ending

Question 28

When the lamellae gets deformed due to pressure, the sensory nerve ending gets pressed , what does this cause?

Answer 28

This causes a deformation on the stretch-mediated sodium ion channels in the sensory neurone

Question 29

Where in the Pacinian corpuscle are the stretch mediated sodium ion channels found?

Answer 29

Cell surface membrane of the sensory neurone

Question 30

What happens when the stretch mediated sodium ion channels are deformed?

Answer 30

The sodium ion channels open and sodium diffuses inside te cell creating a generator potential, if the generator potential reaches threshold then the action potential will be triggered

Question 31

What do all three of the neurons have?

Answer 31

A cell body which contains a nucleus and all the other organelles you usually get in a cell

Question 32

What neuron has a dendron?

Answer 32

Sensory

Question 33

dendrites in neurons

Answer 33

Sensory - short dendrites relay - many shot dendrites Motor- Many short dendrites

Question 34

What do dendrites and dendrons do?

Answer 34

Carry nerve impulses towards the cell body

Question 35

What do axons do?

Answer 35

Carry nerve impulses away from the cell body

Question 36

What does the dendron and the dendrites in the sensory neuron do?

Answer 36

Carry impulses from the receptor cells to the cell body

Question 37

What does the axon in the sensory neurone do?

Answer 37

Carries impulses from the cell body to the CNS

Question 38

What do they dendrites in the relay neuron do?

Answer 38

Carry impulses from the sensory neuron to the cell body

Question 39

What does the axon in the relay neurone do

Answer 39

carries impulses from the cell body to the motor neurones

Question 40

What do the dendrities do in the motor neurone

Answer 40

Carry nerve impulses from the CNS to the cell body

Question 41

What does the axon do in the motor neuron?

Answer 41

Carry nerve impulses from the cell body to the effector cells