Structure And Functions Of Neurons

Question 1

What are the three types of neuron

Answer 1

Sensory
Motor
Relay

Question 2

What is the function of the sensory neuron

Answer 2

Carries messages from receptors in the skin/eyes to the brain and spinal cord. PNS to CNS

Question 3

What is the function of the relay neuron

Answer 3

Receives messages from sensory neurons and pass these to other relay neurons or motor neurons. They allow neurons to communicate. Found in CNS.

Question 4

What is the function of the motor neuron

Answer 4

Carries messages away from the brain and spinal cord to the muscles and effectors in the body to cause a response. CNS to PNS

Question 5

Structure/function of dendrites

Answer 5

Branch like structures that receive nerve impulses from neighbouring neurons or sensory receptors and carry them towards the cell body

Question 6

Structure/function of the cell body

Answer 6

The cell body contains the nucleus which holds the genetic material of the cell.

Question 7

Structure/function of the axon

Answer 7

The axon is a long thin projection that carries impulses in the form of an electrical signal called an action potential away from the cell body down the length of the neuron to the axon terminal

Question 8

Structure/function of the myelin sheath

Answer 8

The axon is insulated by the myelin sheath to protect it and speed up electrical transmission of the impulse

Question 9

Structure/function of the nodes of ranvier

Answer 9

The myelin sheath is segmented by the nodes of ranvier. These are gaps between the myelin sheath that speed up the transmission of impulses by forcing the impulse to jump across the gaps

Question 10

Structure/function of the axon terminal

Answer 10

Axon terminals are at the end of the axon - these communicate with the next neuron across the synapse.

Question 11

What is a reflex

Answer 11

A reflex is a fast, automatic and protective response to a stimulus. Reflexes are not under conscious control and are involuntary. Examples include gag reflex and knee jerk reflex

Question 12

Reflex action and how the neurons work in the process.

Answer 12

STIMULUS - a change in the environment eg touching a hot tray triggers sensory RECEPTORS in the body. The SENSORY NEURON carries the electrical impulse from the receptor to the SPINAL CORD. This acts as the COORDINATOR and passes the signal to the RELAY NEURON which connects the sensory and MOTOR NEURON which transmits the impulse to the EFFECTOR. This is the muscle or gland that carries out the RESPONSE eg withdrawing your hand from the hot tray