Biopsych -> sensory, relay and motor neurons

Question 1

Neuron

Answer 1

Neurons are specialised nerve cells that move electrical impulses to and from the CNS.

Question 2

Cell Body:

Answer 2

Control centre of the neuron.

Question 3

Nucleus:

Answer 3

Contains genetic material.

Question 4

Dendrites:

Answer 4

Receives an electrical impulse (action potential) from other neurons or sensory receptors (e.g. eyes, ears, tongue and skin).

Question 5

Axon:

Answer 5

A long fibre that carries the electrical impulse from the cell body to the axon terminal.

Question 6

Myelin Sheath:

Answer 6

Insulating layer that protects the axon and speeds up the transmission of the electrical impulse.

Question 7

Schwann cells:

Answer 7

Make up the myelin sheath.

Question 8

Nodes of Ranvier:

Answer 8

Gaps in the myelin sheath. They speed up the electrical impulse along the axon.

Question 9

Sensory Neuron

Answer 9

Found in sensory receptors. They carry electrical impulses from the sensory receptors to the CNS via the PNS. Sensory neurons convert information from sensory receptors into electrical impulses. When these impulses reach the brain they are converted into sensations, such as heat, pain etc. so that the body can react appropriately. Some sensory impulses terminate at the spinal cord. This allows reflexes to occur quickly without the delay of waiting for the brain to respond.

Question 10

Motor Neuron

Answer 10

Motor neurons are located in the CNS but project their axons outside of the CNS. They send electrical impulses via long axons to the glands and muscles so they can affect function. Glands and muscles are called effectors. When motor neurons are stimulated they release neurotransmitters that bind to the receptors on muscles to trigger a response, which leads to movement.

Question 11

Relay Neuron

Answer 11

Relay neurons are found in the CNS. They connect sensory neurons to motor neurons so that they can communicate with one another. During a reflex arc (e.g. you put your hand on a hot hob) the relay neurons in the spinal cord are involved in an analysis of the sensation and decide how to respond (e.g. to lift your hand) without waiting for the brain to process the pain.

Question 12

Synaptic Transmission

Answer 12

pre-synaptic neuron
post-synaptic neuron
neurotransmitters
exocytosis
diffuse across the synaptic cleft
fraction of a second

excitatory or inhibitory
excitatory postsynaptic potential (EPSP) inhibitory postsynaptic potential (IPSP)
summation

Question 13

Direction of Synaptic Transmission

Answer 13

Information can only travel in one direction at a synapse
vesicles
receptors
Diffusion

Question 14

Medication

Answer 14

Psychoactive drugs
transmission of neurotransmitters
mimic the effects of inhibitory neurotransmitters
less likely to fire
summation
overall activity