Nervous System

Question 1

What is a relay neurone?

Answer 1

A neurone that carries signals inside the coordinator

Question 2

What is a positive feedback loop?

Answer 2

This is when a change in one direction is followed by another change in the same direction

Question 3

How fast are reflex action response?

Answer 3

Automatic and repaid to minimise damage to the body

Question 4

What is the axon covered in?

Answer 4

Myelin sheath to send nerve impulses efficiently

Question 5

What happens when a nerve impulse reaches a synapse?

Answer 5

The impulse arrives at the end of the presynaptic neurone.
Vesicles move towards, and fuse with, the presynaptic membrane. This releases neurotransmitters into the synaptic cleft.
The neurotransmitters diffuse across the synaptic cleft (down a concentration gradient).
Neurotransmitters attach to receptors on the postsynaptic membrane.
This triggers an impulse which travels along the postsynaptic neurone.
The neurotransmitters are recycled or destroyed once an impulse is sent.

Question 6

What is a stimulus?

Answer 6

A change in the internal or external environment

Question 7

What is a feedback mechanism?

Answer 7

A physiological regulation system to return the body to its normal internal state

Question 8

What is a motor neurone?

Answer 8

A neurone that carries signals from the coordinator to the effectors

Question 9

What is an effector?

Answer 9

Something that brings about response to a stimulus

Question 10

What is a negative feedback loop?

Answer 10

This is when a change in one direction is followed by a change in the other direction

Question 11

What is the peripheral nervous system?

Answer 11

All nerves that aren’t part of the brain and spinal cord which send signals between receptors, the central nervous system, and effectors

Question 12

What is a sensory neurone?

Answer 12

A neurone that carries signals from receptors to the coordinator

Question 13

What is the coordinator in a typical control system?

Answer 13

The brain

Question 14

How do drugs affect synaptic transmission?

Answer 14

They can bind to neurotransmiter receptors, triggering impulses in different regions of the brain. This also reduces the receptors available to process the neurotransmitters. Frequent drug-use can lead to overstimulation of neurones, leading to loss of function or overstimulation of different regions of the brain and the body.

Question 15

What is a receptor?

Answer 15

A specialised cell that detects a stimulus

Question 16

What is the central nervous system?

Answer 16

The brain and spinal cord to coordinate responses to stimuli

Question 17

What is homeostasis?

Answer 17

The regulation of the internal condition of an organism to maintain optimum conditions for enzymes to work properly

Question 18

Is homeostasis voluntary or involuntary?

Answer 18

Involuntary

Question 19

When does the brain know about responses from reflex action?

Answer 19

After the response has occurred

Question 20

What is a coordinator?

Answer 20

A place that receives and processes electrical impulses from receptors

Question 21

What are 3 examples of homeostasis?

Answer 21

Controlling blood glucose levels
Controlling body temperature
Controlling water levels

Question 22

What is a synapse?

Answer 22

A gap between two neurones

Question 23

Which part of the central nervous system does reflac action use as the coordinator?

Answer 23

The spinal cord

Question 24

What is a response?

Answer 24

It could be a muscle contraction or a release of a hormone

Question 25

What components does a neurone have?

Answer 25

A cell body containing a nucleus, an axon and dendrites

Question 26

What are the elements of a control system

Answer 26

Stimulus -> Receptor -> Coordinator -> Effector -> Response