The Nervous System

Question 1

Why do organisms have to be aware of what’s happening around them?

Answer 1

It effects their chances of survival.

Question 2

Which two systems co-ordinate an organisms activities?

Answer 2

• The Nervous System

- The Endocrine System

Question 3

What does a nervous system allow for in relation to stimuli?

Answer 3

It allows for an organism to detect and respond to stimuli in its internal and external environment.

Question 4

What is a stimulus?

Answer 4

It is any change in your environment.

Question 5

What does the nervous system rely on and what are they carried by?

Answer 5

It relys on electrical signals and they are carried by neurons.

Question 6

Name two stimuli.

Answer 6

• A flash of Light

- Noise

Question 7

What is contained in the Central Nervous System (CNS)?

Answer 7

• The brain

- The spinal cord

Question 8

What does the brain keep a track of?

Answer 8

The brain keeps a track of all activities and internal organs in the body.

Question 9

Give an example of what the brain would keep in check.

Answer 9

The levels of CO2 and or H2O in the blood.

Question 10

What is contained on the Periferal Nervous System (PNS)?

Answer 10

The PNS are the nerves branching from the CNS to all parts of the body.

Question 11

What is a receptor?

Answer 11

A receptor is a nerve cell that detects the stimulus.

Question 12

What is a neuron?

Answer 12

A neuron is a specialised cell that carries electrical impulses around the body.

Question 13

What is an impulse?

Answer 13

An impulse is an electrical signal.

Question 14

What does the cell body contain?

Answer 14

The cell body contains the nucleus and other organelles.

Question 15

What does the cell body produce?

Answer 15

The cell body produces neurotransmitter chemicals.

Question 16

What is a dendron?

Answer 16

A dendron is a small fibre that receives information and carries it towards the cell body.

Question 17

What’s an axon?

Answer 17

An axon is a long fibre that conducts impulses away from the cell body.

Question 18

What are dendrites?

Answer 18

Dendrites are small fibrous branches at the end of a dendron.

Question 19

What do schwann cells do?

Answer 19

They wrap their fatty cell membranes around an axon.

Question 20

What is it called when a schwann cells wrap around an axon?

Answer 20

A myelin sheath.

Question 21

What does a myelin sheath do?

Answer 21

It insulates the neuron from electrical signals from other neurons.

Question 22

What do sensory neurons do?

Answer 22

They carry messages from the sensory organ to the CNS.

Question 23

What does an inter-neuron do?

Answer 23

It connects sensory and motor neurons together and so carries messages in the CNS.

Question 24

What does a motor neuron do?

Answer 24

It carries the impulses from the CNS to the muscles and glands.

Question 25

What is a synapse?

Answer 25

A synapse is a region in which two neurons come into close contact with eachother.

Question 26

What is a synaptic cleft?

Answer 26

It is the gap between two neurons, bridged by chemicals (neurotransmitters).

Question 27

What is a neurotransmitter?

Answer 27

It is a chemical released across a synaptic cleft to carry a signal from one neuron to another. After this happens, the chemical is destroyed/removed.

Question 28

What are the three body parts that the brain is protected by?

Answer 28

- Skull - Meninges (three membranes on inside of inside of skull) - Cerebral fluid

Question 29

What is the cerebrum?

Answer 29

This is where the conscious part of the brain is located, each part having different jobs to do.

Question 30

What is the hypothalamus?

Answer 30

This is the centre for the regulation of the internal organs.

Question 31

What is the pituitary glands function?

Answer 31

This secretes hormones that stimulate other glands to release their horomones.

Question 32

What does the cerebellum do?

Answer 32

This co-ordinates the processes that we have learned to do automatically for example, speaking.

Question 33

What does the medulla oblongata do?

Answer 33

This co-ordinates involuntary, automatic processes for example, breathing or your heart beating).

Question 34

What does the spinal cord do?

Answer 34

It transmits impulses to and from the brain and controls many reflex actions.

Question 35

Describe the layout of a cross-section of the spinal cord.

Answer 35

It shows a small central canal filled with cerebrospinal fluid, surrounded by an area of grey matter, shaped somewhat like the letter 'H' which is then surrounded by white matter.

Question 36

What does grey matter contain?

Answer 36

It contains the cell bodies and dendrites (the regions of a neuron that have no white myelin covering).

Question 37

What is outside of grey matter and what does it contain?

Answer 37

Outside the grey matter is white matter and it contains the axons only.

Question 38

How many pairs of spinal nerves branch off from the spinal cord in humans?

Answer 38

It has 31 pairs.

Question 39

What are the two parts that come along with a spinal nerve?

Answer 39

A dorsal root and a ventral root.

Question 40

What does the dorsal root consist of and what does it do?

Answer 40

The dorsal root consists of nerve fibres carrying information into the spinal cord from the senses.

Question 41

What does the ventral root consist of and what does it do?

Answer 41

It consists of nerve fibres carrying information out from the spinal cord to the muscles or glands.

Question 42

What is contained within the grey matter cord?

Answer 42

The cell bodies of the motor neurons.

Question 43

What is a reflex action?

Answer 43

A reflex action is a quick, automatic response to a particular stimulus.

Question 44

Give an example of a reflex action to a stimulus.

Answer 44

Suppose you touch a hot flame, almost instantly you would pull your hand away.

Question 45

Explain how reflex actions work (using the example of a hot flame).

Answer 45

- In a brief instant, a message has been carried by a sensory neuron from pair receptors in the skin to the spinal cord. - In the spinal cord, the message is passes onto an inter-neuron and then onto a motor neuron, and so muscles respond by contracting and pulling your hand away from the flame.

Question 46

What is a disorder affecting the nervous system in humans?

Answer 46

Parkinson's disease

Question 47

What is parkinson's disease?

Answer 47

It is a nervous system disorder normally seen in older people in which muscles become ridged and movement is slow and difficult, with persistant tremors.

Question 48

What is Parkinson's disease caused from?

Answer 48

It is caused from the brain reducing the amount of dopamine produced.

Question 49

What is the cure for Parkinson's Disease?

Answer 49

There are no ways of preventing it, but giving 'L-dopa' (which the body turns to dopamine) can relieve the symptom.