The Nervous System

Question 1

What is stimulus?

Answer 1

Any change in your environment
Ex: light, sound, etc

Question 2

What is the Central Nervous System?

Answer 2

The nerves connected to your brain and spinal chord

Question 3

What is the peripheral nervous system?

Answer 3

The nerves that branch from the CNS to all parts of the body

Question 4

What is an impulse?

Answer 4

An electrical message that Is carried along a neuron

Question 5

What is the role of the sensory neuron

Answer 5

Carries a message from a sense organ to the CNS

Question 6

What is the role of the motor neuron

Answer 6

Takes a message from the CNS to a muscle or gland

Question 7

What is the role of the inter neuron

Answer 7

Connects sensory and motor neurons and carries messages within the CNS

Question 8

What is the role of the cell body

Answer 8

Produce neurotransmitters

Question 9

What is the role of dendrites

Answer 9

Fibres that receive information and carry it towards the cell

Question 10

What is the role of the axon

Answer 10

Conducts impulses away from the cell body

Question 11

What is the role of the schwann cell

Answer 11

Wrap their fatty cell membranes around axon, produce myelin sheath

Question 12

What is the role of the myelin sheath

Answer 12

1. Insulates neuron
2. Speeds up transmission

Question 13

What is the role of the nerve endings

Answer 13

Connects sensory neurons to receptor cells or sense cells

Question 14

What is the role of the neurotransmitter swellings

Answer 14

Release chemicals that carry impulses from one nerve cell to another

Question 15

What is a ganglion?

Answer 15

A group of cell bodies located outside the CNS

Question 16

What is the transmission of nerve impulse?

Answer 16

The movement of electrical impulse along a neuron involving the movement of ions in and out of neurons

Question 17

What is a resting neuron?

Answer 17

A neuron that is not carrying an impulse

Question 18

Define threshold

Answer 18

The minimum stimulus needed to cause an impulse

Question 19

What is the all or nothing law?

Answer 19

A law that states that if the threshold is not reached, no impulse is carried

Question 20

What is the refactory period?

Answer 20

Short span of time after a neuron has carried an impulse during which stimulus fails to cause a response

This is necessary to allow the impulse to pass from one neuron to another

Question 21

What is a synapse?

Answer 21

Region where two neurons come into close contact

Question 22

What is the synaptic clef?

Answer 22

The gap between two neurons, bridged by neurotransmitters

Question 23

What is a neurotransmitter

Answer 23

Chemical released across a synaptic clef to carry a signal from one neuron to another

Question 24

Give a summary of the passage of impulse across a synapse

Answer 24

1. Electrical impulse arrives at axon terminal
2. This stimulates neurotransmitter swellings in the pre-synaptic neuron to diffuse neurotransmitters across the synaptic clef
3. Neurotransmitters combine with receptors on post synaptic neuron and are broken down by enzymes and impulse starts in next neuron
4. Digested Neurotransmitters reabsorbed back into the swellings which allows them to be recycled and reused upon the arrival of new impulse

Question 25

What factors does the speed of impulse depend on?

Answer 25

1. Presense of myelin 2. Diameter of dendrite or axon. Larger = faster

Question 26

What are the most common examples of neurotransmitters?

Answer 26

1. Dopamine 2. Noradrenaline 3. Acetylcholine

Question 27

Name a disorder that affects the nervous system, a cause, symptoms, preventative measures and treatment for it

Answer 27

**Name:** Parkinsons **Cause:** brain reduces the normal amount of dopamine it makes **Symptoms:** 1. Trembling hands/legs. 2. Stiff and rigid muscles. 3. Difficulty walking **Prevent:** No way to prevent **Treatment:** Physiotherapy

Question 28

What is the role of the cerebrospinal fluid

Answer 28

1. Shockabsorber 2. Exchange medium between blood and brain

Question 29

What is the role of the cerebrum

Answer 29

1. Control voluntary movements 2. Receiving and interpreting impulses from the sense organs 3. Thinking, intelligence, personality, memory, language

Question 30

What is the role of the cerebellum

Answer 30

1. Controls muscle coordination and balance 2. Responses are involuntary

Question 31

What is the role of the modula oblongata

Answer 31

Controlls involuntary actions such as breathing, swallowing, blood pressure, coughing

Question 32

What is the role of the thalamus

Answer 32

Sorting centre, sends all incoming impulses to the correct part of the brain

Question 33

What is the role of the hypothalamus

Answer 33

Regulates constant internal environment (homeostasis)

Question 34

What is the spinal chord protected by

Answer 34

The meningees (3 membranes) and cerebrospinal fluid

Question 35

What is the role of the spinal chord

Answer 35

Transmits impulses to and from the brain and controls reflex actions

Question 36

Why is grey matter called so?

Answer 36

Contains cell bodies and dendrites with few axons

Question 37

Why is white matter called so?

Answer 37

Contains many axons and much myelin

Question 38

What is reflex action?

Answer 38

Involuntary response to a stimulus Eg: coughing, blinking

Question 39

What is the process of reflex action

Answer 39

1. Stimulus is detected by pain in the skin 2. A message is carried by the sensory neuron in the spinal chord 3. The message is passed on to the interneuron and then to a motor neuron and so into the muscles 4. The muscles respond by contracting and pulling your hand from the stimulus