Nervous System

Question 1

Describe the CNS (Central Nervous System)

Answer 1

• Consists of the brain and spinal cord

- Receives information from all over the body, process that information, and then tells the body how to respond

Question 2

Describe the PNS (Peripheral Nervous System)

Answer 2

-Consists of nerves that carry messages to and from the CNS and other parts of the body

Question 3

Functions of parts of a nerve cell:

a. myelin sheath
b. dendrites
c. neurotransmitters

Answer 3

a. protects axon and allows nerve impulse to travel down the axon quicker
b. makes contact with an other nerve cell to receive electrical impulses
c. relays message across the synapse to another nerve cell

Question 4

Describe a sensory neuron

Answer 4

have specialised receptors which are sensitive to stimuli (includes things like light or heat). Carry messages to CNS from sense organs (these include eyes, ears, etc.)

Question 5

Define ‘reflex’

Answer 5

A reflex is a fast, involuntary reaction designed to keep your body from harm

Question 6

What is the cerebellum responsible for?

Answer 6

co-ordination and balance, without it walking would be impossible

Question 7

Why are reflexes important?

Answer 7

So that your body is removed from a source of danger as soon as possible, instead of waiting for your brain to process what has happened.

Question 8

What do motor neurons do?

Answer 8

Take messages from the CNS and relay them to effectors, where the message is translated into an action.

Question 9

What is the difference between white and grey matter?

Answer 9

Grey matter contains the cell bodies, dendrites and axon terminals of the neurons, therefore containing synapses. Whereas, white matter consists of axons connecting different parts of the grey matter together.

Question 10

Describe the function of inter-neurons

Answer 10

transmit messages between neurons and the CNS

Question 11

Explain the path of the electrical message as it is transferred from one nerve cell to another

Answer 11

• Message is received by the dendrites of a nerve cell
• Message travels down the axon, jumping quickly between the gaps within the myelin sheath
• Axons terminals detect electrical impulse (message) and releases neurotransmitters (chemical that transfer message across the synapse)
• Dendrites of another nerve cell receive the message from the neurotransmitters

Question 12

What is the function of the cerebrum?

Answer 12

Cerebrum makes up 80% of the brain and contains 10 billion neurons. Where the higher intellectual functions of humans take place, controls conscious thoughts and intentional movement of every body part. The cerebrum consists of a right and left hemisphere, the left hemisphere controls the right side of the body and the right hemisphere controls the left side.

Question 13

What is meant by the normal neural pathway in responding to stimuli

Answer 13

for the body to perform a normal reaction, sensory neurons carry the message to the brain where the message is processed. The brain then relays the message onto the motor neurons and then effectors where the message is translated into action.

Question 14

How are reflexes so fast?

Answer 14

Reflexes are so fast because the brain is bypassed when making the decision of the movement, instead the movement is processed in the spine. If a reflex action didn’t occur more damage would be done to the body as it would take longer for the brain to process what is happening.

Question 15

How do reflexes occur?

Answer 15

message is carried only up to the spine where it is then instantly sent back out to the motor neurons.

Question 16

What are neurons?

Answer 16

Nerve cells that carry messages to and from the brain