Chapter 5 - nerves and nerve impulses

Question 1

What is the nervous system?

Answer 1

The nervous system is the communication network and control centre of the body.

Question 2

What is the central nervous system?

Answer 2

Is the part of the nervous system that consists of the brain and spinal cord.

Question 3

What is the peripheral nervous system?

Answer 3

Is the part of the nervous system that connects the central nervous system with the receptors, muscles and glands

Question 4

What are neurons?

Answer 4

Neurons are a nerve cell; the basic structural and functional unit of the nervous system

Question 5

What does a neuron consist of?

Answer 5

• Dendrite: often have many branches. they recieve the messages from other neurons and carry them towards the cell body
• The Cell body: contains the nucleus and many other organelles
• Axon: it is often long and is unbranched for most of its length. Axons carry impulses away from the cell body.

Question 6

Which way does the nerve impulse travel on a neuron?

Answer 6

Dendrite –> Cell body –> Axon

Question 7

Most axons are covered in…

Answer 7

a layer of fatty material called a myelin sheath

Question 8

Fill in the blanks

Those that have a myelin sheath are calledand those that dont are said to be .

Answer 8

1. Myelinated
2. Un mylenated

Question 9

Interneurons are found where?

Answer 9

In the brain and spinal cord

Question 10

Why do interneurons have many branches?

Answer 10

To send or recieve messages to or from adjacent neurons

Question 11

What is the difference between grey matter and white matter?

Answer 11

• Grey matter: consists of nerve cell bodies and unmyelinated fibres
• White matter: are composed of myelinated fibres

Question 12

What are Schwann cells?

Answer 12

A cell that wraps around a nerve fibre, forming the myelin sheath

Question 13

What is the sheaths three important functions?

Answer 13

1. acts as an insulator
2. protects the axon from damage
3. speeds up the movement of nerve impulses along the axon

Question 14

What is the role of the neurilemma?

Answer 14

It helps the repair of injured fibres

Question 15

What are the three functional types of neurons?

Answer 15

1. sensory neurons
2. motor neurons
3. interneurons

Question 16

What are the the three structural types of neurons?

Answer 16

1. Multipolar neurons
2. Bipolar neurons
3. Unipolar neurons

Question 17

What is the difference between a neuron, nerve fibre and a nerve?

Answer 17

• neuron: a nerve cell
• Nerve fibre: Any long extension of cytoplasm of a nerve cell body, although the term usually refers to an axon
• Nerve: A bundle of nerve fibres held together by connective tissue

Question 18

What is the synapse?

Question 19

What is the neuromuscular junction?

Question 20

What is an impulse nerve?

Question 21

A nerve impulse is…

Question 22

Why is a nerve impulse described as electrochemical?

Question 23

How fast is a nerve impulse?

Question 24

What is saltatory conduction?

Question 25

When are nerve impulse responses almost instantaneous? Give examples.

Question 26

Why do we send nerve impulses?

Question 27

What is membrane potential?

Question 28

What is resting membrane potential?

Question 29

What is a sodium potassium pump?

Question 30

When is the membrane said to be polarised?

Question 31

When is the membrane said to be depolarised?

Question 32

What is the all-or-none response?

Question 33

When there is rapid depolarisation and repolarisation of the membrane it is called what?

Question 34

What is the refractory period?

Question 35

Describe the transmission along myelinated fibres.

Question 36

Describe conduction along unmyelinated fibres.

Question 37

Describe the transmission across a synapse.

Question 38

What happenes to the nervous system as you age?

Question 39

What is the difference between Alzheimer’s disease and Parkinson’s disease?