Co-ordination in mammals

Question 1

What is the nervous system based on?

Answer 1

On a series of neurones that transmit electrical nerve impulses through the body

Question 2

What are nerves?

Answer 2

Bundles of nerve cells

Question 3

How are nervous controls different to hormone action?

Answer 3

It is faster and more precise

Question 4

What is the central nervous system made up of?

Answer 4

The brain and spinal cord

Question 5

What does the peripheral nervous system consist of?

Answer 5

Cranial nerves attached to the brain
Spinal nerves attached to spinal cord

Question 6

What is a stimulus?

Answer 6

A change in the environment - something you see, smell, hear or feel

Question 7

What is a receptor?

Answer 7

Receive the stimulus - eye responds to stimulation from light

Question 8

What is an effector?

Answer 8

Brings about a response - usually a muscle or gland

Question 9

What are the 3 parts of a neurone?

Answer 9

Cell body - centron
Extensions - dendrons
Extensions - axon

Question 10

What does a cell body consist of?

Answer 10

A nucleus
Organelles
cytoplasmic extensions

Question 11

What are extensions (dendrons)

Answer 11

transmit impulses to the cell body

Question 12

What are small and numerous dendrons called?

Answer 12

Dendrites

Question 13

What are extensions (axons)

Answer 13

Transmit impulses away from the cell body
Terminate synaptic bulbs

Question 14

How long can axons be?

Answer 14

May be over 1m long

Question 15

What are the 3 main types of neurone?

Answer 15

Sensory neurone
Motor neurone
Association neurone

Question 16

What is the role of a sensory neurone?

Answer 16

An impulse from the receptor is sent

Question 17

Where is this neurone found?

Answer 17

Central Nervous System

Question 18

What is the role of the motor neurone?

Answer 18

Impulse from the central nervous system

Question 19

What is the grey matter?

Answer 19

The outermost layer of the brain and is pinkish grey in tone

Question 20

What does the association neurone do?

Answer 20

Connect neurones within the central nervous system

Question 21

Where is the cell body found?

Answer 21

The central nervous system/ grey matter

Question 22

What is the rough endoplasmic reticulum?

Answer 22

Membrane system - flattened sacs on the outer nuclear membrane - covered in ribosomes

Question 23

What are mitochondria?

Answer 23

Involved in ATP synthesis
Needed for aerobic respiration

Question 24

What is the myelin sheath?

Answer 24

This is what covers the axons and dendrons found in mammals which are myelinated

Question 25

What is one of the roles of the myelin sheath?

Answer 25

Increases speed and allows efficient transmission of impulses along the nerve cells.

Question 26

What is the myelin sheath made up of?

Answer 26

Many layers of cell membrane of Schwann cells which wrap themselves round the axon of the nerve

Question 27

What nerves does the myelin sheath wrap around?

Answer 27

Nerves in the brain, spinal cord and throughout the body.

Question 28

What does the myelin sheath insulate and what does it prevent?

Answer 28

It insulates the axon
Prevent ion movement between the axon and tissue fluid

Question 29

What does each Schwann cell form?

Answer 29

Forms a sheath about 1mm long

Question 30

What do the small spaces between Schwann cells cause?

Answer 30

Gaps in the myelin sheath which are called nodes of Ranvier where the axon is exposed.

Question 31

What is the myelin sheath made up of?

Answer 31

Protein and fatty substances - rich in lipids

Question 32

What happens if the myelin sheath is broken down?

Answer 32

Impulses slow down and lead to diseases such as multiple sclerosis

Question 33

How do nerve impulses start?

Answer 33

Several types of receptors of mechanic stimuli

Question 34

What are some outside forces that effect sensory neurones?

Answer 34

Touch
Pressure
Stretching
Sound waves