B10 Nervous Control In Humans

Question 1

Stimuli

Answer 1

Changes in the environment

Question 2

Examples of sense organs

Answer 2

Ears, eyes, skin etc.

Question 3

The types of skin receptors

Answer 3

1) touch corpuscle
2) free nerve ending (pain)
3) pressure corpuscle
4) cold receptor
5) heat receptor

Question 4

Central nervous system

Answer 4

AKA the CNS. Formed by the brain and the spinal cord. It is for processing information

Question 5

The peripheral nervous system

Answer 5

AKA the PNS. Formed by many different kinds of nerves and extends throughout the body. It is for movement and senses.

Question 6

Sensory neurone

Answer 6

The cell that connects the receptor to the CNS

Question 7

Co-ordinator

Answer 7

What brings about a response (usually the brain) in a message

Question 8

Motor neurone

Answer 8

The cell that connects the CNS to the effector

Question 9

The effector

Answer 9

The organ, muscle or gland that starts a response

Question 10

Flow chart of how a response is produced

Answer 10

Receptor to sensory neurone to co-ordinator to motor neurone to effector

Question 11

Relay neurone

Answer 11

Connects the sensory neurone to the motor neurone. They look like a smaller version if the motor neurone. It bypasses the brain so the body can react faster*

A message is STILL sent to the brain so you register the sensation (e.g pain)

Question 12

Receptors and where they are found

Answer 12

Groups of specialized cells that detect stimuli and turn them into electrical impulses. They are often located in the sense organs. Each organ has receptors sensitive to particular kinds of stimulus

Question 13

Features of a motor neurone

Answer 13

Very long axons- allows it to transmit nerve impulses over long distances
Has many branches- so it can receive signals from all directions
Axon surrounded by fatty myelin sheath- acts as insulation, prevents electrical impulses from leaking out of the neuron

Question 14

Nerve fibres

Answer 14

Strands of cytoplasm. What dendrites and axons are made up of

Question 15

Difference between nerve and neurone

Answer 15

Nerve- compromised of a bundle of nerve fibres wrapped in connective tissue
Neurone- a specialised cell with a cell body, dendrites and axon

Question 16

Synapse

Answer 16

The gap where two neurones meet.

Question 17

Neurotransmitters

Answer 17

The chemicals that cross the synapse and pass the message on.

Question 18

Change in pupil size in dim, bright and normal lighting

Answer 18

Dim- large, to absorb more light
Bright- small, to minimize damage to eye
Normal- medium/ normal sized

Question 19

Iris

Answer 19

What controls the amount of light entering the eye

Question 20

Pupil

Answer 20

The space that allows light to enter

Question 21

Choroid layer

Answer 21

The black layer of the eye containing blood vessels that stops light being reflected around inside the eye. It absorbs light

Question 22

Scleroid layer

Answer 22

AKA the scelera. Tough, white and protective layer around the pupil.

Question 23

Fovea

Answer 23

The most sensitive part of the retina. Yellow in color

Question 24

Cornea

Answer 24

Lets light enter the eye. Transparent

Question 25

Suspensory ligament

Answer 25

What molds the lens in place

Question 26

Lens

Answer 26

A part of the eye that can change its shape to focus light onto the retina

Question 27

Optic nerve

Answer 27

What carries the nerve impulses away from the brain

Question 28

Vitreous humour

Answer 28

A transparent, jelly-like substance which supports the back of the eye

Question 29

Aqueous humour

Answer 29

A watery liquid at the front of the eye

Question 30

Ciliary muscle

Answer 30

Changes the thickness of the lens when focusing

Question 31

Retina

Answer 31

The inner, sensitive layey of the eye that continas light receptors

Question 32

Radial muscles

Answer 32

The “straight lines” around the pupil of the eye. They contract in dim light and relax in bright light

Question 33

Circular muscles

Answer 33

The “round” muscles that surround the pupil. They contract in bright light and relax in dim light

Question 34

Photoreceptors

Answer 34

Specialised cells that respond to light. They are the rods and the cones

Question 35

How do we see things?

Answer 35

1) Light rays bounce off an object
2) The light rays are bent (refracted) as they go through the cornea and lens
3) An upside down picture of image forms on the retina
4) The optic nerve carries a messahe to the brain. In the brain the pciture is turned up the right way.

Question 36

Accommodation

Answer 36

The special process that involves focusing light to achieve a sharp image

Question 37

How does the lens accommodate?

Answer 37

It makes the final adjustments by changing its shape so that light coming from far or hear objects can be focused