Nerves And Sensitivity

Question 1

What are the three things that a coordinated response requires ?

Answer 1

A stimulus , a receptor and an effector

Question 2

What is a stimulus?

Answer 2

Change in the animals surrounding

Question 3

What is a receptor?

Answer 3

The organ which detects the change

Question 4

What is an effector ?

Answer 4

Muscles that move

Question 5

What happens when receptors detect a stimulus ?

Answer 5

Receptor changes its energy into nerve impulses

Question 6

What are the two types of nervous system ?

Answer 6

• Central nervous system

* peripheral nervous system

Question 7

What is the central nervous system made up of ? And what does it do ?

Answer 7

Brain and spinal cord

And coordinates all the nervous responses like moving or reflexes

Question 8

What is the peripheral nervous system made up of?

And what does it do ?

Answer 8

Nerves and it sends impulses to all the effectors

Question 9

What are nerve cells ?

And give examples of some ?

Answer 9

neurones,

And skin and muscles are examples of them

Question 10

What are the three types of neurone ?

Answer 10

• sensory neurone
• relay neurone
• Motor neurone

Question 11

What neurone do impulses from receptors pass along ?

Answer 11

Sensory neurone

Question 12

What neurone do you impulses from the CNS pass along ?

Answer 12

Relay neurone

Question 13

What neurone do impulses to effectors pass along ?

Answer 13

Motor neurone

Question 14

Why is your response to a stimulus quicker by sight then touch ?

Answer 14

• Optic nerve to the brain/CNS is closer than the fingers to the brain
• not as many synapses to pass across
• synapses slow impulses down as neurotransmitters need to diffuse across the synapse

Question 15

What is a dendrite ?

Answer 15

Tree like projections which connect to different neurons

Question 16

What is the cell body of a neurone ?

Answer 16

The main section of the cell, containing the nucleus

Question 17

What is the axon ?

Answer 17

The long section in which the signal is sent

Question 18

What is the myelin sheath ?

Answer 18

The insulating layer

Question 19

What are reflexes ?

Answer 19

Are automated actions which do not involve the brain. They are very fast actions which involve the three neurones

Question 20

What is the movement of the impulse from receptor to effector called ?

Answer 20

Reflex arc

Question 21

Order of the reflex arc

Answer 21

• The receptors detect stimulus change and send an impulse along a sensory neurone
• The sensory neuron passes the impulse across the spinal cord to a relay neurone , the gap between neurones are called a synapse. The relay neurone then passes the impulse to a motor neuron
• The motor neuron causes the factor to contract and move the body put away from the stimulus

Question 22

Order of the synapse

Answer 22

• and impulse travels along the sensory neurone until it reaches a synapse
• The impulse triggers the release of chemical transmitters called neurotransmitters, which diffuse across the synapse
• The neurotransmitters are complimentary to receptors on the other neurone and bind to the surface
• A new impulse travels along the relay neurone

Question 23

What sort of organ is the eye ?

Answer 23

A sensory organ

Question 24

What does the brain do to the impulse that is sent from the eye ?

Answer 24

Convert that information into an image which is what we “see”

Question 25

What is the cornea

Answer 25

Are curved transparent disk at the front of the eye. Does most of the focusing.

Question 26

What is the pupil ?

Answer 26

A circular opening who size is controlled by the iris

Question 27

What is the iris ?

Answer 27

Ring of muscle with a hole in the middle called the pupil . The iris controls how much light enters the eye

Question 28

What is the lens ?

Answer 28

This is soft, flexible and transparent. Its shape can be changed to find tune the focusing of light on the retina

Question 29

What is the ciliary muscles ?

Answer 29

Ring of muscle at the edge of the eye which circles the lines. When it contracts the lens gets fatter. When it relaxes the lens gets thinner

Question 30

What is the suspensory ligament ?

Answer 30

Strong fibres which attach the lens to the ciliary muscle

Question 31

What is the retina?

Answer 31

Contains light sensitive cells called rods and cones

Question 32

What is the optic nerve?

Answer 32

Consisting of many neurones which carry impulses from the retina to the brain

Question 33

What is the fovea ?

Answer 33

The region of the retina with the greatest number of cones

Question 34

What is conjunctiva ?

Answer 34

Mucous membrane that covers the eye to prevent infection

Question 35

What happens to your eye in dim light ?

Answer 35

Pupil dialation • radial muscles contract • circular muscles relax

Question 36

What happens to your eye in bright light ?

Answer 36

Pupil contraction • radial muscles relax • circular muscles contract

Question 37

What is the anagram to help remember what happens to your eye in different lights ?

Answer 37

Pupil contraction , circular , contract

Question 38

What is the name given to describe the ability of the eye to focus on near and far objects ?

Answer 38

Accommodation

Question 39

What happens to the eye when a object is far away ?

Answer 39

* Ciliary muscles relax * this makes the suspensory ligaments tight * making the lens long and thin * meaning less convex * refracting less light

Question 40

What happens to the eye when object is close ?

Answer 40

* ciliary muscles contract * making the suspensory ligaments relax * making the lens short and fat * and more convex * refracting more light

Question 41

What is the anagram to remember what happens to the eye when objects are close and far away ?

Answer 41

Close, ciliary contract, more convex

Question 42

What happens in short-sighted people ?

Answer 42

* light focuses short of the retina * it is corrected by using a diverging lens * short-sighted people can't see objects far away

Question 43

What happens in long-sighted people ?

Answer 43

* light focuses long of the retina * it is corrected using a converging lens * long-sighted people cannot focus on close objects very well

Question 44

What is a blind spot ?

Answer 44

What your optic nerve is and there are no rights or cones on the optic nerve, so you cannot see anything there .