Nervous system and homeostasis

Question 1

What is the nervous system made up of

Answer 1

Central nervous system which compromises of the brain and the spinal cord

Question 2

Give the pathway of a nervous response

Answer 2

Stimulus
Receptor
Coordinator
Effector
Response

Question 3

What is the function of the nervous system

Answer 3

It enables organisms to react to their surroundings and coordinates behaviour

Question 4

Why are reflex actions important

Answer 4

For survival and to prevent damage to the body

Question 5

Why are reflex actions described as rapid and automatic

Answer 5

They do not involve the conscious part of the brain

Question 6

What do neurones do

Answer 6

Carry electrical impulses around the body

Question 7

Adaptions of a nerve cell

Answer 7

Branched endings (dendrites) make connection to other neurones

Myelin sheath insulates the axon increasing speed of electrical impulses

Question 8

What is a synapse

Answer 8

Gap between two neurones allowing impulses to cross

Question 9

Explain what happens at a synapse

Answer 9

Impulse arrives in neurone

Sacs containing chemicals

Chemicals are releases into the gap between neurones (synapse)

Chemicals attach to the receptor site of the next neurone and set up a new electrical impulse

Question 10

Give the function of a cerebral cortex

Answer 10

Outer layer of the brain playing an important role in consciousness

Question 11

Give the function of the medulla oblongata

Answer 11

Part of three brain above the spinal cord that controls breathing and heart rate

Question 12

Give the function of the cerebellum

Answer 12

Part at the back of the brain involved in coordinating muscle activity

Question 13

Why is it difficult to treat brain disorders

Answer 13

Brain is very complex and delicate

Question 14

Why is treatment for brain damage and diseases difficult

Answer 14

It is not fully understood what each area of the brain does

Drugs do not always reach the brain through its membranes

Surgery can easily cause unintended damage

Question 15

Function of the iris

Answer 15

Coloured part of the eye containing muscles that relax and contract changing the size of the pupil and allowing more or less light in

Question 16

Function of ciliary muscle

Answer 16

Contracts and relaxes to change the shape of the lens

Question 17

Function of the retina

Answer 17

Layer of receptors at the back of the eye containing light sensitive cells

Question 18

Function of the sclera

Answer 18

White layer that is tough to protect the eye

Question 19

Function of optic nerve

Answer 19

Nerve that connects eye to the brain

Question 20

Function of suspensory ligament

Answer 20

Tightens and slackens to change shape of the lens

Question 21

Function of lens

Answer 21

Sits behind the pupil and focuses light on the retina

Question 22

Function of cornea

Answer 22

Transparent and curved, letting light in and changing its direction so that light is focused on the retina

Question 23

What is accommodation

Answer 23

The process of changing the shape of the lens to focus on near or distant objects

Question 24

How to focus on a near object

Answer 24

Ciliary muscles contract

Suspensory ligaments are slack

So lens is thicker and more curved and refracts light rays more strongly

Question 25

How to focus on a distant object

Answer 25

Ciliary muscles relax Suspensory ligaments are pulled tight So lens is thinner and flatter and only refracts light rays slightly

Question 26

What is myopia and what lenses correct it

Answer 26

Short sightedness Concave lenses

Question 27

Why is hyperopia and what lenses correct it

Answer 27

Long sightedness Convex lenses

Question 28

What is homeostasis

Answer 28

Maintenance of a constant internal environment

Question 29

Give three interval conditions controlled in homeostasis

Answer 29

Body temperature Blood glucose concentration Water levels

Question 30

Give three things all control systems include

Answer 30

Receptors Coordination centres Effectors

Question 31

How can eye defects be treated

Answer 31

Spectacle lenses Contact lenses Laser surgery Replacement lenses in the eye

Question 32

Where is body temperature monitored and controlled

Answer 32

Thermoregulatory centre in the brain

Question 33

What happen if body temperature is too high

Answer 33

Blood vessels dilate (vasodilation) and sweat is produced

Question 34

What happens if body temperature is too low

Answer 34

Blood vessels constrict (vasoconstriction), sweating stops, and shivering takes place

Question 35

Explain the reaction time experiment

Answer 35

Hold ruler between thumb and index finger lined up with 0cm Drop from the same height each time Drop without warning and record measurement where the ruler was caught Repeat and calculate mean

Question 36

How can you introduce a variable into the reaction time experiment

Answer 36

Sugary drink Caffeine Distractions

Question 37

What is an independent variable

Answer 37

What you change

Question 38

What is a dependant variable

Answer 38

What you measure

Question 39

What is a control variable

Answer 39

What is kept constant