B1e

Question 1

How does alcohol damage your liver?

Answer 1

• alcohol is poisonous
• it is broken down by enzymes in the liver and some of the products are toxic.
• if you drink too much alcohol over a long period of time these toxic products can cause the death of liver cells, forming scar tissue that stops blood from reaching the liver.
• this means the liver can’t do its job of cleaning the blood
• therefore dangerous substances will build up and damage the rest of the body.

Question 2

What does being drunk cause?

Answer 2

• dehydration (which can damage other body cells including the brain)
• impaired judgement
• poor balance
• poor coordination
• slurred speech
• blurred vision
• sleepiness

Question 3

What does smoking cause?

Answer 3

• heart disease due to carbon monoxide
• lung, throat, mouth and oesophageal cancer as tar from the smoke collects in the lungs. It’s full of toxic chemicals, some of which are carcinogens
• smoker’s cough and a severe loss lung function.
• low birth weight babies as the low oxygen in the blood of a pregnant woman can deprive the foetus of oxygen, leading to a small baby at birth,

Question 4

What are the parts of the eye?

Answer 4

-cornea
-iris
-retina
-pupil
ciliary muscles
-suspensory ligaments
-optic nerve

Question 5

What does the iris do?

Answer 5

-controls how much light enters the pupil

Question 6

What does the lens do?

Answer 6

-refracts light, focuses it onto the retina

Question 7

What does the cornea do?

Answer 7

-refracts light into the eye

Question 8

What does the retina do?

Answer 8

-light sensitive part at the ‘back’ of the eye that is covered in rods and cones, which detect light

Question 9

What do cones do?

Answer 9

-sensitive to colours but not to good in dim light.

Question 10

What do rods do?

Answer 10

-sensitive in dim light but can’t see colours

Question 11

What does the optic nerve do?

Answer 11

-carries impulses from the receptors to the brain

Question 12

What happens when we look at near objects?

Answer 12

• the ciliary muscle contracts, which slackens the suspensory ligaments.
• the lens becomes more rounded, so light is refracted more.

Question 13

What happens when we look at distant object?

Answer 13

• the ciliary muscle relaxes, which allows the suspensory ligaments to pull tight.
• this pulls the lens into a less rounded shape, so light is refracted less.

Question 14

What is long-sighted vision and how is is corrected?

Answer 14

• unable to focus on near objects
• the lens is the wrong shape and doesn’t bend the light enough or the eyeball is too short
• the images of near objects are brought into focus behind the retina.
• convex lens

Question 15

What is near-sighted vision and how is it corrected?

Answer 15

• unable to focus of distant objects
• the lens is the wrong shape and bends the light too much or the eyeball is too long.
• the images of distant objects are brought into focus in front of the retina.
• concave lens or corneal laser surgery

Question 16

What is binocular vision and how does it work?

Answer 16

• two eyes which work together
• when we look at an object, our brain compares the images seen by each eye.
• the more similarities between the images, the further away the object.
• allowing us to judge distances well, but gives us a narrow field of vision

Question 17

What are carcinogens?

Answer 17

• chemicals that cause cancer
• they make mutations in the DNA more likely.
• if this happens, cell division can go out of control and malignant tumours can form.

Question 18

How is smoker’s cough caused?

Answer 18

• smoking damages the cilia on the epithelial tissue lining the trachea, bronchi and bronchioles
• this encourages mucus to be produced
• but excess mucus can’t be cleared because the cilia are damages
• so it sticks to the air passages causing smokers cough.