Gas exchange

Question 1

What are alveoli?

Answer 1

tiny air sac at the end of the bronchioles where gas exchange occurs

Question 2

How are the alveoli adapted for gas exchange?

Answer 2

short diffusion distance -> thin walls
large surface area -> folded walls
high concentration gradient -> capillaries

Question 3

What are bronchioles?

Answer 3

airways branching from each bronchi in each lung

Question 4

bronchi

Answer 4

airways branching from the trachea that lead into the lungs

Question 5

capillaries

Answer 5

thin narrow blood vessels where the exchange of substances between the blood and tissues

Question 6

diaphragm

Answer 6

muscle that contracts and relaxes to change volume of thorax

Question 7

intercostal muscles

Answer 7

muscles between rib that contract and relax to move the ribcage and change the volume and pressure during inhalation and exhalation

Question 8

pleural membranes

Answer 8

airtight membranes covering the lungs and the thorax to maintain pressure changes and stop the lungs from sticking to the ribcage

Question 9

trachea

Answer 9

windpipe connecting the lungs to the mouth and the nose.

Question 10

What shape is the cartilage in the trachea

Answer 10

C-shaped

Question 11

What is ventilation?

Answer 11

process of moving air in and out of lungs

Question 12

What happens in inhalation?

Answer 12

diaphragm contracts, moves down and flattens
intercostal muscles contract
rib cage moves up and out
volume increases
air pressure decreases so is less than atmospheric pressure which causes air to move into the lungs

Question 13

What happens in exhalation?

Answer 13

diaphragm relaxes, moves up and domes
intercostal muscles relax
rib cage moves down and in
volume decreases
air pressure increases so is more than atmospheric pressure so air is moved out

Question 14

Describe gas exchange in the alveoli

Answer 14

oxygen diffuses into the red blood cells where is bonds with haemoglobin
carbon dioxide diffuses into the alveolus by the blood where it is dissolved in plasma

Question 15

Investigating the effects of exercise on breathing

Answer 15

the investigation compares the content of exhaled air and inhaled air.
you could use limewater : colourless -> milky white
OR hydrogen carbonate :
red -> yellow
1. count number of breaths for minute
2. count number of breaths during or after exercise for minute

Question 15

Why does breathing rate increase during exercise?

Answer 15

carbon dioxide in blood can be excreted faster
oxygen can be supplied to contracting muscles faster
oxidise lactic acid in liver

Question 16

What is the effect of nicotine on the body?

Answer 16

Nicotine is highly addictive and affects the synpase (gap between 2 neurons) -> makes smoker feel more alert and active

Question 17

Explain how cigarettes may lead to Bronchitis

Answer 17

The heat from the cigarettes kills cilia cells, this causes an increase in mucus production but the excess mucus cannot be removed so builds up. This increases the risk of infections and Bronchitis.

Question 18

Explain how carbon monoxide may harm the body

Answer 18

Tobacco smoke contains carbon monoxide which can irreversibly bond with haemoglobin to form carboxyhaemoglobin. This reduces the amount of oxygen that can be transported by blood

Question 19

Explain how smoking can cause emphysema

Answer 19

Smoke can reach the alveoli and damage them. The alveoli walls break don and fuse together forming larger irregular air spaces. This decreases the surface area for gas exchange so less oxygen can be diffused into blood.

Question 20

Explain how smoking can cause cancer

Answer 20

carcinogens found in cigarettes cause DNA mutations which causes a tumour to grow