Chapter 3: Breathing & Gas Exchange

Question 1

If cells are to respire aerobically they need…

Answer 1

….a continuous supply of oxygen from the blood

Question 2

Also, was product of respiration is…

Answer 2

….carbon dioxide which needs to be removed from the body

Question 3

Respiration is…

Answer 3

…the oxidation reaction that releases the energy from foods

Question 4

The lungs are enclosed by the….

Answer 4

chest (or thorax) and the diaphragm

Question 5

The air passages of the lungs for a highly branching network known as…

Answer 5

…the bronchial tree

Question 6

Air comes in down the…

Answer 6

…windpipe or trachea (lined by cartilage to keep aways open)

Question 7

Air goes down…

Answer 7

bronchus/i…to smaller tubes called bronchioles…to microscopic air sacs called alveoli…where the gas exchange with the blood takes place

Question 8

The chest/thorax is separated from the lungs by two thin membranes called…

Answer 8

…the pleural membranes…which form an airtight seal (between the two membranes is pleural fluid so lungs dont stick to chest when we breathe)

Question 9

The trachea and larger airways are lined with…

Answer 9

…mucus which traps dirt of bacteria that are breathed in

Question 10

Ventilation is…

Answer 10

…action of moving air in and out of lungs

Question 11

What are the two actions that take place for air to enter into the lungs?

Answer 11

The external intercostal muscles on the ribs contract, pulling ribs up, as do the muscles of the diaphragm, pulling the diaphragm down…causing drop in pressure inside the chest/thorax compared to the air outside

Question 12

What are the two actions that take place for air to exit the lungs?

Answer 12

The internal intercostal muscles contract pulling ribs down and diaphragm muscles relax…plus as lungs are elastic they help and tend to empty like a balloon

Question 13

Gas exchange at the alveoli…

Answer 13

….absorbing oxygen into the blood and removing carbon dioxide from it …the distance between the blood & air is less than 1/1000th of a millimetre (blood has come from the body where it gives oxygen to the cells and gains carbon dioxide in return)

Question 14

What is the number of alveoli & surface area?

Answer 14

700m and 60m2

Question 15

Smoking related diseases include…

Answer 15

….lung cancer, bronchitis, emphysema & contributes to heart disease and ulcers…dont do it…it’s very bad for you…just say no!

Question 16

Smoking destroys…

Answer 16

…the cilia in the throat…which means the mucus is not swept away and clogs and irritates the airways and leaves bacteria in the mucus which causes infections

Question 17

Emphysema

Answer 17

damages walls of alveoli and causes enlarged irregular spaces…meaning reduced gas exchange. Kills about 20,000 people a year in UK

Question 18

Lung cancer

Answer 18

Cigarette contain addictive nicotine…along with 17+ chemicals (known as carcinogens) which cause cancer Cancer happens when cells start to mutate and divide uncontrollably…forming a tumor Kills around 120,000 people a year