Section 3: Gas Exchange in Humans

Question 1

What happens in respiration?

Answer 1

Food is oxidised such as glucose to get energy

Question 2

What do cells need to respire aerobically?

Answer 2

A continuous supply of oxygen

Question 3

What is ventilation?

Answer 3

The movement of air in and out of the lungs

Question 4

What is a more general term for ventilation?

Answer 4

Breathing

Question 5

How has the trachea adapted to keep its airway clean?

Answer 5

They have a thin layer of cells, which release mucus and they have cilias

Question 6

What is the purpose of mucus?

Answer 6

To collect dirt particles and bacteria

Question 7

What do cilias do?

Answer 7

They beat backwards and forwards to sweep the mucus towards the mouth and not the lungs

Question 8

How does smoking impact the cilias?

Answer 8

It kills them which stops this protection mechanism from fully working

Question 9

How is ventilation able to work?

Answer 9

By the change in air pressure. Air goes to places of low concentration.

Question 10

When we breathe, what happens to our thorax?

Answer 10

The thorax changes the volume of it. This alters the pressure in it which causes air to go in or out of the lungs.

Question 11

What happens when we breathe in?

Answer 11

Our ribs are moved by intercostal muscles. This outer intercostals contract, pulling the rib up. Also, the diaphragm contract, making it a flatter shape. This increases the volume of air and drops the pressure inside the thorax. Air then enters the lungs.

Question 12

What happens when we breathe out?

Answer 12

Our external intercostal muscles relax, while the internal intercostals contract which pulls the rib down and in. The diaphragm relaxes which means it goes to its regular dome shape. The volume of the thorax decreases so the pressure is raised. Pressure forces the air to go out.

Question 13

What do our lungs absorb into our blood and what does it remove from it?

Answer 13

It absorbs oxygen and removes carbon dioxide

Question 14

How is the alveoli adapted to do its job efficiently?

Answer 14

They have a structure which makes the blood close to the air, they have a very large surface area and their walls are one cell thick

Question 15

What is the concentration level of oxygen in the alveolus?

Answer 15

It is very high; it diffuses into the blood

Question 16

What is the concentration level of carbon dioxide in blood?

Answer 16

It is very high; it diffuses into the lungs

Question 17

How does smoking upset the air passages?

Answer 17

They disrupt air passages being free and having a large surface area

Question 18

How does smoking impact pregnant woman?

Answer 18

She will deprive her unborn fetus of oxygen. This stunts growth and development, which makes the baby lighter and smaller.

Question 19

How are cilias destroyed when people smoke?

Answer 19

The chemicals in cigarette smoke destroys them

Question 20

How do smokers develop smokers cough?

Answer 20

As their cilias are destroyed, the mucus is not being swept away to the mouth. This clogs up the lungs and forces them to cough.

Question 21

How does smoking impact the rate of mucus being secreted from the lungs?

Answer 21

The smoke irritates the lining of cells in the thorax

Question 22

How does smoking damage the wall of the alveoli?

Answer 22

The smoke damages the walls of alveoli, which breaks down and fuse together, forming enlarged, irregular air spaces

Question 23

How does smoking make the alveoli inefficient for gas exchange?

Answer 23

When the damaged walls of the alveoli break down and fuse together, this greatly reduces the surface area for gas exchange

Question 24

How does emphysema impact the volume of oxygen being pumped per red blood cell?

Answer 24

The blood of a person with emphysema carries less oxygen

Question 25

Why is lung cancer so deadly?

Answer 25

As when the cells start to mutate and start to divide uncontrollably, they create a tumour. Tumours in the lungs cause no pain, so they are not discovered until it is too late.

Question 26

How does smoking impact your chances of getting lung cancer?

Answer 26

Smoking does not guarantee you that you will get lung cancer, but will increase your chances

Question 27

What is a harmful chemical in cigarette smoke?

Answer 27

Carbon monoxide

Question 28

How does carbon monoxide impact our ability to transport oxygen around our body?

Answer 28

When it is breathed in, it enters our bloodstream and interferes with the ability of blood to carry oxygen

Question 29

How does carbon monoxide interfere with haemoglobin?

Answer 29

Haemoglobin bonds with carbon monoxide to form carboxyhaemoglobin. This compound is tighter than oxyhaemoglobin. This means that carboxyhaemoglobin is being carried in the bloodstream rather than oxyhaemoglobin.

Question 30

Why have most smokers not quit smoking?

Answer 30

As nicotine is a very addictive drug that always causes withdrawal symptoms.

Question 31

What are some various ways smokers can use to stop smoking?

Answer 31

• Use nicotine patches or gum
• Use of drugs that reduce withdrawal symptoms
• Acupuncture
• Hypnotism