Gaseous Exchange In Humans

Question 1

Where is the gaseous exchange system located in the body ?

Answer 1

Thorax

Question 2

Describe the path of the air in the thorax

Answer 2

• trachea
• bronchi
• Bronchioles
• alveoli

Question 3

What is the function of the ribs ?

Answer 3

Protect organs in the thorax

Question 4

What is the function of the pleural membrane ?

Answer 4

This prevents the lungs from sticking to the thorax wall as they inflate and deflate

Question 5

What are the functions of the intercostal muscles ?

Answer 5

They help connect with bones, and are important in moving at into and out of the lungs

Question 6

What is the function of the diaphragm ?

Answer 6

Helping move air into and out of the lungs

Question 7

What is ventilation ?

Answer 7

The process of moving into and out of the lungs

Question 8

Describe inhalation

Answer 8

• intercostals muscles contract, moving rip cage up and out
• diaphragm contracts, moving down and flattening
• this causes the volume of the thorax to increase and the air pressure in the thorax to fall
• pressure in the thorax is now less than atmospheric pressure, causing air to move into the lungs

Question 9

Describe the process of exhalation

Answer 9

• intercostal muscles relax, moving rib cage down and in
• rib cage relaxes , moving up and doming
• this causes the volume of the thorax to decreases and air pressure in the thorax to rise
• Air pressure in the thorax is now more than atmospheric pressure, causing air to move out of the lungs

Question 10

What gas defuses into the blood during gaseous exchange in the alveoli ?

Answer 10

Oxygen defuses into the blood from a high concentration of oxygen in the alveoli from a low concentration in the blood, it then binds to haemoglobin for transport

Question 11

What gas defuses into the alveoli in gaseous exchange in the alveoli ?

Answer 11

Carbon dioxide defuses into the alveoli from a high concentration of carbon dioxide in the blood into a low concentration in the alveoli

Question 12

Percentage of oxygen inhaled and exhaled ?

Answer 12

Inhaled - 21%

Exhaled - 17%

Question 13

Percentage of carbon dioxide inhaled and exhaled

Answer 13

Inhaled - 0.04%

Exhaled - 4%

Question 14

Percentage of nitrogen inhaled and exhaled

Answer 14

Inhaled - 78%

Exhaled - 78%

Question 15

What are the three adaptions of the alveoli ?

Answer 15

• large surface area
• lots of capillaries
• thin walls

Question 16

What does large surface area of the alveoli help ?

Answer 16

Increases the rate of diffusion

Question 17

What does large network of capillaries help in the alveoli ?

Answer 17

This maintains a high concentration gradient and so speed up diffusion

Question 18

What do thin walls in the alveoli help ?

Answer 18

The walls of the alveoli are only one cell thick and so are the capillaries. This means gases only need to move a very small distance, speeding up diffusion

Question 19

How do we measure breathing rate ?

Answer 19

We simply count the number of breaths a person takes each minute

Question 20

How do you scientist measure the volume of air inhaled and exhaled?

Answer 20

Using a spirometer

Question 21

How many chemicals does cigarette smoke contain ?

Answer 21

4000

Question 22

What is the nicotine and what does it cause ?

Answer 22

It is a highly addictive drug in tobacco smoke, and can increase the chance of blood clots

Question 23

What is a carcinogen?

Answer 23

Some thing that can cause cancer

Question 24

How many carcinogens are there in tobacco smoke ?

Answer 24

17

Question 25

Where can you find tar in cigarettes ?

Answer 25

In tobacco smoke

Question 26

Where do you find carbon monoxide and a cigarette and what does this do ?

Answer 26

You can find it in tobacco smoke and this irreversibly binds to the haemoglobin, forming Carboxyhaemoglobin, and so reduces the amount of oxygen transported by the blood

Question 27

What do you chemicals in tobacco smoke destroy and what does this do ?

Answer 27

Cilia, reducing there number.
At the same time mucus production will increase-this is in response to the smoke. The mucus cannot be moved out of the airways quickly and so builds up-this causes smokers cough and increases the risk of infection

Question 28

What is bronchiolitis ?

Answer 28

A disease resulting from the buildup of infected mucus in the bronchi and bronchioles

Question 29

What happens to the alveoli when smoke reaches them ?

Answer 29

The alveoli walls breakdown, in places and fuse together, forming the larger irregular airspaces. This decreases The suface area for gas exchange, so less oxygen defuses into the blood

Question 30

What diesease is caused by the destruction of alveoli ? And how many people does it kill ?

Answer 30

Emphysema and it kills around 20,000 people in Britain every year