Topic B: Breathing

Question 1

What is breathing or Ventilation?

Answer 1

The movement of air in and out of the lungs.

Question 2

What is Gas Exchange?

Answer 2

This is the uptake of oxygen from the lungs into the blood and the movement of CO2 from blood to lungs. gas exchange takes place by diffusion.

Question 3

What is respiration?

Answer 3

The process in which energy is released from food molecules, which occurs in all living organism.

Question 4

Oxygen + Glucose =

Answer 4

Carbon Dioxide + Water (+ energy)

Question 5

Describe what happens during inhalation?

Answer 5

The external intercostal muscles contracts making the ribs move up and out. the diaphragm contracts and lowers. These changes cause the volume of the thorax to increase. This causes the air pressure inside the thorax to reduce. the air pressure inside the lung is lower than the pressure outside the body. this causes air to rush in to the lungs.

Question 6

Describe what happens during exhalation?

Answer 6

The external intercostal muscles relax, allowing the ribs to drop back down. The diaphragm relaxes and returns to its original position. this means it pushes up on the lungs. These changes cause the volume of the thorax to decrease. This causes the air pressure inside the thorax to increase. The air pressure inside the lungs is now higher than the pressure outside the body. This cases the air to escape the lung.

Question 7

How many alveoli are there in a human?

Answer 7

300 million

Question 8

What are adaptations of the alveoli that make it good for diffusion?

Answer 8

The alveoli surface is moist - gasses diffuse better in solution.
The alveoli are only one cell thick.
There is also 300 million to diffuse lots of gas.

Question 9

Oxygen is transported by?

Answer 9

Hemoglobin in red blood cells.

Question 10

What are the adaptations of the capillary’s that make them good at diffusion?

Answer 10

They are only one cell think, diffusion can happen quickly

There are lots of them spreading over a large area.

Question 11

What are the components of cigarette smoke?

Answer 11

• Nicotine, addictive component.
• Tar (approx 2000 different dangerous chemicals)
• Dust & ash (debris form burning cigarette)
• Carbon monoxide - deadly gas.

Question 12

Why do people smoke?

Answer 12

• peer pressure
• addiction
• relaxing

Question 13

Main smoking related diseases?

Answer 13

• Lung cancer
• Bronchitis ‘smokers cough’
• Emphysema
• Coronary heart disease.

Question 14

What is lung cancer?

Answer 14

Tar is cigarettes contains ‘carcinogenic’ chemicals which make cells divide abnormally.

Question 15

What is Bronchitis?

Answer 15

Dust particles prevent the normal work of cilia in the wind pipe.

Question 16

What is Emphysema?

Answer 16

Airways begin to lose there shape causing shortness of breath. This normally eventually leads to smokers cough.

Question 17

What is Coronary heart disease?

Answer 17

Carbon monoxide prevents oxygen from binding to hemoglobin in lungs - reduced oxygen in blood. Carbon dioxide causes fatty deposits (atheroma) in the blood, that leads to blood clots, poor oxygen supply to tissue.

Question 18

The effect of exercise on humans?

Answer 18

heart rate increases as more oxygen needs to be umped from the lungs to the rest of the body.

Question 19

Experiment to look at the effect of exercise on Breathing rate?

Answer 19

Sit still for five minutes and then count number of breaths taken in a minute. You can get other people to do this as well and compare results. This should be repeated three times. Then do some exercise such as running then repeat.

Question 20

Experiment to look at the effects of exercise on heart rates?

Answer 20

Same as breathing but count heart rate.

Question 21

Ways for efficient gas exchange?

Answer 21

• large area
• thin walls
• permeable