Chapter 11

Question 1

Gas Exchange System

Answer 1

The system in which gases diffuse into our blood and out of our blood through our alveoli. The lungs are a part of the gas exchange system.

Question 2

Lungs

Answer 2

Lungs are spongy organs in our thorax which inhales oxygen for respiration and exhales carbon dioxide for excretion. They are surrounded by the ribs and the sternum (breastbone).

Question 3

Thorax

Answer 3

The upper part of our torso which holds our lungs

Question 4

Diaphragm

Answer 4

A sheet of fibrous tissue and muscle that separates the thorax from the abdomen. Its movement up and down changes the volume of the lungs to move air when you breathe out and in.

Question 5

Intercostal Muscles

Answer 5

They are in-between the ribs and move the ribs during breathing, especially deep breathing.

Question 6

Larynx

Answer 6

The voice box

Question 7

Trachea

Answer 7

windpipe

Question 8

Bronchi

Answer 8

A connection between the two lungs which is also connected to the trachea

Question 9

Bronchioles

Answer 9

Branches of the lungs that spread from the bronchi

Question 10

Alveoli

Answer 10

Tiny air sacs in the lungs which are a part of the gas exchange system. They are connected to blood vessels
next to the lungs.

Question 11

Epiglottis

Answer 11

A flap which covers your larynx when you are eating to prevent food from entering your trachea.

Question 12

The way air enters blood

Answer 12

Nose -> larynx -> trachea -> bronchi -> bronchioles -> alveoli -> blood vessels

Question 13

Efficient oxygen absorption through the alveoli

Answer 13

Large surface area, surrounded by capillaries, thin walls, moist for oxygen diffusion, continuous ventilation of the lungs (maintains gas gradient)

Question 14

C-shaped cartilage

Answer 14

Rings around the trachea that prevent them from collapsing.

Question 15

What is the percentage of gas in inspired air?

Answer 15

21% oxygen
0.04% carbon dioxide
78% nitrogen
water vapour is variable

Question 16

What is the percentage of gas in expired air?

Answer 16

16% oxygen
4% carbon dioxide
78% nitrogen
water vapour is saturated

Question 17

Why is it okay that gas has to pass through two cells to reach the blood? What are the two cells?

Answer 17

Oxygen has to pass through the wall of the alveolus and the capillary wall in order to make it into the blood. It is okay as they have thin wall meaning it does not have to travel far.

Question 18

Why are the alveoli surrounded by elastic tissue?

Answer 18

It is so it can stretch when you breath and recoil when you breathe out to help remove air from the lungs.

Question 19

Why do we breath out air saturated with water vapour?

Answer 19

It is the water vapour evaporated from the moist walls of the alveoli

Question 20

Inwards breathe

Answer 20

When you breathe in, your ribs and chest cavity expand so the lungs can occupy as much air as possible; also decreasing the air pressure inside your lungs to force air to get into your lungs.

Question 21

Outwards breathe

Answer 21

When you breathe out, your ribs and chest cavity relax to decrease the volume of air in your lungs; also increasing the air pressure inside your lungs to force air out of your lungs.

Question 22

Inspiration

Answer 22

-The external intercostal muscle contracts while the internal intercostal muscle relaxes.
- The diaphragm contracts and flattens
Increases the volume inside the thorax, causing pressure in the thorax to decrease and since the atmospheric pressure is lower, air moves into the lungs

Question 23

Expiration

Answer 23

• The external intercostal muscles relaxes while the internal intercostal muscles contracts
• The diaphragm relaxes and goes up due to pressure of organs below the thorax.
  Decreases the volume inside the thorax, causing pressure in the thorax to increase and since the atmospheric pressure is higher, air moves out of the lungs

Question 24

Cleaning the air

Answer 24

Hairs in your nose filter the air removing some particles and pathogens. The trachea, bronchi and bronchioles are lined with ciliated epithelial cells and goblet cells which use mucus which removes pathogens and dust particles (upwards or downwards).

Question 25

Describe how you can test how exercise affects one’s breathing rate and depth of breathing

Answer 25

Just look in the book man.

Question 26

Why does exercise increase one’s breathing rate?

Answer 26

This is because your muscles need to respire in order to contract. This produces much carbon dioxide and means the muscles need more oxygen. Therefore, you breathe faster/harder.

Question 27

Vital Capacity

Answer 27

The most amount of air you can breathe out and in. For adults, should be around 3.5 litres.

Question 28

Tidal Volume

Answer 28

How much someone breathes in and out at rest. Around 0.45 litres.

Question 29

Residual Volume

Answer 29

Amount of air left in your lungs after breathing out. Around 1.5 litres.

Question 30

Most amount of air in your lungs

Answer 30

5 litres

Question 31

How do you control your breathing?

Answer 31

When you exercise harder, your body respires more. This creates more carbon dioxide which lowers one’s pH in the blood. Your brain detects this and increases the rate of breathing to help with respiration. Therefore more physical activity leads to an increase in the rate and depth of breathing.

Question 32

Homeostasis

Answer 32

An ideal constant condition.

Question 33

Chemical Equation for the acid produced due to increase in CO_2

Answer 33

CO_2 + H_2O —-> H_2CO_3

Question 34

Name and identify the lungs, diaphragm, ribs, intercostal muscles, larynx, trachea, bronchi, bronchioles, alveoli and associated capillaries

Answer 34

ok.

Question 35

How do you test for carbon dioxide to investigate the differences in composition between inspired and expired air?

Answer 35

using limewater

Question 36

Name and identify the internal and external intercostal muscles

Answer 36

ok.

Question 37

List the features of gas exchange surfaces in humans

Answer 37

large surface area, thin surface, good blood supply and good ventilation with air

Question 38

Investigate and describe the effects of physical activity on rate and depth of breathing