Gas Exchange In Mammals

Question 1

Outline the path in which air moves from outside to inside the body.

Answer 1

Mouth
Trachea
Bronchi
Bronchioles
Alveoli

Question 2

What is the gas exchange organ in mammals?

Answer 2

The lungs

Question 3

Why are there lots of alveoli in the lungs?

Answer 3

To provide a large surface area for diffusion.

Question 4

What works together to move air in and out of the lungs?

Answer 4

Ribcage, intercostal muscles and diaphragm.

Question 5

What do the goblet cells do to help exchange gases efficiently?

Answer 5

Hey secrete mucus which traps microorganism and dust particles and stops them entering the alveoli.

Question 6

How does cilia help exchange gases efficiently?

Answer 6

They beat the mucus upwards and away from the alveoli towards the throat. This prevents lung infection.

Question 7

Where are the goblet cells and cilia found?

Answer 7

Lining the airways.

Question 8

How do elastic fibres contribute to effective gas exchange?

Answer 8

Elastic fibres in the trachea, bronchi, bronchioles and alveoli help the process of breathing out by elastic recoil.

Question 9

How does smooth muscle help with effective gas exchange?

Answer 9

The muscles in the trachea, bronchi and bronchioles relax which makes the tubes wider which lets air move in and out easily.

Question 10

How does cartilage help with effective gas exchange?

Answer 10

C-shaped rings in the trachea and bronchi provide support and stop them collapsing.

Question 11

Why are the cartilage rings C-shaped?

Answer 11

To allow room for the oesophagus so we can swallow.

Question 12

What is ventilation?

Answer 12

It consists of inspiration (breathing in) and expiration (breathing out).

Question 13

What muscles contract during inspiration?

Answer 13

The external intercostal muscles and diaphragm contract.

Question 14

What happens to the ribcage during inspiration?

Answer 14

It moves upwards and outwards.

Question 15

What happens to the diaphragm during inspiration?

Answer 15

Contracts and flattens so it moves down.

Question 16

What is increased and decreased in the thorax during inspiration?
What does this cause?

Answer 16

Volume inside the thorax increases.
Pressure inside the thorax decreases.
This causes air to enter into the lungs.

Question 17

Inspiration is an active process. What does this mean?

Answer 17

It requires energy to happen.

Question 18

What muscles relax during expiration?

Answer 18

External intercostal muscles and diaphragm relax

Question 19

What happens to the ribcage during expiration?

Answer 19

Moves down and inwards.

Question 20

What happens to the diaphragm during expiration?

Answer 20

Relaxes and moves up. Becomes curved again.

Question 21

What increases and what decreases during expiration?

What does this cause?

Answer 21

Volume decreases inside the thorax.
Pressure increases inside the thorax.
Air is forced out of the lungs.

Question 22

Normal expiration is passive. What does this mean?

Answer 22

It doesn’t require energy to happen.

Question 23

What happens during forced expiration?

Answer 23

The internal intercostal muscles contract which pulls the ribcage down and in. This decreases the volume and increases the pressure in the thorax, forcing air out.

Question 24

What is a spirometer?

Answer 24

A machine that can be used to investigate breathing.

Question 25

How does a spirometer work (step by step)?

Answer 25

1) Person breathes through a tube connected to the oxygen chamber
2) As person breathes in and out, the lid of the chamber moves up and down
3) Soda lime in the tube absorbs carbon dioxide when the person breathes out.
4) Movements are recorded by a pen attached to the lid and a rotating drum
5) A spirometer trace is made

Question 26

What is tidal volume?

Answer 26

The volume of air that moves into and out of the lungs with each resting breath.

Question 27

What is vital capacity?

Answer 27

The volume of air that can be breathed in when the strongest possible exhalation is followed by the deepest possible inhalation.

Question 28

What is inspiratory reserve volume?

Answer 28

The maximum volume of air you can breathe in over and above a normal inhalation.

Question 29

What is expiratory reserve volume?

Answer 29

The extra amount of air you can force out of your lungs over and above the normal tidal volume of air you breathe out.

Question 30

What is residual volume?

Answer 30

The volume of air that is left in your lungs when you have exhaled as hard as possible.

Question 31

What is total lung capacity?

Answer 31

He sum of the vital capacity and the residual volume.

Question 32

What is breathing rate?

Answer 32

How many breaths are taken per unit time.

Usually per minute

Question 33

What is oxygen uptake?

Answer 33

The rate at which a person uses up oxygen.

Question 34

What is lung surfactant?

Answer 34

A soapy substance made from phospholipids that is secreted by epithelial cells in alveoli.

Question 35

Why is lung surfactant important?

Answer 35

Without it, the watery lining of the alveoli would create s surface tension which causes the alveoli to collapse.

Question 36

What three ways can be used to measure breathing rates?

Answer 36

A peak flow meter
Vitalographs
Spirometer