Gas Exchange (in humans)

Question 1

Describe the path which air enters the human body

Answer 1

Trachea (windpipe)
Two bronchi (one bronchus leading to each lung)
Bronchioles (smaller tubes)
Alveoli (air sacks)

Question 2

What is ventilation?

Answer 2

Breathing in and out (inspiration and expiration)

Question 3

Describe the process of inspiration

Answer 3

Intercostal and diaphragm muscles contract
Causes ribcage to move up and outwards Diaphragm to flattens
Lung pressure decreases below atmospheric pressure
Air flows into lungs

Question 4

Describe the process of normal expiration

Answer 4

Intercostal and diaphragm muscles relax 
Ribcage moves down and inwards
Diaphragm becomes curved again
Volume of thorax decreases and case air pressure to increase 
Air forced out of lungs

Question 5

Is inspiration active or passive?

Answer 5

Active

Question 6

Is normal expiration active or passive?

Answer 6

Passive

Question 7

Describe the process of forced expiration (e.g. Blowing out candle)

Answer 7

External intercostal muscles relax
Internal intercostal muscles contract
Movement of intercostal muscles is antagonistic (opposing)

Question 8

Where does gas exchange happen in the lungs?

Answer 8

Alveoli

Question 9

How are alveoli adapted for gas exchange?

Answer 9

Large surface area
One cell thick
Next to blood capillary

Question 10

What is tidal volume?

Answer 10

Volume of air in each breath

Question 11

What is ventilation rate?

Answer 11

Number of breaths per minute

Question 12

What is forced expiration volume?

Answer 12

The maximum volume of air that can be breathed out in 1 second

Question 13

What is forced vital capacity?

Answer 13

The maximum volume of air that is forcefully breathed out after a deep breath

Question 14

What is TB?

Answer 14

Tuberculosis bacteria

Question 15

How does TB form tubercles? (Small, hard lumps in lungs)

Answer 15

Immune system builds a wall around the tuberculosis bacteria
Infected tissue within tubercle dies and damages gas exchange surfaces

Question 16

What are the symptoms of TB?

Answer 16

Coughing blood and mucus, shortness of breath, chest pains, fatigue

Question 17

What is fibrosis?

Answer 17

The formation of scar tissue in the lungs

Question 18

What is residual volume?

Answer 18

The volume of air remaining in the lungs after expiration

Question 19

How does fibrosis prevent gas exchange?

Answer 19

Scar tissue is thicker and less elastic - lungs can’t expand as much

Question 20

What is asthma?

Answer 20

A respiratory condition where the airways become inflamed and irritated (result of allergy to pollen/dust)

Question 21

What happens during an asthma attack?

Answer 21

The muscle lining the bronchioles contract and lots of mucus produced- causes constriction of the airways

Question 22

What is emphysema?

Answer 22

Lung disease caused by smoking or long term exposure to air pollution

Question 23

Explain how emphysema causes shortness of breath

Answer 23

Particles become trapped in alveoli
Causes inflammation
Phagocytes attracted to area
Produce enzyme which breaks down elastin
Leads to destruction of alveoli walls