Gas Exchange in Humans

Question 1

What is the pathways through the respiratory systems as we breathe?

Answer 1

nose & mouth
trachea
bronchi
bronchilles
alveoli

Question 2

What happens when we exhale?

Answer 2

intercostal muscles relax
rib cage moves down and in
diaphram relaxes & domes
volume of thorax decreases
pressure on thorax increases
air flow out

Question 3

What happens when we inhale?

Answer 3

intercostal muscles contract
rib cage moves up and out
diaphram contracts & flattens
volume of thorax increases
pressure on thorax decreases
air flow in

Question 4

Where does gas exchange happen in humans?

Answer 4

alveoli

Question 5

What happens when oxygen diffuses in alveoli?

Answer 5

high conc. in alveoli
low conc. in bloodstream

Question 6

What happens when carbon dioxide diffuses in alveoli?

Answer 6

low conc. in alveoli
high conc. in bloodstream

Question 7

What are the adaptions of alveoli?

Answer 7

• large surface area - gas exchange
• rich blood supply
• short diffusion distance - walls are 1 cell thick
• moist surfaces - gases can dissolve which aids diffusion

Question 8

What are the damages from the chemicals from smoking?

Answer 8

• inflammation of bronchi - bronchitis, damages walls of alveoli leading to emphysema
• carcinogenic - can cause cancer

Question 9

What are the damages from the nicotine from smoking?

Answer 9

• addictive
• withdrawal symptoms when stopped

Question 10

What are the damages from the tar from smoking?

Answer 10

damaged cilia, lining trachea - prevents ability to shift mucus

Question 11

What are the damages from the carbon dioxide from smoking?

Answer 11

binds to haemoglobin not oxygen so heart needs to pump faster for same volume of oxygen - causes coronary heart disease & stroke