topic 8 - gas exchange - humans

Question 1

whats included in the thorax?

Answer 1

ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli, pleural membranes

Question 2

role of the intercostal muscles in ventilation?

Answer 2

they contract and move the ribs upwards and outwards
which increases the size of the chest and decreases the air pressure inside it which sucks air into the lungs.

Question 3

role of the diaphragm in ventilation?

Answer 3

during inhalation, the diaphragm contracts and flattens and the chest cavity enlarges which creates a vacuum, pulling air into the lungs. during exhalation, the diaphragm relaxes and returns to its domelike shape, and air is forced out of the lungs.

Question 4

alveoli adaptations for gas exchange

Answer 4

• thin walls that are one cell thick - shorter diffusion distance
• large surface area
• permeable walls - allow gases to pass through
• Good blood supply - ensures oxygen rich blood is taken from the lungs and CO2 rich blood is taken to the lungs

Question 5

what is found in cigarettes?

Answer 5

carbon monoxide and nicotine

Question 6

role of cillia?

Answer 6

To sweep any debris and pathogens trapped in the mucus up the airways/trachea to be swallowed and destroyed in the stomach or to be coughed/sneezed out

Question 7

impacts of smoking

Answer 7

• the cilia could be damaged and wont waft as normal, which leads to a build up of mucus that cant be moved out of the airways.
• the alveoli could be damaged and wont be as elastic. The thin walls would also lead to less efficient gas exchange.
• could cause diseases e.g. Coronary heart disease (CHD) which is when blood vessels that supply blood and oxygen to the heart become narrow.