11: Gas Exchange in humans

Question 1

Describe the features of gas exchange surfaces in humans

Answer 1

• Large surface area
• Thin surface
• Good blood supply
• Good ventilation with air

Question 2

What is the function of cartilage in the trachea?

Answer 2

It keeps the trachea open when air passes through it

Question 3

What is the role of the ribs, the internal and external intercostal muscles and the diaphragm in producing volume and pressure changes in the thorax?

Answer 3

It all leads to the ventilation of the lungs –> muscle contracts because the pressure changes INSIDE the thorax that force air IN and OUT of the lungs

Question 4

What’s the difference between inspired and expired air? (know a few differences)

Answer 4

Inspiration -> rib cage is drawn up and out, volume of lungs increases WHILE pressure in lungs decreases, airflow is DRAWN INTO THE LUNGS

Expiration -> rib cage falls downwards & inwards, volume of lungs decreases WHILE pressure in lungs increases, airflow is FORCED OUT OF THE LUNGS (into an environment of lower pressure)

Question 5

How does physical activity affect the rate and depth of our breathing?

Answer 5

MORE PHYSICAL ACTIVITY = INCREASES DEPTH & NUMBER OF BREATHS PER UNIT TIME

• muscles need to contract more -> require ENERGY
• ENERGY is got from aerobic respiration
• depth and rate of of breathing INCREASES -> muscles are working harder

Question 6

Explain the link between physical actovoty and the rate and depth of breathing

Answer 6

there is increased carbon dioxide concentration IN THE BLOOD which is detected by the brain which leads to an increased rate and a greater depth of breathing

Question 7

Explain the role of goblet cells in protecting the breathing system from pathogens and particles

Answer 7

Secrete (produce mucus)

• much smaller
• prevent lungs from infection

Question 8

Explain the role of mucus in protecting the breathing system from pathogens and particles

Answer 8

Sticky substance coating the lining of the respiratory tract -> TRAPS dust and pathogens

Question 9

Explain the role of ciliated cells in protecting the breathing system from pathogens and particles

Answer 9

beating of cilia MOVES mucus & trapped substances up respiratory tract and into the oesophagus, stomach acid destroys most pathogens