Gas Exchange In The alveoli

Question 1

What is sufactant in the alveoli?

Answer 1

Sufactant is a liquid in the alveoli that prevents collapse of alveoli during exhilation

Question 2

What is simple squamous epithelium?

Answer 2

• simple squamous epithelium is found in the alveoli
• they have thin walls - for short diffusion pathway
• if part of a blood vessel, it is known as epithelium cells
• the wall of the capillary around the alveoli is only 1 cell thick

Question 3

Adaptations in the alveoli which are sufficient for gaseous exchange

Answer 3

• lumen of capillaries are very small - RBC’s pass through in single file, slowing down long enough for diffusion of gases to take place
• alveoli epithelium is 1-cell thick - has a short diffusion pathway - faster rate of diffusion of oxygen into the blood
• capillary endothelium is one-cell thick - gives short diffusion distance
• good blood supply in capillaries - maintains a steep conc. Gradient
• large surface area - highly folded
• elastic fibres + recoil - flexbility

Question 4

Describe ventilation in the alveoli

Answer 4

• ventilation in the alveoli creates a steep concentration gradient for CO2 and O2 - air is replenished
• low conc. of CO2 in alveoli
• high conc. of oxygen in alveoli
• high conc. of CO2 diffuses out of the alveolar epithelium cells

Question 5

Describe the effect of the break down of elastic fibres of the alveoli

Answer 5

• elastic fibres break down, alveolus epithelial breaks down, decreasing surface area
• also decreases ventilation, lungs won’t be able to inflate or deflate properly
• wont maintain a steep conc. gradient (will be less steep)
• won’t be able to remove CO2
• causes pH to decrease in the blood