gas exchange and lungs

Question 1

what is the purpose of lungs?

Answer 1

to give oxygen from the surroundings to the bloodstream, where it can be transported to the rest of the body for cellular respiration

Question 2

what is the direction that oxygen takes to reach the alveoli?

Answer 2

mouth to trahea to bronchi to bronchioles to alveoli

Question 3

what is the site of gas exchange?

Answer 3

alveoli

Question 4

what are the adaptations of alveoli which increase the rate of gas exchange?

Answer 4

very large surface are, moist walls, steep concentration gradient, short diffusion pathway

Question 5

how does alveloi have a very large surface area?

Answer 5

adults have a huge number of alveoli which have a combined surface area which is huge

Question 6

how does alveoli having moist walls increase rate of gas exchange?

Answer 6

walls are moist, meaning gases can dissolve, which increases the rate of diffusion

Question 7

how do alveoli have a steep concentration gradient?

Answer 7

blood in capillaries is low oxygen (low conc) and high carbon dioxide (high conc). alveoli have fresh oxygen (high conc) and no carbon dioxide (low conc). gases diffuse from high conc to low conc, allowing oxygen to enter and carbon dioxide to leave at a fast rate

Question 8

how does the alveoli have a short diffusion pathway?

Answer 8

alveolus and capillaries are both one cell thick