6.4: The Respiratory System

21/10/2013 § Leave a comment

I hope everyone will forgive me for not writing a general summary about the reading this time, it’s been a busy – wait, I’m not going to apologise to the Internet, hahahAHAHAHA.

What am I doing with my life.


Page 140, concentration gradients

1. Explain why the oxygen concentration in the alveoli is not as high as in fresh air that is inhaled. The oxygen concentration in the alveoli is not high because the oxygen is used immediately for cellular respiration, which is constant, therefore oxygen is constantly depleted, while in fresh air, it can remain. 


a) Calculate the difference in oxygen concentration between air in the alveolus and blood arriving at the alveolus. = 65 mm Hg

b) Deduce the process caused by this concentration difference. It is…. DIFFUSION???


  • i. Calculate the difference in carbon dioxide concentration between air inhaled and air exhaled. = 24 mm Hg
  • ii. Explain this difference. More carbon dioxide is exhaled because of cellular respiration. In humans, cellular respiration is powered by oxygen, which provides ATP, to produce carbon dioxide. Hence, when humans exhale, they exhale more carbon dioxide than they inhale carbon dioxide.

d) Despite the high concentration of nitrogen in air in alveoli, little or none diffuses from the air to the blood. Suggest reasons for this. Nitrogen cannot diffuse through the epithelial layers of the alveoli – it’s too big.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

What’s this?

You are currently reading 6.4: The Respiratory System at i am so.


%d bloggers like this: