The document discusses gas exchange and the mammalian lung structure. It describes how the rate of diffusion is dependent on factors like surface area to volume ratio and concentration gradients, as calculated by Fick's Law. The mammalian lung is highly adapted for rapid gas exchange, containing over 480 million alveoli that provide a large surface area of 40-75 square meters. The lung anatomy includes features like the nasal cavity, trachea, bronchi, bronchioles and alveoli that facilitate efficient oxygen intake and carbon dioxide removal while also regulating water loss on land.

1. Chapter 2A

2.  Understand how the rate of diffusion is dependent on
surface area : volume ratio, thickness of the exchange
surfaces and difference in concentration, and can be
calculated using Fick’s law of diffusion.
 Understand how the structure of the mammalian lung
is adapted for rapid gas exchange.

3.  There is a continual conflict between the need for
oxygen and the need for water for organisms which live
on land.
 The conditions that favour the diffusion of oxygen into
an organism also favour the diffusion of water out of
that organism.

7.  Nasal cavity
 Mouth
 Epiglottis
 Larynx
 Trachea
 Incomplete cartilage rings
 Bronchi
 Bronchioles
 Alveoli
 Ribs
 Intercostal muscles
 Pleural membranes
 Pleural cavity
 Diaphragm

11.  Number of alveoli: 480-500 million alveoli
 Surface area: 40-75 𝑚2