Exchange of Gases in the Lungs Flashcards
Where is the site of gas exchange in mammals?
The epithelium of the alveoli
What must happen to ensure a constant supply of oxygen to the body?
A diffusion gradient must be maintained at the alveolar surface
Why are the alveoli located inside the body?
They are small and thin, therefore easy to damage
What does the ability to ventilate the air in the lungs mean for mammals?
They can maintain a diffusion gradient by constantly moving the external medium over their gas exchange surface
What is each alveoli lined with?
Epithelial cells
What surrounds each alveoli?
A network of pulmonary capillaries
How narrow are pulmonary capillaries?
So narrow that red blood cells are flattened against the thin capillary walls in order to fit through
How thick are pulmonary capillaries?
One cell thick
What does the thickness of pulmonary capilarries allow for?
Short diffusion pathways therefore, rapid diffusion
What happens to red blood cells as they squeeze through pulmonary capillaries?
They are slowed down, allowing for more diffusion time
What happens to diffusion rate as a result of red blood cells being flatten against capillary walls?
The distance between alveolar air and red blood cells is reduced therefore diffusion is increased
What happens as a result of alveoli and capillaries being thin?
Diffusion distances are short so diffusion is rapid
How is a concentration gradient maintained in the lungs
Blood flow and ventilation
When does correlation occur?
When a change in one of two variables is reflected by a change in another variable
What does correlation not imply?
Causation
