Exchange Of Gases In The Lungs Flashcards
What must be maintained in order to ensure a constant supply of oxygen?
A diffusion gradient at the alveolar surface.
What 3 features of gas exchange surfaces make them efficient for gas exchange?
They are thin;
Partially permeable;
Large surface area.
What is needed to maintain a diffusion gradient?
Movement between both the environmental medium and the internal medium.
How thick are the capillary walls?
One cell thick.
What can be found inside the alveoli?
An air space
What is breathing a form of?
Mass transport.
What is each alveolus lined with?
Epithelial cells.
What is around each alveolus?
A network of pulmonary capillaries. This are very narrow.
Why is it beneficial that red blood cells can only just fit into the pulmonary capillaries?
It slows them down which allows more time for diffusion.
Why is the distance between the alveolar air and red blood cells short?
The red blood cells are flattened against the capillary.
Why is the overall diffusion distance short?
The alveoli and capillary walls have very thin walls.
What type of surface area do the alveoli and pulmonary capillaries have?
A very large total surface area.
What constantly ventilates the lungs?
Breathing movements.
What constantly circulates the blood around the alveoli?
The heart
What maintains the steep concentration gradient?
The constant ventilation and circulation.
