CF effects- lqc 7a Flashcards
rate of diffusion =
surface area x difference in concentration / thickness of surface
rate of diffusion is directly proportional to
to surface area - as the surface area increases, the rate of diffusion increases
rate of diffusion is also directly proportional
to the difference in concentration - as the difference in concentration increases, the rate of diffusion increases
rate of diffusion is inversely proportional to
the thickness of the surface (diffusion distance) –
as the thickness increases, the rate of diffusion decreases
What is the role of mucus in the lungs and how is it removed from the lungs?
- Traps dust, debris and microorganisms
- Cilia in the epithelial cell lining of the respiratory system (trachea and bronchi) continually remove the mucus by a wave-like beating. Mucus is then coughed up and removed or swallowed. Stomach acid (hydrochloric acid) destroys the pathogens.
how does many alveoli allow for rapid gas exchange
Large surface area for gas exchange
how do alveoli walls being thin and one cell thick allow rapid gas exchange
Short diffusion distance
how are capillary walls being thin and one cell thick allow rapid gas exchange
Short diffusion distance
how is ventilation of alveoli allow rapid gas exchange
Maintains a steep concentration gradient
how does blood flow to capillaries allow rapid gas exchange
Maintains a steep concentration gradient
How does stickier mucus in people with CF impairs the functioning of the gas exchange system Reduced gas exchange
Thicker and sticker mucus cannot be moved by cilia , so mucus remains in the lungs and blocks the bronchioles , restricting airflow through these tubes which prevents the ventilation of the alveoli below the blockage. This reduces the number of alveoli involved in gas exchange, which reduces the surface area, leading to reduced gas exchange. It also reduces the concentration gradient for oxygen and carbon dioxide diffusion, which also reduces gas exchange. Blockages can also cause over-inflation of alveoli, which can cause damage to the elasticity of the lungs.
Why do people with CF get short of breath?
Reduction in gas exchange results in a lower oxygen supply to the cells and tissues. This means during exercise the muscle cells receive less oxygen.
Persistent lung infections
Cilia cannot move mucus, so mucus builds up in the lungs. Anaerobic bacteria which enter the lungs rapidly multiply in the mucus, due to the lack of oxygen in the mucus, causing a lung infection. White blood cells, which try to kill the bacteria, die and break down releasing DNA which makes the mucus even stickier. Repeated infections damage the lung tissue.
