2.1 - The Effects of CF on the Lungs Flashcards
What tube is responsible for allowing air to be drawn into the lungs?
The Trachea
What are the bronchi?
The trachea divides into two bronchi, carrying air to and from each lung
What are the narrow tubes that make up most of the lung network called?
Bronchioles
What is the site of gaseous exchange?
The Alveoli
What produces mucus?
Goblet cells in the walls of the airways
What is the function of mucus?
To trap any dust, debris or microorganisms in the airways.
How is mucus removed?
By the wave-like beating of cilia
Where are cilia found?
They cover the epithelial cells, which line the tubes of the gas exchange system
What is different about CF mucus?
It contains less water than usual, meaning it is sticky
What is wrong with having sticky mucus?
It makes it very difficult for it to be removed by the cilia.
What are the two major health problems caused by having sticky mucus?
- Increases chances of lung infection
- Makes gas exchange less efficient
What holds the epithelial lining cells in position in the airways?
Basement membrane
Where are epithelial cells found?
They line cavities and tubes and cover the surface of organs.
What is the tissue called that is made up of epithelial cells?
Epithelium
What is the basement membrane made of?
Protein fibres in a carbohydrate matrix
What is the membrane surface of an epithelial cell called that touches the basement membrane?
The Basal membrane
What is the membrane surface of an epithelial cell called that faces away from the basement layer?
The apical membrane
What is the epithelium called in the walls of alveoli and capillaries?
Squamous (or pavement) epithelium
In which direction does the apical membrane face in capillaries?
Towards the lumen
What are epithelial cells called in the small intestine?
They extend further out from the basement membrane and are columnar epithelium
What is the surface of columnar epithelium in the small intestine like?
It has microvilli to increase surface area
What kind of epithelium lines the trachea, bronchi and bronchioles?
Pseudostratified ciliated epithelial cells
Why does there appear to be more than one layer of epithelium in the airways?
Some of the cells have nuclei in different locations
How do we remove pathogens from the body?
Cilia move pathogens within the mucus to the back of the throat, where they are either coughed out or swallowed and killed by stomach acid
Why are there lots of bacteria in CF lungs?
Mucus builds up into several layers and contains little oxygen as it diffuses slowly through mucus and the surrounding epithelial cells use more oxygen. Bacteria thrive in anaerobic conditions
Why do white blood cells also cause problems for CF victims?
The white blood cells fight infections but also break down and release DNA, making mucus stickier.
What properties make the alveoli suitable gas exchange surfaces?
- Large surface area
- Rich blood supply
- Thin walls means short diffusion pathway
What is Fick’s Law?
Rate of Diffusion is proportional to (S.A x Concentration gradient / diffusion pathway)
How does sticky mucus effect gas exchange?
It blocks narrow airways and prevents movement of air into the alveoli beyond the blockage.
Why does blocking branches of alveoli reduce exchange?
It reduces the number of alveoli providing a surface for exchange
Why can blockages be problematic other than reducing exchange surface?
They often allow air to flow through but not back out, causing over-inflation of lungs.
Why is over-inflation a problem?
It damages lung elestacity
Why do CF people find physical activity difficult?
Their exchange system cannot deliver enough oxygen to the muscle cells
Why is oxygen needed for exercise?
It is used in the chemical process of aerobic respiration which releases the energy used to initiate contraction.
