Lung Structure/ Spirometery Flashcards
What brings about ventilation of the lungs?
- Pressure changes in thoracic cavity brings about ventilation.
List all the features in gross structure of human gas exchange system.
- Alveoli
- Bronchioles
- Bronchi
- Trachea
- Lungs
What happens to different parts of the lungs during the mechanism of breathing in?
- Ribcage moves up and out.
- External intercostal muscles contract/ internal intercostal muscles relax.
- Diaphragm contracts/ flattens.
- Volume of thoracic cavity increases.
- Pressure of thoracic cavity decreases.
- Air moves into lungs (down pressure gradient ie. from high to low pressure.)
What happens to different parts of the lungs during the mechanism of breathing out?
- Ribcage moves down and in.
- External intercostal muscles relax/ internal intercostal muscles contract.
- Diaphragm relaxes; returns back to its dome-shape.
- Volume of thoracic cavity decreases.
- Pressure of thoracic cavity increases.
- Air moves out of lungs (down pressure gradient ie. from high to low pressure.)
What are the two types of intercostal muscles? What are these muscles described as?
- External
- Internal
- Antagonistic muscles ie. one contracts, the other will relax.
Give the essential features of the alveoli.
- Single layer of epithelial cells.
- Oxygen will diffuse across this alveolar epithelium.
- Capilaries = single layer of cells.
- Good blood supply: maintains steep concentration gradient.
What is the alveolar epithelium?
- Alveolar epithelium is a surface (of the alveoli) over which gas exchange takes place.
What is tidal volume?
- Volume of air that moves into and out of lungs with each resting breath.
What is the vital capacity?
- Vital capacity is the largest volume of air that can be inhaled/ exhaled.
How is pulmonary ventilation rate calculated?
- Pulmonary ventilation rate = tidal volume (dm3) x no of breaths per minute.
How would you work out tidal volume from a spirometer trace?
- From peak to trough of one breath.
How would you find the vital capacity on spirometer trace?
- Highest value (peak/ trough) on trace.
How does a spirometer work?
- Inhaling takes O2 from chamber/ exhaling causes chamber to push up.
- Movements of chamber recorded by data logger; forming spirometer trace.
What happens if a person breathes into a spirometer for too long? What is done to solve this issue?
- The CO2 will build up in the spirometer to dangerous levels.
- Soda lime (within the chamber) will absorb the CO2 on exhalation.
What is the “pulmonary ventilation rate?” What are the units?
- Pulmonary ventilation rate is the total volume of air that is moved into the lungs during 1 minute.
- UNITS: dm³min⁻¹
What does trachea cartliage do?
- Holds trachea open/ prevents collapsing.
- Rings = incomplete so trachea can bend when food is swallowed.
Other than cartliage, what else is found in the trachea? Functions of these other components?
- Smooth muscle/ elastic fibres.
- Smooth muscle: will narrow/ constrict airways.
- Elastic fibres: recoil the smooth muscle (keeping the airway open.)
What do we find in bronchioles/ bronchi that we also find in the trachea?
- Smooth muscle.
- In bronchioles, you also have elastic fibres.
Given graph: x axis = number of cigarettes smokes. y axis = lung cancer deaths.
Overall, the GENERAL trend of points plotted = increase in no of smoked cigarettes = more lung cancer deaths.
Student made conclusion that “data shows more cigarettes smoked per day will increase no of deaths.” Do you agree?
Refer to Miss Estruch video on analysing data on lung disease: 10.26
- FOR: positive correlation between lung cancer deaths and cigarettes smoked.
- AGAINST: Data overlaps (ie same no of deaths from lung cancer at different no of cigarettes smoked.)
- AGAINST: Correlation doesn’t prove causation - other factors ie. genetics, pollution could be causing the deaths.
- No correlation coefficient stastic to know if correlation is significant.
Causation vs correlation?
- Correlation: shows two variables are linked somehow.
- Causation: experimental evidence has proved that one factor is causing another.
Exam Q
What are the lungs like for smokers?
- Airway constricted/ narrowed.
- Inflammation of airways.
- Excess mucus, in airway
