Past%20Exam%20Question

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Past Exam Question
Remember this was an A4 sheet! So your answer
should be approx half!
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Ventilation - Inspiration
Lung volume increases
External intercostals contract Internal
intercostals relax
Ribs pulled up and out
Diaphragm flattens
Atmospheric pressure greater Lung pressure less
INSPIRATION air forced into lungs
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Ventilation - Expiration
Lung volume decreases
Internal intercostals contract External
intercostals relax
Ribs move down and in
Diaphragm relaxes into dome
Lung pressure greater Atmospheric pressure less
EXPIRATION air forced out of lungs
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Label the Lungs
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Tuberculosis
Bacteria inhaled by person not immune to it
Bacteria start to reproduce in upper lung where
plenty of oxygen
Immune system responds, phagocytes arrive and
ingest bacteria
Usually in young children
In healthy, more resistant people
Primary Infection
Lymph nodes that drain area of lungs become
inflammed and enlarged
Few symptoms and the infection is controlled, but
some bacteria remain
Many years later bacteria re-emerge in a second
infection
Post-Primary Infection (may not happen)
More difficult to control. Lung tissue damaged,
scar tissue forms
Lung tissue and blood coughed up,without
treatment can fatally spread throughout body
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Lung Structure
Structure Features
Trachea Supported by c-shaped rings of cartilage Lined with cilliated epithelial cells to sweep mucus up to throat Goblet cells produce mucus to trap dirt microbes
Bronchi Larger branches supported by cartilage, less in smaller Lined with cilliated epithelial cells to sweep mucus up to throat Goblet cells produce mucus to trap dirt microbes
Bronchioles Walls are made of muscle and epithelial cells Muscle allows them to constrict to control air flow to alveoli
Alveoli Tiny air sacs (100-300µm in diameter) Lined with epithelial cells Membrane is gas exchange surface Contain collagen and elastic fibres (stretch and spring back)
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TB Exam Question
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(b) After 4 minutes of exercise, the breathing
rate was 20 breaths per minute. Explain how you
could use this information and the graph to
calculate tidal volume. (c) When a person
starts to breathe out, the percentage of oxygen
in the air first exhaled is the same as the
percentage of oxygen in the atmospheric air.
Explain why.
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Answers

1. Immediate/rapid increase, steady rise and plateau
   clearly identified Ignore references to rest
   period if clearly identified as such 1
2. Find value of pulmonary ventilation from graph /
   26-28 Divide by breathing rate/20 2
3. Air is from nose/trachea/bronchi/not been in
   alveoli/dead space Gas exchange/diffusion only
   in alveoli / not in these structures 2