Flashcards in Week 6-7: Lungs Deck (68)
3 pathologies of pneumonia
2) droplet transmission
3) hematogenous spread
What colour is gram positive?
What colour is gram negative?
What sort of shape is a coccobacilli?
Rods and spheres and rod/spheres
Ex: haemophilus influenzae
What do diplococci look like?
cocci in pairs
Ex: moraxella catarrhalis
Most common pathogens in community-acquired pneumonia?
the amount you normally breathe in and out (500 mL)
Inspiratory reserve volume
The amount you can breathe in if you tried really hard (1900 mL additional)
Expiratory reserve volume
The amount you can breathe out if you try really hard (700 mL additional)
the amount left in your lungs that will never be breathed out. 1200 mL
the total amount you can forcibly breathe in (TV + IRV)
Functional Residual Capacity
Residual Volume + Expiratory reserve volume (the amount left in your lungs if you are just breathing normally)
Inspiratory reserve volume + Tidal Volume + Expiratory Reserve Volume
Total Lung Capacity
All lung volumes combined (including residual capacity)
ventilation exceeds the metabolic demands of the body
ventilation is insufficient to meet the demands of the body
the amount of air inhaled or exhales from the lungs per minute.
Product of Tidal Volume x Resp Rate
The amount of air reaching the alveolus per minute. This is air that takes part in gas exchange.
Dead Space Ventilation
The volume of air inhaled that does not take part in gas exchange because it remains in the conducting airways or it reaches alveoli that are not perfused or poorly perfused.
Anatomic Dead Space
Total volume of the conducting airways from the mouth/nose down to the level of the terminal bronchioles.
~150 mL on average in humans
Alveolar Dead Space
Volume of air in the alveoli that does not participate in gas exchange (ventilation without perfusion)
Physiologic Dead Space
Sum of anatomic and alveolar dead space
Name the factors that affect diffusive transport of gas from alveolar air to pulmonary capillary blood and discuss how these relate to the diffusing capacity of the lungs
1. Membrane thickness
2. Membrane surface area
3. Pressure difference across the membrane
4. Diffusion coefficient of gas
Partial pressures of O2 and CO2 in alveoli
PAO2 = 105 mmHg (compared to 159 in atmospheric air)
PACO2 = 40 mmHg (compared to 0.3 in atmospheric air)
Partial pressures of O2 and CO2 in mixed venous blood
PO2 in venous blood = 40 mmHg
PCO2 in venous blood = 45 mmHg
Partial pressures of O2 and CO2 in arterial blood
PaO2 = 100 mmHg
PaCO2 = 40 mmHg
Pneumonia is a generic term that refers to inflammation of the pulmonary parenchyma. It is often associated with consolidation (solidification) of the lung. Usually infectious etiology.
Predisposing factors for pneumonia
1. suppression of cough reflex (anaesthesia, neuromuscular disorders)
2. Impaired immunity
3. Impaired mucociliary apparatus (smoking, syndrome)
4. Impaired alveolar macrophage function (alcohol, smoking)
5. Pulmonary edema (cardiac failure)
6. General debility (alcoholism, post-op, malnourishment)
Restricted to lobe; Most common CAP; majority are strep pneum