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Elderly woman that has a viral infection of the lungs and pneumonia…
Elderly woman that has a viral infection of the lungs and pneumonia
Upstream Causes
Age
as we age, lungs (among other body parts) become weaker
alveoli can lose their shape and become baggy
decreases in measures of lung function, ex- vital capacity
weakening of the respiratory muscles (external intercostals)
Location
higher altitudes
impaired O2 delivery
hypobaric hypoxia
need more breaths to get same amount of O2 as you would at lower altitudes
higher exposure air pollution (vehicle admissions)
viral infection
more susceptible to infection w/ age due to weakened immune system
caused pneumonia; alveoli (which perform gas exchange) are filled w/ puss//fluid, which makes breathing painful and limits O2 intake
Down stream effects
(already listed effects of the factors identified in upstream causes)
fast and shallow breathing
body senses low O2 levels at high altitude (this becomes the main drive to breathe)
vasoconstriction: body trying to send more O2 from blood directly to lungs
wheezing/fluid in the lungs
pneumonia
if left untreated, can result in respiratory failure
Physiology
Alveolar level
sites of actual gas exchange
exchange O2 and CO2 to and from the blood stream
Type 1 alveolar cells: compromise the major gas exchange surface
Type 2 alveolar cells: secrete surfactant and antimicrobial proteins
alveolar macrophages: keep alveolar cells sterile
concepts of partial pressure and how elevation effects partial pressure
Partial pressure: pressure exerted by each gas in mixture; Is directly proportional to its percentage in mixture ; **see Dalton's Law
Oxygen makes up 20.9% of air, so PO2 = 0.209 760 mm Hg 159 mm Hg
At high altitudes, partial pressures declines, but at lower altitudes (under water), partial pressures increase significantly
effects of inflammation on the respiratory system
pneumonitis/pneumonia
occurs when irritating substance causes the alveoli in lungs to become inflamed/filled with fluid
makes it difficult for oxygen to pass through the alveoli into the bloodstream.; poor gas exchange/trouble breathing
pleurisy: inflammation of plurae that often results from pneumonia
inflamed pleurae become rough, resulting in friction and stabbing pain with each breath
Pleurae may produce excessive amounts of fluid to help reduce friction; may exert pressure on lungs, hindering breathing
**if any structure in the respiratory system becomes inflammed, breathing can be impaired slightly or more severely depending on structure
Anatomy
lungs (cells --> organs)
Bronchi
left/right main (primary) bronchi
lobar (secondary) bronchi
segmental (teritary) bronchi
Respiratory membrane (blood air barrier of capillary and alveolar walls)
alveolar walls= simple squamous epithelium
type 1 alveolar cells
type 2 alveolar cells: surfactant
lungs mostly consist of alveoli, but the rest is STROMA (elastic connective tissue)
Plurae
visceral plura: membrane on external lung surface
pleural fluid: fills slitlike pleural cavity between two pleurae
; Provides lubrication and surface tension that helps lungs expand and recoil
parietal plura: membrane on thoracic wall, superior face of diaphragm, around heart, and between lungs
alveoli: main sites of gas exchange
Gas Laws (diffusion of gases across membranes)
Dalton’s law of partial pressures: states that the total pressure exerted by mixture of gases is equal to sum of partial pressures exerted by each gas
Henry’s law: states that when a gas is in contact with a liquid, the gas will dissolve in the liquid in proportion to its partial pressur:
Grahams Law: When gases are dissolved in liquids, the relative rate of diffusion of a given gas is proportional to its solubility in the liquid and inversely proportional to the square root of its molecular mass
Fick's Law: The net diffusion rate of a gas across a fluid membrane is proportional to the difference in partial pressure, proportional to the area of the membrane and inversely proportional to the thickness of the membrane.