Pathophysiology of the lungs Flashcards
know the basics of the lung
conducting zone
from the nose to the terminal bronchioles.
Does ventilation
NO GAS EXCHANGE!!
Respiratory zone
alveoli and respiratory bronchioles
SITE OF GAS EXCHANGE!!!
function of the conducting zone
is controlled by sympathetic and parasympathetic nervous system.
- Parasympathetic (muscarinic receptors)- constrict bronchi which leads to increased resistance of airflow.
- Sympathetic (B2 receptors)- relaxes bronchi which leads to decreased resistance to airflow.
Type 1 pneumocytes
structural, gas exchange
Type 2 pneumocytes
secretes surfactant (prevents the alveoli from callapsing)
pleura
a sac of mesothelium surrounding each Lung.
Allows for frictionless expansion of the lungs.
Major driving force in ventilation.
Costodiaphragmatic recess/ costophrenic angle
space located at the base of the lung.
Common site for plural effusion to settle.
tidal volume
volume of air with normal breathing.
residual volume
volume of gas remaining in the lungs after maximal expiration.
Helps in keeping alveoli open.
forced vital capacity (FVC)
volume that can be expired following maximal inspiration
Forced Expiratory volume (FEV1)
maximal volume of air that can be forcefully exhaled within one second following maximal inspiration.
normal FEV1/FVC ratio
.8 or 80%
dead space
volume of the airways and lungs that does not participate in gas exchange
functional dead space
volume of air within the alveoli that does not participate in gas exchange.
air is in the alveoli but there is no perfusion. (ventilation without perfusion).
hypercapnia vs hypocapnia
hypercapnia-leads to respiratory acidosis
Hypocapnia- leads to respiratory alkalosis
negative intra-pleural pressure
keeps alveoli open and helps to draw air into the alveoli
what is the driving force in ventilation
diaphragm is the most important muscle for respiration.
Accessory muscles.
ventilation vs perfusion
Base- V < Q. V/Q ratio is going to be low.
Apex- V>Q, so V/Q ratio is going to be high.
VQ mismatch
some diseases alter ventilation or perfusion.
Dead space- no perfusion, but great ventilation.V/Q= infinity.
Shunt- no ventilation, but perfusion is great. V/Q=0
what causes crackles
pneumonia
fibrosis
CHF
pulmonary edema
What causes wheezing
obstructed airway and HF. Asthma Pulmonary edema bronchitis CHF Foreign body tumor
What causes stridor
upper airway obstruction.
partial obstruction of the larynx or trachea
What causes pleural rub
inflammation of the pleura.
pneumonia
pulmonary infarction
increase negative intra-thoracic pressure
happens what the diaphragm contracts.
