lecture 9 - lung function and disease Flashcards
what do the conducting airways do
carry air to lungs where gas exchange of O2 and CO2 occurs
what does the right side of the heart pump
deoxygenated blood
what is pulmonary circulation
Deoxygenated blood from veins -> lungs
what does pulmonary circulation allow
gas exchange
Reoxygenated blood -> left side of heart -> body
why is circulation important
Simple diffusion of O2 and CO2 is sufficient for metabolism in single cell organisms.
Small multicellular organisms circumvent this with thin walls and tubular structures.
what is the primary purpose of respiratory system
gas exchange - submission of O2 and removal of CO2 from tissues
regulation of acid-base status by con trolling co2
what are the disadvantages of respiratory system
easy access for micropathogens, dust
warm moist environment in lungs
how is o2 carried
by being bound to Hb
how many o2s bind to hb
4
is o2 soluble or insoluble in water
insoluble
what does blood o2 content depend on
PO2
why is the o2 dissociation curve steep
due to the cooperative nature of O2 binding, facilitating the delivery of O2 to the tissues as the PO2 falls.
what is o2 delivery facilitated by?
increased PCO2, temperature and low acid
how do things facilitate o2 delivery
reduces the affinity of Hb to O2 -> shifting the curve to the right
what does water and CO2 form
weak carbonic acid
what does carbonic acid dissociate to
HCO3- and H+
what speads up the reaction between H20 and CO2
carbonic anhydrase
what happens to HCO3- and H+
HCO3- enters plasma
H+ - buffered by Hb
why is Hb and O2 a bad buffer
H+ increases and inhibits the reaction
leads to creation of HCO3- from CO2
what is asthmas symptoms
wheezing and difficulty breathing due to airway narrowing
what is asthma caused by
inflammation and bronchoconstriction
due to the release of mediators from inflammatory cells
what is COPD caused by
chronic airway inflammation with obstruction of airflow due to excessive mucus production
aveoli destruction
what kind of infection is pneumonia
bacterial or viral infection
what causes pneumonia
alveoli fill in one or more lobes with pus or fluid
preventing gas exchange
what is lung fibrosis due to
scarring of the lungs
lungs becoming stiffer and smaller
inhaled irritants e.g. asbestos
what is asthma
a complex heterogenous disease
