Respiratory System Flashcards
conditioning
warming of air by the body’s heat and moistened by water evaporating from the mucosal lining of the airways
once air reaches the trachea it is conditioned to 100% humidity and 37*C
mucociliary escalator
cilia beat in an upward motion continuously towards the pharynx which moves mucous up and out of the lungs to be expelled via coughing or swallowing
cystic fibrosis
inadequate ion secretion decreases fluid movement
lack of saline layer traps cilia in thick sticky mucous that cannot be cleared, allowing bacteria to colonize the airways
alveoli
primary function is to exchange gases between themselves and the blood
clustered at the ends of terminal bronchioles and make up the bulk of lung tissue
type I alveolar cells
larger, occupy 95% of alveolar surface area
very thin to allow gases to rapidly diffuse through them
type II alveolar cells
smaller and thicker
synthesize and secrete surfactant
prevent fluid buildup by reabsorbing Na+ and H2O
surfactant
mixes with the thin fluid lining of the alveoli to aid the lungs as they expand during breathing
decreases alveolar surface tension
Dalton’s law
total pressure of a mixture of gases is the sum of pressures of the individual gases
pressure exerted by an individual gas is determined only by its relative abundance in the mixture
tidal volume (VT)
volume of air that moves during a single inspiration or expiration
quiet breathing
inspiratory reserve volume (IRV)
additional volume of air that is inspired above the tidal volume
as much air taken in as possible, after the end of a quiet inspiration
expiratory reserve volume (ERV)
amount of air forcefully exhaled after the end of a normal expiration
as much additional air exhaled as possible, after the end of a quiet exhalation
residual volume (RV)
volume of air in the respiratory system after maximal exhalation
cannot be measured directly
inspiratory capacity
VT + IRV
vital capacity
IRV + ERV
total lung capacity
VT + IRV + ERV + RV
functional residual capacity
ERV + RV
eupnea
normal quiet breathing
hyperpnea
increased respiratory rate and/or volume in response to an increased metabolism
exercise
hyperventilation
increased respiratory rate and/or volume without an increased metabolism
emotional hyperventilation or blowing up a balloon
hypoventilation
decreased alveolar ventilation
shallow breathing, asthma, or restrictive lung disease
tachypnea
rapid breathing, usually an increased respiratory rate with decreased depth
panting
dyspnea
difficulty breathing or “air hunger”
asthma or hard exercise
apnea
cessation of breathing
voluntary breath holding or depression of CNS control centers
obstructive lung disease (diameter of airways)
air flow diminished due to increased air resistance
lower airway diseases - wheezing sound during forced exhalation
high RBC count and hematocrit
asthma, cystic fibrosis, obstructive sleep apnea
COPD
chronic obstructive pulmonary disease (COPD)
emphysema and chronic bronchitis
upper airways (diameter of airways)
affected by physical obstruction
mediated by mucus and other factors
bronchioles (diameter of airways)
affected by bronchoconstriction; mediated by parasympathetic neurons, histamine, and leukotrienes
affected by bronchodilation; mediated by CO2 and epinephrine
compliance
ability of the lung to stretch
change in volume that results from a given force or pressure exerted on the lung
amount of force that must be exerted in a body to deform it
high compliance
lung that stretches easily
low compliance
lung requires more force from inspiratory muscles to stretch it, increasing energy expenditure and affecting ventilation
inelastic scar tissues formed in fibrotic lung diseases
inadequate surfactant production
elastance
ability of the lung to resist being deformed
ability of a body to return to its original shape when a deforming force is removed
low elastance
destruction of elastin in a high compliance lung and cannot return to its original resting volume
restrictive lung disease
categorized by reduced compliance
TB, pulmonary fibrosis, asbestosis
pulmonary fibrosis
characterized by the development of stiff, fibrous scar tissue that restricts lung inflation
hypoxia
low levels of O2 in body tissues
hypoxic hypoxia
low arterial pressure of O2
caused by high altitude, alveolar ventilation, decreased lung diffusion capacity, abnormal ventilation-perfusion ratio
anemic hypoxia
decreased total amount of O2 bound to hemoglobin
caused by blood loss, anemia (low[Hb] or altered HbO2 binding), carbon monoxide poisoning
ischemic hypoxia
reduced blood flow
caused by heart-failure (whole-body hypoxia), shock (peripheral hypoxia), thrombosis (hypoxia in a single organ)
histotoxic hypoxia
failure of cells to use O2 because cells have been poisoned
caused by cyanide and other metabolic poisons
emphysema
destruction of alveoli - less surface area for gas exchange
fibrotic lung disease
thickened alveolar membrane slows gas exchange
loss of lung compliance decreases alveolar ventilation
