Exam 2 Respiratory Flashcards
zone that contains nose, nasopharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles, and functions in bringing air into or out of the lungs as well as warming and humidifying it
conducting zone
zone lined with alveoli where gas exchange occurs; contains respiratory bronchioles, alveolar ducts and sacs
respiratory zone
synthesize surfactant
Type II pneumocytes
phagocytic cells that keep alveoli free of dust and debris
alveolar macrophages
pulmonary blood flow is mainly regulated by (blank) which is determined mainly by O2 (hypoxic vasoconstriction)
arteriolar resistance
volume inspired or expired with each normal breath (normal quiet breathing)
tidal volume (~500 ml)
volume that can be inspired over and above the tidal volume, used during exercise
inspiratory reserve volume (~1200 ml)
volume that can be expired after the expiration of the tidal volume
expiratory reserve volume (~1200 ml)
volume that remains in the lungs after maximal expiration, cannot be directly measured
residual volume (~1200 ml)
Tidal Volume + Inspiratory Reserve Volume
Inspiratory Capacity (~3500 ml)
Expiratory Reserve Volume + Residual Volume
Functional Residual Capacity (~2400 ml)
Tidal Volume + Inspiratory Reserve Volume + Expiratory Reserve Volume
Vital Capacity (~4700 ml)
volume of air that can be forcible expired after a maximal inhalation
Forced Vital Capacity
sum of all lung volumes
Total Lung Capacity (~5900 ml)
air which does not take part in gas exchange in conducting airways
anatomic dead space
volume of lungs which does not participate in gas exchange, may be greater in diseased lungs
physiologic dead space
total rate of air moved in and out of the lungs
minute ventilation
rate of air moved in and out of lungs corrected for physiologic dead space
alveolar ventilation
volume of air that can be expired in 1 second after a maximal inspiration, normally 80% of FVC
FEV1 (forced expiratory volume 1)
condition in which both FEV1 and FVC are reduced; ratio >80%
restrictive lung disease (fibrosis)
condition i which FEV1 is reduced more than FVC so that FEV1/FVC ratio is decreased to <80%
obstructive lung disease (asthma, COPD, emphysema)
distensibility of the lungs (change in lung volume for a given change in pressure), inversely related to elastance
compliance
when the pressure outside of the lungs is negative the lungs [expand or collapse] and the volume [increases or decreases]
expand, increases
at high expanding pressure, compliance is [high or low]
low
pressure in intrapleural space is [positive or negative] relative to the atmospheric pressure
negative
disease with increased lung compliance
Seeks a new higher FRC, Barrel-shaped chest
Emphysema
disease with decreased lung compliance, seeks a new lower FRC
fibrosis
Law of Laplace
pressure tending to collapse an alveolus is directly proportional to the surface tension of liquid molecules and inversely proportional to alveolar radius
reduces surface tension in the lungs, thereby reducing collapsing pressure and increasing lung compliance
surfactant
most important constituent of surfactant, amphipathic, breaks up attracting forces between liquid molecules lining the alveoli
DPPC
neonatal respiratory distress syndrome
lacking surfactant
increased pressure causes collapse of small alveoli during expiration
lung compliance is decreased
hypoxemia develops
sites of highest airway resistance
medium sized bronchi
parasympathetic stimulation affect on airway resistance
constriction - decrease radius, increase airway resistance (muscarinic receptors)
sympathetic stimulation affect on airway resistance
relaxation- increase radius, decrease airway resistance
(B2 receptors)
methemoglobin
Heme moieties in the ferric, or Fe3+, state (rather than the normal Fe2+ state)
Does not bind O2
can be acquired or congenital
hemoglobin S
abnormal hemoglobin variant that causes sickle cell, have lower affinity for oxygen, can occlude small blood vessels
The maximum amount of O2 that can be bound to hemoglobin per volume of blood, assuming that hemoglobin is 100% saturated
O2 binding capacity
The actual amount of O2 per volume of blood
O2 content
O₂ content = (O₂-binding capacity x % saturation) + dissolved O₂
forms of CO2 in blood
dissolved CO2
carbaminohemoglobin
HCO3 (most CO2)
an adaptive mechanism, reducing pulmonary blood flow to poorly ventilated areas where the blood flow would be “wasted
hypoxic vasoconstriction
The major factor regulating pulmonary blood flow is the
partial pressure of O2
Thromboxane A2,
vaso/veno constrictor
Prostacyclin (prostaglandin I2)
vasodilator
Leukotrienes
airway constrictor
cardiac output that bypasses alveoli; small amount of coronary blood flow that goes from left ventricle to veins without perfusing lungs; bronchial flow
physiologic shunts
Pulmonary stenosis
RVH
Overriding aorta (over the VSD connecting to both left and right ventricle)
Ventricular Septal Defect
tetralogy of fallot
defect between the ventricles that cause hypoxemia (blue babies)
right to left shunt
Single artery arising from both ventricles giving rise to aortic and pulmonary vessels
Truncus arteriosus
Congenital heart defect that enables blood flow between the left and right atria via the interatrial septum, will not notice until child becomes active
atrial septal defect
do not cause hypoxemia but cause late cyanosis (blue kids)
left to right shunts
Congenital heart defect that enables blood flow between the left and right atria via the interatrial septum
patent ductus arteriosus
responsible for inspiration, generates breathing rhythm, innervated by CNX and CNIX, innervates diaphragm and phrenic nerve
dorsal respiratory group
responsible for expiration, active during exercise but not normal breathing
ventral respiratory group
located in lower pons, stimulates inspiration
apneustic center
located in upper pons, inhibits respiration
pneumatic center
lesion to pneumatic center would cause
inability to stop inspiring (apneustic breathing)
sensitive to pH of CSF, low pH causes hyperventilation
central chemoreceptors
located in carotid and aortic bodies, detect changes in arterial PO2, PCO2, and H+
peripheral chemoreceptors
mechanoreceptors in smooth muscle of airways stimulated by lung and airway distention, responsible for Hering-Breuer reflex
lung stretch receptors
mechanoreceptors that detect limb movements and instruct inspiratory center to increase breathing rate
joint and muscle receptors
located between epithelial cells of airways, causes reflex constriction of bronchial smooth muscle, increase breathing rate
irritant receptors
located near capillaries of alveolar walls, activated by increases in interstitial fluid volume (ex pulmonary edema), cause an increase in breathing rate
juxtacapillary receptors
decrease in arterial PO2
hypoxemia
decrease in O2 delivery to, or utilization by, the tissues
hypoxia
