Smallest bronchioles that terminate into clusters of alveoli
Air sacs of the lungs
lines the chest wall
is on the surface of the lungs
Between the parietal and visceral pleura that prevents friction
keeps the membranes together during breathing
Sight of gas exchange in the lungs
Within the alveoli are ___ that phagocytize pathogens
Each alveolus is lined with a thin layer of what and why?
it is essential for the diffusion of gases
(because a gas must dissolve in a liquid in order to enter or leave a cell)
Alveolar type 2 cells
a secretes a lipidprotein (pulmonary surfactant) -- that mixes with the tissue fluid and decreases its surface tension, permitting inflation
Movement of air to and from the alveoli/lungs
Medulla and Pons
Domed shaped muscle made of skeletal muscle (separates the thoracic and abdominal cavities) and is below the lungs that is
external and internal intercostals
The pressure of the air around us? At sea level it is 760 mmHg
The pressure within the potential pleural space between the parietal and visceral pleura
-usually slightly below atmospheric pressure
the pressure within the bronchial tree and alveoli; fluctuates during breathing
Motor impulses from the medulla travel along the phrenic nerves to the diaphragm, which contracts and moves down.
Impulses are sent along intercostal nerves to external intercostal muscles, which pull ribs up and out
Process of Inhalation
As the lungs expand, intrapulmonic pressure ___ (inc/dec) and air enters the ____?
the amount of air in one normal inhale and exhale
average = 500 mL
Minute respiratory volume (MRV)
the amount of air inhaled and exhaled in 1 minute
MRV = Tidal vol X # of respiration's/min
Residual air volume
the amount of air that remains in the lungs after the most forceful exhalation
average =1000-1500 mL
What test is used to diagnose emphysema?
Forced Expiratory Volume (FEV)
2 Sites of gas exchange
1) Between air in alveoli and blood
2) Between blood and tissue fluid
The exchange of gases between the air in the alveoli and the blood in the pulmonary capillaries
The exchange of gases between blood in the systemic capillaries and the tissue fluid
Inhaled air composed of
0.04 % CO2
Exhaled air composed of
16 % O2
concentration of each gas in a particular site
measured in mmHg
Carries O2 in the blood
Factors that increase the release of more O2?
The O2 - Hemoglobin bond is formed by the lungs when PO2 is ___ (high/low), when the blood passess through the tissues with a low PO2 the bond breaks and the ___ is released into the tissue
The lower the O2 concentration the ___ (+/-) O2 the hemoglobin will release?
The higher the PO2 the ___ (+/-) the SaO2
the are related
Carbon dioxide is carried by what in the blood?
Hemogloboin - Carbaminohemoglobin
Most carbon in the plasma is carried in the form of?
Where does the CO2 diffuse when it enters the blood?
Red blood cells
Two types of mechanisms that regulate breathing
The Medulla contains which centers?
the inspiration and expiration centers
The respiratory centers in the pons work with the with inspiration centers to produce what?
normal rhythms of breathing
This center prolongs inhalation and then interrupted
Interrupts the apneustic center, and contributes to exhalation
Refers to the effect on breathing of blood pH and blood levels of O2 and CO2
detect changes in blood gases and pH
located in the carotid and aortic bodies
decrease in blood oxygen levels
excess of CO2
makes the blood more acidic
Major regulator of respiration
Carbon dioxide (b/c it affects the pH of blood)
Reasons why O2 would be the major regulator of respirations
People with severe chronic pulmonary diseases: emphysema