exam 1 class 7 Flashcards
As inhaled air becomes humidified passing down the airways,
what happens to the PO2 of the air?
the partial pressure of oxygen decreases (addition of water vapor dilutes the concentration of oxygen in the air mixture)
4 lung volumes
tidal volume
inspiratory reserve volume
expiratory reserve volume
residual volume
lung volumes vary considerably with?
age, sex, height, and weight
the volume of air that moves during a single inspiration or expiration ( breath quietly)
tidal volume
average tidal volume
500 mL
additional volume that you inspire above the tidal volume ( breathing in as much additional air as you can)
inspiratory reserve volume
amount of air forecefully exhaled after the end of a normal expiration ( pushing out as much air as possible)
expiratory reserve volume
expiratory reserve volume average
1100 mL
after you blow out as much air as you can the air left over that remains in your lungs still ( maximum exhalation what is left over still inside)
residual volume
T or F lung volumes differ between male and females
true
sum of two or more lung volumes is called?
lung capacity
Primary muscles involved in quiet breathing (breathing at rest) are:
diaphragm, external intercostals, and scalenes
Air flow in the respiratory tract obeys:
flow of change in pressure /resistance
delta P/R means
- air flows in response to a pressure gradient
- flow decreases as the resistance of the system to flow increases
inspiration occurs when?
alveolar pressure decreases
- at rest
- inspiration
- expiration
-at rest: diaphragm is relaxed
- inspiration: thoracic volume increases
- expiration: diaphragm relaxes thoracic volume decreases
what do external intercostal and scalene muscles do during inhalation
contract and pull the ribs upwards and out
inspiratory muscles
external intercostals and scalenes
brief pause between breaths, alveolear pressure is equal to atmospheric pressure ( when pressures are equal there is no air flow)
time 0
inspiration increase in the thoracic volume, alveolar pressure falls about 1 mm Hg below atmospheric pressure, and air goes into the alveoli
time 0-2
expiration occurs when?
alveolar pressure increases
expiration during quiet breathing does not require active muscle contraction
passive expiration
air pressure in the lungs increases and reaching maximum 1 mm Hg above atmospheric pressure, alveolar pressure is higher than atmospheric pressure
time 2-4 expiration
after expiration air movement stops when alveolar pressure is equal again to atmospheric pressure
time 4
active expiration uses what muscles?
internal intercostal muscles and abdominal muscles
these muscles line the inside of the rib cage and, when they contract they pull the ribs inwards and reduce the volume of the thoracic cavity
internal intercostal
this muscle pulls the lower rib cage inward and decreases abdominal volume and displaces the intestines and liver upward
abdominal contraction
how much of the body’s energy is used on quiet breathing?
3-5 %
ability of the lung to stretch
compliance
the fluid lining the alveoli helps to create?
surface tension
lungs secrete a surfactant to?
reduce surface tension
surfactant decreases the surface tension of the alveolar fluid which….
decreases resistance of the lung to stretch
Newborn respiratory distress syndrome babies have low or high compliance lungs?
low compliance lungs
Primary muscles involved in quiet breathing (breathing at rest) are:
diaphragm, external intercostals, and scalenes
the systems length, the viscosity of the substance flowing through the system and the radius of the tubes in the system
Poiseuille’s law
90% of airways resistance is from
trachea and bronchi
Airway _______ Determines Airway Resistance
Diameter
decrease in bronchioles diameter can cause?
airway resistance
increases resistance to air flow and decreases the amount of fresh air that reaches the alveoli.
Bronchoconstriction
Relaxation of bronchiolar smooth muscle causes
Bronchodilation
the volume of air moved into and out of
the lungs each minute
Total pulmonary ventilation
Anatomic dead space averages?
150 mL
