Mastering CH 22B

A - Intrapulmonary pressure Intrapulmonary pressure rises when the thorax volume is reduced (during exhalation) and drops when the thorax volume rises (during inhalation). When there is no change in thorax volume, intrapulmonary pressure equalizes with the atmospheric pressure.

A - Intrapleural pressure Intrapleural pressure is created as the lungs attempt to shrink away from the thoracic wall. This negative pressure, as well as the adherence due to moisture, is what keeps the lungs from collapsing.

A - Ppul < Patm When the atmospheric pressure exceeds the pressure in the alveoli of the lungs (pulmonary pressure), air will flow into the lungs (inspiration).

B - the internal intercostal muscles and abdominal wall muscles During forced expiration, the internal intercostal muscles and the oblique, and transversus abdominal muscles contract to increase the intra-abdominal pressure and depress the rib cage.

Oxygen diffuses from the alveoli into surrounding capillaries. --> Oxygen enters a red blood cell. --> Oxygen binds to a molecule of hemoglobin. --> Oxygen is carried through blood vessels to a capillary. --> Oxygen diffuses from the blood to the body's tissues.

C - the diaphragm and rib muscles contract. The contraction of these muscles causes air to enter the lungs.

E - Alveoli Alveoli are tiny sacs in the lungs surrounded by capillaries. The alveoli are where oxygen diffuses from the lungs to the blood.

D - In the blood, oxygen is bound to hemoglobin, a protein found in red blood cells. When oxygen diffuses from the alveoli to the surrounding capillaries, it enters a red blood cell and binds to hemoglobin.

B - it returns to the heart, and is then pumped to body cells.

C - is a protein that can bind four molecules of oxygen.

B - the elasticity of the chest wall The natural elasticity of the chest wall pulls the thorax outward and enlarges the lungs. Whereas alveolar surface tension and lung elasticity work in the opposite direction by collapsing the lungs and making them smaller

D - Transpulmonary

B - an active process; a passive process During quiet breathing, inspiration requires muscle actions, while expiration is caused by elastic recoil.

- True When the external intercostal muscles are activated, the rib cage is elevated, increasing thoracic volume. This increases ventilation.

A - partial pressure of oxygen in the air Partial pressures affect the diffusion and dissolving of gasses into and out of the blood.

B - The pressure of gas in your lungs is inversely proportional to the volume in your lungs. Yes, Boyle's Law describes how air moves into and out of the lungs during inspiration and expiration. By changing the volume of the thoracic cavity, the pressure changes in the lungs. Increasing volume of the thoracic cavity leads to a decreased pressure, causing air to flow into the lungs (down its pressure gradient) and thus causing inspiration.

C - diaphragm and external intercostals Yes, contraction of both the diaphragm (the diaphragm flattens) and the external intercostals (pulls the ribs up and out) will increase the volume of the thoracic cavity. This will cause air to move into the lungs (inspiration).

B - intrapleural pressure Yes, the lungs tend to decrease their size while the chest wall tends to pull the thorax outward. This makes the intrapleural pressure more negative than the other two pressures (described as subatmospheric), thus keeping the lungs inflated.

D - epinephrine Yes, during an allergic reaction, there is increased resistance in the bronchioles and epinephrine dilates the bronchioles, thus making it easier to breathe. Epinephrine is released from the adrenal gland during stressful situations. People with severe allergies carry an EpiPen in case the allergic reaction produces anaphylaxis.

B - lungs will collapse Yes, the transpulmonary pressure creates the suction that keeps the lungs inflated. When room air enters the pleural space, transpulmonary pressure is zero and the lungs deflate - this is known as a pneumothorax.

False Residual volume cannot be measured; it has to be estimated, generally based on the size and sex of an individual. The volume cannot be detected with a spirometer because the volume of residual air left in the lungs at the end of expiration cannot pass through a spirometer to be measured.

D - tidal volume (TV) and inspiratory reserve volume (IRV) The inspiratory capacity, which is the total amount of air that can be taken into the lungs after a normal relaxed exhalation, is equal to the tidal volume (TV) plus inspiratory reserve volume (IRV).

C - 4800 milliliters The total volume of exchangeable air (vital capacity) for a normal male is the amount of air that can be drawn into the lungs after a forced exhalation and, in this case, is 4800 milliliters.

A - Rapid shallow breathing can reduce the amount of gas exchange without changing the total amount of gas moved in a minute. Minute ventilation, the total amount of gas moved in a minute, might not be reduced during rapid shallow breathing, but because much of that gas remains in the dead space, less gas is available for gas exchange.

A - tidal volume A tidal volume is a normal breath. One way to remember this is to compare tidal breathing to ocean tides that go in and out, day and night, without ceasing.