SOLUTIONS TO EXERCISES, LESSON 7
The processes of respiration and breathing serve to provide oxygen to the body
cells. This oxygen is used in the process of metabolic oxidation, which releases the
energy trapped in glucose molecules.
Also, the gas carbon dioxide is removed along with other unwanted gases.
In general, respiration is the exchange of gases. The two kinds of respiration in
the human body are external and internal respiration. In external respiration, gases are
exchanged between the blood and the surrounding air. In internal respiration, gases
are exchanged between the blood and the individual cells of the body. (para 7-2a)
Breathing is the process by which air is moved into and out of the lungs. The two
types of breathing in humans are costal breathing and diaphragmatic breathing. In
costal breathing, the rib cage is used. In diaphragmatic breathing, there is reciprocal
interaction between the diaphragm and the abdominal wall.
When the air flows inward, we call it inhalation or inspiration. When the air flows
outward, we call it exhalation or expiration. (para 7-2b)
In respiration and breathing, the movement of air and various gases is due to
differences in their relative pressures from one space to another. If the pressure or
concentration of a substance is greater in one space than another, then there is a
pressure gradient for that substance. As a result, the substance will move from the area
of higher pressure to the area of lower pressure.
Boyle's Law: If we increase the volume of a closed container, the pressure inside
will decrease. Likewise, if we decrease the volume, the pressure inside will increase.
Pascal's Law: A pressure applied to the fluid filling a closed container will
produce an equal pressure at each and every point on the inner surface.
More gases can be exchanged or treated as the surface area increases.
Since the wall of the thorax is reinforced by muscles, bones, and cartilages, we
can consider the thorax to be "solid-walled container" filled with gas.
The abdominopelvic cavity is filled with a fluid continuum, the water of the soft