Overview of the Respiratory Control System Breathing is one of those things in life that you almost never think about until something goes wrong with it. However, those with pulmonary disease become intensely aware of breathing, as do people who…
Although diffusion is at the very heart of the gas exchange, as we discussed in Chapter 30 , two other parameters are also extremely important. Ventilation and perfusion—both of which require energy—are critical because they set up the partial-pressure gradients…
The complex anatomy of the pulmonary tree, the mechanics of the respiratory system, and the sophisticated carriage mechanisms for O 2 and CO 2 combine to serve two essential purposes: the ready diffusion of O 2 from the alveoli to…
Carriage of O 2 The amount of O 2 dissolved in blood is far too small to meet the metabolic demands of the body Blood carries oxygen in two forms. More than 98% of the O 2 normally binds to…
Acid-base physiology is really the study of the proton, or hydrogen ion (H + ). Although they are present in exceedingly low concentrations in most intracellular and extracellular fluids, protons nevertheless have a major impact on biochemical reactions and on…
The field of pulmonary mechanics —the physics of the lungs, airways, and chest wall—deals with how the body moves air in and out of the lungs, producing a change in lung volume (V L ). When we examine these mechanical…
Comparative Physiology of Respiration External respiration is the exchange of O 2 and CO 2 between the atmosphere and the mitochondria For millennia, people have regarded breathing as being synonymous with life. Life begins and ends with breathing. The Bible…
The cells of the human body live in a carefully regulated fluid environment. The fluid inside the cells, the intracellular fluid (ICF), occupies what is called the intracellular compartment, and the fluid outside the cells, the extracellular fluid (ECF), occupies…
What is physiology? Physiology is the dynamic study of life. Physiology describes the “vital” functions of living organisms and their organs, cells, and molecules. For centuries, the discipline of physiology has been closely intertwined with medicine. Although physiology is not…
Because virtually every biological process is sensitive to changes in pH, acid–base homeostasis is of critical importance to cells and organisms, and has attracted considerable attention. Until relatively recently, acid–base homeostasis, for both clinicians and basic scientists, has been synonymous…