The stomach plays several important roles in human nutrition and has secretory, motor, and humoral functions. These activities are not separate and distinct, but rather represent integrated functions that are required to initiate the normal digestive process. The stomach has…
Overview of Digestive Processes The gastrointestinal tract is a tube that is specialized along its length for the sequential processing of food The gastrointestinal (GI) tract consists of both the series of hollow organs stretching from the mouth to the…
Two separate but closely interrelated control systems regulate the volume and osmolality of the extracellular fluid (ECF). It is important to regulate the ECF volume to maintain blood pressure, which is essential for adequate tissue perfusion and function. The body…
The lungs and the kidneys are largely responsible for regulating the acid-base balance of the blood (see Chapter 28 ). They do so by independently controlling the two major components of the body's major buffering system: CO 2 and (…
Water Balance and the Overall Renal Handling of Water The kidney can generate a urine as dilute as 40 mOsm (one seventh of plasma osmolality) or as concentrated as 1200 mOsm (four times plasma osmolality) In the steady state, water intake and…
Potassium Balance and the Overall Renal Handling of Potassium Changes in K + concentrations can have major effects on cell and organ function The distribution of K + in the body differs strikingly from that of Na + . Whereas…
The kidney plays a central role in controlling the plasma levels of a wide range of solutes that are present at low concentrations in the body. The renal excretion of a solute depends on three processes—filtration, reabsorption, and secretion (see…
The kidneys help to maintain the body's extracellular fluid (ECF) volume by regulating the amount of Na + in the urine. Sodium salts (predominantly NaCl) are the most important contributor to the osmolality of the ECF; hence, where Na +…
Glomerular Filtration A high glomerular filtration rate is essential for maintaining stable and optimal extracellular levels of solutes and water Qualitatively, the filtration of blood plasma by the renal glomeruli is the same as the filtration of blood plasma across…
The kidneys serve three essential functions. First, they act as filters, removing metabolic products and toxins from the blood and excreting them through the urine. Second, they regulate the body's fluid status, electrolyte balance, and acid-base balance. Third, the kidneys…