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Advanced Physiology: Kidneys & Regulation of Water and Inorganic Ions//Digestion and Absorbtion Food// Regulation of Organic Metabolism, Growth, and Energy Balance

In the following questions, determine whether they are True of False, and explain your reasoning. (Text may be helpfull: Vander, Sherman & Luciano's, "Human Physiology The Mechanisms of Body Function")
Plese note that the following T/F are extremely misleading.

T/F The concentration of water in the extracellular fluid is dependent upon the concentration of sodium in the extracellular fluid.

T/F Ingestion of large amounts of potassium triggers reflexes to limit the amount of potassium reabsorbed by the cortical collecting ducts.

T/F Polysaccharides must be broken down to disaccharides in order to be absorbed.

T/F Food is propelled down the esophagus primarily as a result of segmentation contractions of esophageal smooth muscle.

T/F Bile secreted by the liver contains the major enzymes for digestive fats.

Solution Preview

1. Sodium is the most important ion in the extracellular fluid (ECF) as it detrmines the ECF osmolarity or the concentration of hydrated Na+ ions in solution (mosmol/L). Therefore the concentration of Na+ will ultimately determine the amount of free water available in solution. Answer: T.
<br>2. Hyperkalemia is defined as a higher than normal concentration of potassium ions in the circulating blood. A balance between intake and excretion maintains plasma potassium levels within a narrow range (3.5-4.5 mEq/L). Less than 10% of potassium is excreted through sweat and stools, while more than 90% is excreted by the kidneys. Aldosterone affects potassium secretion in the distal nephron by its action on the sodium- and potassium-activated adenosine triphosphatase (Na+/K+-ATPase) pump. Elevated levels of aldosterone stimulate potassium secretion, while low levels inhibit potassium secretion by the cortical collecting duct. Increased sodium ...