![]() For instance, more protein is inside cells than outside and more chloride anions exist outside of cells than inside.įigure 3.2 Distribution of Body Water Image by Allison Calabrese / CC BY 4.0 Osmoregulation The composition of solutes differs between the fluid compartments. The extracellular water compartment is subdivided into the spaces between cells also known as interstitial, blood plasma, and other bodily fluids such as the cerebrospinal fluid which surrounds and protects the brain and spinal cord (Figure 3.2 “Distribution of Body Water”). In the human body, water and solutes are distributed into two compartments: inside cells, called intracellular, and outside cells, called extracellular. Solutes refers to all dissolved substances in a fluid, which may be charged, such as sodium (Na+), or uncharged, such as glucose. For example, in water sodium chloride (the chemical name for table salt) dissociates into sodium cations (Na+) and chloride anions (Cl−). Positively charged electrolytes are called cations and negatively charged electrolytes are called anions. Electrolytes are substances that, when dissolved in water, dissociate into charged ions. įigure 3.1 The Water Molecule “Water Molecule” by Chris Martin / Public Domain Fluid and Electrolyte BalanceĪlthough water makes up the largest percentage of body volume, it is not actually pure water but rather a mixture of cells, proteins, glucose, lipoproteins, electrolytes, and other substances. Additionally a study conducted at the Fred Hutchinson Cancer Research Center in Seattle found that women who drank more than five glasses of water each day had a significantly decreased risk for developing colon cancer. But, we do know that dehydration accelerates the aging process whereas keeping hydrated decreases headaches, muscle aches, and kidney stones. Does the loss in body water play a role in the aging process? Alas, no one knows. This also means that if a person gains weight in the form of fat the percentage of total body water content declines.) As we age, total body water content also diminishes so that by the time we are in our eighties the percent of water in our bodies has decreased to around 45 percent. (This gender difference reflects the differences in body-fat content, since body fat is practically water-free. Adult males typically are composed of about 60 percent water and females are about 55 percent water. Fortunately, humans have compartmentalized tissues otherwise we might just look like a water balloon! Newborns are approximately 70 percent water. An adult consists of about 37 to 42 liters of water, or about eighty pounds. Water is made up of 2 hydrogen atoms and 1 oxygen atom (Figure 3.1 “The Water Molecule”). University of Hawai‘i at Mānoa Food Science and Human Nutrition Program and Human Nutrition Program For a complete diagram of body fluid compartments, see body fluid compartments of a 70-kg man and body fluid compartments of a 55-kg woman.Overview of Fluid and Electrolyte Balance Note that this diagram places focus only on these three major fluid compartments. Plasma is the smallest fluid compartment (~8% of total body water). Interstitial fluid contains ~25% of the total body water. The intracellular fluid compartment contains most of the water in the body (~67% of total). The right diagram shows the three major fluid compartments drawn to scale. The left diagram allows for a better demonstration of the relationship between the intracellular fluid, interstitial fluid, and plasma, however, the relative size of each of the compartment is not drawn to scale. Waste products produced by cells follow the reverse path from the cytoplasmic compartment to plasma. They then must cross the plasma membrane to enter the cytoplasmic compartment of cells. Nutrient molecules traveling in the blood must first cross the capillary endothelium to enter the interstitial fluid. The capillary endothelium is the physical barrier that separates the interstitial fluid from plasma. The physical barrier separating the intracellular fluid compartment (i.e., cytoplasm) and the interstitial fluid is the cell plasma membrane. Fluid, molecules, and ions flow across physical barriers between the fluid compartments. These are the (1) intracellular fluid compartment, (2) interstitial fluid, and (3) plasma. In the human body plan, there are three major fluid compartments that are functionally interconnected.
0 Comments
Leave a Reply. |