NTR 108 - Chapter 7 Nutrients Essential to Fluid and Electrolyte Balance

Water Gain

-Concentration of electrolytes outside the cells is decreasing compared to that inside the cells. -Net movement of water is into the cells. -The fluid volume in blood is increasing. -Urine becomes lighter in color. (Recall that water gain will ultimately result in the movement of fluids into the cells, while water loss, conversely, will result in the movement of fluids out of the cells. Both processes happen via osmosis.)

Hydration status can be determined by paying attention to various indicators. Read the statements below and select the correct statements regarding how to assess hydration.

-Reduced saliva production can be an indicator of dehydration. -Dark urine can be an indicator of water imbalance. -Weighing the body before and after exercise can be used to detect overhydration and dehydration. (All of these indicators (dry mouth, urine color, and body weight change) are ultimately the result of changes in hydration status and the changing concentration of electrolytes in the blood.)

Water Loss

-The fluid volume in the blood is decreasing. -Urine becomes darker in color -The thirst mechanism is triggered. -Net movement of water is out of the cells. (Recall that in order for the net movement of water into and out of a cell to be zero (that is, fluid would be in balance), the concentrations of electrolytes inside and outside the cell must be equal.)

Water plays an important role in solubility, transport, blood volume, blood pressure, and regulation of body temperature. Electrolytes help maintain fluid balance and assist with the generation of nerve impulses. Each of these contributions is essential for life and must remain in balance. Choose the correct statement about water and electrolytes.

After a muscle fiber is stimulated by a nerve signal, a release of stored calcium ions leads to muscle contraction. Sodium and potassium help generate nerve impulses. When a muscle is stimulated by these signals, calcium helps stimulate the muscle contractions.

One way the body works to maintain fluid balance is via the thirst mechanism. This mechanism stimulates the desire to drink fluids in response to changes in blood volume, blood pressure, and concentration of sodium in the blood. Fluids are regularly lost through urine, feces, sweat, evaporation, and exhalation. In some cases, the amount is small, but in certain situations, the fluid loss can be significant. From the list below, choose all the correct statements about fluid intake and excretion.

An increased concentration of sodium and other dissolved substances in the blood leads to increased thirst. Low blood pressure can stimulate thirst. The thirst mechanism is prompted by both an increased concentration of sodium (and other dissolved substances) as well as a decrease in blood volume and pressure. Keep in mind that this mechanism may not be the best indicator of thirst in all age groups or situations. It is also important to understand factors that can increase risk of dehydration like intense physical activity, diarrhea, or diuretic use.

electrolytes

Charged ions such as sodium, potassium, and chloride are called

Beverage choices are plentiful, and all contribute to a person's fluid needs. Some provide important nutrients like calcium and vitamin D, while others contribute a substantial amount of sugar and caffeine. Choosing wisely can affect overall health as well as weight-management efforts. From the list below, choose all the correct statements about popular beverages.

Flavored milk and milk substitutes may provide important nutrients, but can also be a significant source of added sugars Sports beverages offer no established benefits for people who do little or no regular exercise or manual labor. (If a person is looking to avoid unwanted calories and ingredients, pure water is generally the best beverage choice. Another healthful choice is skim milk for those looking for a source of calcium and vitamin D and who can tolerate lactose.)

dehydration

If you are not consuming enough water, or if you are excreting too much water from your body, _____ can occur.

Imbalances of fluid and electrolytes can be caused by a variety of situations and health conditions. From the list below, choose all the correct statements about risks of electrolyte imbalance.

Overweight football players practicing in a humid environment have several risk factors for heatstroke Muscle cramps or weakness can occur as a result of electrolyte imbalances.

thirst mechanism

The feeling of dry mouth experienced during dehydration is part of the body's

Water contained in the food or drink you consume is absorbed from the digestive tract into the bloodstream. There are many routes by which water can then leave the body, resulting in water loss. Read the statements below and select the correct statements regarding water loss.

The greatest amount of water loss occurs via production of urine by the kidneys. Water loss through breathing (respiration) is a type of insensible water loss.

interstitial fluid

The liquid that is between cells is called

osmosis

The process by which water moves in and out of cells from an area of lower concentration of solutes to an area of higher concentration of solutes is called

Dehydration

This state can occur as a result of severe diarrhea and vomiting, or abuse of diuretics. Older adults, those with vigorous jobs, and individuals who are physically active are particularly at risk for this state.

Hyponatremia

This state can occur when too much fluid (particularly pure water) is consumed in a short period of time. This state can result in swelling of tissues, including the brain, and lead to seizures, coma, and death. (Remember that fluid balance describes equilibrium between electrolytes and water concentration outside of the cells and inside the cells.)

Water Balance

This state occurs when the thirst mechanism has been successful. This state occurs when enough fluid is consumed to allow for an equal concentration of electrolytes between the intra- and extracellular fluid compartments.

Sodium is an essential nutrient but many adults consume very high levels of sodium and not enough potassium. Many researchers believe this high sodium-to-potassium ratio increases risk of hypertension. Choose the meal below that would be the best choice for a person trying to limit sodium while consuming adequate potassium.

a low-fat yogurt parfait with granola, sliced bananas, and dried apricots with water To optimize your sodium and potassium intakes, consume more whole fruits, vegetables, legumes, and whole grains. Limit processed foods and fast food.

Diuretics

are substances that cause the body to lose water via urine

Over half of a healthy adult's weight comes from fluid. It is present as extracellular fluid (which includes tissue fluid, plasma, and lymph) or intracellular fluid. Complete the sentence below about body fluid. About two-thirds of our body fluid is known as _______________.

intracellular fluid All cells contain fluid; therefore, proper fluid balance is vitally important.

Fluid balance

is achieved when there is an equal concentration of water and electrolytes inside and outside the body's cells.

Hyponatremia

occurs when the extracellular concentration of sodium is too low.