Module 7 Review: Module Objectives Flashcards
Describe osmosis.
The movement of water through a selectively permeable membrane from an area where water is highly concentrated to an area where water is not as concentrated.
Describe the major functions of water in the human body.
Transportation vehicle-
Water has been termed the “universal solvent” because more substances dissolve in it than any other fluid. Blood is the primary transport fluid in the body.
Medium for chemical reactions - Enzmyes conduct reactions in a medium (environment); in the human body the medium is water.
Lubricant and shock absorber- Water is the main component of the fluids that protect and lubricate tissues. For example:
cerebrospinal fluid surrounding the brain and spinal cord protects these organs against sudden changes in the environment
amniotic fluid provides a cushion of protection for a pregnant woman’s developing baby
pleural fluid lubricates the lungs to make breathing easier
digestive secretions allow for easy passage of material through the gastrointestinal tract
mucus lines the walls of the intestines which eases the movement of food along the gastrointestinal tract
synovial fluid lubricates joints and eases the movement
Temperature regulator-Water is good at storing heat and buffers the body against extreme variations in temperature.
Identify sources of sodium, chloride, potassium, and phosphorus.
Most sodium in the typical American diet comes from processed and prepared foods.
Most chloride in the diet comes from salt. (Salt is 60% chloride.) Other dietary sources of chloride include processed foods containing sodium chloride, as well as tomatoes, lettuce, olives, celery, rye, whole-grain foods, and seafood. Although many salt substitutes are sodium-free, they may still contain chloride.
Fruits, vegetables, and whole grains tend to be good sources of potassium.
Phosphorus is found in many foods and is found in high amounts in foods that contain protein (e.g., meat, milk, eggs).
Describe the major functions of water in the human body.
Water As a Transportation Vehicle-
Water is called the “universal solvent” because more substances dissolve in it than any other fluid. The dissolved substances (solutes) include many materials including ions, sugars, amino acids, vitamins, and minerals. Molecules dissolve in water because of the hydrogen and oxygen molecules ability to loosely bond with other molecules. Molecules of water (H2O) surround substances, suspending them in a sea of water molecules. The solvent action of water allows for substances to be more readily transported. Blood, the primary transport fluid in the body, is mostly made up of water. Dissolved substances in blood include proteins, lipoproteins, glucose, electrolytes, and metabolic waste products, such as carbon dioxide and urea, all of which are either dissolved in the watery surrounding of blood to be transported to cells to support basic functions or are removed from cells to prevent waste build-up and toxicity.
Water As a Medium for Chemical Reactions-
Water is required for even the most basic chemical reactions. Previously, you learned that enzymes are proteins that conduct specific chemical reactions. Enzmyes conduct these reactions in a medium (environment); in the human body the medium is water. Water is an ideal medium for chemical reactions as it can store a large amount of heat, is electrically neutral, and has a pH of 7.0, meaning it is not acidic or basic. Additionally, water is involved in many enzymatic reactions as an agent to break bonds or, by its removal from a molecule, to form bonds.
Water As a Lubricant and Shock Absorber-
Water is the main component of the fluids that protect and lubricate tissues. For example:
cerebrospinal fluid surrounding the brain and spinal cord protects these organs against sudden changes in the environment
amniotic fluid provides a cushion of protection for a pregnant woman’s developing baby
pleural fluid lubricates the lungs to make breathing easier
digestive secretions allow for easy passage of material through the gastrointestinal tract
mucus lines the walls of the intestines which eases the movement of food along the gastrointestinal tract
synovial fluid lubricates joints and eases the movement
Water As a Temperature Regulator-
Water plays an important role in thermoregulation (temperature regulation). Human life is supported within a narrow range of temperature, with the temperature set point of the body being 98.6°F (37°C). Too low or too high of a temperature causes enzymes to stop functioning and metabolism is halted. At 82.4°F (28°C) muscle failure occurs and hypothermia sets in. At the opposite extreme of 111.2°F (44°C) the central nervous system fails and death results. Water is good at storing heat, an attribute referred to as heat capacity. Water has a high heat capacity which means that it takes alot of external energy to raise water’s temperature. This ability helps maintain the temperature set point of the body despite changes in the surrounding environment (e.g., high temperatures outside).
There are several mechanisms in place that move body water from place to place as a method to distribute heat in the body and equalize body temperature. The hypothalamus in the brain is the thermoregulatory center The hypothalamus contains special protein sensors that detect blood temperature. The skin also contains temperature sensors that respond quickly to changes in immediate surroundings.
When the surrounding temperature is cold, sensors in the skin send a signal to the hypothalamus, which then sends a signal to smooth muscle tissue surrounding blood vessels causing them to constrict and reduce blood flow. This reduces heat lost to the environment. The hypothalamus also sends signals to muscles to erect hairs and shiver and to endocrine glands like the thyroid to secrete hormones capable of ramping up metabolism. These actions increase heat conservation and stimulate its production in the body in response to cooling temperatures.
Describe water balance including sources of water intake and water output.
To maintain water balance, a cell controls the movement of electrolytes to keep the total number of dissolved particles the same inside and outside the cell.
Water Output
The kidneys are the organ primarily responsible for maintaining fluid balance. They constantly help maintain fluid balance by either excreting or retaining the fluid we consume.
insensible water loss: occurs without us being aware of it and includes water lost through breathing (exhalation) and evaporation from the skin
sensible water loss: noticeable water loss through sweating as well as excretion of urine and feces
Certain situations can cause a significant loss of fluid from the body:
Illnesses
Blood loss
Exercise
Environmental conditions
Pregnancy and breastfeeding
Diuretics (increase fluid loss via urine), including:
certain medications
alcohol
Describe the thirst mechanism.
The thirst mechanism is activated in response to changes in water volume in the blood and the concentration of sodium in the blood. The urge to drink results from a complex interplay of hormones and nervous system responses that coordinate to increase water input and contribute toward fluid balance and composition in the body. The “thirst center” is contained within the hypothalamus.
Describe the functions of the following electrolytes:
sodium
chloride
potassium
phosphorus
Describe the impact of sodium, chloride, potassium, and phosphorus imbalances.
Identify sources of sodium, chloride, potassium, and phosphorus.
Summarize the following fluid and electrolyte imbalance disorders:
overhydration
dehydration
various heat illnesses (heat cramps, heat exhaustion, heat stroke)
