Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fluids Substances composed of freely moving molecules Have the ability to conform to the shape of their container There are different types of fluids in our bodies. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Our bodies are composed mainly of fluid ~50 70% of a healthy adults body Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fluids Intracelluar Fluid Within the cell 2/3 of body fluid Extracellular Fluid Outside the cell 1/3 of body fluid Interstitial fluid flows between cells that make up a particular tissue or organ Intravascular fluid is the water in the blood and lymph Plasma transports blood cells within arteries, veins, and capillaries Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Intracellular vs. Extracellular fluid Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fluids Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fluids Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fluids Extracellular fluids include Tissue fluid found between the cells within tissues and organs of the body. Plasma, the fluid portion of blood that carries the blood cells. Plasma is composed of electrolytes, proteins and water and accounts for ~55% of blood volume Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fluids The body fluid composition of tissue varies by (1) Tissue type lean tissues have higher fluid content than fat tissues (2) Gender males have more lean tissue and therefore more body fluid (3) Age lean tissue is lost with age and body fluid is lost with it Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Electrolytes Body fluid is composed of Water Electrolytes: mineral salts dissolved in water, including: Sodium Potassium Chloride Phosphorus Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Electrolytes Electrolytes carry electrical charges: Sodium (Na + ) and potassium (K + ) are positively charged Chloride (Cl - ) and phosphorus (HPO 4 2-, phosphate) are negatively charged Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Electrolytes Fluids have an overall neutral charge due to the balances between electrolytes. In intracellular fluid, K + and HPO 4 2- are the predominant electrolytes. In extracellular fluid, Na + and Cl - predominate. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of Fluids Fluids dissolve and transport substances. Water is an excellent solvent because it can dissolve many different substances. The dissolved materials, or solutes, include ions, sugars, amino acids, vitamins, and minerals. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of Fluids Fluids account for blood volume. Blood volume is the amount of fluid in the blood. Increased blood volume can cause blood pressure to rise. Decreased blood volumes can cause low blood pressure. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of Fluids Fluids help maintain body temperature. The high heat capacity of water means that the temperature of our body fluids remains quite stable. Sweating releases heat as the evaporation of water from the skin cools the skin and blood. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of Fluids Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of Fluids Fluids protect and lubricate body tissues. Cerebrospinal fluid protects the brain and spinal column. Amniotic fluid protects the fetus. Synovial fluid is a lubricant around joints. Digestive secretions allow for easy passage of material. Grays Anatomy Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of Electrolytes Electrolytes help regulate fluid balance. osmosis Water follows the movement of electrolytes, moving by osmosis to areas where the concentration of electrolytes is high. This allows for the controlled movement of fluids into and out of cells. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of Electrolytes: Osmosis Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of Electrolytes Fluid and electrolyte balance Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of Electrolytes Electrolytes help nerves respond to stimuli. Movement of Na + and K + across the membranes of nerve cells changes the electrical charge across the membrane. This change in electrical charge carries the nerve impulse along the nerve cell. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Sodium-Potassium pump --Active transport: requires energy! ATP!!! Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of Electrolytes Electrolytes signal our muscles to contract. The movement of calcium (Ca 2+ ) into a muscle cell stimulates the muscle to contract. The Ca 2+ is pumped back out of the cell after the muscle contraction. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Maintaining Fluid Balance Any water lost from the body must be replaced. Water is lost through urine, sweat, exhalation, and feces. Water is gained through beverages, food, and metabolic reactions. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Maintaining Fluid Balance Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Maintaining Fluid Balance Loss of water Most water is lost through urine. The kidneys control how much water is reabsorbed. Excess water is processed by the kidneys and excreted as urine. Insensible water is lost through the skin (sweat) or through the lungs during exhalation. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Maintaining Water Balance Taking in water Most water enters the body through beverages Some foods have very high water contents Metabolic water is a product of many chemical reactions in the body and contributes 10-14% of the bodys needs Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Water Functions of water Essential for life Required for fluid and electrolyte balance and many metabolic reactions Recommended intake 1.0 to 1.5ml for each kcal expended Varies with environment, activity level Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Water What if you drink too much water? Becoming over hydrated is rare Can result in a dilution of sodium What if you dont drink enough water? Dehydration Infants and the elderly are especially vulnerable Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Medical Disorders Disorders related to fluid and electrolyte imbalance include: Dehydration Heat stroke Water intoxication Hypertension Neuropsychiatric disorders Muscle disorders Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Dehydration Dehydration occurs when water loss exceeds water intake. Commonly due to heavy exercise or high environmental temperatures. Infants and the elderly are more at risk. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Heat Stroke Heat stroke occurs if the bodys temperature regulation mechanisms fail. Occurs in hot, humid environments Symptoms include rapid pulse, hot, dry skin, high body temp, weakness Has been fatal for athletes during exercise in extreme heat Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hypertension Hypertension is a chronic condition characterized by high blood pressure. Systolic pressure over 140mm Hg Diastolic pressure over 90mm Hg May not show symptoms Increases a persons risk of heart disease, stroke, kidney disease Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Muscle Disorders Electrolyte imbalances can result in seizures or muscle cramps. Electrolyte imbalances cause changes in nervous system function. Nervous system changes can alter proper muscle function. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antioxidants! Antioxidants Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings What Are Antioxidants? Antioxidants: chemicals that protect cells from damage from oxidation, including Vitamin E Vitamin C Beta-carotene Vitamin A Selenium Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Oxidation Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Oxidation Oxidation: the loss of electrons from a molecule. Reduction: the gain of electrons by a molecule. Oxidation and reduction usually occur together as an exchange reaction. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Oxidation Stable atoms contain an even number of paired electrons. Free radical: an atom that has lost an electron and is left with an unpaired electron. Free radicals are highly reactive and can cause damage to molecules in the cell. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Formation of Free Radicals Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Formation of Free Radicals Many metabolic processes involve oxidation reactions and can produce free radicals. Free radicals are also produced by Pollution Ultraviolet light Toxic substances Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Formation of Free Radicals Free radicals cause damage to Cell membranes Low-density lipoproteins (LDL) Proteins in the cell Genetic material (DNA) Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antioxidants Antioxidants can function in different ways Some vitamins donate their electrons to free radicals to stabilize them Some minerals act with complex enzyme systems to destroy free radicals Superoxide dismutase Catalase Glutathione peroxidase (Selenium) Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antioxidant nutrients Vitamin E Vitamin C Selenium Beta-carotene (mild antioxidant) Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Beneficial effects of antioxidants May reduce the risk for cancer May reduce the risk for cardiovascular disease Have been proposed to slow the aging mechanism Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Two aged-related diseases may be prevented by antioxidants in the diet: Macular degeneration deterioration of the macula, the center of the retina Cataracts damaged regions of the lens of the eye causing cloudy vision Copyright: public domain, credit to NIH National Eye Institute requestedNIHNational Eye Institute Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bones! Bones Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bone Health Bone structure Provides strength to support the body Allows for flexibility Contains about 65% minerals providing the hardness of bone Contains 35% organic structures for strength, durability, flexibility Collagen: fibrous protein in bone tissue Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bone Health Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bones are comprised of hydroxyapatite Calcium and phosphorous Ca 5 (PO 4 ) 3 (OH) Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bone Health Two types of bone tissue: Cortical bone (compact bone): very dense tissue making up 80% of the skeleton. Trabecular bone (spongy bone): scaffolding on the inside of bones; supports cortical bone and makes up 20% of the skeleton. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bone Health Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bone Health Bones develop through three processes: Bone growth increase in bone size; completed by age 14 in girls and age 17 in boys Bone modeling shaping of bone; completed by early adulthood Bone remodeling reshaping of bone Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bone Health Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bone Health Bone remodeling involves: Resorption surface of bones is broken down Osteoclasts cells that erode the surface of bones Formation of new bone by cells called osteoblasts Osteoblasts produce the collagen-containing component of bone Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bone Health Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Regulation of Ca 2+ in blood and bone Drop in blood [Ca2+] results in increased PTH PTH stimulates conversion of vitamin D to active form, calcitriol, in kidneys (so more Ca2+ will be absorbed) PTH stimulates the breakdown (resorption) of bone Ca 2+ is not excreted in urine, but P is Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Vitamin D Regulates calcium and phosphorous levels in blood by promoting their absorption in the intestines and promoting re-absorption of Ca 2+ in the kidneys Promotes bone formation and mineralization (=strong, intact skeleton) Inhibits parathyroid hormone secretion Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bone Health Bone density Peak bone density is reached before the age of 30 Remodeling maintains bone density during early adulthood Density begins to decrease after age 40 because resorption exceeds new bone formation Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bone Health Dual energy X-ray absorptiometry (DXA) Measures bone density Uses very low level X-ray energy Provides a full body scan Is a non-invasive procedure Recommended for postmenopausal women Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Osteoporosis Osteoporosis is a disease characterized by Low bone mass Deterioration of bone tissue Fragile bones leading to bone fractures Compaction of bone; decreased height Shortening and hunching of the spine Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Osteoporosis Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Osteoporosis Factors influencing the risk of osteoporosis include: Age Gender Genetics Nutrition Physical activity Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Osteoporosis Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Osteoporosis Age is a factor for osteoporosis because Bone mass decreases with age Age-related hormonal changes influence bone density Older adults are less able to absorb vitamin D Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Osteoporosis Gender is a risk factor for osteoporosis. 80% of Americans with osteoporosis are women. Women have lower bone density than men. Estrogen loss in post-menopausal women causes increased bone loss. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Osteoporosis Physical activity influences the risk for osteoporosis. Regular exercise causes stress to bones, leading to increased bone mass. Weight-bearing activities (walking, jogging) are especially helpful in increasing bone mass. Copyright 2006 Pearson Education, Inc., publishing as Benjamin Cummings Osteoporosis There is no cure for osteoporosis. The progression of osteoporosis may be slowed by Adequate calcium and vitamin D intake Regular exercise Anti-resorptive medications