Transcript lecture 9x
Fluid & Electrolyte Balance HLTH 120N; Lecture 9 Objectives Describe 3 reasons fluid composition varies. Identify the 4 electrolytes and their 3 functions. Identify the other mineral essential for muscle contraction. Indicate the 4 main functions of body fluids. Know your recommendations for water, sodium & potassium. Explain how to effectively hydrate to support exercise Describe what occurs with dehydration, heat stroke, and hypertension. Body Fluid The liquid portion of cells and tissues Able to move freely, adapting to the shape of the area that contains it About 50−70% of healthy adult body weight Intracelluar fluid: within the cell ◦ of body fluid Extracellular fluid: outside the cell ◦ of body fluid ◦ Interstitial fluid flows between cells that make up a particular tissue ◦ Intravascular fluid is in the blood and lymph Plasma transports blood cells within arteries, veins, and capillaries Fluid composition varies by: Tissue type ◦ Gender ◦ tissues tissues have higher fluid content than more Age have more lean tissue, so they have . ◦ With age, lean tissue is lost so body water . Electrolytes Predominant electrolytes ◦ Extracellular fluid: ◦ Intracellular fluid: , chloride , phosphorus Dissolved substances that disassociate in solution into electrically charged particles ◦ Positive charge: ◦ Negative charge: , . , . Body Fluid Functions Dissolve and transport substances ◦ Water is an excellent solvent ◦ Water-soluble substances are easily transported in the bloodstream: , AA’s, glucose, minerals, meds ◦ Fatty substances? Fluid Functions cont. Account for blood volume ◦ Correct body fluid levels maintain a healthful blood volume ◦ Blood pressure when volume rises ◦ Low blood pressure ◦ Kidneys help regulate blood volume and pressure Blood Volume/Pressure Regulation Renin responds to decreased blood pressure Anti-diuretic hormone ◦ Angiotensin II (vasoconstrictor) Aldosterone signals the kidneys to retain sodium & chloride to retain water Fluid Functions Cont. Help maintain body temperature ◦ Must be within a safe range ◦ Only sustained high heat can increase body temperature ◦ releases heat as water evaporates to cool skin and blood Fluid Functions Cont. Protect and lubricate tissues Examples: ◦ Cerebrospinal fluid ◦ Amniotic fluid ◦ Synovial fluid lubricates ◦ Tears cleanse & lubricate ◦ Saliva moistens food for swallowing Fluid Function Recap Electrolyte Functions Help regulate fluid balance ◦ Cell membranes are permeable to water, not electrolytes ◦ Water moves by osmosis to areas of solute concentration Provides control of water movement in & out of the cells Electrolyte Function Cont. Enable nerves to respond to stimuli ◦ Nerve impulses are initiated at nerve cell membranes in response to a change in electrical charge across the membrane ◦ Sodium & potassium ensure nerve impulses are generated, transmitted, and completed Depolarization—Action Potential—Repolarization Electrolyte Functions Cont. Signal muscle contractions ◦ Muscles contract in response to stimulation of nerve cells ◦ Influx of into the muscle causes contraction ◦ Muscles relax after contraction once the electrical signal is complete and calcium is pumped out of the muscle cell Thirst & Fluid Balance Like hunger, thirst is signaled by the with ◦ Increased salt & substances in the blood ◦ Reduced blood volume & pressure Can occur with profuse sweating, diarrhea, or low . ◦ Dry mouth and throat from reduced saliva Anti-diuretic hormone will signal the to retain water , Water Loss Sensible water loss ◦ Kidneys excrete water as urine ◦ Sweat during exercise/hot environment Insensible water loss ◦ Skin (not sweating) or lungs Significant loss ◦ Illness, injury, exercise, high altitude, pregnancy, breastfeeding, diuretics Supports all body functions Fluid Recommendations: ◦ Women: Men: Can be very individualized Lost water from & replaced Best Food Sources: must be Water Balance Issues Deficiency ◦ Fluid in < Fluid out ◦ One of the leading causes of death around the world: ◦ Hypernatremia: Toxicity ◦ Hyponatremia: dilution of blood sodium Very rare; occurs mostly in . Sodium charge Functions -cellular ◦ Exchanges with potassium for fluid balance, pH balance, blood pressure ◦ Transmits nerve signals ◦ Aids in glucose absorption RDA: ◦ Most Americans consume: ◦ AHA, ADA recommend under: Hypernatremia/High intake Hyponatremia/Low intake ◦ Hypertension ◦ Osteoarthritis/osteoporosis ◦ Type II Diabetes ◦ Respiratory complications ◦ Gallbladder disease ◦ blood pressure ◦ Poor kidney function ◦ Heart failure ◦ Cirrhosis of liver Sodium Imbalance Potassium Functions: ◦ Fluid balance, nerve impulses RDA: Sources Toxicitiy – ◦ weakness, vomiting, irregular heartbeat Deficiency◦ weakness, paralysis, confusion, high BP Chloride Functions: ◦ Fluid balance, nerve impulses ◦ In the stomach as , aids white blood cells Best Source: Deficiency is rare Phosphorus Role: ◦ ◦ ◦ ◦ Component of body’s energy source: 80% of body phosphorus is in: Buffering agent In the cell membrane, forms: Sources: meat, nuts, seeds, fish, veggies ◦ High amounts in bottled/canned beverages Toxicity: ◦ Renal disease, Vit D Supp’s, Antacids ◦ Causes spasms & convulsions Dehydration Fluid losses ◦ Causes: fluid intake Classified by % weight loss from fluids Small losses: Severe loss: ◦ Sleeplessness, nausea, flushed skin, poor concentration Untreated: cardiac arrest, coma, death Fluid replacement & exercise Consume water before, during, after ◦ ◦ ◦ ◦ 2-3 hours prior: 30-60 min prior: During <1 hr: During >1 hr: Measure body weight before & after ◦ For each lb lost, consume . Urine Color Chart Heat Stroke Fatal heat illness ◦ Failure of body’s heating mechanisms ◦ Rapid pulse, hot skin, loss of consciousness Most vulnerable? ◦ More muscle mass = greater heat production Ability to lose heat through sweat very limited in humid environments Hypertension Inability to maintain blood pressure in a healthy range % of US adults hypertensive Increases risk for: Reduces brain function, impairs mobility Type of blood pressure Systolic ◦ Pressure arteries exert during contraction. ___________________ Diastolic ◦ Pressure in arteries during Optimal: Pre-hypertensive: Hypertensive is > 140/90 . Causes of hypertension Primary cause unknown for 90-95% 5-10% from kidney disease, sleep apnea, alcohol abuse Over half have salt sensitivity Others are salt resistant 5 lifestyle changes ◦ 5-10% The DASH diet Low-fat & high fiber Encourages potassium, calcium, magenesium ◦ 10 servings fruits & vegetables/day Sodium <3g Blood pressure lowers within __________ The lower sodium intake, the better Also reduces risk of _________________ Fluid & electrolyte considerations Neuromuscular issues: ◦ Seizures – due to nerve impulse issues ◦ Muscular dystrophy ◦ Muscle cramps – involuntary spasms Obesity ◦ 21% of calories come from beverages ◦ Researchers believe sweetened beverages contribute to half the rise in calorie intake DASH diet assignment Create a 2,000 calorie diet meeting DASH diet guidelines Enter the diet into MyDiet Analysis Hand in the list of foods with the print out of nutrients for that day 1 paragraph: How does this diet compare to your own? Should it only be recommended with hypertension?