nutrition

• a unified whole
• body water compartments
• particles in the water solution

all water inside body surrounding cells protected and held by skin

• dynamic areas within the body.
• total body water
• total in individual locations in body
• membranes seperate
• water is shifted to where its needed

• concentration and distribution of part in water
• determines internal shifts and balance amung compartments

bodys state of dynamic balance

homeostasis

• acts as solvent
• serves as means of transport
• regulates temp control
• provides lubrication for body

water is basic liquid solvent for all chem reactions

• interaction bs the pos charged end of one molecule and neg end of another.
• effectively dissolves and ionizes substances

water circulates thru body to meet the needs of cells

temp rises = sweat cools body

lubes moving bd parts eg joints

• 2.7 L
• 19% from food
• 74 oz fluid

• 3.7 L
• 0.7 from food
• 101 oz fluid

• physical activity
• environment temp

• hot- body sweats
• cold - body shivers

cold induced diuresis

• more water is lost in sweat
• more water needed in metabolic demand

5-7 ml per kg bd wt 4 hrs before

16-24 oz per lb lost during exercise

disease altered, water loss often thru urine

1000ml water needed for metabolism of every 1000kcal in diet

high infancy

• 70-75% total bd wt
• mostly outside cells, easily lost

• additives and meds
• natural diuretic effect
• individuals need monitored
• alcohol and caffeine

• excessive loss
• after 2% of normal wt lost
• thirst, ha, decreased urine output, drymouth, dizziness

visual impairment, hypotension, loss of appetite, muscle weakness, kidney failure, seizures

increase resting heart rate, kidney infections, fallstones, constipation, adversely influence cognitive functions

regulatory center for thrist, hunger, bd temp, water balance, and bp

• hypothalamus changes occur
• decreased thirst, reduced fluid intake

• pysiological changes
• eg kidneys

low serum sodium levels of less than 136 meq/l

• hyponatremia
• blood volume is diluted
• water moves into intracellular fluid spaces to reestablish equilibrium w na concentration--EDEMA, LUNG CONGESTION, MUSCLE WEAKNESS

excessive thirst and drinking

infants, psychiatric pts w polydipsia, pt taking psychotrpic drugs, prolonged endurance

45-75% total bd wt

higher ration of muscle to fat mass

muscle

• total amount outside cell
• ecf
• 20% total bd wt
• 34 % total bd water

blood plasma

• water that surrounds and bathes tiss
• water in lymphatic circulation
• water moving thru bd tiss secretions

• smallest component of ecf
• in gi tract, ocular and jnt fluid, urine in bladder

• total bd water insde cells
• twice amount of % total bd water

water enters and leaves bd various routes controlled by basic mechanisms

2.5 - 3 L of water per day

• liquids consumed
• foods
• product of cell oxidation when nutrients in body are burned for energy

severe reduction in flow of saliva that negativelty effects food intake

1500-200 ml per day

kidneys, skin, lungs, and feces

water that must be excreted thru urine to eliminate metabolic waste

2400 ml

electrolytes and plasma proteins

small inorganic substances that can dissaciate or break apart in solution and carry an electrical charge

ion

• carry pos charge
• eg na, k, ca, mg

• carry neg charge
• cl, becarbonate cho, phosphate po, sulfate so

electrochemical and cell membrane potentials

number of ionic charges or electrovalent bonds in a solution

• albumin and globulin
• are organic compounds of large molecular size
• dont move as freely
• retained in bld vessels
• control water movement and blood v

influence shift of water in and out of capillaries in balance w the surrounding water

plasma proteins

maintian integrity of bld vol

• dissolved in bd water
• too small to influence shifts of water
• can be found in large concentration to influence movement

• glocuse
• can increase water loss leading to polyuria when in high concentrations

seperate and contain water thruout bd

capillary membranes, cell membranes

• water molecules and small parts can move across thin capillary walls
• electrolytes and nutrient materials flow free

• specially constructed to protect and nourish cells contents
• molecules and ions use channels within the phospholipid bilayer to pass across membrane

movement of water molecules from an area of low solute to an area w high solute concentraion

when solutions of concentrations exist on either side of selectively permeable membranes this pressure moves water across membrane to help equalize both sides

force by which parts move outward in all directions from an are of greater concentration to an area of lesser

membrane transporters assist parts w the crossing of the membrane.

water is forced or filtered thru small pores of membrane

• vital part must move thru bd processes at all tiems
• carries upstream
• helper-carrier ferries

• larger molecule attach to outside cell and cell engulfs them
• encased in vacuole
• main way fat in absorbed in sml intestine

capillary fluid shift mechanism

• water and nutrients must get out of bld vess--
• metablolites must get back to cap--
• by means of opposing fluid pressure

• 1 hydrostatic pressure- intracapillary bp from contracting heart muscle pushing bld into circ
• 2 cop - pressure from plasma prot draws tiss fluids back into ongoing circ

• greater bp from heart forces water and small parts into tissues to bathe and nourish cells--then cop draw back water and metabolites--
• balanced bw bp and osmotic pressure of plasma proteiin parts

gi circ and renal circ

all secretions, except bile, are water--latter portions of intestines water is reabsorbed--constant movement maintained isotonicityw surrounding extracellular water-- risk for clinical imbalances

• gi fluids part of ecf capartments, also include blood--
• isotonic state of equal osmotic pressure--
• if you consume only water, electrolytes and salts enter intestine to even out--
• if you consume only food, additional water is drawn into intestine

upper and lower gi losses

kidneys filter blood, reaborb water and needed nutrients-- laundering of bld by millions of nephrons water balance and proper solution of bld are maintained

• antidiuretic hormone mechanism
• renin-angiotensin-aldosterone system

• vasopressin
• syntehsized by hypothalamus
• stored in pit gland for release

• conserves water
• works on kidneys nephrons to induce reabsorption of water
• stressful situation-released to conserve water

• when bld flow to kidneys drop below normal, enzyme renin is released into bld.
• renin converts angiotensinogen to "1, "1 travels to lungs where ace converts to "2- vasoconstriction triggers release of aldosterone from adrenal glands- aldo stim kidneys nephrons to reabsorb na

• SODIUM CONSERVING MECHANISM
• SECONDARY CONTROL OVER WATER REABSORPTION (WATER FOLLOWS NA)
• activated by stress also

• optimal degree acid/alkin must be maintained
• achieved by chem and physical buffer systems

• hydrogen ion concentration. pH
• higher hydro ion concentration = lower pH
• lower than 7 acidic
• higher alkaline

compound that has more h+ and has enough to relase extra when it is in solution

• compound w fewer h+
• in solution, accepts H+, reducing solutions acidity

bd deals w degrees of acidity by maintaining buffer systems to handle and excess acid or base

• mixture of acidic and alkalinine components
• acid and base partner that protect solution from wide variants of pH

carbonic acid/becarbonate

• availability of materials
• base-to-acid ratio

• resp and renal systems respond
• when chem buffers cannot reestablish equilibrium

co2 leaves w breath, changes in resp rate can incr or decr loss of acids

• pH less than 7.35
• accumulation of co2
• significant loss of bicarbonate

• pH more than 7.45
• resp alk caused by hyperventilation and excess loss of carbon dioxide
• extensive vomitting w hydrochloric acid lost and bicarbonate secreted

• when chem and resp buffers do not reestablish pH, kidneys can adapt by excreting more or less H+
• if blood is too acidic, kidneys will accept more H+ in exchange for na+
• na+ are basic, blood is losing an acid while gaining base- increasing blood ph back to normal