basic-nursing.ppt

Unit4 STRUTURE AND FUNCTION护英二班护英二班 0783022607830231 PPT制作：姚芮制作：姚芮 讲解：沈沐，邹莉，戴亚子，张敏讲解：沈沐，邹莉，戴亚子，张敏Electrolytes:An electrolyte is an element or compound that will An electrolyte is an element or compound that will dissociate intodissociate into ions ions(see discussion below)when(see discussion below)when dissolved in water.dissolved in water.Electrolytes are found in all body fluids.The concentrations of electrolytes are measured according to their chemical activity and expressed as milliequivalents(mEq毫当量毫当量).Ions:An atoms that has gained or lost one or An atoms that has gained or lost one or more electrolytes is called an more electrolytes is called an ionion and has and has acquired an electrical charge.acquired an electrical charge.Some ions have the ability to bond with only Some ions have the ability to bond with only one other ion,others can bond with two or one other ion,others can bond with two or more.more.The ability is expressed in terms of a The ability is expressed in terms of a positive(+)or a negative(-)value and is positive(+)or a negative(-)value and is called the called the valencevalence.Na+Cl-NaClValence:+-0Opposites attract.CationAnionIonization:The process of ionization involves the The process of ionization involves the dissocationdissocation of compounds into their respective ions.of compounds into their respective ions.H H2 2O OOH-+H+NaClNa+Cl-HCl,NaOHionizationionizationImportant Electrolytes:The major The major intracellularintracellular electrolytes:electrolytes:K K,Mg,Mg,SO4,SO4,HPO4,HPO4.The major The major extracellularextracellular electrolytes:electrolytes:Na Na,ClCl,Ca,Ca,HCO3,HCO3.Is saline solution a mixture or a compound?The balance of intracellular potassium to extracellular sodium is an extremely important aspect of energy production.The body needs all these important electrolytes for normal functioning of nerves and muscles.Major functions and food sources of eletrolytes.Electrolyte balance refers to the maintenance of normal serum concentrations of electrolytes in the blood.Serum concentrations(ECF:intravascular)ImbalanceFluid And Electrolyte TransportNutrients and oxygen must enter the cells of the body while waste products exit the body.The cell membrane separates the intracellular The cell membrane separates the intracellular environments from the environments from the extracellularextracellular environment.environment.Permeability of Membrane:The ability of a membrane to allow molecule to pass The ability of a membrane to allow molecule to pass through is known as through is known as permeabilitypermeability.And the affective factors:And the affective factors:The size of the pores in the membraneThe size of the pores in the membrane Osmotic pressureOsmotic pressure Hydrostatic pressureHydrostatic pressure The electrical charge of the molecule,the plasma The electrical charge of the molecule,the plasma membrane,or the body fluidmembrane,or the body fluid The solubility or the moleculesThe solubility or the molecules The size of the moleculesThe size of the moleculesFreely permeable membraneFreely permeable membrane allow almost any food or waste substance to allow almost any food or waste substance to pass through.pass through.Selectively permeable membraneSelectively permeable membrane allow only certain specific substances to allow only certain specific substances to pass though.pass though.Movement across the cellular membrane occurs in one of four ways:1)Molecules move through the cell membrane 2)Membrane channel3)Barrier4)Vesicle Passive TransportPassive TransportDiffusion Osmosis FiltrationDiffusionDiffusionDiffusionDiffusion is the random movement of molecules is the random movement of molecules from an area of higher concentration to an from an area of higher concentration to an area of lower concentration.area of lower concentration.Diffusion commonly occurs in liquids and gases.Diffusion commonly occurs in liquids and gases.Diffusion is the most important mechanism by Diffusion is the most important mechanism by which nutrients and wastes pass across the which nutrients and wastes pass across the cell membrane.cell membrane.Osmosis is the diffusion of water is the diffusion of water across a across a semipermeablesemipermeable membrane.membrane.The homeostatic mechanism of osmosis equalizes the concentration of solutes within the body.Filtration is the transport of water and dissolved materials through a membrane from an area of higher pressure to an area of lower pressure.Active transport mechanisms require energy expenditure Active transport mechanisms require energy expenditure in the form of adenosine in the form of adenosine triphosphatetriphosphate(ATP).(ATP).Active transport processes can move solutes uphill.Active transport processes can move solutes uphill.Active Transport Active transportPrimary active transportSecondary active transport