Slide 1 Mosby items and derived items © 2006 by Mosby, Inc. Chapter 9 Water Balance.
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Transcript of Slide 1 Mosby items and derived items © 2006 by Mosby, Inc. Chapter 9 Water Balance.
Mosby items and derived items © 2006 by Mosby, Inc. Slide 3
Key ConceptsKey Concepts
• Throughout the body, water exists as a unified whole with constant ebb and flow among its interfacing parts.
• Collective water compartments, inside and outside of cells, maintain a balanced distribution of total body water.
(Cont'd…)
Mosby items and derived items © 2006 by Mosby, Inc. Slide 4
Key ConceptsKey Concepts(…Cont’d)
• The concentration of various solute particles in the body’s water solution determines internal shifts and balances of water.
• A state of dynamic equilibrium (e.g., homeostasis) among all parts of the body’s water-balance system sustains life.
Mosby items and derived items © 2006 by Mosby, Inc. Slide 6
Basic PrinciplesBasic Principles
• A unified whole Virtually every space inside and outside of the
cells is filled with water-based fluids
• Body water compartments Dynamic systems within the body Intracellular or extracellular
• Particles in the water solution Determines all internal shifts and balances
between compartments
Mosby items and derived items © 2006 by Mosby, Inc. Slide 7
HomeostasisHomeostasis
• Body’s state of dynamic balance
• Capacity of the body to maintain life systems, despite what enters the system from outside
• Homeostatic mechanisms protect the body’s water supply
Mosby items and derived items © 2006 by Mosby, Inc. Slide 8
Body Water FunctionsBody Water Functions
• Solvent Basic liquid solvent for all chemical processes
within the body
• Transport Nutrients carried through the body in water-
based fluids (blood, secretions)
• Body form and structure Fills in spaces between the body tissues
• Body lubricant
Mosby items and derived items © 2006 by Mosby, Inc. Slide 9
Body Water RequirementsBody Water Requirements
• Surrounding temperature Body water is lost as sweat and must be replaced
• Activity level Water is lost as sweat More water is needed for increased metabolic
demand in physical activity
• Functional losses Disease process affects water requirements
(Cont'd…)
Mosby items and derived items © 2006 by Mosby, Inc. Slide 10
Body Water RequirementsBody Water Requirements(…Cont’d)
• Metabolic needs 1000 ml of water necessary for every 1000
kcal in the diet
• Age Infants need 1500 ml of water per day Adult men need 2900 ml of liquids per day Adult women need 2200 ml of liquids per day
Mosby items and derived items © 2006 by Mosby, Inc. Slide 11
Body Water Amount and Body Water Amount and DistributionDistribution
• Extracellular fluid Total body water outside cells One quarter of extracellular fluid is blood
plasma Three quarters is water surrounding cells and
bathing tissues, water in dense tissue, water moving through the body in secretions
(Cont'd…)
Mosby items and derived items © 2006 by Mosby, Inc. Slide 12
Body Water Amount and Body Water Amount and DistributionDistribution
(…Cont’d)
• Interstitial fluid Fluid surrounding cells in tissues
• Intracellular fluid Total body water inside the cells Twice of that outside the cells
• Overall water balance
(Cont'd…)
Mosby items and derived items © 2006 by Mosby, Inc. Slide 13
Body Water Amount and Body Water Amount and DistributionDistribution
• Water intake Preformed water in liquids that are drunk Preformed water in foods that are eaten Product of cell oxidation Older adults must maintain proper intake of
water due to tendency to dehydration
(Cont'd…)
Mosby items and derived items © 2006 by Mosby, Inc. Slide 14
Body Water Amount and Body Water Amount and DistributionDistribution
(…Cont’d)
• Water output Obligatory water loss• Leaves the body through kidneys, skin, lungs,
and feces Optional water loss• Varies according to climate or physical activity
Mosby items and derived items © 2006 by Mosby, Inc. Slide 15
Volumes of Body Fluid Volumes of Body Fluid CompartmentsCompartments
Mosby items and derived items © 2006 by Mosby, Inc. Slide 16
Approximate daily adult Approximate daily adult intake and output of waterintake and output of water
Mosby items and derived items © 2006 by Mosby, Inc. Slide 17
ElectrolytesElectrolytes
• Small, inorganic substances that break apart in a solution and carry an electrical charge (ions)
• Balance between cation and ion concentration maintains chemical neutrality necessary for life
Mosby items and derived items © 2006 by Mosby, Inc. Slide 18
Balance of Cation and Anion Balance of Cation and Anion Concentrations in Extracellular and Concentrations in Extracellular and Intracellular FluidsIntracellular Fluids
Mosby items and derived items © 2006 by Mosby, Inc. Slide 19
Plasma ProteinsPlasma Proteins
• Mainly albumin and globulin
• Organic compounds of large molecular size
• Retained in blood vessels
• Controls water movement
• Colloids guard blood volume (colloidal osmotic pressure)
Mosby items and derived items © 2006 by Mosby, Inc. Slide 20
Chapter 9Chapter 9
Lesson 9.2Lesson 9.2
Mosby items and derived items © 2006 by Mosby, Inc. Slide 21
Key ConceptsKey Concepts
• Collective water compartments, inside and outside of cells, maintain a balanced distribution of total body water.
• A state of dynamic equilibrium (e.g., homeostasis) among all parts of the body’s water-balance system sustains life.
Mosby items and derived items © 2006 by Mosby, Inc. Slide 22
Separating MembranesSeparating Membranes
• Capillary membrane Thin and porous Water molecules move freely across them
• Cell membrane Thicker membranes Constructed to protect and nourish cell
contents
Mosby items and derived items © 2006 by Mosby, Inc. Slide 23
Moving Water & Solutes Moving Water & Solutes Across MembranesAcross Membranes
• Osmosis Process or force that impels water molecules to
move throughout body. Moves water molecules from an area of greater
concentration to an area of lesser concentration.
• Diffusion Force by which particles in solution move
outward in all directions from an area of greater concentration to an area of lesser concentration.
(Cont'd…)
Mosby items and derived items © 2006 by Mosby, Inc. Slide 24
Moving Water & Solutes Moving Water & Solutes Across MembranesAcross Membranes
(…Cont’d)
• Filtration Water is forced through membrane pores when
pressure outside membrane is different.
• Active transport Necessary to carry particles “upstream” across
separating membranes.
• Pinocytosis Larger molecules attach to thicker cell membrane,
then are engulfed by cell.
Mosby items and derived items © 2006 by Mosby, Inc. Slide 25
Movement of Molecules, Water & Movement of Molecules, Water & Solutes by Osmosis & DiffusionSolutes by Osmosis & Diffusion
Mosby items and derived items © 2006 by Mosby, Inc. Slide 27
Capillary Fluid Shift Capillary Fluid Shift MechanismMechanism
• Cells’ water and nutrients must move from capillaries to cells.
• Water and cell metabolites must return to capillaries.
• Uses opposing fluid pressures: Hydrostatic pressure Colloidal osmotic pressure
Mosby items and derived items © 2006 by Mosby, Inc. Slide 28
The Fluid Shift MechanismThe Fluid Shift Mechanism
Mosby items and derived items © 2006 by Mosby, Inc. Slide 29
Organ Systems Involved in Organ Systems Involved in Body Water BalanceBody Water Balance
• Gastrointestinal circulation Water from blood plasma is continually
secreted into GI tract. In latter portion of intestine, most water and
electrolytes are reabsorbed into blood. Is maintained in isotonicity
(Cont'd…)
Mosby items and derived items © 2006 by Mosby, Inc. Slide 30
Organ Systems Involved in Organ Systems Involved in Body Water BalanceBody Water Balance
(…Cont’d)
• Renal circulation Kidney “laundering” of the blood helps
maintain water balance and proper solution of blood.
• Hormonal controls: Antidiuretic hormone mechanism (ADH) Aldoesterone mechanism
Mosby items and derived items © 2006 by Mosby, Inc. Slide 31
Approximate Total Volume of Approximate Total Volume of Digestive SecretionsDigestive Secretions
Mosby items and derived items © 2006 by Mosby, Inc. Slide 32
Approximate Concentrations of Certain Approximate Concentrations of Certain Electrolytes in Digestive FluidsElectrolytes in Digestive Fluids
Mosby items and derived items © 2006 by Mosby, Inc. Slide 33
Acids & BasesAcids & Bases
• Optimal degree of acidity or alkalinity must be maintained in body water solutions and secretions.
• More or less acid according to degree of concentration of hydrogen ions
• Acidity expressed in terms of pH