Copyright © 2010, Grant Iannelli, DC Unit 8 Seminar: Fluid/Electrolyte Balance Acid/Base Balance

Copyright © 2010, Grant Iannelli, DC

 Fluid balance: homeostasis-constancy of blood fluid levels needed for healthy survival  The total volume and distribution of water must remain normal and relatively constant  Fluid imbalance: the total volume of water in the body or the amounts in one or more of the fluid compartments have increased or decreased beyond normal limits.  Electrolytes-substances such as salts that dissolve or break apart in water solution.

Copyright © 2010, Grant Iannelli, DC  Water is most abundant compound found in the body  60% WEIGHT OF MALE  50% WEIGHT OF FEMALE  Fat tissue contains the least amount of water of any body tissue.  The more fat you have, the less total water content found in your body. Factors that influence fluid levels: 1. Fat content 2. Total body weight 3. Gender 4. Age

Copyright © 2010, Grant Iannelli, DC  Extracellular fluid- consists mainly of the liquid part of blood (plasma) and the interstitial fluid that surrounds the cells.  Intracellular fluid-located inside the cell Where is the larger volume found? EF or IF

Copyright © 2010, Grant Iannelli, DC  Three sources of fluid intake: 1. The liquids we drink 2. The water in the foods we eat 3. The water formed by catabolism of foods Fluid output from the body occurs through four organs: kidneys, lungs, skin and intestines. The body maintains fluid balance by excreting urine to match the fluid intake. What is the most important factor in determining urine volume (pg 463)

Copyright © 2010, Grant Iannelli, DC  Urine volume is regulated by hormones secreted in the pituitary gland and adrenal cortex.  ADH and aldosterone  The rate of water and salt resorption by the renal tubules is the most important factor in determining urine volume.

Copyright © 2010, Grant Iannelli, DC

 Water is continually lost from the body through expired air and diffusion through the skin.  What are some symptoms or signs of dehydration? Pg 463

Copyright © 2010, Grant Iannelli, DC  Why is the body unable to reduce its fluid output to zero no matter how dehydrated it is?

Copyright © 2010, Grant Iannelli, DC  Electrolytes-compounds that break up or dissociate in water solution into separate particles  Example: Ordinary table salt (NaCL) can break up into Na and Cl  They are able to conduct electrical current.  Nonelectrolytes-compounds that do not break up or dissociate in water solution.

Copyright © 2010, Grant Iannelli, DC  Ion-a dissociated particle of an electron.  Cation-a positively charted ion  Anion-a negatively charged ion  Cations: sodium, calcium, potassium, magnesium  Ions: chloride, bicarbonate, phosphate and many proteins  Most common cation in EF?  Most common cation in IF?  Most common anion in EF?  Most common anion in IF?

Copyright © 2010, Grant Iannelli, DC  Required for things such as nerve conduction, acid base balance, bone formation, blood clotting, hydrochloric acid production in the stomach.  WHERE SODIUM GOES, WATER SOON FOLLOWS!  If you give normal saline solution, the sodium will go into the blood and then cause fluid to move from the interstitual fluid and into the plasma. This will increase blood volume and stabilize blood pressure.  Edema-tissue swelling-caused by the presence of high amounts of sodium and fluid in the IF.  What is pitting edema?

Copyright © 2010, Grant Iannelli, DC

 Capillary blood pressure-pushes water out of the blood in the capillaries and into the IF.  Higher capillary blood pressure equals more fluid being pushed out of the blood and into the IF.  Fluid shift-a decrease in blood volume and an increase in IF volume.  Constant movement of water from the capillaries into the IF and vice versa.  The amount that moves out of the capillary blood depends on the blood pressure.  The amount that moves from the IF into the capillary blood depends on the concentration of blood proteins found in the plasma.

Copyright © 2010, Grant Iannelli, DC  Plasma proteins act as water pulling or water holding.  They hold water in the blood and also pull water into the blood from the IF.  A deficiency in blood proteins can cause less water to move from the IF and into the blood.  This causes blood volumes to decrease and IF volumes to increase.

Copyright © 2010, Grant Iannelli, DC  Where sodium goes, water soon follows  The kidneys are the chief regulator of sodium levels in the body.  Aldosterone controls sodium reabsorption in the kidney.  Renal tubule regulation of salt and water is the most important factor in determining urine volume.

Copyright © 2010, Grant Iannelli, DC  What is dehydration? Total volume of bod fluids is less than normal. IF decreases first, then plasma volume decreases  What is overhydration? Total volume of body fluids greater than normal

Copyright © 2010, Grant Iannelli, DC

Acid-Base Balance

Copyright © 2010, Grant Iannelli, DC Keeping the concentration of hydrogen ions in the body fluids relatively constant. Maintaining this balance involves mechanisms in the blood, lungs, kidneys and other body fluids. Hydrogen ions and hydroxide ions- found in water and all water solutions

Copyright © 2010, Grant Iannelli, DC  A pH of 7.0 is Neutral  A pH lower than 7 indicates an acid solution_this means it has more hydrogen ion concentration and is more acidic.  A pH of more than 7.0 is alkaline- the more alkaline the solution, the higher its pH.  Gastric juice is the most acidic substance in the body.  The term pH indicates a solutions hydrogen ion concentration  Which is more alkaline-venous blood or arterial blood?

Copyright © 2010, Grant Iannelli, DC CO2 is formed during cellular breakdown of the nutrient glucose. This is known as aerobic respiration. When the CO2 enters the blood, some combines with H2O and is converted to carbonic acid. H2CO3 The lungs remove this carbonic acid when CO2 is breathed out.

Copyright © 2010, Grant Iannelli, DC  1) the buffer mechanism  2) the respiratory mechanism  3) the urinary mechanism Blood pH All of these mechanisms work together to keep blood slighly alkaline.

Copyright © 2010, Grant Iannelli, DC  Chemical substances that prevent a sharp change in the pH of a fluid when an acid or base is added to it.  More acids than bases are usually added to body fluids.  Catabolism produces acids. Some hydrogen ions are absorbed through the GI tract.  Buffer pairs-two kinds of substances  Sodium bicarbonate and carbonic acid are buffer pairs

Copyright © 2010, Grant Iannelli, DC

 Explain the respiratory mechanism of pH control.

Copyright © 2010, Grant Iannelli, DC  Respirations play a crucial role in regulating H+ concentrations and controlling body ph.  CO2 diffuses out of venous blood as it moves into the lung capillaries.  The arterial blood leaving the lung capillaries has less CO2 available.  This means less CO2 is available to combine with water to form carbonic acid (remember page 477)  Arterial blood contains less carbonic acid and has a higher pH (more alkaline) than venous blood.

Copyright © 2010, Grant Iannelli, DC  Anything that causes a marked decrease in respirations will in time produce acidosis.  Anything that causes an excessive increase in respirations will in time produce alkalosis  If you hold your breath, no CO2 leaves and the blood content of CO2 rises. This causes an increase in carbonic acid-which results in acidosis.  If you breath rapidly, the levels of CO2 leaving the body increase, which result in less carbonic acid production-which results in alkalosis.

Copyright © 2010, Grant Iannelli, DC  More acids than bases enter the blood, therefore more acids than bases are excreted by the kidneys.  The distal tubules rid the blood of excess acid and also help conserve base at the same time.  See page 481 for more info.

Copyright © 2010, Grant Iannelli, DC  Metabolic acidosis-bicarbonate deficit  Metabolic alkalosis-bicarbonate excess  Respiratory acidosis-carbonic acid excess  Respiratory alkalosis-carbonic acid deficit  Which is more common, acidosis or alkalosis? Why?

Copyright © 2010, Grant Iannelli, DC  Metabolic alkalosis is a complication of vomiting.  There is a bicarbonate excess because of the massive loss of chloride from the stomach as hydrochloric acid.  There is excess bicarbonate in the extracellular fluid-uncompensated metabolic alkalosis.  First the body slows down respiration to retain more CO2 which helps increase carbonic acid levels  Second it increases the elimination of bicarbonate in the urine.  Chloride administration may also be given

Copyright © 2010, Grant Iannelli, DC  Respiratory acidosis-carbonic acid excess caused by the retention of CO2 in the body. This occurs when respiration ceases and blood flow through the lung capillaries stops.  After breathing is restored, the body attempts to “blow off” some additional CO2.  See page 485.

Copyright © 2010, Grant Iannelli, DC