1. Chapter 6: Fluid, Electrolyte, and Acid- Base Imbalances Pathophysiology With intermission sessions & card questions

2. Serum pH HOMEOSTASIS Water (H2O) Sodium (Na) Potassium (K) Magnesium Phosphate Chloride Calcium (Ca)

3. Fluid Imbalances ~60% of the body is ______________. (in infants, its more like 70%)  females typically a little lower; males a little higher More or less? Elderly? Overweight? water

4. Fluids: ICF and ECF 2 Compartments ICF= intracellular fluid (inside the cells) ECF= extracellular fluid (outside the cells) –Intravascular fluid (IVF)= blood –Interstitial fluid (ISF)= intercellular –Cerebrospinal fluid (CSF) –Transcellular fluid= secretions (in the bursa, pericardial cavity)

5. overview

6. Most water is ICF (40%). About 20% is ECF.

7. Input=output Ideally, amount of water entering has to equal the amount of water leaving the body. –In: food and beverage ingested and waste from cell respiration (cell metabolism). –Out: urine, feces, skin, exhalation

8. Fluid balance controls Thirst- osmoreceptor cells “sense” any imbalances and hypothalamus causes thirst. ADH (antidiuretic hormone)- controls how much water comes out in urine (ADH promotes reabsorption in the kidneys) Aldosterone- hormone that conserves water by acting on kidneys as well.

9. Hematocrit

10. Question The incubation period refers to the time period between: –Entry of the pathogen and the first signs of infectious disease –The onset of the prodromal period and the peak of the acute infection –The onset of clinical signs and recovery from infection –The acute period and establishment of chronic infection

11. Entry of the pathogen and the first signs of infectious disease

12. Fluid Balance Moves freely between the compartments by processes of osmosis and filtration. Things diffuse (move from hi  low) –Depends on the hydrostatic and osmotic pressures Think of hydrostatic pressure as the “push” Think of osmotic pressure as the “pull”

14. I. Hypervolemia Increase in Blood volume Termed “edema” Interstitial fluid (ISF) builds up and tissues swell

15. Effects of Edema ( Hypervolemia) Swelling Pitting-pinching skin together, remove your fingers and the skin stays together because excess fluid has been moved aside Increase in body weight Functional impairment-(i.e. accumulated fluid around the heart or lungs Pain- edema exerts pressure on nerves Arterial circulation-increases interstitial pressure may restrict arterial blood flow to an area

16. Question Choose the correct proportion of water to body weight to be expected in a healthy male adult’s body: –30% –45% –60% –70%

17. 60%

18. Kidneys

19. Just think about it! Lost water lowers blood volume and pressure to: decrease renal output low glomerular filtration and increased ADH activity both of which act to conserve fluids.

20. glomerular filtration - The passive process by which water and small dissolved solute molecules, including the smallest proteins, e.g., albumin are forced through the capillary tuft within the renal corpuscle, and through the endothelial capsular membrane, and into the capsular space; the main driving force is the glomerular blood hydrostatic pressure

21. How body compensates for Hypervolemia Increase blood pressure Tachycardia Adjust body’s Na content

22. II. Hypovolemia Insufficient body fluid resulting from inadequate intake or excess loss or a combination of both. i.e.-vomiting Mild-decrease of body weight 2% Moderate-decrease 5% Severe-decrease 8%

23. Effects Infants Hypovolemia-decreased urine output and increased lethargy caused by their need to have increased fluids in their system because of their systemic increased metabolic rate (affects heart, brain, kidneys)

24. Question What is a typical sign of dehydration? –Rapid, strong pulse –Low hematocrit –Increased urine output –Rough oral mucosa

25. Rough oral mucosa

26. Specific Gravity Water-SP=1

27. Effects of (Hypovolemia) Dehydration Dry mucous membranes in mouth Decreased skin turgor or elasticity Lower blood pressure Weak pulse Fatigue Increased hematocrit (higher proportion of RBC compared to water in blood

28. Hypovolemia Body compensates by Increased thirst Increased heart rate Constricting blood vessels (pale skin) Decreased urine output (water retention- leads to higher SG, more concentrated urine as a result of renal vasoconstriction and increased secretion of ADH and aldosterone

29. Severe effects Brain cells loose water Decreasing metal function Confusion Loss of consciousness

30. Intermission Using a venn diagram or T-chart. Compare and contrast hypovolemia to hypervolemia

32. Fluid Deficit and Fluid Excess Third-spacing=fluid shifts out of the blood into a body cavity or tissue where it is no longer available as circulating fluid Examples: Peritonitis-inflammation Burns-extensive inflammation –Fluid deficit as a result of the shift of blood into body cavities (ie hypovolemia) ….fluid excess in interstitial spaces

33. Question When many hydrogen ions accumulate in the blood, what happens to serum pH? –It increases –It decreases –It stays the same –It fluctuates

34. It decreases

35. Electrolytes in body

36. Electrolytes Na= primary cation in extracellular fluid- (salts) Diffusion occurs between vascular and interstitial fluids Controlled by sodium-potassium pump What is another name for this process? _______ –Normally: Na levels are high in extracellular fluids Na low inside cell

37. Na Input = output Na into our system –Foods –Beverages Na out of our system –Perspiration –Urine –feces

38. Who controls Na levels? Kidneys through the action of aldosterone Aldosterone –Hormone –Determines reabsorption Na+ and H 2 O from kidney tubules –It conserves more fluid when there is a fluid deficit (hypovolemia) in body

39. Retention of sodium by the kidneys increases the retention of water, resulting in increased blood volume blood pressure

40. What is a common cause of hyponatremia? –Loss of the thirst mechanism –Excessive sweating –Excessive aldosterone secretion –Prolonged period of rapid, deep respirations

41. Excessive sweating

43. Na+= Why? sodium is the primary determinant of extracellular fluid volume extracellular fluid Maintenance of extracellular fluid volume via osmotic pressure Aids in: Conduction of nerve impulses Muscle contraction

45. Na & Circulatory system In the circulatory system, pressure receptors (baroreceptors) sense changes in blood pressure and send excitatory or inhibitory signals to the nervous system and/or endocrine glands to affect sodium regulation by the kidneys. In general, sodium retention results in water retention and sodium loss results in water lossendocrine glands

46. Hyponatremia Sodium deficit due to loss of Na from the body or from excess of water in extracellular compartments, which causes low serum levels in blood Causes: Excessive sweating Vomiting Diarrhea Low salt diets Insufficient aldosterone Renal failure

47. Hypernatremia Excessive sodium level in the blood and extracellular fluids Causes: –Insufficient ADH –Loss of thirst mechanism –Watery diarrhea –Period of rapid respiration

48. Signs of Na imbalance Hyponatremia Anorexia Nausea Cramps Muscle weakness Headache Confusion Seizures Decreased blood pressure Hypernatremia Thirst Weakness Lethargy Agitation Edema Elevated blood pressure

49. Potassium Imbalance K+ intracellular cation Ingested in foods Excreted in urine (which is influenced by aldosterone) Insulin (hormone) promotes movement of potassium into cells

50. Acid-Base Balance hypokalemia Low potassium serum levels Causes –Diarrhea –Diuretic drugs (heart meds) –Excessive aldosterone –Alcoholism –Starvation diets hyperkalemia High potassium serum levels Causes –Renal failure –Deficit of aldosterone –Potassium-sparing diuretic drugs –Intracellular into extracellular fluids –burns –Severe acidosis

51. Calcium Imbalance Ca++ extracellular cation-controlled by parathyroid hormone (PTH) & calcitonin, Influenced by vitamin D & phosphate ion levels Ingested in foodExcreted –Milk (stored in bone) urine » feces

52. Calcium In=out Calcium high=phosphate low Functions of Calcium –Structural strength bones and teeth –Stability nerve membranes (permeability and excitability nerve conduction)

53. Calcium imbalance hypocalemia Hypoparathyroidism Malabsorption Deficient serum albumin Increased serum pH Signs –Skeletal muscle spasms –Tingling fingers –Mental confusion hypercalcemia Uncontrolled release of Ca ions from bones due to neoplasms Malignant bone tumors Excessive vitamin D Signs –Lethargy –Nausea –thirst

54. Other electrolytes Magnesium-needed for enzyme reactions in the body, DNA synthesis Imbalances are rare –Green vegetables Phosphate-needed for cellular energy – ATP, removal of H+ from body via kidneys Chloride-assist in maintaining acid-base balance

55. Acid-base imbalance Cell enzymes function narrow pH range Normal serum levels: 7.35-7.45 Death-below 6.8, above 7.8

56. Acidosis or Alkalosis pH below 7.4 Acidosis More H+ ions present and acidosis results Body normally toward acidosis (lower pH) Cell metabolism is constantly producing CO 2 or carbonic acid H 2 CO 3 pH above 7.4 Alkalosis Fewer H+= ions present and alkalosis results

57. Nonvolatile Metabolic Acids –Lactic acid-anaerobic metabolism of glucose –Ketoacids-incomplete oxidation of fatty acids –Sulfates-protein metabolism –Phosphates-protein metabolism

58. Control of serum pH Blood circulates through body, nutrients diffuse from the blood into cells, metabolic procsses take place in cells using nutrients, metabolic wastes This metabolic waste diffuses from the cells into the blood

59. Buffer Systems Combination of a weak acid and its alkaline salt and blood Components react with any acids or alkali added to the blood neutralizing them and therefore-maintains constant pH of blood

60. How serum pH controlled 1. Buffer pairs circulating in blood respond to pH changes immediately 2. Respiratory system alters carbon dioxide levels in the body by changing respiratory rate 3. Kidneys modify excretion rate of acids and the production & absorption of bicarbonate ion

61. Treatments of Imbalances Maintain homeostasis by: Diagnosis and remove the underlying cause….. Increasing fluids of the particular electrolytes Diuretic drugs to increase the excretion of fluid through the kidneys

62. THE END Exam over Chapter 4, 5, & 6 March 4th & 5th