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Renal Physiology for Lab

Renal Physiology for Lab. Urinalysis Lab . 1. What would most likely be the cause of a urine sample with a positive test for nitrites, leukocytes and a slightly higher than normal pH? Urinary tract infection

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Renal Physiology for Lab

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  1. Renal Physiology for Lab

  2. Urinalysis Lab • 1. What would most likely be the cause of a urine sample with a positive test for nitrites, leukocytes and a slightly higher than normal pH? Urinary tract infection • 2.Are proteins or blood normally found in urine? If they are present, how might they get there? No; kidney infection, glomerulonephritis, trauma, kidney stones • 3. If the urine sample tests positive for ketones and glucose, for what disease should the patient be checked? Diabetes mellitus • 4. Elevated levels of urobilinogen and bilirubin may indicate problems with what organ? • Liver • 5. What dietary habits may cause an acidic urine sample (more acidic than normal)? High proteins or acidic foods • 6. What would cause a basic urine sample?vegetarian diet

  3. Urinalysis Lab 7. Normal urine is usually yellow to amber in color, due to the presence of what pigment? Urochrome 8. What blood protein (like all other proteins) is too large to pass through the glomerular filtration membrane, and so is not normally found in the urine? Albumin 9. Circle the correct term: Hematuria / Ketonuria, the appearance of red blood cells in the urine, indicates pathology. 10. The appearance of bile pigments in the urine is known as __________________, and indicates liver disease. Bilirubinuria 11. Circle the correct term: Casts / Caliculi are hardened cell fragments formed in the DCT and collecting ducts and flushed out of the urinary tract. 12. When determining the presence of inorganic constituents such as sulfates, phosphates, and chlorides, you look for the formation of a precipitate. What is a precipitate? A cloudy solid that forms

  4. Urinalysis

  5. 1 Glomerulus 2 Bowman’s capsule 3 Proximal convoluted tubule 8 Late Distal convoluted tubule 7 Early Distal convoluted tubule Collecting duct 9 6 Thick Ascending Limb Descending limb 4 5 Loop of Henle (tip)

  6. 1 Glomerulus 2 Bowman’s capsule colloid osmotic pressure here is essentially zero Capillary hydrostatic pressure is very high here. 3 Proximal convoluted tubule • Secretes creatinine, antibiotics, diuretics, H+ and uric acid.

  7. 6 Thick Ascending Limb • Is sensitive to the diuretic furosemide (Lasix). • This area is impermeable to water unless a hormone like aldosterone or ADH allows it. 4 Descending limb Secreted into the lumen here is 50% Urea, small amount of sodium and water 5 Loop of Henle (tip) Tubular fluid here is hyperosmotic to plasma, and is not hormone sensitive

  8. 8 Late Distal convoluted tubule Reabsorbs salt and H2O water if aldosterone and ADH are present. 7 Early Distal convoluted tubule This area is the site of hormonallyregulated potassium • Macula densa is found here. • This area is acted upon by aldosterone and ADH • Intercalated cells here secrete hydrogen and make • “new” bicarbonate. • This area is acted upon by parathyroid hormone. • This area Is sensitive to sodium channel blockers like amiloride and aldosterone inhibitors.

  9. 9 Collecting duct No water is reabsorbed unless ADH or aldosterone is present. No salt is reabsorbed unless aldosterone is present. Reabsorbs bicarbonate and urea; Secretes K+ • Intercalated cells here secrete hydrogen and make • “new” bicarbonate. • This area has the maximally • hyperosmotic fluid when ADH levels are high.

  10. Imagine It…. • Each of these particles is like a person who works in a factory in Glomerulus City. • They all leave work at 5pm and have to take the same freeway home (the Tubular Freeway). • Each of them get off at different freeway exits.

  11. The People • THE GOOD NUTRIENTS • Water • Salt (NaCl) • Glucose • Amino acids • THE WASTE PRODUCTS • Urea • Creatinine • Antibiotics • Diuretics • Uric acid • THE GOOD ELECTROLYTES • Potassium (K+) • Calcium (Ca2+) • Magnesium (Mg2+) • Phosphate (PO4) • Bicarbonate (HCO3-) • H+ • THE LAW ENFORCEMENT OFFICIALS • Aldosterone • ADH • Parathyroid hormone • Furosemide (Lasix) • Hormones that regulate potassium (aldosterone and insulin) • Sodium channel blockers like Amiloride (a potassium sparing diuretic) and aldosterone inhibitors

  12. The Freeway Exits • Proximal Convoluted Tubule (PCT) • Priority City Tunnel (these people are rich and have a Fast Track pass!) • Descending limb (DL) • Disneyland! • Loop of Henle, tip (LOHT) • City of Low Hats (and they TIP their hats to you…very polite!) • Thick Ascending Limb (TAL) • City of TALL TALES (this is where all the movie theaters are) • Early Distal convoluted tubule (ED) • City of Education (this is where the schools are) • Late Distal convoluted tubule (LD) • Lucky District (this is where the gambling casinos are) • Collecting duct (CD) • The criminal district

  13. The Workers and their exits THE GOOD NUTRIENTS • Water (picture a water delivery man) • PCT (2/3 of water exits) • DL (1/3 leaves, but it could enter) • TAL (leaves only if aldosterone or ADH present) • ED (leaves only if aldosterone or ADH present) • LD (leaves only if aldosterone or ADH present) • CD (leaves only if aldosterone or ADH present) • Salt (NaCl) (picture a salt shaker) • PCT (2/3 leaves) • DL (1/3 leaves) • TAL (leaves if aldosterone present) • ED (leaves if aldosterone present) • LD (leaves if aldosterone present) • CD (leaves only if aldosterone is present) • Glucose (picture a lollipop) • PCT • Amino acids (picture a cow) • PCT Leaving the freeway means reabsorption Entering the freeway means secretion

  14. The Workers and their exits THE GOOD ELECTROLYTES • Potassium (K+) allows for muscle contraction (picture a body builder) • PCT (leaves) • DL (leaves) • LD (enters the freeway here) • CD (enters the freeway here) • Calcium (Ca2+) for strong bones (picture a skeleton) • PCT (leaves) • LOHT (leaves) • ED (leaves) • Magnesium (Mg2+) for muscle relaxation (picture a massage therapist) • PCT (leaves) • LOHT (leaves) • Phosphate (PO4) for ATP (picture a race car driver) • PCT (leaves) • Bicarbonate (HCO3-) (picture a fire extinguisher) • TAL (leaves) • ED (leaves) • LD (leaves) • CD (enters or leaves here) • H+ (picture an acid-squirting monster) • PCT (enters the freeway here) • ED (enters the freeway here) • LD (enters the freeway here) • CD (enters or leaves here) Leaving the freeway means reabsorption Entering the freeway means secretion

  15. The Workers and their exits THE WASTE PRODUCTS • Urea (a waste product of protein metabolism; picture a Rhea bird, similar to an ostrich) • PCT (leaves) • DL (enters the freeway here) • LD (enters the freeway here) • Creatinine (a waste product of protein metabolism) • PCT (enters the freeway here) • Antibiotics • PCT (enters the freeway here) • Diuretics • PCT (enters the freeway here) • Uric acid • PCT (enters the freeway here) Leaving the freeway means reabsorption Entering the freeway means secretion

  16. The Workers and their exits HORMONES AND MEDICINES (LAW ENFORCEMENT) • Aldosterone • TAL (acts on this site) • ED (acts on this site) • LD (acts on this site) • CD (acts on this site) • ADH • TAL (acts on this site) • ED (acts on this site) • LD (acts on this site) • CD (acts on this site) • Sodium channel blockers like Amiloride (a potassium sparing diuretic) and aldosterone inhibitors; (City salt monitor…no more salt allowed to leave) • TAL (acts on this site to prevent sodium from being reabsorbed) • ED (acts on this site to prevent sodium from being reabsorbed) • LD (acts on this site to prevent sodium from being reabsorbed) • CD (acts on this site to prevent sodium from being reabsorbed) • Parathyroid hormone (school milk man) • ED (acts at this site to increase calcium reabsorption) • Hormones that regulate potassium (aldosterone and insulin); (school banana monitor) • ED (acts on this site to cause potassium to either enter or leave) • Furosemide (Lasix) • TAL (acts on this site to block water reabsorption) Leaving the freeway means reabsorption Entering the freeway means secretion

  17. Cut out the characters to practice moving them into and out of the tubules. Nutrients are green, electrolytes are yellow, waste is black, hormones and medicines are purple. 2/3 water Water Water Water Water 1/3 water Phosphate Salt Salt Salt Salt 1/3 Salt 2/3 Salt Glucose Amino Acids Magnesium Magnesium Potassium Potassium Potassium Potassium

  18. Calcium Calcium Calcium Parathyroid hormone Bicarbonate Bicarbonate Bicarbonate Bicarbonate Hormones that regulate K+ Hydrogen ions Hydrogen ions Hydrogen ions Hydrogen ions Sodium channel blockers Furosemide (Lasix) Aldosterone/ADH Urea Urea Urea

  19. Glomerulus • This area has the maximally • hyperosmotic fluid when ADH levels are high. This area is the site of hormonallyregulated potassium Bowman’s capsule • Secretes creatinine, antibiotics, diuretics, H+ and uric acid. Proximal convoluted tubule (Priority City Tunnel) • Macula densa is found here. Tubular fluid here is hyperosmotic to plasma, and is not hormone sensitive Reabsorbs bicarbonate and urea; Secretes K+ Descending limb (Disneyland) • This area is impermeable to water unless a hormone like aldosterone or ADH allows it. • This area is acted upon by parathyroid hormone. Loop of Henle (tip) (Low Hat Tipping) No water is reabsorbed unless ADH or aldosterone is present. No salt is reabsorbed unless aldosterone is present. • This area Is sensitive to sodium channel blockers like amiloride and aldosterone inhibitors. Thick Ascending Limb (Tall Tales movie theater) • Intercalated cells here secrete hydrogen and make • “new” bicarbonate. • Is sensitive to the diuretic furosemide (Lasix). Early Distal convoluted tubule (Education Department) Reabsorbs salt and H2O water if aldosterone and ADH are present. Capillary hydrostatic pressure is very high here. Late Distal convoluted tubule (Lucky District with casinos) Secreted into the lumen here is 50% Urea, small amount of sodium and water • This area is acted upon by aldosterone and ADH Collecting duct (Criminal district) • Intercalated cells here secrete hydrogen and make • “new” bicarbonate. colloid osmotic pressure here is essentially zero

  20. Print this page. Add the yellow labels on the previous page first, then run the pictures on the previous page through the tubule and make them exit and enter at the right locations. Then place the white text boxes in the locations where they belong.

  21. Acids must be buffered, transported away from cells, and eliminated from the body.These are the most important buffers. Phosphate:important renal tubular buffer HPO4- + H+ H2PO4 Ammonia:important renal tubular buffer NH3 + H+ NH4+ Proteins:important intracellular and plasma buffers H+ + Hb HHb Bicarbonate: most important Extracellular buffer and is also another important renal tubular buffer. H2O + CO2 H2CO3 H+ + HCO3-

  22. Buffering Systems • The three different buffering systems are: 1) Respiratory buffering system • Uses bicarbonate 2) Blood buffering system • Uses bicarbonate, phosphate, and protein 3) Renal buffering system • Uses bicarbonate, phosphate, and ammonia

  23. BUFFERING SYSTEMS BUFFERS USED BY THE BUFFERING SYSTEMS Phosphate Phosphate Respiratory System Bicarbonate Bicarbonate Bicarbonate Blood Proteins Ammonia Kidneys

  24. pH Imbalances • Acidosis • Can be metabolic or respiratory • Alkalosis • Can be metabolic or respiratory

  25. Acidosis • Acidosis is excessive blood acidity caused by an overabundance of acid in the blood or a loss of bicarbonate from the blood (metabolic acidosis), or by a buildup of carbon dioxide in the blood that results from poor lung function or slow breathing (respiratory acidosis).

  26. Respiratory acidosis • Respiratory acidosis is due to an accumulation of CO2 in the blood stream. This pushes the carbonic anhydrase reaction to the right, generating H+: carbonic anhydraseH2O + CO2          H2CO3        HCO3(-)   +   H+

  27. Respiratory acidosis • Cause • The increase in CO2 in the blood is often caused by hypoventilation. • This can be caused by asthma, COPD, and overuse of sedatives, barbiturates, or narcotics such as valium, heroin, or other drugs which make you sleepy. • It can also be caused by other things wrong with the lungs: an accident were the breathing muscles are damaged (causing decreased ventilation), airway obstruction, or lung disease (pneumonia, cystic fibrosis, emphysema, etc.).

  28. Respiratory acidosis • Compensation • Even if the peripheral receptors sense the change in pH, the lungs are unresponsive. • The kidneys will compensate by secreting H+. • If H+ excretion cannot restore the balance, the kidneys will also generate bicarbonate. • Since the primary abnormality is an increase in pCO2, the compensatory response is intracellular buffering of hydrogen (by hemoglobin) and renal retention of bicarbonate, which takes several days to occur.

  29. Respiratory acidosis • Symptoms • May have no symptoms but usually experience headache, nausea, vomiting, and fatigue. • Breathing becomes deeper and slightly faster (as the body tries to correct the acidosis by expelling more carbon dioxide). • As the acidosis worsens, people begin to feel extremely weak and drowsy and may feel confused and increasingly nauseated. • Eventually, blood pressure can fall, leading to shock, coma, and death. • The most common clinical intervention is IV bicarbonate and applying an oxygen mask.

  30. Respiratory acidosis • Treatment • Treatment is aimed at the underlying disease, and may include: • Bronchodilator drugs to reverse some types of airway obstruction • Noninvasive positive-pressure ventilation (sometimes called CPAP or BiPAP) or a breathing machine, if needed • Oxygen if the blood oxygen level is low • Treatment to stop smoking

  31. Metabolic acidosis • Metabolic acidosis is the gain of acid or the loss of bicarbonate. • Cause • Usual causes are the generation of ketone bodies in uncontrolled diabetes mellitus, diarrhea (loss of bicarbonate), excess protein consumption (breakdown products are amino ACIDS), or excess alcohol consumption: (alcohol   formaldehyde    acetic acid). • Can also be caused by ingestion of an acid (aspirin, ethanol, or antifreeze). • Exercise creates a milder, transient metabolic acidosis because of the production of lactic acid.

  32. Metabolic acidosis • Compensation • The body will compensate with hyperventilation and increased bicarbonate reabsorption in the kidney. • Since the primary abnormality is a decrease in HCO3, the compensatory response includes extracellular buffering (by bicarbonate), intracellular buffering (by phosphate and proteins), respiratory compensation and renal hydrogen excretion. • Metabolic acidosis stimulates an increase in ventilation (reducing pCO2). • This hyperventilation is called Kussmaul's respiration.

  33. Metabolic acidosis • Symptoms • Most symptoms are caused by the underlying disease or condition that is causing the metabolic acidosis. • Metabolic acidosis itself usually causes rapid breathing. • Confusion or lethargy may also occur. • Severe metabolic acidosis can lead to shock or death. • In some situations, metabolic acidosis can be a mild, chronic (ongoing) condition.

  34. Metabolic acidosis • Treatment is give i.v. of sodium bicarbonate. • The HCO3- deficit can be calculated by using the following equation: • HCO3- deficit = deficit/L (desired serum HCO3- - measured HCO3-) x 0.5 x body weight (volume of distribution for HCO3-) • This provides a crude estimate of the amount of HCO3- that must be administered to correct the metabolic acidosis; the serum HCO3- level or pH should be reassessed frequently.

  35. Alkalosis • Alkalosis is excessive blood alkalinity caused by an overabundance of bicarbonate in the blood or a loss of acid from the blood (metabolic alkalosis), or by a low level of carbon dioxide in the blood that results from rapid or deep breathing (respiratory alkalosis).

  36. Respiratory alkalosis • Respiratory alkalosis is generally caused by hyperventilation, usually due to anxiety. The primary abnormality is a decreased pCO2. • Cause • Caused from a decrease in CO2 in the blood because the lungs are hyperventilating (anxiety, but not panting). • Fever or aspirin toxicity may also cause respiratory alkalosis.

  37. Respiratory alkalosis • Compensation • The body will reduce the breathing rate if the respiratory problem is from anxiety. • The kidney will excrete bicarbonate. • The kidney will also stop excreting H+, and may also reabsorb more H+.

  38. Respiratory alkalosis • Compensation • The compensatory response to a respiratory alkalosis is initially a release of hydrogen from extracellular and intracellular buffers. • This is followed by reduced hydrogen excretion by the kidneys. • This results in decreased plasma bicarbonates. • In chronic respiratory alkalosis, compensatory measures can make the pH revert to normal.

  39. Respiratory alkalosis • Symptoms • Irritability • Muscle twitching • Muscle cramps

  40. Respiratory alkalosis • Treatment • Treatment for hyperventilation is to breathe into a paper bag for a while, as the person breathes carbon dioxide back in after breathing it out. • For severe cases, need to replace the water and electrolytes (sodium and potassium).

  41. Metabolic alkalosis • Metabolic alkalosis is due to the gain of base or the loss of acid. The primary abnormality is having an increased HCO3 seen in the blood test. • Cause • Caused from an increase in bicarbonate in the blood because of ingestion of excess bicarbonate in the form of an antacid (Tums), eating excess fruits (vegetarian diets and fad diets*), loss of acid from vomiting, or loss of potassium from diuretics.

  42. Metabolic alkalosis • Compensation • This is initially buffered by hydrogen buffers (such as plasma proteins and lactate). • Chemoreceptors in the respiratory center sense the alkalosis and trigger hypoventilation, resulting in increased pCO2. • The respiratory system will hypoventilate but this will not be effective because CO2 will accumulate and the CO2 receptors will override the pH receptors.

  43. Metabolic alkalosis • Compensation • Naturally, the extent of respiratory compensation will be limited by the development of hypoxia with continued hypoventilation. The kidney will make more of a difference by not reabsorbing bicarbonate. • In addition to respiratory compensation, the kidneys excrete the excess bicarbonate. However, this takes several days to occur.

  44. Metabolic alkalosis • Symptoms • Confusion (can progress to stupor or coma) • Hand tremor • Light-headedness • Muscle twitching • Nausea, vomiting • Numbness or tingling in the face, hands, or feet • Prolonged muscle spasms (tetany)

  45. Metabolic alkalosis • Treatment is to give an anti-emetic if the problem is from vomiting. If not, give an i.v. of normal saline to increase the blood volume. • If potassium is also low, would have to add that to the i.v.

  46. Interpreting Arterial Blood Gases (ABG) • This blood test is from arterial blood, usually from the radial artery. • There are three critical questions to keep in mind when attempting to interpret arterial blood gases (ABGs). First Question: Does the patient exhibit acidosis or alkalosis? Second Question: What is the primary problem? Metabolic? or Respiratory? Third Question: Is the patient exhibiting a compensatory state?

  47. Assessment Step 1 • Step One: Determine the acid/base status of the arterial blood. • If the blood's pH is less than 7.35 this is an acidosis, and if it is greater than 7.45 this is an alkalosis. You may hear nurses or doctors say: "The patient is 'acidotic' or 'alkalotic' Know the normal ranges for pH

  48. Assessment Step 2 • Once you have determined the pH, you can move on to determine which system is the 'primary' problem: respiratory or metabolic. • To do this, examine the pCO2 and HCO3 levels.

  49. Assessment Step 3 • Determine if the body is attempting to compensate for the imbalance or not.

  50. Review the three essential steps of ABG analysis • Number One: Determine if the patient is demonstrating an acidotic (remember: pH less than 7.35) or alkalotic (pH greater than 7.45). • Number Two: • What is the 'primary problem? • If the patient is acidotic with a pC02 greater than 45 mmHg it is RESPIRATORY • If the patient is acidotic with a HC03 less than 22 mEq/L it is METABOLIC • If the patient is alkalotic with a pC02 less than 35 mmHg it is RESPIRATORY • If the patient is alkalotic with a HC03 greater than 26 mEq/L it is METABOLIC Know the normal ranges for pCO2 and HCO3

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