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Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Dee Unglaub Silverthorn, Ph.D. H UMAN P HYSIOLOGY PowerPoint ® Lecture Slide.

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Presentation on theme: "Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Dee Unglaub Silverthorn, Ph.D. H UMAN P HYSIOLOGY PowerPoint ® Lecture Slide."— Presentation transcript:

1 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Dee Unglaub Silverthorn, Ph.D. H UMAN P HYSIOLOGY PowerPoint ® Lecture Slide Presentation by Dr. Howard D. Booth, Professor of Biology, Eastern Michigan University AN INTEGRATED APPROACH T H I R D E D I T I O N Chapter 20 Integrative Physiology II: Fluid and Electrolyte Balance

2 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Body Water Balance Figure 20-3: Role of the kidneys in water balance Urine concentration: Dilute: 300 mOsM Concentrated: 1200 mOsM

3 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings What is “put back” and where in the nephron. Proximal tubule Glucose (those carriers) & Na + (Primary active transport) urea (passive transport) Loop of Henle H 2 O and ions ( Na +, K+ & Cl - ) Distal tubule Na + & H 2 O Collecting duct H 2 O, Na + & urea (again)

4 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Overview: starts off isosmotic 300 mOsM (saltiness) Figure 20-4: Osmolarity changes as fluid flows through the nephron

5 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings VASOPRESSIN: If we NEED water, we can get it from the collecting duct!

6 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Vasopressin (a.k.a. ADH) regulates urine OsM: Let’s make concentrated uring part I Figure 20-5: Water movement in the collecting duct in the presence and absence of vasopressin

7 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Formation of Water Pores: Mechanism of Vasopressin Action

8 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 20-7: Factors affecting vasopressin release

9 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Countercurrent exchanger. Loop of Henle Let’s make concentrated uring part II Medullary osmotic gradient; more salty Figure 20-10: Countercurrent exchange in the medulla of the kidney Collecting duct

10 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The players: Loop of Henle Descending/ascending vasa recta Ions: which ones? H 2 O Why is it, countercurrent?

11 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Key facts: 1. descending LOH is water permeable, ascending LOH is NOT. 2. Ascending LOH actively pumps out ions. 3. water goes to where the most stuff is!!! 4. vasa recta removes water so it doesn’t dilute the medullary gradient.

12 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings What happens to the body’s OsM after eating salty fries? Increase/decrease This triggers two responses; can you guess? SODIUM BALANCE:

13 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Vassopressin and thirst; both decrease OsM, but raise blood pressure. To lower blood pressure our kidneys excrete sodium. How does excreting sodium lower BP?

14 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings WATER GOES TO WHERE THE MOST STUFF IS. When sodium leaves, water follows, decreasing ECF volume, and BP.

15 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Sodium Balance: Intake & Excretion Figure 20-11: Homeostatic responses to eating salt

16 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Sodium is regulated by aldosterone from the adrenal cortex. Aldosterone is actually secreted in response to blood pressure, blood volume and OsM. More aldosterone: more sodium reabsorption. Aldosterone target: principal cell (P cell) of the distal tubule & collecting duct.

17 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Mechanism of Na + Selective Reabsorption in Collecting Duct Figure 20-12: Aldosterone action in principal cells !water does not follow! Vassopressin must be present

18 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 20-13: The renin-angiotensin-aldosterone pathway How does aldosterone get released? RAAS: renin-angiotensin-aldosterone-system

19 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Artial Natruretic Peptide: Regulates Na + & H 2 O Excretion Figure 20-15: Atrial natriuretic peptide

20 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Potassium Balance: Critical for Excitable Heart & Nervous Tissues Hypokalemia – low [K + ] in ECF, Hyperkalemia - high [K + ] Reabsorbed in Ascending Loop, secreted in Collecting duct

21 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Potassium Balance: Critical for Excitable Heart & Nervous Tissues Figure 20-4: Osmolarity changes as fluid flows through the nephron

22 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Potassium Balance: Critical for Excitable Heart & Nervous Tissues Figure 20-12: Aldosterone action in principal cells

23 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Dee Unglaub Silverthorn, Ph.D. H UMAN P HYSIOLOGY PowerPoint ® Lecture Slide Presentation by Dr. Howard D. Booth, Professor of Biology, Eastern Michigan University AN INTEGRATED APPROACH T H I R D E D I T I O N Chapter 20, part B Integrative Physiology II: acid-base balance

24 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Acid/Base Homeostasis Acidosis:  plasma pH Protein damage CNS depression Alkalosis:  plasma pH Hyperexcitability CNS & heart Buffers: HCO 3 - & proteins H + input: diet & metabolic H + output: lungs & kidney Neutral pH is 7.0 Biological pH is 7.4 Determined based upon H + concentration.

25 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Acid/Base Homeostasis: Overview Figure 20-18: Hydrogen balance in the body

26 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Low pH – acidosis – nervous tissue becomes less exciteable – respiratory centers shut down. High pH – alkalosis – neurons become hyperexciteable – twitching, numbness – tetenay and paralyzed respiratory muscles.

27 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings pH homeostasis depends on 3 things: 1. buffers 2. the lungs 3. the kidneys

28 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Buffer systems Bicarbonate, phosphate ions, and proteins (Hb) Buffers prevent significant changes in pH by binding or releasing H + CO2 + H2OH2CO3 H + + HCO3 - carbonic anhydrase

29 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings What will drive the equation to the right? What will drive the equation to the left? CO2 + H2OH2CO3 H + + HCO3 - carbonic anhydrase How can ventilation compensate for pH disturbances? Pg. 647.

30 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Acidosis prevention at the Proximal Tubule: H+ excreted, bicarbonate reabsorption. Figure 20-21: Proximal tubule secretion and reabsorption of filtered HCO Na + - H + antiport activity 2.Glutamine metabolism

31 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Type A Intercalated cells excrete H + absorb HCO 3 - Type B intercalated cells absorb H + secrete HCO 3 - Kidney Hydrogen Ion Balancing: Collecting Duct

32 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Kidney Hydrogen Ion Balancing: Collecting Duct Figure 20-22: Role of the intercalated cell in acidosis and alkalosis The polarity of the two cells is reversed with the transport proteins on opposite sides.

33 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Acid-base disturbances: respiratory or metabolic Respiratory acidosis – hypoventilation & CO2 retention. COPD- loss of alveolar tissue Metabolic acidosis Metabolic acids increase protons Lactic acid from anaerobic metabolism burn sugar not oxygen. Respiratory alkalosis Hyperventilation rids CO2 Hysterical hyperventilation Renal compensation can occur Metabolic alkalosis Vomiting stomach acids and taking bicarbonate-containing antacids. Respiratory compensation takes place rapidly.


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