Chapter 20, part B

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings

Dee Unglaub Silverthorn, Ph.D.

HUMAN PHYSIOLOGYHUMAN PHYSIOLOGY

PowerPoint® Lecture Slide Presentation byDr. 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 BChapter 20, part BIntegrative Physiology II:

Fluid and Electrolyte Balance


Sodium Recycling: Recycling and ExcretionSodium Recycling: Recycling and Excretion

• Ascending loop of Henle

• H2O impermeable

• Na+ Active Transport

• To ECF

• Gradient

• Diffuses to blood

• Collecting Duct:

• Aldosterone regulates

• Na+ recycled or excreted


• Aldosterone: steroid H from adrenal cortex

• Stimulates Na+ uptake (& K+ secretion)

• channel synthesis

Mechanism of Na+ Selective Reabsorption in Collecting DuctMechanism of Na+ Selective Reabsorption in Collecting Duct


Mechanism of Na+ Selective Reabsorption in Collecting DuctMechanism of Na+ Selective Reabsorption in Collecting Duct

Figure 20-12: Aldosterone action in principal cells

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 20-13: The renin-angiotensin-aldosterone pathway

Angiotensin Pathway: Maintains BP , Volume & Osmolarity Angiotensinogen, ANGI, ANG II, rennin, & ACE

Angiotensin Pathway: Maintains BP , Volume & Osmolarity Angiotensinogen, ANGI, ANG II, rennin, & ACE


Artial Natruretic Peptide: Regulates Na+ & H2O ExcretionArtial Natruretic Peptide: Regulates Na+ & H2O Excretion

• Hormone from myocardial cells

• Stimulates: hypothalamus, kidney, adrenal, & medulla


Artial Naturetic Peptide: Regulates Na+ & H2O ExcretionArtial Naturetic Peptide: Regulates Na+ & H2O Excretion

Figure 20-15: Atrial natriuretic peptide


Potassium Balance: Critical for Excitable Heart & Nervous TissuesPotassium Balance: Critical for Excitable Heart & Nervous Tissues

• Hypokalemia – low [K+] in ECF, Hyperkalemia - high [K+]

• Reabsorbed in Ascending Loop, secreted in Collecting duct



Figure 20-4: Osmolarity changes as fluid flows through the nephron



Figure 20-12: Aldosterone action in principal cells


• Thirst & "salt craving", or avoidance behavior

• Integrated circulatory & excretory reflexes

Response to Dehydration & Osmolarity ImbalanceResponse to Dehydration & Osmolarity Imbalance


Response to Dehydration & Osmolarity ImbalanceResponse to Dehydration & Osmolarity Imbalance

Figure 20-17 : Homeostatic compensation for severe dehydration


• Acidosis: plasma pH

• Protein damage

• CNS depression

• Alkalosis: plasma pH

• Hyperexcitability

• CNS & heart

• Buffers: HCO3- & proteins

• H+ input: diet & metabolic

• H+ output: lungs & kidney

Acid/Base Homeostasis: OverviewAcid/Base Homeostasis: Overview


Acid/Base Homeostasis: OverviewAcid/Base Homeostasis: Overview

Figure 20-18: Hydrogen balance in the body


• H+ & NH4+ secreted into lumen and

excreted

• HCO3- is reabsorbed

Kidney Hydrogen Ion Balancing: Proximal TubuleKidney Hydrogen Ion Balancing: Proximal Tubule


Kidney Hydrogen Ion Balancing: Proximal TubuleKidney Hydrogen Ion Balancing: Proximal Tubule

Figure 20-21: Proximal tubule secretion and reabsorption of filtered HCO3-


• Type A Intercalated cells excrete H+ absorb HCO3

-

• Type B intercalated cells absorb H+ secrete HCO3

-

Kidney Hydrogen Ion Balancing: Collecting DuctKidney Hydrogen Ion Balancing: Collecting Duct


Kidney Hydrogen Ion Balancing: Collecting DuctKidney Hydrogen Ion Balancing: Collecting Duct

Figure 20-22: Role of the intercalated cell in acidosis and alkalosis







Classifications of Acute Kidney Injury and Chronic Kidney Disease.


Pathophysiological Features of Acute Kidney Injury Leading to Chronic Kidney Disease.




Figure 1Figure 1• An overview of the pathogenesis of CKD

progression. Although there is considerable interaction between BPdependent and BP-independent initiating mechanisms, BP-dependent mechanisms predominate in hypertensive CKD states. BP independent mechanisms may modulate hypertensive injury and also contribute to CKD progression in normotensive states. AR, autoregulation; BP, blood pressure; CKD, chronic kidney disease; NO, nitric oxide; RAAS, renin–angiotensin–aldosterone system; ROS, reactive oxygen species


SummarySummary• Electrolyte balance depends on integration

of circulatory, excretory and behavioral physiology

• Water recycling and ECF/plasma balance depends on descending loop of Henle and vasopressin regulated collecting duct for conservation

• Osmolarity depends on aldosterone and angiotensin pathway to regulate CNS & endocrine responses

• Along with respiration, proximal tubule and collecting duct cells reabsorb or excrete H+ & HCO3

- to balance pH

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Chapter 20, part B