Renal Notes PDF

Copyright © 2009 Pearson Education, Inc., Dr. S. Windvogel publishing as Pearson Benjamin Cummings; Acknowledgements: 1. Silverthorne D (2010). Human Physiology-An integrated approa...

Copyright © 2009 Pearson Education, Inc., Dr. S. Windvogel publishing as Pearson Benjamin Cummings; Acknowledgements: 1. Silverthorne D (2010). Human Physiology-An integrated approach. 5th ed. ([email protected], 3042, BMRI, 938 9613) Pearson Benjamin Cummings; 2. Martini FH (2006). Fundamentals of Anatomy & Physiology. 7th ed. Pearson Benjamin Cummings;  Nier Funksies Kidney Functions 1. Reguleer ekstrasellulêre vloeistof 1. Regulates extracellular fluid (ECF) volume and blood pressure volume (ESV) volume en bloeddruk 2. Regulates osmolarity, i.e. 2. Reguleer osmolariteit, d.w.s. concentration (about 290mOsm) 3. Ion balance konsentrasie (omtrent 290mOsm) 4. pH regulation 3. Ioon balans 5. Hormone production 4. pH-regulering 6. Excretion 5. Hormoon vervaardiging 7. Gluconeogenesis 6. Ekskresie 7. Glukoneogenese 2 Figure 19.1 Anatomy Summary – The Urinary System 26UrinryStruc_A_MOV.mov 26-3 2 kidneys, paired ureters-one for each kidney, the urinary bladder-the storage site for urine and the urethra, the passageway for the excretion of urine Simulation Click the Simulation button to edit this object 26UrinryStruc_A_MOV.mov 26-4 Figure 19.1 Anatomy Summary – The Urinary System 5  +/1. 1 million nephrons/kidney Figure 19.1 Anatomy Summary – The Urinary 6 System  Nier Funksie Renal Function Konsentreer die filtraat deur Concentrates the filtrate by glomerular glomerulêre filtrasie: filtration-failure → dehydration mislukking→ dehidrasie Absorbeer en behou waardevolle Reabsorbs and retains useful materiaal vir gebruik deur ander substances that are used by other weefsels: suikers en aminosure tissues: sugars and amino acids Doel van urien produksie: om Purpose of urine formation: to homeostase te behou deur die maintain homeostasis by regulating regulering van die volume en the volume and composition of blood samestelling van bloed en sluit die and includes the excretion of ekskresie van metaboliese metabolic wastes afvalprodukte in Niere produseer gewoonlik Kidneys usually produce concentrated gekonsentreerde urien: 1200-1400 urine: 1200-1400 mOsm /L mOsm/L 7  (Useful substances e.g. Water, small organic molecules, electrolytes) (Movement of selected substances from blood into tubule fluid, e.g. toxins, drugs e.g. Penicillin, etc.) R: water, small organic R:HCO3-, Na+ Cl- molecules (glucose, S: K+, H+ amino acids, 80% electrolytes; S: wastes e.g. urea, drugs, toxins 20 % Filtered = FILTRATION FRACTION R: HCO3-, Na+ 100% (Aldosterone dependent) Cl-, Urea (medullary collecting duct) , Water (ADH dependent) R: NaCl-, S: K+, H+ R: water 8 Unless reabsorbed, secreted substances destined to become part of urine. Fig. 19.2  (Useful substances e.g. Water, small organic molecules, electrolytes) (Movement of selected substances from blood into tubule fluid, e.g. toxins, drugs e.g. Penicillin, etc.) R: water, small organic R:HCO3-, Na+ Cl- molecules (glucose, S: K+, H+ amino acids, 80% electrolytes; S: wastes e.g. urea, drugs, toxins 20 % Filtered = FILTRATION FRACTION R: HCO3-, Na+ 100% (Aldosterone dependent) Cl-, Urea (medullary collecting duct) , Water (ADH dependent) R: NaCl-, S: K+, H+ R: water 8 Unless reabsorbed, secreted substances destined to become part of urine. Fig. 19.2 Renal Handling Glomerular filtration rate (GFR)=125ml/min which is equivalent to 180l/day Fig. 19.3 9  Filtration occurs in the renal corpuscle Fig. 19.5 Renal filtrate= Plasma (iso- osmotic) minus blood cells and Proteinuria blood proteins ‘protein in urine’ May result from: Prolonged (hypoxia) to cells of filtration membrane. Defective /damaged  M.w. 7000 Da freely filtered filtration apparatus.  7000-70000 Da variable  Albumin 66000Da 0.02%, +/-7nm (+/-6-9nm) (+/- 60-100nm) GFR=125ml/Min/180L/Day 10 Fig. 20.03 11  3 Vlakke van GFS Beheer 3 Levels of GFR Control 1. Outoregulering: (plaaslike vlak: 1. Autoregulation: (local level: myogenic miogene respons, tubuloglomerulêre response, tubuloglomerular feedback) terugvoer) 2. Hormonal regulation (initiated by kidneys) 2. Hormonale regulering (geïnisieer deur Renin–angiotensin system , natriuretic die niere) peptides Renien-angiotensien-stelsel, natriuretiese peptiede Angiotensin II Angiotensien II Prostaglandins Prostaglandiene 3. Autonomic regulation: sympathetic 3. Outonomiese regulasie: simpatiese division Why must GFR be regulated? afdeling 1. Too high pressures can cause flow to occur too fast for reabsorption to take place, thus causing loss of essential solutes and water. 2. Too low a GFR can cause wastes/toxins to build up 12 5 Funksies van die 5 Functions of the Proksimale Buisie Proximal tubule 1. Herabsorpsie 1. Reabsorption of van organiese organic nutrients voedingstowwe 2. Active reabsorption 2. Aktiewe of ions herabsorpsie van ione 3. Reabsorption of water 3. Herabsorpsie 4. Passive van water reabsorption of ions 4. Passiewe herabsorpsie 5. Secretion van ione 5. Sekresie ook lipied-oplosbare materiale, Cl- 13  Principle governing the tubular reabsorption of solutes and water Meer as 99% van glukose, aminosure, ander organiese voedingstowwe word herabsorbeer Over 99% of glucose, amino acids, other organic nutrients reabsorbed. Herabsorpsie van H20 en opgeloste stowwe benodig dus indirek, aktiewe transportmeganismes. Aktiewe vervoer skep elektrochemiese of konsentrasie gradiënte om toe te laat dat stowwe in die ESV beweeg. H20 and solute reabsorption thus indirectly requires active transport. Active transport creates electrochemical or concentration gradients to allow substances to move into ECF. 14 Fig. 19.11 Sekondér aktiewe oordrag: natrium gekoppelde simport Secondary active transport: sodium linked symport Filtrate is similar to interstitial fluid. 1 Na+ moving down its electrochemical gradient Glucose and Na+ + using the SGLT protein pulls glucose into the [Na+] high [Na+] low reabsorbed cell against its concentration gradient. [glu] low [glu] high 2 [glu] low 2 Glucose diffuses out the basolateral side of glu glu the cell using the GLUT protein. 1 Na+ Na+ 3 3 Na+ is pumped out by Na+-K+-ATPase. [Na+] high ATP K+ KEY ATP = Active transporter = SGLT secondary active transporter Tubule lumen Proximal tubule cell Interstitial fluid = GLUT facilitated diffusion carrier 15 Fig. 19.8c Fig. 19-13  Sekresie Secretion Aktiewe sekresie vind plaas by die PKB Active secretion occurs at PCT but also maar ook by die DKB at DCT. Sluit in K+, H+, dwelmmiddels bv. Include, K+, H+, drugs e.g. penicillin, penisillien, metaboliese produkte, ensv. metabolic products, etc. Vervoer oor die buisie epiteel is dmv. Transport across the tubule epithelium aktiewe vervoer is via active transport. 7/20/2023 16 Figure 19.10 GLUCOSE HANDLING BY THE NEPHRON Filtration Reabsorption Reabsorption rate of glucose Filtration rate of glucose Filtration of glucose is proportional to the Tm Reabsorption of (mg/min) (mg/min) plasma concentration. glucose is proportional 375 Filtration does not to plasma concentration saturate. Approximate until the transport normal range maximum (Tm) is reached. 0 100 300 500 0 100 200 300 500 Plasma glucose (mg/100 mL plasma) Plasma glucose (mg/100 mL plasma) Excretion = Filtration − Reabsorption Composite graph shows the relationship between filtration, reabsorption, and excretion of glucose. excretion rates of glucose (mg/min) Excretion rate of glucose Filtration, reabsorption, and (mg/min) Glucose excretion Transport is zero until the renal 375 maximum threshold is reached. Renal threshold Renal threshold 0 100 300 500 0 100 300 500 Plasma glucose (mg/100 mL plasma) Plasma glucose (mg/100 mL plasma) Glycosuria-glucose in urine: MAY BE due to defective glucose carriers (Renal glycosuria)  Changes in Tubular Fluids Slegs 15-20% van die Only 15–20% of aanvanklike filtraatvolume N initial filtrate volume bereik DCT H a + K + reaches DCT + ATP Concentrations of Konsentrasies van electrolytes and elektroliete en organiese Hormonal organic wastes in regulation afvalstowwe wat in die 1. Aldosterone arriving tubular fluid buisievloeistof arriveer nie (Na+ reabsorption) no longer resemble langer soortgelyk aan 2. Antidiuretic blood plasma hormone bloedplasma nie. (water Selective reabsorption) reabsorption or Selektiewe herabsorpsie of secretion, primarily sekresie, hoofsaaklik langs along DCT, makes DCT, maak finale aanpassings final adjustments in aan opgeloste samestelling solute composition en volume van and volume of buisievloeistof tubular fluid Ook afgeskei: dwelmmiddels Also secreted: drugs bv. penisillien, metaboliese e.g. penicillin, produkte, ensovoorts. metabolic products, etc. 18 Urien Produksie Urine Production Proximal tubule Na+ and other substances removed Water follows Ascending limb passively Na+, Cl-, K+ Filtrate volume transported out of reduced filtrate Water remains Descending limb Urine concentration Water exits varies by regulating passively amount of H20 or Na+ Filtrate volume reabsorbed in distal reduced 15% tubule & collecting duct Urine is hypo/hyperosmotic depending on amount of ADH present 19 Membraan Funksies Membrane Functions Plasma membrane is selektief – Plasma membranes are selectively deurlaatbaar permeable Ione betree of verlaat via spesifieke – Ions enter or leave via specific membraan kanale membrane channels Draer meganismes beweeg spesifieke – Carrier mechanisms move specific ions ione in en uit die sel in or out of cell Osmotiese Konsentrasie Van Die Osmotic Concentration Of ICF And ISV En ESV ECF Is identies Is identical Osmose elimineer klein verskille in Osmosis eliminates minor differences in konsentrasie concentration Want meste plasma membrane is vir Because most plasma membranes are water deurlaatbaar permeable to water 20  Homeostatiese Meganismes Homeostatic Mechanisms – ↑ in bloed volume ↑ bloeddruk – ↑ in blood volume ↑ blood pressure – ↓ in bloed volume ↓ bloeddruk – ↓ in blood volume ↓ blood – Monitor ESV volume indirek deur pressure bloeddruk te monitor Baroreseptore by die – Monitor ECF volume indirectly by aortaboog en karotissinus en monitoring blood pressure regter- atrium Baroreceptors at carotid sinus, aortic sinus, and right atrium Groot verandering in ESV volume word reggestel deur homeostatiese Large changes in ECF volume meganismes wat bloeddruk en bloed are corrected by homeostatic volume reguleer mechanisms that regulate blood volume and pressure 21 RAAS RAAS= complex pathway regulating blood pressure Fig. 20.10 Overall Effect of Angiotensin II Increase in systemic blood volume and blood pressure Restoration of normal GFR 22 Natriuretiese peptiede Natriuretic peptides 26-23 Fig. 20.11  Gedrags meganismes in sout & water homeostase Behavioural mechanisms in salt & water homeostasis Sout-lus, dors, vermy hitte Salt seeking behaviour, thirst, avoiding heat As osmolarity ↑, volume ↓, moet vloeistowwe verwang word. Under ↑osmolarity, ↓ volume, fluids need to be replaced. Om balans te restoureer: Vloeistowwe moet ingeneem word om To restore balance: volume te restoureer – Fluids must be ingested to restore Sout moet ingeneem word om volume [Na+]liggaam te ↑as dit benodig word – Salts must be ingested to ↑ [Na+]body only if it is needed 24  Osmolariteit & volume kan onafhanklik verander Osmolarity & volume can change independantly Homeostasis: FLUID LOSS = EQUAL FLUID GAIN Fluid can be lost by:1) diarrhea, 2) excessive sweating, 3) vomiting, 4) hemorrhage, 5) dehydration Fluid can be gained by drinking too much imbalance occurs when osmolarity < acceptable range 25 Elektroliet Balans Electrolyte Balance Homeostasis N[Na+] ECF=135-145mosm/L ↑ [Na+]ECF Generalised regulation by osmoreceptors. Once blood volume, pressure is impacted, pathways are much more ↑ Osmoreceptor activity complex. Reference: Silverthorne D (2010). Human Physiology-An integrated approach. 5th ed. Pearson Benjamin Cummings; 2. Martini FH (2006). Fundamentals of Anatomy & Physiology. 7th ed. Pearson Benjamin Cummings ADH ↑ thirst Water conserved ↑ Water intake ↓[Na+]ECF ↑ ECF volume 26 Elektroliet Balans Electrolyte Balance Homeostasis ↓ [Na+]ECF [Na+] ECF=135-145mosm/L ↓ Osmoreceptor activity ↓ ADH ↓ thirst ↑Water loss ↓ Water intake ↑ [Na+]ECF ↓ ECF volume 27  Waterstof Balans Hydrogen Balance Sysverteringstelsel dieet: inset Selle (metabolisme vetsure, aminosure, suur CO2+H20,ketoonligaampies vrugte melksure) pH=7.38-7.42 + − Co2+H20↔ 𝐻𝐻2𝐶𝐶𝐶𝐶3 ↔ 𝐻𝐻 +𝐻𝐻𝐻𝐻𝐻𝐻3 ISV Buffers ESV pH= power of hydrogen pH= -log[H+] More Hydrogen=more acidic Less hydrogen=more basic N uitset Ventilasie Urien, niere (longe) 28  Acid-base Balance For homeostasis to be preserved, 1. Disorders: captured H+ must: Circulating buffers 1. Be permanently tied up in water Respiratory performance molecules: Renal function – through CO2 removal at lungs 2. Be removed from body fluids: 2. Cardiovascular conditions: - through secretion at kidney Heart failure Hypotension Requires balancing H+ gains and losses – Coordinates actions of buffer 3. Conditions affecting the CNS: systems with respiratory and renal Neural damage or disease that affects mechanisms by, respiratory and cardiovascular reflexes – Secreting or reabsorbing H+ Regulating the excretion of acids and bases Generating additional buffers 29  Acidosis and Alkalosis Alle sisteme is sensitief, veral die All systems vulnerable, esp. nervous, senuwee stelsel en kardiovaskulêre cardiovascular systems stelsel Acidosis and alkalosis are dangerous Asidose en alkalose is gevaarlik Metabolic processes generate acids, so Metaboliese prosesse genereer sure, acidosis is more common dus kom asidose meer algemeen voor Voedsel bronne is meestal sure Dietary sources are mainly acids Asidose Fisiologiese toestand wat geassosieer Acidosis word met ʼn abnormale lae plasma pH Physiological state associated with an abnormally low plasma pH Asidemie: plasma pH < 7.35 Acidemia: plasma pH < 7.35 Alkalose Alkalosis Fisiologiese toestand wat geassosieer word met ʼn abnormale hoë plasma pH Physiological state associated with an Alkalemie: plasma pH > 7.4 abnormally high plasma pH Alkalemia: plasma pH > 7.45 31  Metaboliese Suur-basis Steurnisse Metabolic Acid–Base Disorders – As gevolg van: – Result from: Generasie van vaste en Generation of organic or fixed organiese-sure acids Toestande wat HCO3- Conditions affecting HCO3- konsentrasie in die ESV affekteer concentration in ECF Respiratoriese Suur-basis steurnisse Respiratory Acid–Base Disorders Ontwikkel deur wanbalans tussen Result from imbalance between CO2 opwekking in perifere weefsels CO2 generation in peripheral tissues en CO2 ekskresie by die longe and CO2 excretion at lungs Veroorsaak abnormale CO2 vlakke in Cause abnormal CO2 levels in ECF ESV 32  Acid–Base Balance Disturbances (Martini, 2006) 33 (Martini, 2006) 34  Mikturisie Figure 19-14: The micturition reflex 35