20150521 Renal Lecture Student Version.pptx
If you have questions, email Michael: m.chirillo@utexas.edu Na engliskom, molim vas :) 19 May, 2015 Systems Physiology Renal/Urinary System: FIZIOLOGIJA SISTEMA ZA EKSKRECIJU 21 May, 2015 Physiology I Renal Physiology The main functions of the kidney Regulate ECF volume and blood pressure Maintain the balance of ions Regulate osmolarity Acid/base homeostasis Produces hormones Excrete wastes The Urinary System retroperitoneal Fig. 19.1a, p. 630, Human Physiology, D. Silverthorn 20% of minute volume! 0.4% of total body weight Fig. 19.1b, p. 630, Human Physiology, D. Silverthorn arteriae segmentariae bubrežna cevčica Arteriae arcuatae renis calices renales korteks Renal/ Malpigijeva Piramida pelvis renalis Bladder Mokraćna bešika Nephron = Function unit of the kidney arteriae interlobares renis Fig. 19.1c-d, p. 630, Human Physiology, D. Silverthorn Cortical Radiate Arteries (arteriae radiatae corticalis???) Aferenta arteriola Arteriae arcuatae renis Fig. 19.1e, p. 630, Human Physiology, D. Silverthorn Tubuli contori proximalis Tubuli contori distalis Efferent arteriole Afferent arteriole Glomerulus or Glomerular Capillaries Sabirni kanalić Distal Tubule Silazna deo Single layer of transporting epithelium Uzlazna deo Henlejova petlja Mokraćna beška what is an epithelium? Human Physiology, D. Silverthorn, 6th Edition, Fig. 3.9b Tubuli contori proximalis Tubuli contori distalis Efferent arteriole Glomerulus or Glomerular Capillaries Efferent arteriole Afferent arteriole Afferent arteriole Glomerulus or Glomerular Capillaries Sabirni kanalić Silazna deo Uzlazna deo Mokraćna beška Peritubular Capillaries Peritubulna kapilarna mreža Fig. 19.5a, p. 635, Human Physiology, D. Silvethorn You MUST know the basic anatomy of the nephron Afferent Arteriole Bowman’s Capsule Glomerular Capillaries Proximal Tubule Efferent Arteriole Peritubular Capillaries Descending Limb Ascending Limb (tubi recti proximalis/ silazna deo) (tubi recti distalis/ uzlazna deo) Loop of Henle (Henlejova petlja) Distal Tubule Venous Circulation Collecting Duct NET NET Capillary Hydrostatic Pressure Oncotic Pressure Hyd rosta tic P r essu re Net Filtration P Oncotic Pressure Net Absorption Length of Capillary We have 3 pressures to think about for filtration in the glomerulus Hydrostatic = 60 mm Hg Oncotic = 28 mm Hg Fluid = 20 mm Hg Lumen Fluid P 12 mm Hg out Capillary Oncotic P (due to proteins in plasma) Capillary Hydrostatic P (due to blood pressure) Dee Silverthorn, Human Physiology, 6th Ed.: Fig 19.5 GFR Glomerular Filtration Rate Stopa Glomerularne Filtracije Volume of plasma that flows from glomerular capillaries into Bowman’s capsule per unit time ~125 mL/min or ~180 L/d GFR (glomerular capillaries to Bowman’s capsule) Dee Silverthorn, Human Physiology, 6th Ed.: Fig 19.5 3 barriers plasma must pass to get into Bowman’s Capsule podociti visceralnog sloja epitela Boumanove kapsule -‐ -‐ -‐ -‐ -‐ -‐ Most proteins can’t get through Glomerular Capillary Podocyte Podocyte https://blogs.princeton.edu/research/files/2013/10/podocyte.jpg Plasma (GRF) Nephron Tubule Urine YOU MUST UNDERSTAND THIS. What happens to GFR if the afferent arteriole dilates/constricts? Lumen Fluid P Capillary Oncotic P Capillary Hydrostatic P Dee Silverthorn, Human Physiology, 6th Ed.: Fig 19.5 We have 3 pressures to think about for filtration in the glomerulus Hydrostatic = 60 mm Hg Oncotic = 28 mm Hg Fluid = 20 mm Hg Lumen Fluid P 12 mm Hg out Capillary Oncotic P (due to proteins in plasma) Capillary Hydrostatic P (due to blood pressure) Dee Silverthorn, Human Physiology, 6th Ed.: Fig 19.5 Autoregulation Myogenic Response and Tubuloglomerular Feedback Myogenic Response Miogena autoregulacija stretches ↑BP ↑Pa → otvaranje kanala za Ca2+ osetljivih na istezanje → vazokonstrikcija Efferent arteriole Glomerulus or Glomerular Capillaries Afferent arteriole Peritubular Capillaries Peritubulna kapilarna mreža Tubuloglomerular Feedback Tubuloglomerulna Povratna Sprega Macula densa (sense GFR) Granular Cells (juxtaglomerular cells) Juxtaglomerular Apparatus GFR Contrict Aff. Arteriole Cathecholamines Angiotensin II Endothelin Dilate Aff. Arteriole ANP/BNP Prostaglandins Azot oksid (nitric oxide) Dee Silverthorn, Human Physiology, 6th Ed.: Fig 19.5 To Peritubular Capillaries Bowman’s Capsule ~80% ~20% Filtration Fraction Afferent Arteriole Efferent Arterioles Plasma in 180 L/d Glomerular Filtration Rate (flow of “plasma” into nephrons) Peritublar Capillaries Urine Out 180 L/d Urine Flow GFR (flow of “plasma” into nephrons) Afferent Arteriole Filtration Filtracija Reabsorption/Reapsorpcija Peritubular Capillaries Nonselective Selective Secretion/Sekrecija Excretion/ Ekskrecija To Bladder Urine Flow Back to Venous Circulation Reabsorption glukoza (98%) AK (99%) Na+(67%) Ca2+(65%) K+ (80%) HCO3- (80%) urea (50%) kreatinin (0%) sekundarno aktivni transport glukoza aminokiseline mikroresice Na+ Na+ K+ Na+/K+-ATPaza nosači Na+ kotransporteri kontratransporteri kanali nizak nivo Na+ Secretion • What is secreted? – Xenobiotics and metabolites – Ex: penicillin Let’s all take a second to marvel (diviti se) at the bean-shaped, evolutionary Miracles (čuda) that are your KIDNEYS The kidney can excrete a urine that ranges in concentration. ~50 - ~1200 mOsM! veoma razblaženoj veoma koncentrovano In fact, the kidneys can excrete as much as 20 L a day (WHAT?!?!) of a 50 mOsM urine The Australian Hopping Mouse can excrete a urine that is 10,000 mOsM! CONTEXT! Maple syrup = 67% sugar (mostly sucrose) 67 g sucrose/100 mL water = (670 g/L)*(1 mol/342.30 g) = 1.957 OsM or about 2,000 mOsM 10,000 mOsM! Probably doesn’t taste as good. Animals that live in aquatic environments can’t concentrate their urine as much For example, beavers (dabrovi) only concentrate urine to ~500 mOsM ADORBS Renal Interstitium Fakultativna Obligatorna Aldosterone C= S V Anti-diuretic hormone (ADH)/ vasopressin Diluting Segment/ Segment u kojem se razblažuje Propustljiv za vodu S C= V Nepropustljiv za vodu C= S V Vasopressin éVolume/êOsmolarity êVolume/éOsmolarity êVasopressin éVasopressin êAquaporins éAquaporins Fluid Volume Starting Volume Min ADH Proximal Tubule Descending Limb Ascending Limb Loop of Henle Distal Nephron (Distal tubule and Collecting Ducts) Tubule Fluid Concentration Fluid Osmolarity (mOsM) Tubule Fluid Volume 300 Min ADH Proximal Tubule Descending Limb Ascending Limb Loop of Henle Distal Nephron (Distal tubule and Collecting Ducts) Aldosterone êBlood Pressure Angiotensinogen renin ANGI ACE ANGII Acid/Base Homeostasis Why it this so important for the body? Normal pH = 7.38-7.42 Uhhhhh, but the stomach has a pH ≈ 1??? STOMACH LUMEN IS OUTSIDE THE BODY Body normally needs to excrete acids or bases? We eat acidic foods (for example, orange juice has pH ≈ 3.5) Tissues produce H+ (for example, lactic acid) from metabolism Proximal Tubule Epithelium Interstitium H+ Secrete HCO3- H+ Reabsorb HCO3- Peritubular Capillaries Lumen of Tubule Lumen of Tubule Proximal Tubule Epithelium Interstitium H+ Carbonic Anhydrase Karbonatna Dehidrataza CO2 CO2 CA H+ Na+ H+ + HCO3Na+ HCO3Na+ Peritubular Capillaries HCO3- Kidneys use ammonia (NH3) and phosphate (HPO42-) buffers (пуфере) Ammonia (NH3) CO2 KA H+ H+ NH3 NH4+ NH3 Phosphate (HPO42-) CO2 HCO3-‐ NH4+ H2O glutamin H+ H+ KA HCO3-‐ HPO42-‐ H2PO4-‐ H2O Ammonia also highly toxic to the body! Urea is the main substance we use to dispose nitrogenous wastes ~90% of nitrogenous wastes in urine! Humans and all mammals are “ureotelic” (ureotelični) Means most nitrogen waste becomes urea Contrasts with ammonotelic (ammonotelični) and uricotelic (urikotelični) animals Urea made in liver (jetra) Have fun today!
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