Renal Module Lecture Notes 2022-2023 PDF

Renal module Course code: IMP-07- 20318 Phase: I Year/ semester: 2nd year / Semester (3) 2022-2023  Lecture 1 Endocrinal Function of the kidney  Tutorial 1- EndocrinalFunction of the kidney Intended Learning Outcomes (ILOs) On...

Renal module Course code: IMP-07- 20318 Phase: I Year/ semester: 2nd year / Semester (3) 2022-2023  Lecture 1 Endocrinal Function of the kidney  Tutorial 1- EndocrinalFunction of the kidney Intended Learning Outcomes (ILOs) On completion of this lecture, the student will be able to: -Describe functions of renal system. -Identify types of nephrons and functions of each type. -Describe Juxtaglomerular apparatus and its significance.  Structure of the Urinary System Renal Renal artery vein Inferior Kidney vena cava Aorta Urinary Ureter bladder Urethra Kidney composed of 6-18 lobes Each lobe formed of A pyramid of medulla Covered with cortex  Renal cortex Renal Renal pyramid medulla Renal pelvis Renal Ureter Renal artery vein Inferior Kidney vena cava Aorta Urinary Ureter bladder Urethra  Functional unit of kidney is Nephron Each kidney has one million nephrons  ¼ of kidney nephrons can carry the function more loss causes renal disorders  Nephron 1- Renal corpuscles 2- Renal tubules Reabsorption Filtering part & Secretion  Renal corpuscle Glomerulus Bowman’s capsule Ball of tuft of capillaries between 2 Expanded blind end of arterioles, afferent tubules forming and efferent arteriols double walled cup  Renal tubules Proximal Distal convoluted tubules convoluted tubules PCT DCT Loop of Henle Highly coiled Highly coiled Only in cortex U shaped Only in cortex One Cuboidal Thin descending cell layer & One Cuboidal Thick ascending cell layer Has luminal brush border In medulla no brush border Collecting tubules (CT) cross whole medulla Up to 8 DCT open in each CT CT has Principles cells affected by vasopressin, I cells secrete acids  1)Proximal tubule 3) Distal tubule Juxtaglomerular Collecting apparatus 4) duct Efferent arteriole Afferent arteriole 1 Artery 2 Vein Cortex Medulla Renal circulation Peritubular 2) capillaries Loop of Henle To renal pelvis  Types of Nephrons Cortical Juxta medullary -20% -80% -Glomeruli near medulla -Glomeruli close to surface -Long loop penetrate to papilla -Loop of Henle short -Ascending has both thin & thick -function is formation of urine -Function is formation and -Supply with Peritubular concetration of urine capillaries -Peritubular capillaries & vasa recta  Distal Distal Glomerulus tubule Proximal tubule Bowman’s tubule capsule Juxtamedullary Cortical nephron nephron Proximal tubule Cortex Medulla Descending Collecting Loop of Henle limb of duct loop of Henle Other nephrons emptying into the same collecting duct Vasa recta Ascending limb of To renal loop of pelvis Henle  Functions of the Kidney 1- Homeostasis of ECF: (H2O, electrolytes Volume, PH& osmolarity). 2- Excretion of metabolic wastes ( urea ,uric acid, creatinine) and foreign compounds i.e.. drugs. 3-Gluconeogensis: Kidney synthesise glucose from amino acids during prolonged fasting. 4-Regulation of arterial blood pressure through secretion of renin. 5-Endocrinal functions : secreting erythropoietin * secreting renin converting vit D into active form Secrete prostaglandins: vasodilator: PGE & I2 vasoconstrictors: PGA2 6-Regulation of acid base balance: Elimination of acids produced from proteins metabolism. Regulation of the buffer 2019-2020 stores in the body.  Renin It is a hormone that triggers reaction which is important in salt conservation by the kidneys. It is secreted by the Juxtaglomerular apparatus into the blood in response to fall in Na CL, ECF volume and ABP. Renin acts on angiotensinogen which is synthesized by the liver into angiotensin I angiotensin II(by angiotensin converting enzyme) VC, stimulation of aldosterone secretion. Renin angiotensin aldosterone system (RAAS) is the most important & best known hormonal system involved in regulation of Na+ level.  Factors stimulating renin secretion: Renal ischemia as in cases of hypotension and hemorrhage. Sympathetic stimulation. Increase blood level of catecholamines.  Factors inhibiting renin secretion: Increase ABP due to increase blood volume. Increase Cl or Na reabsorption across the macula densa. Angiotensin II Vasopressin (ADH) & aldosterone.  Erythropoietin It is hormone secreted rom endothelial cells of peritubular capillaries in the renal cortex of the kidney in response to hypoxia. It stimulates the red bone marrow to produce RBCs, so the kidney plays an important role in erythropoiesis. The kidney secretes about 85% of its level in the body, so in chronic renal diseases the patients suffer from anemia. 2019-2020  Prostaglandins The kidney secretes two main types PGE2 &PGI2 They act locally in the kidney to help the autoregulation of the glomerular filtration rate and renal blood flow.  Regulation of 1,25 dihdroxy vit.D3 production By the activity of 1ᾳ hydroxlyase enzyme which converts the 25 hydroxycholecalciferol to 1,25 DHCC. The kidney plays an important role in calcium homeostasis and bone formation, so in chronic renal diseases bone decalcified and weak.  Distal tubule Efferent arteriole Bowman’s capsule Afferent Site arteriole DCT contacts afferent arteriole  Components of Juxta-glomerular apparatus Macula densa Granular cell Modified cells in DCT Modified cells in wall of afferent arteriole Monitor flow rate (↑NaCl transport→ Monitor flow in arteriole ↑adenosine in the DCT → and secrete renin + afferent arteriole→ VC)  Efferent arteriole Endothelial cell Lumen of Bowman’s capsule Smooth muscle cell Glomerular capillaries 1- Macula densa Podocyte 2- Granular cells Distal tubule Afferent arteriole  References  Ganong, W.F.: Review of medical physiology, 23 th ed. New York, Mc Graw- Hill Co, 2011. P640 :642.  Gyton, A.A. and Hall, J.E.: Text book of medical physiology, 12 th ed. Philadelphia, Saunders Co., 2011.P 303:306.  Handbook of the Physiology department, Faculty of medicine for girls, AL-Azhar University, P 1:11