8131MED - Renal Physiology_Part 1 (structure and function)-2.pdf

Kidney structure & function Dr. Nicole Flemming – [email protected] Learning Objectives 1. Describe the gross and microscopic structure of the kidneys and explain how structure serves function Renal system function Water balance and plasma volume Regulating ECF osmolarity and concentration...

Kidney structure & function Dr. Nicole Flemming – [email protected] Learning Objectives 1. Describe the gross and microscopic structure of the kidneys and explain how structure serves function Renal system function Water balance and plasma volume Regulating ECF osmolarity and concentration of most ECF ions Na+, K+, Cl-, other ions… maintains extracellular fluid Conserving nutrients e.g. glucose Regulating blood pH Regulating blood pressure Excretion of waste products Calcium regulation (activation of vit D) Aneamia correction (EPO secretion due to decreased renal O2) Protein catabolism produce urine Kidney Ureters urinary tract ureters paired tubes Bladder Urethra Maintenance of ECF composition (i.e., ECF volume, electrolytes, osmolarity). Therefore, major function of the kidney is… HOMEOSTATIC REGULATION urethra Gross anatomy and location of the kidney fibrous with collagen Associated structures Fibrous capsule collagen covers surface Perinephric fat cushioning Renal fascia Adrenal gland densely packed with renal glomeruli and vessels ureter and lymphatics too in hilum cortisol, adrenaline and aldosterone adrenal glands on top with tubules deliver blood to cortex between pyramids anchor pyramids R kidney - slightly lower due to liver Gross anatomy and location of the kidney External structure Reddish/brown, 10cm long, ~300g Right kidney is slightly inferior due to the presence of the liver Renal hilum Indentation on the medial side Renal artery, vein, ureters, nerves, lymphatics enter/exit kidney Gross anatomy and location of the kidney Internal structure Cortex outer-most region, densely packed with small blood vessels and glomeruli Medulla middle-deep layer Columns Section between pyramids Anchor pyramids in place Allow passage of blood vessels Pyramids Triangular shaped Filled with renal tubules Empties into minor calyx > major calyx > renal pelvis Kidney lobes section of renal pyramid and renal cortex encomasses pyramid and cortex urine produced here -> ureters Renal blood supply Blood supply 25% cardiac output 1 L/min blood highly vascular abdominal aorta to renal artery to efferent associated with tubules closely Blood flow Renal artery Segmental artery Interlobular artery Arcuate artery Interlobular artery Afferent arteriole Glomerulus Efferent arteriole Peritubular capillaries Venule Interlobular vein Arcuate vein Interlobular vein Renal vein single per kidney radiate via renal colums b/w renal pyramids Arteries to glomerular capillaries 5 segmental from renal a. enters into lobular vein in cortex Nephron drains out via renal v Veins blood passes and exits Microscopic anatomy Nephrons are the functional units of the kidney that produce urine predominant Vascular component superficial part to renal medulla surrounding Renal corpuscle (Glomerulus + Bowman’s capsule) renal corpuscle + tubule Tubular component 2 nephron types Renal tubule tubular 1 million tiny short loop of Henle Created with BioRender.com Microscopic anatomy Cortical nephron 85% of all nephrons Short Loop of Henle Efferent arteriole deliver blood to peritubular capillaries Juxtamedullary nephron 15% of all nephrons Long Loop of Henle Efferent arterioles deliver blood to vasa recta concentration of urine deeper much deeper Created with BioRender.com Microscopic anatomy: nephron C. Glomerulus distal convoluted reabsorb water + ions capillaries, high pressure network proximal convoluted tubule reabsorbs crucial ions, glucose + water E. PCT exit B. Efferent arteriole G. DCT H. Collecting duct funnels into renal pelvis A. Afferent arteriole small interlobular into glomerulus D. Bowman’s Glomeruluscapsule surrounding, collects glomerular filtrate thinner cuboidal - thick taller epithelium F. Loop of Henle