Urinary system 2022 (2).ppt

The Urinary System Objectives  Describe the anatomy of the urinary system  Describe the functions of the urinary system  Describe the structure and function of:   Kidneys  Ureters  Bladder Describe the Renin-Angiotensin-Aldosterone system Urinary System  Consists of:  2 kidneys  2 ureters...

The Urinary System Objectives  Describe the anatomy of the urinary system  Describe the functions of the urinary system  Describe the structure and function of:   Kidneys  Ureters  Bladder Describe the Renin-Angiotensin-Aldosterone system Urinary System  Consists of:  2 kidneys  2 ureters  1 bladder  1 urethra Urinary System Functions  Kidneys regulate blood volume and composition, help regulate blood pressure, synthesize glucose, release erythropoietin, participate in Vitamin D synthesis and excrete waster by urine  Ureters transport urine from kidneys to bladder  Bladder stores urine  Urethra discharges urine from body Kidneys  Reddish, kidney bean shaped  Retroperitoneal  Partially protected by 11th and 12th ribs  Right, slightly lower than Left  Approx 10-12cm long  Approx 5-7cm wide, mass of 135-150g Anatomy Kidneys  Renal cortex = superficial part  Renal medulla = deeper dark couloured region  Consists of renal pyramids  Each faces renal cortex  Narrower end (apex) called renal papilla points towards renal hilum  Renal cortex and pyramids constitute the parenchyma (functional portion) of kidney  In parenchyma – approx. 1million nephrons (microscopic) Kidney functions  Regulation of blood ionic composition  Regulation of blood pH  Regulation of blood volume  Regulation of blood pressure  Maintenance of blood osmolarity  Production of hormones (calcitrol and erythropoietin)  Regulation of blood glucose level  Excretion of wastes from metabolic reactions and foreign substances (drugs or toxins) Anatomy of the kidneys  Urine formed by nephron drains into Papillary ducts Minor and major calyces Renal pelvis Ureter Urinary bladder Blood and nerve supply of the kidneys  Blood supply  Although kidneys constitute less than 0.5% of total body mass, they receive 20-25% of resting cardiac output  Left and right renal artery enters kidney  Branches into segmental, interlobar, arcuate, interlobular arteries  Each nephron receives one afferent arteriole  Divides into glomerulus – capillary ball  Adult renal blood flow approx. 1200ml/min The Nephron 2 parts Renal corpuscle – filters blood plasma  Glomerulus – capillary network  Glomerular (Bowman’s) capsule – doublewalled cup surrounding glomerulus Renal tubule – filtered fluid passes into  Proximal convoluted tubule  Descending and ascending loop of Henle (nephron loop)  Distal convoluted tubule Copyright 2009, John Wiley & Sons, Inc. Cortical nephrons – 80-85% of nephrons Juxtamedullary nephrons – other 25-20% Facts  Number of nephrons stay same number as at birth  If kidneys grow – nephrons grow in size – not number  If nephrons die, they are not replaced  Kidney disease loss of function is not apparent until