Lecture 8 3 URINARY SYSTEM Chapter 24 Function removal of metabolic waste materials mostly urea Urea metabolic waste material formed from the digestion of proteins Protein digestion releases ammonia which is detoxified in the live by attaching a CO2 molecule producing urea Urinary System Nutrients digestive system blood liver urea production blood urinary system excretion Kidneys Functions o Removal of waste from blood urine formation o Regulate body water volume Diluted urine removal of excess water Concentrated urine conservation of water Location o Retroperitoneal o Level of T12 L3 vertebrae Capsule o Fibrous capsule outer layer of kidney maintains shape Hilum o Where the renal artery renal vein and ureter leave the kidney Internal Cortex o Renal cortex Contains millions of nephrons Medulla and renal pyramids o Renal medulla Pyramids Collect urine from tubules Papilla tip of the pyramid that points inward Renal columns separate adjacent pyramids Renal lobe single renal pyramid plus the cortical tissue that surrounds that pyramid Renal sinus o Filled space that contains the renal vessels and nerves some fat and urine carrying tubes called renal pelvis and calices Renal pelvis expanded part of the ureter o Major and minor calyces branches superior from the renal pelvis from the ureter collect urine draining from the papillae and empty it into the renal pelvis and into the ureter to the bladder Minor encloses the papillae of the pyramids at the tip of pyramids Major each divide to form several minor calyx Nephron each contain about the corpuscle tubule Renal corpuscle only in the cortex o Glomerulus efferent and afferent arterioles Supplied by the Afferent arteriole enters and drained by the efferent arteriorle o Glomerular Bowman s capsule Filtration membrane o Capsular space is usually urine o Efferent arteriole exits Renal tubule is divided into the o Proximal convoluted tubule o Nephron loop Loop of Henle o Distal convoluted tubule o Collecting tubule Peritubular capillaries surround the tubules Ureters o Slender tube Connects renal pelvis to bladder Approx 25 cm 12 inches long Approx 3 mm in diameter Where you get kidney stones they are so painful because the diameter is small Bladder and micturition o Stores urine o Expels urine detrusor muscle layer o Bladder is larger in males than in females o Detrusor muscle muscle that surrounds and makes up part of the bladder o Trigone white triangle thing o Ureteric openings Internal urethral sphincter o Urination o Micturation reflex Initiated by stretching of bladder Detrusor muscle contraction Internal sphincter relaxation involuntary External sphincter relaxation voluntary Urethra o Tube from bladder to external excretion opening o Longer in males than in females o Internal sphincter o Smooth muscle that keeps urethra closed o External sphincter o Skeletal muscle o External urethral orifice Blood vessels figure 24 4b o Arteries Left and Right o Aorta Renal Segmental Interlobar Arcuate Cortical radiate interlobular Afferent arteriole Glomerulus Efferent arteriole Peritubular capillaries and vasa recta o Veins Left and Right o Vasa recta Interlobular cortical radiate Arcuate Interlobar Renal IVC Renal plexus
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