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UNIT 6 URINARY SYSTEM

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FUNCTIONS Removes unwanted waste products from blood Return materials to the blood Regulate BP Regulate Blood pH Activate Vitamin D3 Secrete Erythropoetin

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KIDNEYS 2 [PAIR] Location : retroperitoneal on post. abdominal wall ~right is lower than left [pushed down by liver] Shape kidney bean Size of your fist

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EXTERNAL STRUCTURE 3 outer layers 1. renal capsule surface of the kidney 2. adipose capsule fatty tissue that surrounds the kidneys 3. renal fascia membrane that covers the posterior abdominal wall and anchors kidney

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INTERNAL STRUCTURES Renal Artery- supplies blood to the kidney from aorta Renal Vein- returns blood to IVC Ureter- tubes that lead from kidney to bladder Hilum- opening in kidney for vessels to travel through Renal Pelvis- fully expanded upper end of ureter

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Renal Artery Renal Vein

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3 INNER REGIONS Pelvis - innermost region of the kidney Medulla - middle region of the kidney, contains 8-10 r. pyramids, r. column in between Cortex - outer region of the kidney, r. column is cortex tissue, also

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Pyramids - the base of the pyramid borders the cortex; the tip (apex/ papillae) points to a minor calyx (small funnel). several (2-4) minor calyces form a major calyx

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Nephrons - functional unit of the kidney - 1 million, exist in both cortex and medulla 2 parts - Renal corpuscle (cortex) and renal tubule Corpuscle - consists of glomerular (Bowmans) capsule and glomerulus (literally means tiny ball of yarn)

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HOW BLOOD TRAVELS THROUGH THE KIDNEY Blood Supply - Renal artery (from abdominal aorta) eventually branches into the afferent arterioles (into nephron) Blood flow through nephron - arrives via afferent arteriole into glomerulus (capillary network ), which is contained within the Glomerular/Bowmans Capsule

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In B.Capsule, the blood goes into the efferent arteriole efferent is narrower than afferent., thus increased pressure forces material (fluid, solutes) out of the blood and into the B Capsular space material is called filtrate it will eventually become urine (blood drainage is by a reverse system, efferent arteriole eventually leads to renal vein - to inf. vena cava.)

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Glomerulus has openings ( pores), which allows filtrate to escape from the blood B. Capsule wall has specialized cells called podocytes (foot cell) Podocytes form filtration slits to help limit the type and amount of filtrate produced

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Bowmans capsule - drains into the Renal tubule Renal tubule starts at proximal convoluted tubule, which is joined to B capsule descends into medulla and ascends back into cortex via Nephron loop (Loop of Henle). coils into distal convoluted tubule - then collecting duct

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By the time filtrate reaches the collecting duct, it is urine. Urine travels through collecting duct, through the pyramids to the papillae, to the calyx