Week 7 - Urinary system *Functions of Urinary System - Major excretory organ of body -> lies behind the peritoneum on the posterior abdominal wall > right kindey is lower than the left 1. Filtering of blood 2. Regulation of blood volume (thus kidneys help control BP) 3. Regulation of concentration of solutes in blood 4. Regulation of pH of extracellular fluid 5. Regulation of red blood cell synthesis 6. Vitamin D synthesis Hepatic veins (cut)- Esophagus (cut) Inferior vena cava Adrenal gland Aorta Iliac crest Rectum (cut) Uterus (part- of female reproductive system) Copyright @ 2010 Pearson Education, Inc. KIDNEYS Location · behind peritoneum on posterior abdominal wall on either side of vertebral column · Retroperitonium = behind peritoneum · About 11cm long, 5cm wide, 3cm thick * External kidney anatomy 3 capsules around each kidney anterior posterior · Perirenal fat capsule . Fibrous capsule 12th rib (b) Renal artery Renal hilum Renal vein Kidney Ureter Urinary bladder Urethra 1. Renal capsule = smooth transparent layer of fibrous connective tissue close to surface
2. Perirenal fat = dense layer of adipose tissue. protects kidneys by acting as shock absorber 3. Renal Fascia = thin layer of loose connective tissue. Anchors kidney + to abdominal wall + muscles The hilum = small area on medial side where renal artery + nerves enter the kidney, renal vein, lymphatic vessels & ureter exit the kidney. POINT of ENTRY / EXIT Renal hilum Renal cortex Renal medulla- Major calyx Papilla of- pyramid Renal pelvis Minor calyx Ureter Renal pyramid in renal medulla Renal column Fibrous capsule (a) Photograph of right kidney, frontal section Copyright €) 2010 Pearson Education, Int. (b) Diagrammatic view * Internal kidney anatomy - 3 parts ... 1) Renal cortex - has a granular appearance because of structures contained in layer 2) Renal medulla · Contains triangular pyramids called medullary or renal pyramids · Pyramids appear striped as they contain roughly parallel bundles of microscopic urine collecting tubules . Each pyramid and its capsule of cortical tissue forms a lobe (one of about 8) in the kidney 3) Renal Pelvis - Flat funnel shaped tube which drains into the ureter. Contain 5-10mls · Urine drains from microscopic tubules into minor calyces (singular calyx)
· Walls of calyces, renal pelvis & ureter contain smooth muscle, which contracts rhythmically + propels urine by peristalsis Glomerulus * Blood supply Afferent arteriole Peritubular capillaries · rich blood supply Efferent arteriole . Normal resting conditions of renal arteries deliver about 1/4 of the cardiac output (approx 1200ml) to the kidney per minute · Renal arteries arise from the aorta. . 90% of blood entering the kidney perfuses the cortex . Veins leave the kidney in reverse order from the arteries · Renal vein leaves the kidney & empties into inferior vena cava Vasa recta * The Nephron = functional unit of the kidney HAVE NEARLY 2 million - nephrons cannot be remade. Alcohol causes loss of them !! · Each nephron consists of a renal