BSC 2086 01 Anatomy and Physiology II Spring 2013 19 The Urinary System Part 1 2012 Pearson Education Inc An Introduction to the Urinary System Learning Outcomes 26 1 Identify the components of the urinary system and describe the functions it performs 26 2 Describe the location and structural features of the kidneys identify major blood vessels associated with each kidney trace the path of blood flow through a kidney describe the structure of a nephron and identify the functions of each region of the nephron and collecting system 2012 Pearson Education Inc Figure 26 1 An Introduction to the Urinary System Kidney Produces urine Ureter Transports urine toward the urinary bladder Urinary bladder Temporarily stores urine prior to elimination Urethra Conducts urine to exterior in males transports semen as well 2012 Pearson Education Inc Anterior view 26 1 Urinary System Functions Three Functions of the Urinary System 1 Excretion Removal of organic wastes from body fluids 2 Elimination Discharge of waste products 3 Homeostatic regulation of blood plasma volume and solute concentration 2012 Pearson Education Inc 26 1 Urinary System Functions Structures and Functions of the Urinary System Kidneys organs that produce urine Urinary tract organs that eliminate urine Ureters paired tubes Urinary bladder muscular sac Urethra exit tube Urination or micturition process of eliminating urine Contraction of muscular urinary bladder forces urine through urethra and out of body 2012 Pearson Education Inc 26 1 Urinary System Functions 2012 Pearson Education Inc 26 1 Urinary System Functions Homeostatic Functions of Urinary System 3 Helps stabilize blood pH By controlling loss of hydrogen ions and bicarbonate ions in urine 4 Conserves valuable nutrients By preventing excretion while excreting organic waste products 5 Assists liver 2012 Pearson Education Inc In detoxifying poisons Also during starvation deaminates amino acids so other tissues can metabolize them 26 2 The Kidneys The Kidneys located on either side of vertebral column Left kidney lies superior to right kidney Superior surface capped by adrenal gland Position is maintained by Overlying peritoneum Contact with adjacent visceral organs Supporting connective tissues 2012 Pearson Education Inc 26 2 The Kidneys Each Kidney Is Protected and Stabilized By three concentric layers of connective tissue 1 Fibrous capsule innermost layer A layer of collagen fibers Covers outer surface of entire organ 1 Perinephric fat capsule A thick layer of adipose tissue Surrounds renal capsule 1 Renal fascia outermost layer A dense fibrous outer layer Anchors kidney to surrounding structures 2012 Pearson Education Inc Figure 26 2a The Position of the Kidneys Parietal peritoneum Stomach Renal vein Renal artery Aorta Pancreas Spleen Vertebra External oblique Ureter Left kidney Connective tissue layers Fibrous capsule Perinephric fat Renal fascia Quadratus lumborum A superior view of a transverse section at the level indicated in part a Psoas major Inferior vena cava 2012 Pearson Education Inc Figure 26 2b The Position of the Kidneys Diaphragm Left kidney Renal artery and vein Adrenal gland 11th and 12th ribs Right kidney Lumbar L1 vertebra Ureter Inferior vena cava Iliac crest Abdominal aorta Urinary bladder Urethra 2012 Pearson Education Inc A posterior view of the trunk Figure 26 3 The Gross Anatomy of the Urinary System Diaphragm Inferior vena cava Celiac trunk Right adrenal gland Right kidney Hilum Quadratus lumborum muscle Iliacus muscle Psoas major muscle Peritoneum cut Rectum cut Urinary bladder 2012 Pearson Education Inc Anterior view Esophagus cut Left adrenal gland Left kidney Left renal artery Left renal vein Superior mesenteric artery Left ureter Abdominal aorta Left common iliac artery Gonadal artery and vein 26 2 The Kidneys Typical Adult Kidney Is about 10 cm long 50 5 cm wide and 3 cm thick 4 in 2 2 in 1 2 in Weighs about 150 g 5 25 oz Hilum Point of entry for renal artery and renal nerves Point of exit for renal vein and ureter 2012 Pearson Education Inc 26 2 The Kidneys Renal Cortex Renal Pyramids Superficial portion of kidney in contact with renal capsule Reddish brown and granular 6 to 18 distinct conical or triangular structures in renal medulla Base abuts cortex Tip renal papilla projects into renal sinus 2012 Pearson Education Inc 26 2 The Kidneys Renal Columns Bands of cortical tissue separate adjacent renal pyramids Extend into medulla Have distinct granular texture 2012 Pearson Education Inc 26 2 The Kidneys Renal Lobe Consists of Renal pyramid Produces urine Renal Papilla drain 2012 Pearson Education Inc Overlying area of renal cortex Adjacent tissues of renal columns Ducts discharge urine into minor calyx a cup shaped 26 2 The Kidneys Major Calyx Renal Pelvis Formed by four or five minor calyces Large funnel shaped chamber Consists of two or three major calyces Fills most of renal sinus Connected to ureter which drains kidney 2012 Pearson Education Inc Figure 26 4a The Structure of the Kidney Inner layer of fibrous capsule Renal sinus Adipose tissue in renal sinus Renal pelvis Hilum Renal papilla Ureter 2012 Pearson Education Inc A diagrammatic view of a frontal section through the left kidney Renal cortex Renal medulla Renal pyramid Connection to minor calyx Minor calyx Major calyx Renal lobe Renal columns Fibrous capsule Figure 26 4b The Structure of the Kidney Renal cortex Renal medulla Hilum Ureter Renal columns 2012 Pearson Education Inc A frontal section of the left kidney Renal pyramids Renal sinus Renal pelvis Major calyx Minor calyx Renal papilla Renal lobe Fibrous capsule 26 2 The Kidneys Nephrons functional unit of the kidney Microscopic tubular structures in cortex of each renal lobe Each kidney has approximately 1 25 million nephrons Where urine production begins 2012 Pearson Education Inc 26 2 The Kidneys Blood Supply to the Kidneys Kidneys receive 20 25 of total cardiac output 1200 mL of blood flows through kidneys each minute Kidney receives blood through renal artery Blood flow from renal artery segmental arteries interlobar arteries arcuate arteries cortical radiate interlobular arteries afferent arterioles glomerulus efferent arteriole peritubular capillaries venules cortical radiate interlobular veins arcuate veins interlobar veins renal vein 2012 Pearson Education Inc Figure 26 5a The Blood Supply to the Kidneys Cortical radiate veins Cortical radiate arteries Interlobar arteries Segmental artery Adrenal artery
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