15 The Urinary System

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I. Introduction: A. Parts 1) 2) 3) 4) B. Overall Functions: The blood is modified to produce: Elimination of: Nitrogenous wastes Toxins Drugs Kidney Ureter Bladder Urethra

Functions of the Urinary System … 2. Regulate Blood Levels of: Water, which affects Blood Pressure Electrolytes/ions H+: To maintain blood pH

II. Kidney Anatomy Location: Retroperitoneal = B. Gross Anatomy At T12 to L3 vertebrae B. Gross Anatomy Adrenal Glands Renal Hilum Cortex Medulla 12th rib

C. Microscopic Anatomy: The Nephron Bowman’s Capsule 1. Glomerulus: 2. Renal Tubule: a. Bowman’s Capsule Glomerulus Cortical nephron Fibrous capsule Renal cortex Collecting duct Renal medulla Renal cortex Proximal convoluted tubule Renal pelvis Glomerulus Ureter Distal convoluted tubule Loop of Henle Renal medulla (a)

3. Nephron … b. Proximal Convoluted Tubule c. Nephron Loop or Loop of Henle d. Distal Convoluted Tubule Cortical nephron Fibrous capsule Collecting duct Renal cortex Proximal convoluted tubule Glomerulus Ureter Distal convoluted tubule Loop of Henle Renal medulla (a)

D. Other Microscopic Parts Collecting Duct 2. Afferent Arteriole  Glomerulus Renal Artery Cortical nephron Fibrous capsule Collecting Duct Collecting duct Renal cortex Afferent Arteriole Proximal convoluted tubule Glomerulus Ureter Distal convoluted tubule Loop of Henle Renal medulla

III. KIDNEY FUNCTIONING: A. Glomerular Filtration - Occurs at Glomerulus and Bowman’s Capsule Review Filtration Small substances are filtered into Kidney– Water and solutes– are forced through holes in capillary walls And Nitrogenous : Urea 2. Large substances stay in the blood: Proteins and blood cells:

B. Tubular Reabsorption = Locations: Proximal Convoluted Tubule and Nephron Loop, Collecting duct mostly 2. Materials that are reabsorbed: Water Glucose Amino acids Ions 3. Materials not reabsorbed: Nitrogenous waste products– Urea, Uric acid, Creatinine

C. Tubular Secretion = Location: Distal Convoluted Tubule and Loop mostly 2. Substances secreted: Hydrogen and potassium ions

D. Water Balance 1. Osmotic Gradient of Nephron Loops 2. Collecting Duct 3. Antidiuretic hormone (ADH) Prevents excessive water loss in urine Causes the kidney to reabsorb more water

Hepatic veins (cut) Inferior vena cava Renal artery Adrenal gland Renal hilum Aorta Renal vein Kidney Iliac crest Ureter Rectum (cut) Uterus (part of female reproductive system) Urinary bladder Urethra (a) Figure 15.1a