The Urinary System: Anatomy, Functions, and Kidney Disorders

1. 15 The Urinary System

2. 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

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

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

5. Bowman’s Capsule 1.Glomerulus: 2. Renal Tubule: a. Bowman’s Capsule C. Microscopic Anatomy: The Nephron 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)

6. 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)

7. 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

8. III. KIDNEY FUNCTIONING: A. Glomerular Filtration - Occurs at Glomerulus and Bowman’s Capsule • Review Filtration 1. WHY: to get the plasma with dissolved chemicals into the Kidney tubes for processing 2. Small substances are filtered into Kidney • Water and solutes– are forced through holes in capillary walls • And Nitrogenous : Urea 3. Large substances stay in the blood: • Proteins and blood cells

9. B. Tubular Reabsorption = = • Locations: Proximal Convoluted Tubule and Nephron Loop, Collecting duct mostly 2. WHY: to get the nutrients and important chemicals needed by the body back into the blood 3. Materials that are reabsorbed: • Water • Glucose • Amino acids • Ions: amount reabsorbed depends on how high the level are in the blood 4. Wastes usually not reabsorbed: • Nitrogenous waste products– Urea, Uric acid, Creatinine

10. C. Tubular Secretion = • Location: Distal Convoluted Tubule and Loop mostly 2. Substances secreted: Hydrogen and potassium ions 3. WHY: if there are too high of levels in the blood, filtration does not move enough of these chemicals into the kidney tubes. Then more can be put their by secretion.

11. D. Water Balance Must be Maintained in Body • WHY: to keep the proper concentrations of chemicals in blood and cells AND maintain proper Blood Pressure 2. Most water is reabsorbed: occurs automatically throughout the tubes so that the body will not dehydrate 3. Control of amount of water in urine: Only at the end of the Nephron Tubes is the water content of urin controlled • Locations: Nephron Loop & Collecting Duct are most important • Control System: Endocrine System • Hormone: = Antidiuretic hormone (ADH) • High levels cause more water to be reabsorbed to prevent dehydration • Low levels cause more water to stay in urine

12. 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

13. IV. Characteristics of Urine A. *Normal amount produced in 24 hr = B. *Color range: • *How is urine color affected by concentration • How is the amount of water one drinks affect the concentration and color of urine: C. *pH = D. Specific Gravity = Weight as compared to pure water:

14. Characteristics of Urine … E. Solutes in Urine: 1. Ions: Sodium and potassium ions and other ions 2. Nitrogen-containing substances: Urea, uric acid, creatinine, Ammonia F. *Substances Not in Urine: Bile, and RBC, WBC, Platelets, Protein, Nutrients G. Kidney Disorders: What abnormal substances in the urine indicates • Kidney Failure: Proteins in urine • Hemodialysis: Blood passes into machine which functions as the kidney; takes hours per day

15. Abnormal Urine Constituents KNOW Indicates Kideny Damage

16. V. Ureters * = describe *Function VI. Urinary bladder = Smooth, collapsible, muscular sac that connects to the Ureters superiorly and the Urethra inferiorly • *Function: Ureters Uterus Bladder Urethra

17. VII. Urethra • = describe • *Function: • Location • Females—anterior to the vaginal opening • Males—travels through the prostate and penis

18. VIII. The Link Between Water and Salt • Water easily diffuses between the 3 Compartments • Most important solutes are electrolytes = Ions • Changes in solute concentration of a compartment changes the concentration of water and creates a High  Low • When solutes move from one compartment to another, the water will diffuse and follow the solute. Consequences: • Alters blood volume and blood pressure • Can impair the activity of cells • So, Water Intake Must = Water Output and the Concentrations of ions must be kept at Homeostasis by the Kidneys

19. Water Intake– controlled by Hypothalamus via making one thirsty. Stimuli that trigger Thirst are: • Increase in plasma solute content • *Mouth is: • *Blood volume or blood pressure that: • Water loss– via • *Skin:called what? • Evaporation from Lungs • *End Product of Digestive System: ? • KIDNEYS: then compensate for the above water losses by altering the amount of water in the urine :

20. IX. Acid-Base Balance END