EXCRETORY SYSTEM

1. EXCRETORY SYSTEM Karen LancourPatty Palmietto National Bio Rules National Event Committee Chairman Supervisor – A&P

2. Excretory System • Humans produce waste products that must be removed from their body. • Most animals have a system that deals with nitrogen-rich wastes from the breakdown of proteins and nucleic acids. • Ammonia (NH3) is toxic. • it helps maintain homeostasis – balancing osmotic action and pH.

3. Excretory System Functions: • Excrete toxins and nitrogenous waste • Regulate levels of many chemicals in blood • Maintain water balance • Helps regulate blood pressure

4. Organs of Excretory System • Kidney – filters blood and forms urine • Ureter – carries urine to bladder • Bladder – stores urine • Urethra – releases urine

5. URINARY BLADDER

6. KIDNEY STRUCTURE human kidney

7. Kidney • Filtration • Reabsorption • Secretion

9. Nephron

10. The nephron 4 STAGES OF URINE FORMATION • Glomerular filtration – into Bowman’s Capsule • 2. Solute Reabsorption – • from proximal tubule to capillary • Water Reabsorption – • from proximal tubule and Loop of Henle to capillary • 4. Tubular Secretion – from capillary to distal tubule

12. Blood vessels in the glomerulus Bottleneck Effect The blood enters the Bowman’s capsule by the afferent arteriole and leaves by the efferent arteriole. The diameter of afferent arteriole is greater than that of the efferent arteriole. Therefore, when the blood enters the efferent arteriole, it is under high pressure as it tries to force its way out of the smaller efferent arteriole.

13. Nephron

14. URINE FORMATION • Glomerular Filtration • substances move from blood in glomerulus to the Bowman’s capsule • Tubular Reabsorption • substances move from renal tubules into blood of peritubular capillaries • glucose, water, urea, proteins, creatine • amino, lactic, citric, and uric acids • phosphate, sulfate, calcium, potassium, and sodium ions • Tubular Secretion • substances move from blood of peritubular capillaries into renal tubules • drugs and ions

15. Composition of Urine

16. HYDRATION

17. Glomerular Filtration Rate • GFR– amount of filtrate formed per minute in all nephrons of both kidneys • The amount of fluid filtered from the glomeruli into Bowman's space per unit of time.  • Renal capillaries are much more permeable than others. • The flow rate is 180 L/day (125 ml/min) compared to 4 L/day in the other capillaries. • The entire plasma volume is filtered about 60 times a day! Most is reabsorbed! • GFR = UV = Urine concentration x Rate of Urine Flow = g/ml x ml/min = ml/min P Blood Plasma Concentration g

18. Excretory System Problems • Kidney stones– crystalized mineral salts and uric acid salts in the urine. Stones block flow of urine and cause excrutiating pain. • Kidney failure- can be caused by long-term diabetes, infections, physical injuries, chemical poisoning. Causes toxic materials to build up to lethal levels. Dialysis or kidney transplant is the treatment.

19. Diseases of Excretory System • Obstructive Disorders • Urinary tract infections (UTI) • Glomerular Disorders • Renal Failure • Acute • Chronic • Treatment for Renal Failure • Incontinence, Prostatitis, BPH (national)