1. Essentials of Human Anatomy & Physiology Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Chapter 38-3 The Excretory System

2. QUICK REVIEW OF ELIMINATION Lungs eliminate CO2 Sweat glands eliminate excess heat, salt Digestive tract- indigestible solids, bacteria Urinary tract is the main system of elimination

3. Vocabulary Hints Uria or Ur - urine Nephr or renal - kidney Cyst - bladder Dys - painful Cystitis - inflammation of bladder Dysuria - painful urination Hematuria - blood in urine Hydronephrosis - water in kidney

4. The Urinary Tract Urinary tract consists of 2 kidneys, 2 ureters, one bladder and one urethra. Kidney location: –Retroperitoneal –Dorsal wall of abdominal cavity –12th thoracic and 3 rd lumbar vertebrae Urethra –1.5 inches in women, –8 inches in men

5. Kidneys filter blood- 2,000 L/day (500 gal) –remove waste products and reabsorb water, other valuable substances. –1.5 L of urine/day Metabolism produces toxic substances- nitrogen containing waste as a by-product of protein breakdown Nitrogen eliminated as urea - water soluble

6. Outer layer- Cortex Inner layer- Medulla Calyx- collects urine as it is formed, join together to form the ureter Structure of Kidney

7. The main functional unit of the kidney is called the nephron. 1 million per kidney Most of nephron located in renal cortex Loop of Henle is located in the renal medulla

9. Capillaries in glomerulus filter blood- Bowman’ capsule collects ultra filtrate Through passive and active diffusion, 95% of water is reabsorbed, along with K, Na, Ca Other things are actively excreted, like drugs. Excretion is controlled by hormones such as ADH from hypothalamus

10. Urine is made in 4 steps 1.Filtration 2.Reabsorption 3.Secretion 4.Excretion A urinalysis is the most common non-invasive medical test ordered

11. Diseases of the Kidney Acute Kidney failure- –Causes: nephritis, shock, injury, heart failure or poisoning –Symptoms: anuria or oliguria. Uremia, nausea, coma, death Chronic Kidney failure- –gradual loss of function due to hypertension (high blood pressure) or endocrine disease Causes: nephritis, shock, injury, heart failure or poisoning –Symptoms: anuria or oliguria. Uremia, nausea, coma, death Cystitis- inflammation of the urinary bladder

12. Kidney Dialysis

13. Dialysis, Kidney transplant Hemodialysis- serves as an “artificial kidney” 2-3 times per week for 2-4 hours Peritoneal dialysis- uses patient’s own peritoneal lining to filter blood Kidney transplant- need suitable donor. Only need one, but must take anti- rejection drugs for the life of the patient