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  1. 1. EXCRETORY SYSTEM Celeste R. Desingaño
  2. 2. Excretory System <ul><li>Consists of 2 kidneys, 2 ureters, urinary bladder and urethra </li></ul><ul><li>Essential in the removal of wastes from the body </li></ul>
  3. 3. Parts of the Excretory System <ul><li>1. Kidneys </li></ul><ul><li>The bean-shaped organs found just above the waistline </li></ul><ul><li>Renal Fascia </li></ul><ul><li>This is the thin fibrous layer, which anchors the kidney to the surrounding structures to maintain the normal position of the organ. </li></ul>
  4. 4. The Work of the Kidneys <ul><li>The work of the kidney is to separate urine from the blood which flows through it. </li></ul><ul><li>Kidney plays a role in regulating the composition of the plasma by extracting excess wastes and other substances into the urine. </li></ul><ul><li>Each kidney receives the renal artery directly from the dorsal aorta and are drained by the renal veins which pass to the postcaval vein. </li></ul>
  5. 5. The Work of the Kidney <ul><li>Three Processes: </li></ul><ul><li>1. Filtration </li></ul><ul><li>The blood plasma is filtered through the walls of the glomerulus and collects in the Bowman’s capsule </li></ul><ul><li>This process forms a fluid, the nephric filtrate , which contains all the ions and small molecules present in the blood plasma. </li></ul>
  6. 6. The Work of the Kidney <ul><li>Three Processes: </li></ul><ul><li>2. Tubular reabsorption </li></ul><ul><li>The nephric filtrate passes through the tubular parts of the nephron where very large quantities of water and smaller quantities of glucose and other useful compounds are saved and reabsorbed. </li></ul><ul><li>This process of selective reabsorption demands that the gland cells in the tubule wall transfer the reabsorbed compounds back into the blood through the capillaries surrounding the tubule. </li></ul>
  7. 7. The Work of the Kidney <ul><li>Three Processes: </li></ul><ul><li>3. Tubular secretion </li></ul><ul><li>The nephric tubules secrete additional quantities of metabolic wastes into the nephric filtrate </li></ul><ul><li>Waste are extracted from the capillaries around the tubule and passed into the lumen of the nephron. </li></ul><ul><li>Reabsorption and secretion greatly change the composition of the nephric filtrate as this fluid drains through the nephron toward the collecting tubules. </li></ul><ul><li>The fluid as it reaches the collecting tubule contain a number of amber colored liquid with metabolic waste called urine </li></ul>
  8. 8. Excretory System <ul><li>2. Ureters </li></ul><ul><li>These are two tubes which function to convey urine from the kidneys to the bladder. </li></ul><ul><li>Passes from the pelvis to the posterior aspect of the urinary bladder </li></ul><ul><li>Peristalsis begins at the renal pelvis and ending at the bladder. </li></ul>
  9. 9. Parts of the Excretory System <ul><li>3. Urinary Bladder </li></ul><ul><li>This sac lies posterior to the pubis. </li></ul><ul><li>Separated from the rectum by the seminal vesicles in the male and by the vagina and uterus in the female. </li></ul><ul><li>Serves as reservoir for urine, gradually fills and becomes distended </li></ul><ul><li>Peritoneum </li></ul><ul><li>Covering of the superior surface of the bladder. </li></ul>
  10. 10. Parts of Excretory System <ul><li>4. Urethra </li></ul><ul><li>This is where urine is expelled. </li></ul>
  11. 11. <ul><li>1. Skin </li></ul><ul><li>Excretes wastes, secretes fluid and make possible growth and repair of hair cells. </li></ul><ul><li>Through sweating, the skin excretes excess salt, water and other metabolic wastes in the form of perspiration through pores </li></ul><ul><li>2. Large intestine </li></ul><ul><li>12-24 hours are required for the waste products of digestion to pass through the colon and rectum. </li></ul>Other Excretory Organ
  12. 12. <ul><li>3. Lungs </li></ul><ul><li>Excreting CO 2 </li></ul><ul><li>4. Liver </li></ul><ul><li>Produces bile which is concentrated by the removal of water and salts. </li></ul>Other Excretory Organ