Anatomy & Physiology Unit 8

Kidneys  Organ that filters the blood and removes wastes Ureter  Tube that carries wastes from the kidney to the bladder  Urinary bladder  Sac that stores liquid wastes  Urethra  Tube that carries liquid waste from the bladder to outside the body

 Kidney  They are located in the lower back and receive some protection from the rib cage  There is three parts to the kidney: renal cortex, renal medulla and renal columns

 Kidney  The renal artery supplies the kidney with the “dirty” blood supply and the renal vein takes the “clean” blood back to the heart to be re-circulated  The kidney contains millions of structures called nephrons  Nephrons are responsible for forming urine

 Ureters  Tubes about 25cm in length and 6mm in width  They carry the urine from the kidney to be stored in the bladder

 The bladder  A smooth, collapsible sac that stores urine temporarily  It is made of a special type of epithelial tissue  When empty it collapses to about 5cm long  When full it is about 12.5 cm long and can hold about 500ml of urine

 Urethra  The tubes that carry the urine out of the body  In females the urethra is about 3-4cm long  In males it is about 20cm long (it is both part of the urinary and reproductive system in males)

 Purpose is to remove liquid wastes from the body and maintain the water/salt balance  Urea: waste that results from the breakdown of body protein  Urine: liquid waste

 Pathway of excretion:  The blood flows into the kidney  Water, salt, sugar and urea are forced out of the blood  The blood continues in the vessel and the waste stays in tube and carried through the ureter to the bladder  The clean blood travels back to the heart  A healthy person will excrete 1 liter of urine a day

 Urine can range in color from clear to dark amber  The yellow is due to urochrome, a pigment that results from the destruction of hemoglobin  The more solutes in urine the deeper the yellow; therefore, dilute urine is a pale yellow color

 Urine is sterile and has a slight aroma  Some drugs, vegetables and diseases will alter the smell of urine  Normally found in urine:  Na and K ions  Urea  uric acid  Creatinine  Ammonia  Bicarbonate ions

 Substances NOT normally found in urine  Glucose  Blood proteins  Red blood cells  Hemoglobin  White blood cells (pus)  bile

 Glucose – excessive intake of sugary foods &/or Diabetes mellitus  Proteins – excessive physical exertion or pregnancy  Pus – urinary tract infection  RBCs – injury to kidneys, kidney stones, infection  Hemoglobin – transfusion reaction, hemolytic anemia  Bile – Liver disease &/or hepatitis