1. The Urinary System UNIT 6.12

2. Objectives:  Define, pronounce, and spell all key terms.  Label a diagram of the Urinary System.  State the functions of the ureter, bladder, and urethra.  Explain the action of the Nephron.  Explain why the urethra is different in males and females.

3. Introduction The parts of the Urinary System are:  2 kidneys  2 ureters  1 bladder  1 urethra

4. Lets begin!  The Urinary System is also known as the Excretory System.  Function: responsible for removing certain wastes and excess water from the body and for maintaining the body’s acid-base balance.  Controls the volume and pressure of body fluids by eliminating wastes not needed in our body  Filters the blood and maintains balance of pH in the blood

5. Kidneys  2 bean shaped organs  4-6 ounces each  4 inches long, 2-3 inches wide, 1 inch thick  Left is slightly larger than the right  Protected and enclosed by adipose (fat pads)  Located on each side of the vertebral column, behind the upper part of the abdominal cavity

6. Kidneys…  Divided into 2 main sections: the cortex and the medulla  Cortex -the outer section that contains most of the nephrons (aids in the production of urine)  Medulla- is the inner section with 12-18 medullary pyramids that contains most of the collecting tubules (which carry the urine from the nephrons through the kidneys)

7. Kidneys…  Each kidney has a Hilum (hilus) -an indented area where the ureter, nerves, blood vessels such as the renal artery and the renal vein enter and leave the kidney  Renal pelvis -funnel shaped reservoir of the calyces that collect urine and funnel it into the ureter

8. Kidney-Anatomy  Nephrons -is the functional unit of the kidney.  They are approx 1 million in each kidney  They are microscopic filtering units  Each contain a glomerulus, Bowmans capsule, a proximal tubule, a distal tubule, and a collecting duct (tubule)

9. Function of the Nephron  The renal artery carries blood to the kidney  Branches of the renal artery pass thru the medulla to the cortex  Blood then enters the first part of the nephron called the glomerulus  Glomerulus -( a cluster of capillaries)as blood enters, water, mineral salts, sugar, metabolic products, and other substances are filtered out of the blood and then leaves the glomerulus.

10. Nephron function  Next!  The now filtered blood enters the renal vein and carries it away from the kidney  The substances that were filtered by the glomerulus enters the Bowmans capsule  The Bowmans’s capsule - is C-shaped, picks up the substances filtered from the blood and glomerulus then passes it to the tubules

11. Nephron function  Now in the tubules - substances that are needed by the body are reabsorbed and returned to the blood capillaries  The excess substances (including urea, uric acid, and creatine) remain in the tubule and becomes a concentrated liquid called urine !

12. Ureters  2 muscular tubes  Approx 10-12 inches long  Extends from the renal pelvis to the bladder  Peristalsis -rhythmic wave-like motion of muscle that moves the urine through to the bladder

13. Bladder  Receives urine from the ureters  Hollow muscular sac  Surrounded by mucous membranes in folds called rugae  The urge to urinate begins when it holds approx 250 cc of urine (about a cup)  When full, receptors will send out a reflex action which opens the muscle  Infants have no control over this reflex action  Children learn to control the reflex

14. Urethra  Tube that carries the urine from the bladder to the outside  The external opening is the urinary meatus  Females-the urethra is approx 1 to 1 ½ inches in length that opens in front of the vagina  Males-the urethra is approx 8 inches long, passes thru the prostate gland, and out thru the penis. It carries both urine and semen.

15. Urine  A liquid waste  Approx 95% water  Mostly urea, uric acid, creatine, and mineral salts  Urea is produced as a break down product of protein and creatine is metabolic by product of muscle metabolism  Sugar found in the urine usually indicates disease (diabetes)  Approx 1 ½ - 2 quarts of urine is produced daily

16. Key Terms  BLADDER  BOWMANS CAPSULE  CORTEX  EXCRETORY SYSTEM  GLOMERULUS  HILUM  KIDNEYS  MEDULLA  NEPHRONS  RENAL PELVIS  URETERS  URETHRA  URINARY MEATUS  URINARY SYSTEM  URINE

17. You survived again!!! Good job!!!