Urinary System and Kidney Function

How does waste leave the body?

Facts about your Kidneys:• The kidneys are bean-shaped• each about the size of a fist• They are located near the middle of the back,

just below the rib cage, one on each side of the spine.

• Every day, a person’s kidneys process about 200 quarts of blood

• About 2 quarts of waste products and extra water are processed out of the blood

• Liquid wastes become urine

Functions of the Kidney & Urinary System

Elimination of waste products–Nitrogenous wastes–Toxins–Drugs

How does the kidney work?

• Wastes in the blood come from the normal breakdown of active tissues and from food

• After the body has taken what it needs from food, wastes are sent to the blood

• Wastes would build up in the blood and damage the body if the kidneys did not remove them

How does the kidney work?

What do your kidneys do?

• Regulate electrolytes• Maintain Water/Salt Balance• Regulates Blood Pressure• Maintains acid/base balance of blood and

bodily fluids• Diverts liquid wastes to the urinary bladder• Help with Red Blood Cell production

Circulation for the Kidney

Renal Circulation flow of blood through the kidney

Renal ArteryProvides kidney with oxygenated blood

Renal VeinDeoxygenated blood flows out of the kidney

How is waste filtered?

• Removal of wastes occurs in tiny units inside the kidneys called nephrons

• Each kidney has about a million nephrons • Glomerulus—a tiny blood vessel in the nephron• The glomerulus acts as a filtering unit:

keeps normal proteins in bloodstream keeps cells in the bloodstream

• allowing extra fluid and wastes to pass through• Waste materials & Water leave the blood

(to then enter the urinary system)

How is waste filtered?

Glomerulus Function

Formation of Urine

Solutes normally found in urine

– Sodium and potassium ions– Urea, uric acid, creatinine– Ammonia– Bicarbonate ions

Solutes NOT Normally Found in Urine

– Glucose– Blood proteins– Red blood cells– Hemoglobin– White blood cells (pus)– Bile

Flow of Urine

Kidney

Ureters

Urinary Bladder

Urethra

Balance of minerals

The kidney maintains important levels of:--Sodium--Potassium--Phosphorus--Erythropoeitin--Renin Hormone (for blood pressure)--Calcitrol (helps regulate Calcium usage)

What is the “excretory system”

• Body’s ability to eliminate wastes• Parts of this system are parts of other body

systems• “Waste”things the body can’t use and may

harm the body if they are not moved

out of the body

Wastes that leave the body:

• Urine • Ureafrom protein breakdown • Uric Acidfrom nucleic acid breakdown• Creatinine—associated with creatine breakdown

• Solid Wastes (defacation)• Sweat• Tears• Carbon Dioxide