Urine

• Urine is 95% water, 5% solute

• Nitrogenous waste containers in urine include:

  • Urea – from metabolism and proteins, is the most common solute

  • Uric acid – a waste product of nucleic acid metabolism

  • Creatinine- from creatine metabolism in muscles

• typical urine

  • has a pH near 6

  • is straw-colored

  • is sterile

• The specific gravity of pure water is 1.0, urine is generally 1.001 (dilute) to 1.035 (concentrated)

• Urinalysis (urine testing) can provide a lot of information about the bodies processes

• Atypical substances found in the urine include:

  • glucose

  • blood protein

  • red blood cells hemoglobin

  • white blood cells

  • bile

how does urine leave the body?

• From the kidneys, urine enters the tube-like ureters and empties into the elastic urinary bladder for storage

• In the bladder, the urine passes through the ureter and is released from the body by two sphincter muscles

• Just as in the rectum, there is an internal (involuntary) sphincter and an external (voluntary) sphincter

• loss of control (often with age) and the external urethral sphincter is the cause of incontinence

• The process of emptying the bladder is called micturitionn or voiding