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Biology LibreTexts

19: Urinary System

  • Page ID
    16843
  • This chapter discusses the concept of excretion and explains the excretory functions of the skin, liver, large intestine, lungs, and kidneys. It also describes the other organs of the urinary system and several urinary system disorders.

    • 19.1: Case Study - Waste Management
      As you will learn in this chapter, the liver and kidneys are important organs of the excretory system, and impairment of the functioning of these organs can cause serious health consequences. At the end of the chapter, you will learn which hormone Tricia was referring to, and some of the ways alcohol can affect the excretory system, both after the occasional drink and in cases of excessive alcohol use and abuse.
    • 19.2: Introduction to the Urinary System
      The actual human urinary system, also known as the renal system, is shown in the drawing below. The system consists of the kidneys, ureters, bladder, and urethra, which is the only structure not visible in the sculpture above. The main function of the urinary system is to eliminate the waste products of metabolism from the body by forming and excreting urine. Between 1 and 2 liters of urine are normally produced every day in a healthy individual.
    • 19.3: Kidneys
      The two bean-shaped kidneys are located high in the back of the abdominal cavity on either side of the spine. A renal artery connects each kidney with the aorta and transports unfiltered blood to the kidney. The kidney has two main layers involved in the filtration of blood and formation of urine: the outer cortex and inner medulla. At least a million nephrons, which are the tiny functional units of the kidney, span the cortex and medulla.
    • 19.4: Ureters, Urinary Bladder, and Urethra
      Ureters are tube-like structures that connect the kidneys with the urinary bladder. They are paired structures, with one ureter for each kidney. The urinary bladder is a hollow, muscular organ that rests on the pelvic floor. It is also lined with transitional epithelium. The urethra is a tube that connects the urinary bladder to the external urethral orifice, which is the opening of the urethra on the surface of the body.
    • 19.5: Disorders of the Urinary System
      The kidneys play such vital roles in eliminating wastes and toxins and maintaining body-wide homeostasis that disorders of the kidneys may be life threatening. Gradual loss of normal kidney function commonly occurs with a number of disorders, including diabetes mellitus and high blood pressure. Other disorders of the kidneys are caused by faulty genes that are inherited. Loss of kidney function may eventually progress to kidney failure.
    • 19.6: Case Study Alcohol Conclusion and Chapter Summary
      You are probably aware that drinking alcohol can cause visual disturbances, slurred speech, drowsiness, impaired judgment, and loss of coordination because of its effects on the brain. Although it may be less obvious, alcohol also can have serious effects on the functioning of the excretory system.