16.1 Urinary System

• The urinary system consists of organs that produce, store, and rid the body of urine.
• The kidneys excrete metabolic wastes and maintain the water-salt and the acid-base balance of the blood within normal limits.

1. How does the reflex to urinate differ in young children when compared with older children and adults?
   Answer
   
   
2. How does the urinary system help to maintain homeostasis?
   Answer
   
   

Essential Study Partner
    Nitrogenous Wastes
    Urinary System
    Human Excretion
    Urine Elimination

General Biology Weblinks
    Anatomy & Physiology

Labeling Exercises
Human Urinary System (43.0K)

16.2 Anatomy of the Kidney and Excretion

• Kidneys have a macroscopic (gross) anatomy and a microscopic anatomy.
• Urine is produced by many microscopic tubules called nephrons.
• Like many physiological processes, urine formation is a multi-step process.

1. What are the three regions of the kidney and which is continuous with the ureter?
   Answer
   
   
2. What adaptations of the proximal convoluted tubule maximize reabsorption?
   Answer
   
   
3. List the three steps of urine formation.
   Answer
   
   
4. How is it possible for an otherwise healthy person to excrete small amounts of glucose in urine?
   Answer
   
   

Essential Study Partner
    Kidney Function
    Kidneys
    Urine Formation
    Glomerular Filtration
    Tubular Reabsorption & Secretion

Art Quizzes
    Nephron
    Transport Processes in Mammalian Nephron

Animation Quizzes
    Kidney Function (1)
    Kidney Function (2)

Labeling Exercises
Anatomy of Kidney and Lobe (29.0K)
Nephron Anatomy (1) (43.0K)
Nephron Anatomy (2) (40.0K)

16.3 Regulatory Functions of the Kidney

• The kidneys are under hormonal control as they regulate the water-salt balance of the body.
• The kidneys excrete hydrogen ions and reabsorb bicarbonate ions to regulate the pH of the blood.

1. What portions of the nephron and kidney are involved in the reabsorption of water?
   Answer
   
   
2. If an individual drinks very little fluid on a hot day, what happens to the quantity of ADH released by the posterior pituitary?
   Answer
   
   
3. How does the buffer/breathing system compare with the ability of the kidneys to maintain acid-base balance in terms of speed and magnitude of the effect on pH?
   Answer
   
   

Essential Study Partner
    Water Balance
    Electrolyte Balance
    Urine Concentration
    Acid-Base Balance

Art Quizzes
    Homeostasis of Blood Volume and Pressure
    Osmotic Balance – Freshwater Fish

16.4 Problems with Kidney Function

• Medical conditions such as diabetes, hypertension, and urinary tract infections can lead to renal failure.

1. What factors may lead to the formation of kidney stones?
   Answer
   
   
2. Why does a person using an artificial kidney machine only need to undergo treatment about twice a week?
   Answer
   
   

Case Studies
    Transplant