The Excretory System – Lesson Summary

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Learning Objective

In this lesson we will learn about excretion in humans, in particular, the urinary system.

Learning Outcomes

By the end of this lesson you will be able to:

  • Discuss the overall function of the excretory system.
  • Describe different ways the human body removes waste.
  • Describe the organs of the urinary system and discuss the role they play in excretion.
  • Identify the main blood vessels flowing to and from the kidneys.

 
the excretory system contents

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Lesson Topics

1 | Excretion

2 | The Urinary System

3 | The Kidneys

4 | The Ureters, Bladder and Urethra

5 | Summary

Lesson Summary

  • Excretion refers to any process that eliminates metabolic waste products from the body.
  • These materials would otherwise accumulate in the body and become toxic.
  • The main excretory process that occur in the body are:
  • Exhalation – the removal of carbon dioxide from the body via the lungs.
  • Urination – the removal of urea from the body via the kidneys.
  • Sweating – the removal of excess heat, salt and urea via glands in the skin.
  • The excretory system incorporates several body systems – the respiratory system, the urinary system and the integumentary system.
  • The urinary system is a group of organs that remove urea and other metabolic wastes from the body as urine.
  • Organs that make up the respiratory system are:
  • The kidneys – the principal organs of the urinary system, that filter blood, separating waste products and removing them as urine.
  • The ureters – long, thin tubes that transport urine from each kidney to the bladder.
  • The bladder – a muscular pouch that stores urine; urethral sphincters at the base of the bladder control urination.
  • The urethra – a tube that transports urine from the bladder out of the body.
  • The kidneys are enclosed in a fibrous capsule and consist of three main sections:
  • The cortex – the outer section of the kidney containing nephrons, where blood is filtered.
  • The medulla – the middle section of the kidney, where water is reabsorbed and urine is funnelled into the renal pelvis.
  • The renal pelvis – the inner section of the kidney, where urine is collected before exiting via the ureter.
  • The main blood vessels leading to and from the kidneys are:
  • The renal arteries, which carry unfiltered blood to the kidneys from the heart.
  • The renal veins, which carry filtered blood from the kidneys to the heart.

 
 
need to pee toilet icons

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