Excretory organs

® The excretory organs of the body are the kidneys, skin, lungs and large intestine. ® The kidneys form urine, which passes to the bladder and is excreted through urination.

® The skin eliminates water and mineral salts through perspiration.

® The large intestine eliminates waste from digested food through defecation.

® The lungs eliminate carbon dioxide and water vapour through exhalation.

The urinary system is made up of:

^ two kidneys - which filter the blood and form urine

^ two ureters - two tubes that carry urine from the kidneys to the bladder

^ the bladder - a hollow sac where urine is stored until it is excreted

^ the urethra - a tube that carries the urine from the bladder out of the body.

Renal artery

Renal artery

Figure 2.22 The urinary system. Top of bladder removed to show openings.
Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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