Excretory System

Overview

A stockman in Ilorin glances at the colour of a bull's urine before he checks anything else that morning: pale and free flowing means all is well, dark and scanty is an early warning. That quick habit rests on the excretory system, the kidneys, ureters, bladder and urethra that filter the blood and carry away what the body no longer needs.

In this lesson you will learn the four parts of the excretory system in the order urine actually travels, what the kidney does to blood as it passes through, and how urine is formed in three plain steps. You will also learn to tell urine and faeces apart properly, a distinction WAEC candidates lose marks on every year, and see why urine and dung together make manure one of the farmer's most valuable free resources.

Objectives

  1. Define excretion
  2. Identify the parts of the excretory system
  3. State the functions of the kidney
  4. Explain the process of urine formation
  5. State the excretory products of a farm animal

Lesson Note

Every cell in a farm animal's body burns food for energy, leaving behind waste, chiefly nitrogen from digesting protein. Left in the blood, that waste would poison the animal. Excretion is the removal of this waste, and the job belongs chiefly to the excretory system. A stockman who understands it can read an animal's urine the way a mechanic reads an oil gauge.

Lesson Evaluation

Congratulations on completing the lesson on Excretory System. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.

You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.

Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.

  1. Which of the following correctly gives the order in which urine passes through the excretory system? A. Bladder, ureter, kidney, urethra B. Kidney, ureter, bladder, urethra C. Kidney, bladder, ureter, urethra D. Ureter, kidney, urethra, bladder Answer: B
  2. The main nitrogenous waste product removed from the blood by the kidney is: A. Glucose B. Urea C. Water D. Carbon dioxide Answer: B
  3. The process by which useful substances filtered out of the blood are taken back into the blood in the kidney tubule is called: A. Filtration B. Egestion C. Reabsorption D. Excretion Answer: C
  4. Which of the following is correct about faeces? A. It is filtered from the blood by the kidney B. It is formed by excretion C. It is undigested food residue removed by egestion D. It leaves the body through the urethra Answer: C
  5. A farm animal producing scanty, dark urine on a hot day is most likely: A. Overfed B. Dehydrated C. Suffering from worms D. Constipated Answer: B