Unit D

Module 8 Introduction


Schools, offices, public spaces, and homes are full of harmful and contagious bacteria and viruses. The human immune system protects the body from these pathogens. The lymphatic system is a network of vessels that contain interstitial fluid. Blood and lymph work together to fight infection and transport fats.

The body's cellular functions create waste products that can be harmful if they are not secreted. The excretory system excretes waste in the form of urine. It also reabsorbs important nutrients and maintains the body's pH levels.

Big Ideas

This module will investigate the human immune and excretory systems and their role in maintaining an internal equilibrium.

By the end of this module, you should be able to
  • explain how the human immune system protects the body from pathogens
  • explain how the excretory system helps maintain a state of equilibrium in the body

Key Concepts

Concepts that you should be able to explain by the end of this module are
  • the three lines of defence
  • the action of white blood cells in the human defence system
  • antigens and antibodies
  • human blood types and their compatibility
  • the structures of the excretory system
  • the filtration, secretion, and reabsorption of substances in the kidneys
  • the role of ADH and aldosterone in maintaining fluid and salt balance in the body


Skills that you should be able to do by the end of this module are
  • interpret blood typing results and determine compatible donors
  • interpret urine samples to determine abnormalities in kidney function
  • predict the effect of exercise, high sodium intake, caffeine intake and alcohol use on the body's internal balance


There are three graded assessments in Module 8.

  1. Unit D: Section 5 Assignment
  2. Unit D: Section 6 Assignment
  3. Unit D Summative Part 3

As you work through this unit and its module, you will find Self-Check questions, labs, and critical thought questions. There will be lesson goals indicated at the beginning of each lesson and then clearly identified throughout the lesson.