We will begin this unit by learning about cells – the building blocks of living organisms. We will see how some organisms are able to live as a single cell, while others are composed of billions and trillions of cells. In multicellular organisms, cells connect together to make up tissues, which make up organs, which work together to make entire organ systems.
We will also study the major organ systems that make up the human body: the circulatory, respiratory, digestive, skeletal, muscular, and nervous systems. We will see the important roles that each of these systems play in the function and well-being of our bodies.
Lesson 1: Cells We will begin our study of body systems by looking at cells, the building blocks of all living things. Some organisms such as bacteria, amoebas, and paramecia are unicellular organisms – living things made entirely of one individual cell. In unicellular organisms, all of the organisms life processes must be carried out by its single cell. Larger organisms, however, are multicellular – they are made up of many cells. In a multicellular organism, there are many different types of cells that each have a specific job. These cells combine to make layers of tissue, which make up organs, which make up organ systems, which work together to carry out the life processes of a multicellular organism. Examples of these specialized cells include skin, nerve, muscle, bone, and blood cells. Download PDF Notes
Lesson 2: The Circulatory and Respiratory Systems In lesson 2, we will explore how our body’s respiratory systems work together to provide oxygen to our body’s cells through the process of respiration. The lungs work to take in oxygen from the air, which is passed into our blood. As the heart circulates our blood, individual blood cells deliver oxygen to all the cells in our body. As our cells carry out their jobs in our bodies, they produce carbon dioxide gas as a waste product. Our blood cells also work to return this carbon dioxide to our respiratory system to be removed from the body when we exhale. Through this lesson, we will further study the individual organs that make up the respiratory and circulatory systems and see the important roles that each plays in these body processes. Download PDF Notes
Lesson 3: The Digestive System Our third lesson looks at the digestive system. The digestive system’s job is to break food down into nutrients that can be used to provide energy for our bodies. Our body uses two types of digestion: mechanical digestion such as chewing crushes and breaks down food into smaller pieces, and chemical digestion such as stomach acid which softens and breaks food into nutrients that can be absorbed by our cells. During the process of digestion, food travels through the mouth, esophagus, stomach, small intestine, and large intestine. at each stage of digestion, mechanical and chemical digestion take place until any remaining non-digestible parts of the food are removed from our body as waste. During this lesson, we will also be making digestive fluid and conducting an experiment to observe the process of digestion. Download PDF Notes
Lesson 4: The Skeletal and Muscular Systems In lesson 4, we will examine the skeletal and muscular systems. The bones that make up our skeletal system serve two major purposes. Long bones, such as those in our arms and legs, provide a supporting framework for our bodies. Bones such as our skull and ribs provide protection for our other body systems and internal organs. The muscular system works together with the skeletal system to allow our bodies to move. Skeletal muscles, or muscles that are attached to our bones with tendons, expand and contract, allowing our bodies to move. Smooth involuntary muscles, such as those that line our digestive organs, work inside our bodies to control important processes such as digestion and respiration. Download PDF Notes
Lesson 5: The Nervous System We will end our study of human body systems by learning about the nervous system. This body system serves as a sort of control center for the entire human body. Our nerves send tiny electrical impulses to and from our brain to relay information about internal and external conditions and to receive instructions. In many ways our brain is similar to a computer, processing information and sending signals to our other organs and body systems related to senses and movement. Our nervous system is made up of the brain, spinal cord, and nerve cells called neurons. Download PDF Notes
Resources and Other Documentation
Unit 1 Guided Notes The guided notes for each unit provide students with a printable copy of notes summarizing the content from each class. Blanks are inserted into the notes where key facts or content should appear. As information is covered during class, students should write missing content into the blanks to complete the guided notes. These guided notes may also be used as a review tool for unit tests. Students may print a copy of the guided notes and fill in the missing content. This can be checked using the complete PDF notes for each lesson.