Major Systems of the Human Body SC.6.L.14.5: Identify and investigate the general functions of the major systems of the human body (digestive, respiratory, circulatory, reproductive, excretory, immune, nervous, and musculoskeletal) and describe ways these systems interact with each other to maintain homeostasis. 2 Handouts: “Human Body Systems Sheet” and “Amoeba Sister Video Recap” sheet

Key Ideas/ Concepts for you to know After this lesson, you should be able to identify some of the major body systems and describe the general function of the system. What does each system do for us? You should understand what homeostasis is and how our body systems work together to keep us stable.

First…what is “homeostasis”? Homeostasis is what our body maintains for us. It means that our body does so many things to keep everything going as it should be…because of homeostasis we have a regular body temperature and heartbeat, for example. The word itself can help to explain what homeostasis is. The prefix “homeo” means alike or resembling something. The suffix (ending) “stasis” means balanced or stable, regular. Put together, it means “to maintain balance”. Homeostasis is the word that explains the processes that our bodies maintain to keep us and everything within us balanced and working.

Before we talk about the major systems of your body… Let’s remember that these systems are made of organs which are made of tissue which are made of cells… …and a cell is the basic building block of any living thing!

Nervous System: What does it do? Our nervous system is the system that receives and send messages inside and outside of our bodies. It also helps us to maintain homeostasis in our body: it helps us to keep a balance in our body even though things around us may affect us. Without our nervous system, we could not smell things, walk or talk, or even think!

What is part of the Nervous System? The brain and the spinal cord (the nerves and tissues inside of your spine) make up the central nervous system. Your brain gathers and stores information and controls everything we do – whether you think about doing it (like drawing a picture), or not (like breathing and blinking).

Muscle-Skeletal System Muscles and bones make up this system. Your skeleton allows you to move with the help of your muscles and it gives your body a shape. Your skeleton is composed of many things including bones—which are alive! Some bones produce red blood cells (to carry oxygen), and others produce white blood cells (fight harmful bacteria in the body)

Muscles Muscles are attached to bones by tendons and other tissues which allow us to move in many ways Muscles are connected to the brain and spinal cord by many nerves Examples of muscles are your heart or a biceps (muscle in your arm)

Circulatory System Is made up of the heart, blood vessels and blood. Your heart pumps blood through the blood vessels, or different types and sizes of tubes in your body. Blood is the sticky, red fluid that travels through the body, taking oxygen and collecting carbon dioxide using veins and arteries Our circulatory system brings needed substances to cells, carries waste from cells and helps to keep your body temperature regulated. .

Respiratory System Your nose, mouth and lungs are the main parts of this system Our respiratory system bring oxygen from the air around us into our lungs and removes water and carbon dioxide from our body. We inhale (breathe in) oxygen and exhale (breathe out) carbon dioxide. The oxygen that we breathe is needed so that our cells can break down sugar in them to give us energy for our bodies to work.

Digestive System Digestion begins in your mouth. Your teeth grind up the food. The tongue detects “good’ and “bad” flavors and helps move food around the mouth and down the throat. Saliva (spit) helps with chewing and swallowing and starts digestion. Food goes down the throat to the stomach. Here chemicals break the food down to be used by the body for energy, building blocks for cells and tissues, and some is stored for later use. The food passes through the small and large intestine where nutrients are absorbed. The parts of food that cannot be used are passed out of the body.

The Reproductive System The main function of the reproductive system is to make egg and sperm cells which can combine to make a zygote (offspring).

The Excretory System The biggest responsibility of this system is to collect and remove waste from our body. Much of this waste is normal: through homeostasis our body cleans up and gets rid of dead cells or water The system includes our skin, lungs, kidneys, and bladder, to name a few We get rid of our waste through our skin (sweating), excreting waste (urine for example) and through breathing out carbon dioxide. By getting rid of wastes, our we keep the internal part of our bodies free of poisons or chemicals (homeostasis)

The Immune System The immune system is made up of a network of cells, tissues, and organs that work together to protect the body. One of the important cells involved are white blood cells, also called leukocytes, which come in two basic types that combine to seek out and destroy disease-causing organisms or substances.

Human Body System Recap: you need your Amoeba Sisters Video Recap Sheet Human Body Systems: The 11 Champions (Updated) Highlight the link above, then right click with your mouse. Click on “open hyperlink”.