Organ Systems — Definition & Overview

(Video) Organs and Organ Systems

by Jennifer Prewitt

What do your body and a symphony orchestra have in common? They're both made up of individual parts that work together. Instruments work together to make the orchestra, notes work together to make a song, and organs work together to build an organ system.

This video explains the ideas behind how organ systems function and are organized.

Organ System (Level of Organization)

An organ system is two or more organs working together to perform a specialized function (job).

Organ systems are the fourth step in the levels of biological organization, found between organs and organisms, as shown in the graphic below. Let's take a look at that.

As the graphic shows, an organ system is made from organs working together.

There are 11 major organ systems in the human body:

Remember, each of these organ systems is made of multiple organs working together.

For instance, the digestive system alone is made of more than ten organs. Here's a look at the organs in the digestive system:

Just as plants have organs, they also have organ systems. However, plants only have two organ systems: the root system and the shoot system.

Key Vocabulary:

1. Organ system
2. Organ
3. Tissue
4. Cell
5. Function

What Is an Organ System?

Organ systems are one of the highest levels of structural organization in an organism, second only to the organism itself. An organ system is a group of two or more organs working together to perform a certain function.

Some examples in the human body are the respiratory system (lungs and heart working together to help us breathe), the nervous system (brain and spinal cord working together to help transmit signals), and the digestive system (stomach and intestines working together to help us digest food). Each of these systems is not just made up of organs. They have a lot of other pieces to connect all the parts together and help the system work.

The organ systems in organisms are like parts of a machine. If one of them fails or breaks, the whole machine will stop working correctly. For example, if your respiratory system failed and you could not breathe, your cardiovascular system would fail because your heart could not carry the oxygen you inhaled to the rest of your body.

Though we commonly think of organ systems as being just in the human body, other organisms have organ systems as well, including small organisms like mice and even ants. Many of the organs that humans have, like a heart, lungs, and stomach, can also be found in other organisms. However, some organisms also have organs and organ systems that are drastically different from human body structures.

The 11 Organ Systems of the Human Body

Organ systems are made up of various organs working together to perform a vital body function.

Before we see some examples, let's take one more look at how we got here. All biological systems, no matter how complex, start at the chemical level of organization. Here, atoms combine to form compounds and molecules. Next, many compounds come together to form a single cell. Many cells with the same cellular structure may come together to form a tissue. When tissues work together, we end up at the organ level. Finally, organs work together to form systems.

From start to finish, we have chemicals, cells, tissues, organs, and organ systems.

What Are Some Examples?

Systems of organs include the digestive system, nervous system, muscular system, and skeletal system. There are 11 total organ systems in the human body. They all have unique structures and functions that help organisms stay alive.

• Nervous system
• Integumentary system
• Lymphatic (Immune) system
• Muscular system
• Circulatory system
• Skeletal system
• Respiratory system
• Digestive system
• Excretory (Urinary) system
• Endocrine system
• Reproductive system

$$\color{#8925AE}{\text{Vocabulary Review:}}$$

$\color{#8925AE}{\text{Cell}}$ : The smallest unit of life

$\color{#8925AE}{\text{Tissue}}$ : A group of specialized cells that do specific jobs

$\color{#8925AE}{\text{Organ}}$ : A structure made up of specialized tissues

$\color{#8925AE}{\text{Organ System}}$ : A system made up of organs working together

$\color{#8925AE}{\text{Organism}}$ : An individual living thing

(Video) Human Body Systems Functions Overview: The 11 Champions

by Amoeba Sisters

This video by the Amoeba Sisters gives a brief overview of the 11 major organ systems of the human body. Remember, organ systems work together to help the body function.