A Team of Systems
The human body is an incredibly complex machine. To perform all the functions necessary for life, the body is organized into a team of organ systems. An organ system is a group of organs that work together to perform a major job. Each system has a specific role, but they are all interconnected and must work together to keep the body healthy and in a state of balance called homeostasis.
Let's look at the jobs of some of the major systems.
Major Organ Systems
Circulatory System
Main Organs: Heart, Blood Vessels (arteries, veins, capillaries)
Main Function: The body's transport system. It transports oxygen, nutrients, and hormones to cells throughout the body and carries away waste products like carbon dioxide.
Respiratory System
Main Organs: Lungs, Trachea (windpipe), Diaphragm
Main Function: Responsible for gas exchange. It brings oxygen from the air into the body and removes carbon dioxide waste from the body.
Nervous System
Main Organs: Brain, Spinal Cord, Nerves
Main Function: The body's control and communication network. It receives information from the senses, processes that information in the brain, and sends out signals to control the body's actions.
Digestive System
Main Organs: Stomach, Small Intestine, Large Intestine, Liver, Pancreas
Main Function: To break down food into small nutrient molecules that the body can absorb and use for energy, growth, and repair.
Skeletal System
Main Organs: Bones, Cartilage, Ligaments
Main Function: Provides support, protection, and shape to the body. It also allows for movement, produces blood cells, and stores minerals.
Muscular System
Main Organs: Skeletal muscles, Smooth muscles, Cardiac muscle
Main Function: Responsible for all movement in the body, from walking to the beating of your heart.
Excretory System (Urinary System)
Main Organs: Kidneys, Bladder, Ureters
Main Function: Filters waste products from the blood and removes them from the body as urine. It is also crucial for maintaining the body's water and salt balance.
Teamwork is Key
No system works alone. They are all constantly interacting.
When you run, your muscular system needs more oxygen. Your nervous system tells your respiratory system to breathe faster and your circulatory system to pump your heart faster to deliver that oxygen.
Your digestive system breaks down food into glucose. The circulatory system transports that glucose to all your cells so your respiratory system can use it for cellular respiration to produce energy.
This constant communication and cooperation between all the organ systems is what allows the human body to function as a single, integrated organism.