The Lungs

Oxygen is the most important air molecule for the body because oxygen is moved from the air to the body cells. In order for this to happen, the body has several systems that work together such as the respiratory system, the cardiovascular system and the muscular system.

These systems work together to move oxygen through the body. There are several different parts that are included in the respiratory system.

Respiratory System

Breathing is an involuntary movement, which means that we breathe without thinking about it. The respiratory system plays a huge role in breathing, and it is connected to the heart and circulatory system through the cardio-pulmonary circulatory process.

This process is what the body uses to make sure that oxygen and carbon dioxide are in a perfect balance.

What Makes Up the Respiratory System?

The respiratory system uses more than the lungs to breathe. First, the trachea, or the windpipe, is a tube that delivers the air from the lungs and is also used to help keep the lungs healthy.

When we breathe air in, this air contains different things such as dust, bacteria, viruses and more. The air is dry and cool, and it travels from the nose to the throat and then down through the trachea where it is cleaned, moistened and warm to enter the other parts of the body.


The larynx is another part of the respiratory system and it helps you to talk. The larynx is part of the respiratory system that helps make sounds.

Cords in the larynx stretch to the vocal folds and when someone talks or sings and air is exhaled from the lungs, the vocal folds vibrate, and this is what causes there to be sound. Don’t forget the tongue, lips and teeth also help you to sing and talk!


Behind the chest are two hollow tubes that the trachea divides into and these tubes go into the lungs and then change to even smaller tubes. The smallest tubes have to be looked at with a microscope and they have sacs at the end, and they have very thin walls.

When a person breathes in or inhales, oxygens passes through these thin walls easily, and it goes into the blood. The red blood cells then carry the oxygen to other parts of the body while the carbon dioxide also passes through the walls so that you can exhale it.

Musculoskeletal System

The musculoskeletal system plays a huge job in breathing because your rib muscles and the diaphragm helps your body take air in and let air out by moving a certain way in the body. The diaphragm is a muscle that helps with breathing.

Energy from Oxygen

Your body needs oxygen to help make energy from sugar. If the body does not have oxygen, it cannot make energy. The body cannot live without oxygen.

Stages of Breathing

The body has three stages of breathing. The first stage is inhaling the oxygen into the body. With this stage, the diaphragm expands, and the lungs expand with air that has entered through the nose and mouth.

The second stage is the gas exchange that happens in the lungs. With this stage, air enters the lungs and oxygen from the inflated lung moves from the alveoli into the capillaries as carbon dioxide moves from the capillaries into the alveoli.

The last stage is exhaling carbon dioxide out of the body. The diaphragm muscles relax and the pressure around the lungs pushes the air out of the body where carbon dioxide is released from the body, traveling from the alveoli to the bronchiole to the bronchi, up the trachea and out through the nose and mouth.

Facts About the Respiratory System:

  • The epiglottis is a trap door to the trachea, this trap door makes sure that food does not enter into the lungs.
  • Nasal cavity helps to bring air into and take air out of the lungs.
  • Cilia is a lining in the nasal cavity that helps catch dust and other matter that does not belong in the lungs.
  • Bronchia’s branch off from the trachea and one of the branches go into the lungs.
  • Alveoli are branches that branch off the bronchioles through the lungs and this is where the oxygen and carbon dioxide exchange happens. There are around 300 million alveoli in the lungs.
  • The lungs are two large organs where the oxygen and carbon dioxide exchange occurs. The left lung is smaller than the right lung.
  • The left lung has two lobes and the right lung has three lobes.
  • The lungs are large and take up most of the space in the chest area.
  • Lungs are soft, light, spongy and they expand.
  • Pleura are airtight sacs that surround the lungs.
  • The diaphragm is the primary muscle in respiration.

What Did You Learn?

  • What gives the lungs movement? The lungs move when the diaphragm and the muscles move. The diaphragm does most of the work.
  • Where is the diaphragm located? The diaphragm is located below the lungs, it is a large, dome shaped muscle.
  • What helps to make sound and is part of the respiratory system? The larynx works with the vocal folds and cords to make sound such as singing and talking.
  • Where does air enter and leave the body? The air enters the body and leaves the body through the mouth and the nose.
  • What system is the diaphragm and the rib muscle’s a part of besides the respiratory system? The musculoskeletal system works the rib muscles and the diaphragm to help the body breathe.