Respiratory System

Functions of the Respiratory System

To provide gas exchange between the air and the body.

Bring oxygen (0₂) into the body from outside.
Expel carbon dioxide (CO₂) produced by the cells out into the air.

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Every‌ ‌cell‌ ‌in‌ ‌the‌ ‌body‌ ‌requires‌ ‌oxygen‌ ‌to‌ ‌produce‌ ‌

energy‌ ‌during‌ ‌the‌ ‌process‌ ‌of‌ ‌cellular‌ ‌respiration.‌ ‌This‌ ‌

is‌ ‌the‌ ‌whole‌ ‌reason‌ ‌that‌ ‌we‌ ‌breathe!!!‌

Important Vocabulary

Diffusion-the process by which molecules move from high concentration to low concentration.

Example: Think about perfume. I spray it in the corner of the room and eventually you will smell it across the room.

Example: See the GIF to the right.

Gas Exchange-the exchange of oxygen for carbon dioxide. This happens in two locations:

1. between alveoli/capillaries,

2. between capillaries/cells of the body.

DIFFUSION. Red molecules start out concentrated in one area and then spread to other areas of low concentration.

GAS EXCHANGE. Blood drops off carbon dioxide in the capillaries of the lungs and picks up oxygen. The oxygen is dropped off for the organs and cells of the body. The blood then picks up more carbon dioxide waste from the cells of the body and returns it to the lungs to be breathed out.

Gas Exchange Explained

When we inhale, we fill our alveoli with oxygen. There is a high concentration of oxygen in the alveolar space. It will diffuse into the blood within the capillaries around the alveolus. The blood entering the capillaries (tiny blood vessels that surround the alveoli) have a high concentration of carbon dioxide. The carbon dioxide diffuses from the blood into the alveolar space. This is gas exchange. Oxygen diffuses from the alveolus into the blood while carbon dioxide in the blood diffuses into the alveolus. We expel the carbon dioxide when we breathe out.

The blood (which is part of the circulatory system, not the respiratory system) will carry the oxygen around the body delivering it to every cell for cellular respiration (a process that produces energy). The cells produce carbon dioxide as a waste product of cellular respiration. The blood picks up the carbon dioxide waste and takes it back to the lungs to be breathed out and exchanged for more oxygen.

Oxygen diffuses from the alveolar space into the capillary, attaching to red blood cells. Carbon dioxide diffused from the red blood cell into the alveolar space to be breathed out.

Organs of the Respiratory System

Nose

Respiratory Tract or Accessory Organ

Respiratory Tract

Function of Organ

Warm and moisten air as it enters the respiratory system. It also traps particles before they get too deep.

Trachea

Respiratory Tract

Tube that transports air between the nose and the bronchi. This is where your voicebox (larynx) is located.

Bronchi

Respiratory Tract

Branching tubes located at the end of the trachea that bring air into the lungs. The tubes branch smaller and smaller and eventually end in alveoli.

Lung

Respiratory Tract

The main organ of the respiratory system responsible for gas exchange.

Alveoli

Respiratory Tract

Technically not an organ

Tiny sacs of of air where gas exchange happens. These are located at the end of bronchioles, inside the lungs. They are surrounded by capillaries. Oxygen diffuses from the alveolus into the blood while carbon dioxide diffuses from the blood into the alveolus.

Diaphragm

Accessory Organ

Dome shaped muscular organ that helps you breathe. Its contraction increases the volume of the chest causing the lungs to expand (inhale).

Respiratory and Circulatory work Together!

Respiratory and Circulatory Systems work together because cells need oxygen for cellular respiration (a process that creates energy).

Oxygen enters our lungs, but it must travel to the other cells of the body.
Gas exchange happens between the alveoli in the lungs and the capillaries that surround them. Oxygen diffuses into the blood from the alveoli.
Oxygen attaches to the red blood cells (part of the circulatory system) and travels to the cells of the body.
Oxygen diffuses from the blood into the cells so the cells can create energy (cellular respiration). The waste product of cellular respiration is carbon dioxide.
Carbon dioxide diffuses from the cells into the blood.
Blood carries carbon dioxide back to the capillaries that surround the alveoli in the lungs.
Carbon dioxide diffuses from the blood into the alveoli to be breathed out. (This happens at the same time as step 2…gas exchange.)

Video explaining how the two systems work together!

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