The Respiratory System

• The respiratory system is the group of organs that takes in oxygen and gets rid of carbon dioxide

• Respiration is another name for breathing• Respiration is the transport of oxygen from outside

the body to cells and the transport of carbon dioxide and wastes away from the cells

• When we inhale, oxygen in the air moves into the blood from the lungs

• Oxygen is used for cellular respiration

The O₂/C O₂ Exchange

• When we exhale, carbon dioxide is released from the body

• When we inhale, O₂ in the air moves into the blood from the lungs

• O₂ leaves the blood and enters the body cell through the capillaries

• O₂ is used for cellular respiration• When we exhale, CO₂ is released from the body• CO₂ moves from the body cells to the capillaries• Blood carries CO₂ through the heart and to the

lungs• CO₂ moves out of the lung capillaries and into the

lungs to be exhaled

Parts of the Respiratory System

• Air enters your respiratory system through your nose and your mouth

• Air flows into the pharynx, or throat• The pharynx branches into two tubes• One tube leads to the stomach• The other tube leads to the lungs• The larynx is the part of the throat that holds the

vocal chords• When air passes across the vocal chords, they

vibrate, making a voice

Parts of the Respiratory System

• The larynx is connected to the trachea, or windpipe• Air flows from the larynx through the trachea to

the lungs• The trachea splits into two branches called bronchi

(bronchus, singular)• The bronchi connect to each lung• The bronchi branch off into smaller tubes called

bronchioles• Bronchioles lead to tiny sacs called alveoli• Alveoli are surrounded by blood vessels• Gases move between the blood vessels and alveoli

Parts of the Respiratory System

• As you breathe, air is sucked into and forced out of the alveoli

• Breathing is carried out by the diaphragm and the rib muscles

• The diaphragm is a dome-shaped muscle below the lungs

• When you inhale the diaphragm contracts, or moves down

• The volume of the chest increases• This creates a vacuum and air is sucked in• Exhaling is the reverse process

Disorders of the Respiratory System

• Asthma – condition in which airways are narrowed because of inflammation of the bronchi

• Pneumonia – inflammation of the lungs that is usually caused by bacteria or viruses – alveoli fill with fluid

• Emphysema – alveoli have been damaged so oxygen cannot pass across into the blood as well as it should – often linked to long term use of tobacco