The Respiratory System

Moves oxygen into the body Functions Moves oxygen into the body Removes carbon dioxide and water from the body.

Oxygen is required for most functions that go on in your body. Taking in Oxygen Oxygen is required for most functions that go on in your body.

Respiration vs. Breathing Respiration is the series of chemical reactions that glucose and oxygen undergo in your body. Breathing is the movement of air into and out of the lungs.

Removing Carbon Dioxide The process of respiration produces carbon dioxide and water, which are then removed from the body through the respiratory system.

The Path of Air

The Path of Air Nose Pharynx Trachea Bronchus Lung

The Path of Air Nose Location where air enters the body. Nasal cavities are lined by mucus which trap particles (dust) and moisten the air.’ Cilia are tiny hairs that line the nasal cavities. They sweep mucus down the digestive system to be destroyed by stomach acid.

The Path of Air Pharynx The pharynx is your throat’ Connects to both the nose and the mouth

The Path of Air Trachea The windpipe The trachea is strengthened by rings of cartilage. Lined with cilia and mucus. Cilia sweep mucus upward so it can be swallowed. Normally only air enters the trachea. If food enters it can block the passage of air to the lungs.

The Path of Air The Bronchi Air moves from the trachea to the bronchi, the passages that direct air into the lungs. The bronchi branch out in the lungs into smaller tubes. At the end of the smallest tube are alveoli, tiny sacs of lung tissue that move gasses from air to blood.

The Path of Air The Lungs - Lungs: the main organs of the respiratory system.

Gas Exchange The alveoli are surrounded by capillaries. When air reaches the alveoli the oxygen moves through the thin wall of the alveoli, through the wall of the capillary, and into the bloodstream. When CO2 and H2O are ready to be disposed of the move from the blood into the alveoli.

Gas Exchange Surface Area for Gas Exchange When opened up and spread out, alveoli have the surface area of a tennis court. This extremely large surface area allows a tremendous amount of oxygen to be absorbed into the lungs.

How You Breathe The rate at which you breathe depends on your body’s need for oxygen. For example, as you run your body needs more oxygen to supply to your muscles, therefore, your rate of breathing increases.

Muscles Used for Breathing Breathing is controlled by muscles. The lungs are surrounded by ribs, which are attached to muscles. The diaphragm is a muscle below the lungs.

Inhaling When you inhale, your chest expands. Your rib muscles move outward and your diaphragm moves downward. There is now more space in your chest for the air that was already there before. Air rushes in from outside of your body to fill up the space.

Exhaling As you breathe out, your muscles relax and the chest cavity gets smaller. As the size of the chest decreases it pushes the air that is inside out.

Breathing and Speaking The larynx is located at the top of the trachea and vocal cords stretch across the top of it. Muscles make the vocal cords contract (tighten) as you speak and the vocal cords vibrate. The vibrations cause the air molecules to move quickly, creating sound.