Respiratory System

• The primary function of the respiratory system is to allow the exchange of gases in the body
• The respiratory system has an upper tract and a lower tract
• The upper tract consists of nose, nasal cavity, and pharynx
• The lower tract consists of the larynx, trachea, bronchial tubes, and the lungs
• The nose is the outer part of the respiratory system
• The nose is mostly made up of cartilage, which makes the nose flexible and strong
• The nose has two opening called nostrils, which lead to the nasal cavity
• The lining of the nasal cavity is moist because of mucus
• The hair and mucus filter out the dust and dirt that come with the air you inhale
• The hair and mucus also warm and moisten the air that enters your body
• The pharynx (throat) is a muscular tube in the middle of your neck.
• Structures called tonsils are found at the opening of the pharynx. They trap and destroy bacteria that enter the body via nose and mouth
• The pharynx is connected to both the nose and mouth, and acts as passageway for both air and food
• When you talk, the vocal cords in the larynx vibrate and sound is produced
• A structure called epiglottis is found covering the larynx
• During swallowing, the epiglottis closes over the entrance to the trachea so that food does not go into the lungs
• The trachea or windpipe, is a tube at the bottom of the larynx. It is lined with mucus that help prevent dust and other particles from entering the lungs.
• Choking happens when food accidentally goes into the trachea
• The trachea divides into two branches, each entering a lung
• These two are tubes called bronchial tube and they branch into smaller tubes called bronchioles (singular, bronchiole)
• Bronchioles end in tiny air sacs called alveoli
• The exchange of oxygen and carbon dioxide occurs in the alveoli
• The absorbed oxygen is transported throughout the body bloodstream, while released carbon dioxide is exhaled
• The lungs are enclosed in a coating called pleura, which allows the lungs to slide freely as they expand and contract when you breathe.
• Below the lungs is a dome-shaped muscle called the diaphragm
• During inhalation, the chest cavity becomes bigger as the rubs and diaphragm contract
• During exhalation, the ribs and diaphragm relax and the chest cavity becomes smaller