Respiratory System Respiratory Pathway

Respiratory System The respiratory system is made up of the system of air tubes that carry air to and from the lungs

Nasal Passage Air enters the respiratory system through nostrils, then into hollow spaces called nasal passages Nasal passages are lined with little hairs called cilia that filter the air

Pharynx The pharynx is commonly called the throat

Larynx The larynx is commonly called the voice box The vocal cords are stretched across the inside of the larynx The epiglottis blocks food from entering the larynx

Trachea The trachea is commonly called the windpipe It is lined with ciliated mucous membranes

Bronchi In the middle of the chest, the trachea divides into two cartilage-ringed tubes that enter the lungs called bronchi

Bronchioles Bronchioles are the finest branches of the bronchial tubes Each bronchiole ends in an air sac called an alveolus

Alveoli Alveoli are small cup-shaped cavities where gas exchange takes place They look like a bunch of grapes The lungs contain about 300 million alveoli

Breathing Inhalation – is the active phase that draws air into the lungs Exhalation – is the passive phase that forces air out of the lungs

Diaphragm The diaphragm is a dome-shaped muscle at the bottom of the rib cage.

Breathing is an involuntary process controlled by the medulla in the brain When the level of CO2 increases in the blood, the rate of breathing is increased

Inhalation The ribs are pulled up and out The diaphragm is pulled downward The chest cavity become larger and the lungs expand

Exhalation The ribs drop and relax The diaphragm relaxes and moves upward The chest cavity becomes smaller