What is the primary function of the lower respiratory tract?

• Transporting air to the lungs and exchanging oxygen and carbon dioxide

• Digesting food

• Circulating blood

• Filtering waste

The structures of the lower respiratory tract include the trachea, bronchi, bronchioles, alveoli, and ____.

• Heart

• Lungs

• Stomach

• Liver

How many tiny, spongy, air-filled sacs are in the lungs of the average adult?

• 500 million

• 600 million

• 700 million

• 800 million

The trachea is commonly known as the ____.

• Windpipe

• Food pipe

• Blood vessel

• Nerve

The trachea is located in which part of the body?

• Chest

• Abdomen

• Head

• Legs

What is the function of cilia in the trachea?

• To move mucus

• To absorb nutrients

• To produce sound

• To store air

What do the bronchioles branch into?

• Alveoli

• Trachea

• Lungs

• Bronchi

The alveoli are encased by a network of ______.

• Arteries

• Veins

• Capillaries

• Nerves

Gas exchange occurs in the ______.

• Bronchi

• Alveoli

• Trachea

• Bronchioles

What structures resemble bunches of grapes?

• Bronchi

• Alveoli

• Bronchioles

• Lungs