Bronchi & Bronchiole

Structure of bronchi:

trachea divides into two bronchi before they enter the lungs

They have glandular tissue, eciliated epithelium and goblets cells. They also have smooth muscle to allow the bronchi to contract

The two main bronchi will divide into smaller air passages to become secondary and tertiary bronchi.

Their function is to allow air to pass into the functional units of the lungs, the alveoli, and to allow expiration.

Structure and function of bronchioles:

transmit air to and from the alveoli.

Bronchioles are smaller than bronchi and most do not have rings of cartilage.

They consist of smooth muscle, cuboidal epithelium and elastic tissue to help them spring back to shape during breathing.

images are on the pp look at the diagrams

erminal bronchiole

have alveoli branching off from them.

They contain club cells which secrete surfactant which prevents the walls of the alveoli or bronchioles from sticking together,

keeping the airways open