Tissues in the lungs

• trachea, bronchi and bronchioles a;; have similar structures
• large airways so there is no obstruction of airflow
• dividing up to smaller airway to reach the alveoli
• strong enough to not collapse under low pressure
• flexible for movement
• is able to strech and recoil

• the wall is mostly made up of carilage
• they are c shaped in the trachea 
• the inner surface of cartilage has a layer of glandular tissue coneective tissue,elastic fibre, smooth tissue and blood cells this layer is called loose tissue
• the epithelium layer has ciliated epithelium and goblet cells

have no cartilage bbut have smooth muscles and elastic fibre

much narrower then bronchi

smalles bronchiole have alveoli clusters at the end

• supports trachea and bronchi so they dont collapse under low pressure
• c shape gives flexibility so throat can move without constricting
• the oesophagus can expand when swalloing

can constrict, the bronchioles can constrict air from the alveoli

used if harmful substances are in the air

happens during asmtha or allergic reaction as it is involuntary

• when inhaling these are stretched
• they recoil during exhaling help push air out
• can helplumen return to normal after smoothmuscle constricting it

• secretes mucus from under the ciliated epithelium 
• helps catch particles such as bacteria or pollen
• allows it to be removed without infection

• has cillias which move in unison to move mucus
• is moved to the back of throar to be swallowed 
• the acid in the stomach kills of any bacteria