The lungs

Learning outcomes

• Explain the terms tissue and organ and the relationship between them

• Identify the differences between squamous epithelium, ciliated epithelium goblet cells

• Make connections between the lung DVD and structure of lungs

definitions

• Tissue – a group of similar cells specialised to carry out the same function

• Organ – a structure made up of different kinds of tissue. E.g. Lung – squamous epithelium; elastic tissue

Squamous epithelium

Squamous epithelium – make up the alveoli (tiny holow sacs in the lungs)

• Thin, flattened cells• Epithelium – a lining tissue• Advantages – short distance between air in

the alveoli and the blood in the capillary. This means gas exchange is very efficient

Goblet cells

Goblet cells

• Shaped like a goblet (hence their name)• Produce large amounts of mucus (a

glycoprotein)• Dirt and bacteria in the air that is breathed in

gets trapped in the mucus. When mucus reaches the throat it is swallowed. The dirt and bacteria is then destroyed by the acid and enzymes in the stomach.

CILIATED EPITHELIUM

Ciliated epithelium Ciliated epithelium

Ciliated epithelium

• Have tiny hairs called cilia.• Beat together in a rhythm moving mucus back

up the trachea into the throat.• Cigarette smoke damages cilia – why do

smokers have a persistent chesty cough and are prone to lung infections?