Cells shaped for the job
Epithelial structure suits its function.
The right tool
A thin sheet of paper stops a draught. A thick brick wall stops a thief. Different jobs need different structures.
Which would give better protection against injury and friction in the skin?
What this lesson covers
The idea
Epithelial types are structurally adapted to function: a single layer of thin, flat cells for exchange, many layers for protection, cuboidal or columnar cells for secretion, receptor cells with cilia for senses, and tall pillar-like cells for absorption.
The right tool
A thin sheet of paper stops a draught. A thick brick wall stops a thief. Different jobs need different structures.
Which would give better protection against injury and friction in the skin?
- Many layers of cells
- One thin layer of cells
- One layer of tall cells
Cell shape and job
Choose each job and look at the shape of the cells that do it.
Structure suits function
Epithelial tissues are structurally adapted to their functions: exchange (single layer of thin, flat cells), protection (many layers, outer cells flat and tightly packed), secretion (cuboidal or columnar cells), sensory functions (receptor cells with hair-like cilia) and absorption (single layer of tall, pillar-like cells).
- Job | Where
- Exchange | blood vessels, lungs
- Protection | skin, mouth, oesophagus
- Secretion | salivary glands, sweat glands, stomach lining
- Sensing | nostrils, taste buds, inner ear
- Absorption | small intestine
Notes
The shape and layers of epithelial cells suit their job: thin and flat for exchange, many layers for protection, cuboidal or columnar for secretion, cilia for sensing, tall pillars for absorption.
Check yourself
Why is the skin made of many layers of cells?
The lining of the small intestine is a single layer of tall, pillar-like cells. Its job is…
Where would you find epithelial cells that make and release saliva?
- To protect against injury, friction and microbes — correct. Yes.
- To let gases pass quickly. A single thin layer does that.
- To absorb nutrients. Absorption is done by tall pillar-like cells in the intestine.
- protection from friction. That needs many layers.
- absorption — correct. Yes.
- sensing smell. That needs cells with cilia.
- Nostrils. Nostrils have receptor cells for smell.
- Blood vessels. Blood vessels have thin flat cells for exchange.
- Salivary glands — correct. Yes. Secretion happens in glands.