Tissues are aggregated into organs. An organ is made from groups of tissues working together to perform a particular function.Organs may have more than one function. For example the pancreas produces both digestive enzymes and hormones.Examples of organs are the heart, veins and arteries. Blood capillaries are not organs as they are made of only one type of tissue, epithelial cells.The stomach is an organ whose function is to digest proteins. It is made of muscle, epithelial cells and connective tissue. The movement of the stomach that churns its contents is called peristalsis and is generated by the muscles in the stomach wall.Epithelial cells protect the stomach wall and specialised epithelial cells called goblet cells produce mucus to protect the stomach lining.Plant leaves, stems and roots are organs. The leaf consists of epidermal cells, palisade and spongy mesophyll and xylem and phloem tissue.
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Specification: AQA Biology (7401), AS-level, 3.2.1.1 Structure of eukaryotic cells. Topic: Cell Structure.
Key terms in this lesson
- peristalsis
- Waves of muscular contraction that push food along the gut.
- xylem
- Plant vascular tissue, made of dead, lignified tubular cells, that transports water and mineral ions from the roots to the leaves.
- phloem
- Plant vascular tissue, made of sieve tube elements and companion cells, that transports organic solutes such as sucrose around the plant.
More in Cell Structure
- Vacuoles
- Cell Structure and Function
- Cell Specialisation
- Tissues
- Organ Systems
- Prokaryotic Cell Structure
- Prokaryotic vs Eukaryotic Cells
- Viruses
All 26 lessons in Cell Structure · All AQA AS-level Biology topics