tissues

• tissue 


  a group of cells (plus any extracellular material secreted by them) that are specialised to work together to carry out a particular function.

  A tissue can contain more than one cell type.
• Squamous epithelium tissue

  a single layer of flat cells lining a surface. It's found in many places in the body, including the alveoli in the lungs, and provides a thin exchange surface for substances to diffuse across quickly.

  A) basement membrane

  
• Ciliated epithelium

  a layer of cells covered in cilia. It's found on surfaces where things need to be moved - in the trachea for instance, where the cilia waft mucus along

  A) cilia

  
• Muscle tissue

  made up of bundles of elongated cells called muscle fibres. There are three different types of muscle tissue: smooth (e.g. found lining the stomach wall), cardiac (found in the heart) and skeletal (which you use to move). They're all slightly different in structure.

  A) bundles of muscle fibres

  B) one muscle fibre

  C) skeletal muscle

  
• Cartilage

  type of connective tissue found in the joints. It also shapes and supports the ears, nose and windpipe. It's formed when cells called chondroblasts secrete an extracellular matrix (a jelly-like substance containing protein fibres), which they become trapped inside.

  A) two cells trapped together

  B) fibre-filled matrix

  
• Xylem tissue

  a plant tissue with two jobs - it transports water around the plant, and it supports the plant. It contains hollow xylem vessel cells (which are dead) and living parenchyma cells.

  A) xylem vessel

  B) pits

  C) xylem parenchyma

  
• Phloem tissue

  transports sugars around the plant. It's arranged in tubes and is made up of sieve cells, companion cells, and some ordinary plant cells. Each sieve cell has end walls with holes in them, so that sap can move easily through them. These end walls are called sieve plates.

  A) sieve cell

  B) sieve tube

  C) ordinary plant cells

  D) companion cell

  E) sieve plate