tissue organisation

• a cell

  The smallest self supporting unit of living things
• A tissue

  A group of similar specialised cells working together with a common purpose
• An organ

  A group of different tissues working together with a common purpose
• An organ system

  A group of several different organs working together to perform one major body function
• Types of Mammalian tissues:

  Epithelial

  Connective

  Muscles

  Nervous
• Epithelial Tissue

  Covering tissue .e.g. lining of the gut
• Connective tissues

  Cells with extracellular material, connects organs e.g. blood
• Muscles

  Contractile tissues.g. Cardiac muscles
• Nervous

  Electrical tissues
• Function of epithelial tissues

  Protects organs

  Secretory e.g. lining of gut

  Absorptive e.g. small intestine lining
• Squamous Epithelia

  Very thin and flat

  Found in thin layers on surfaces
• Functions of squamous epithelia

  Diffusion surfaces e.g. alveolus of lungs and capillaries

  Low friction lining
• Columnar epithelia

  Tall elongated cells
• Function of columnar epithelia

  Mechanical - suport structures

  Secretory - Lots of Golgi to modify proteins

  Absorptive
• Specialisation of columnar epithelia:

  Adaptations to functions:

  Microvilli - increases surface area for absorption

  Goblet cells - makes mucus to line tissues

  Cilia - Creates movement
• Cuboidal Epithelia

  Cube shaped

  Found lining tubes e.g. kidney tubules
• Connective tissues contain:

  Cells

  Fibres like collagen for strength; elastic fibres provide recovery from stretch

  An extracellular matrix - a fluid surrounding the cell
• Classification of connective tissues:

  Connective tissue proper - Areolar and adipose

  Skeletal - cartilage and bone

  Blood
• Areolar

  Connective tissue proper

  Holds tissue together to form organs

  Often wraps around organs
• Adipose tissue

  Connective tissue proper

  Deposits fat in the cytoplasm
• Cartilage

  Skeletal tissue

  Softer than bone. Matrix is mainly mucopolysaccharide

  3 Types:

  Hyaline cartilage

  Fibro-cartilage

  Elastic cartilage
• Bone

  Skeletal tissue

  Matrix is hard and contains calcium salts

  There are fibres

  Can be spongy or compact
• Blood

  Extracellular matrix is plasma

  No elastic or collagen fibres

  Several types of cells e.g. lymphocytes and phagocytes
• Muscle tissues: A contractile tissue

  Contains 2 types of protein; Myosin and actin

  Tendons to attach to the bone
• Skeletal muscles

  Voluntary or striated muscles

  Causes limbs to move
• Smooth muscles

  Involuntary muscles

  Found in blood vessel wall
• Cardiac muscles

  Some striations

  Can relax between contractions so it doesn't cramp
• Types of Plant tissues:

  Packing

  Supporting

  Vascular

  Protective