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Human Bio - Coggle Diagram

- - - - smooth outer membrane surrounds the mitochondrion
      - inner membrane (cristae) arranged into series of folds that extend into the interior of the organelles. Increases surface area.
  - - - microtubules: hollow rods that keep organelles in place/move them around cell
      - microfilaments: moves materials around cytoplasm/ move whole cell.
  - - - 4 types:
        
        Epithelial
        
        cover surfaces of body and line its cavities
        
        function: secretion, absorption, sensory and transport.
        
        cells closely packed with little matrix material (intercellular material)
        
        no blood supply.
        
        Connective
        
        Muscle
        
        Nervous
- - - - muscles cells held tgt in bundles (gives stringy appearance)
      - sheath of connective tissue surrounds each bundles = function as individual unit
      - allows adjacent bundles to slide over each other
      - connective tissue from each bundle join each other + in the end tapers to form tendons.
      - connective tissue gives toughness to meat
      - amount of connective tissue increases with age - decreases muscular strength
    - - 1 muscle bundle consists of muscle cells that lie parallel to each other
      - each cell = muscle fibres
      - around cell = sarcolemma
      - cytoplasm = sarcoplasm
        
        each fibres contain myofibrils - run parallel to each other. May be 100-1000 in each.
        
        structure of myofibrils
        
        composed of many smaller myofilaments (made of protein). Units that are involved in contraction.
        
        2 types:
        
        Thick filament: made of myosin (protein)
        
        Thin filament: made of actin (protein)
        
        arrangement of thick and thin give banded effect to the muscle.
        
        can be divided into units = sarcomeres
        
        variation in actin and myosin content in different parts of sarcomere: give striated appearance of skeletal muscle.
  - - - actin and myosin filament slide over one another
        
        Z lines are drawn closer
        
        Muscle fibres shorten - whole muscle shortens.
        
        myofilaments = same length before + after contraction - fibril shortens because myofilaments over-lap
        
        energy comes from breakdown of ATP into ADP and phosphate group.
        
        ATP: reformed when energy is available from cellular respiration