MOVEMENT IN ANIMALS
- 3 types of skeletons
- Hydrostatic, exoskeleton, endoskeleton
Hydrostatic skeleton
- Consists of fluid-filled chambers inside the body that provide support
against which muscles contract to bring about movement.
- In soft bodied invertebrates → jellyfish
- How do they move?
- Contracting muscles around the fluid-filled cavity creates pressure that
causes a change in shape of the animal → movement.
- DISADVANTAGES:
- Lack well-developed skeletal defense mechanisms
- Restricted range of movement
Exoskeleton
- Exo = outside
- Exoskeleton made from chitin (a type of polysaccharide)
- ADVANTAGES:
- External structure supports and protects the animal
- Has a cuticle to reduce water loss
- DISADVANTAGES:
- Limited mobility due to their rigidity
- Limited growth in their exoskeleton and therefore have to moult
, Endoskeletons
- Within the body
- All vertebrates
- Made from either bone or cartilage
- ADVANTAGES:
- Supports body → gives it shape
- Is made up of living tissue that can grow as the animal increases in size
- TISSUES MAKING UP ENDOSKELETON
1.) Cartilage
2.) Bone
1.) Cartilage
- Occurs in isolated areas of body such as nose
- 3 types → Hylene (in nose), elastic (ear), and fibrous cartilage
(intervertebral discs)
- CARTILAGE MADE UP OF?
- Chondrocytes (mature cartilage cells)
- Surrounded by a matrix made up of jelly-like substance
- Large amount of tissue fluid
- WHY IMPORTANT?
- Lines many joints, facilitating smooth movement
- Acts as shock absorber between vertebrae
2.) Bone
- Hardest tissue in body
- HOW IS BONE TISSUE MADE UP?
- Bone tissue is made up of osteocytes (largest living bone cell) in
lacunae (an unfilled space) set in the matrix = made up of collagen
fibres that stick to each other in a criss-cross pattern, giving bone its
flexibility, making it strong.