Different types of skeletons
Hydrostatic Skeleton
- Fluid-filled cavity surrounded by muscles
- The fluid provides support against which the muscles contract
- The fluid exerts pressure that causes contractions of muscles that change shape and create
movement
Advantages
o Don’t need specialized support because the water they live in provides support
Disadvantages
o Cant move fast
o Only found in water
o Limits size of animal
o No protection
Exoskeleton
- Skeleton occurs on the outside
- Consists of chitin (polysaccharide), which hardens with calcium carbonate
Advantages
o Supports/protects underlying tissues/organs
o Provides place of attachment for muscles making quick movements possible
o Joints are thin and flexible for movement
o Prevents desiccation (drying out)
Disadvantages
o Larger and heavier the exoskeleton which limits the movement
o Limits growth (Chitin can’t expand and animals must shed to grow)
o Impermeable to gases and special respiratory organs are required
Endoskeleton
- Skeleton inside body
- Consist of mainly bone and cartilage
Advantages
o Grow large (bone/cartilage grow with the animal)
o Protects internal organs
o Structural support and shape
o Place of attachment for muscles makes movement possible
o Joints aid flexibility which makes movement efficient
Disadvantages
o Vulnerable to drying out
, Human skeleton
Functions of the skeleton
- Movement
- Protection
- Support
- Mineral storage
- Hearing
- Blood cell formation
Structure of the skeleton
Consists of 206 bone and can be divided into two main sections:
o Axial skeleton
o Appendicular skeleton
Axial Skeleton
Forms the central axis that keeps the body upright. All other parts of the skeleton are attached and it
protects the brain, sense organs, spinal chord and lungs.
Consists of:
→ Skull
→ Vertebral column
→ Rib cage
Hydrostatic Skeleton
- Fluid-filled cavity surrounded by muscles
- The fluid provides support against which the muscles contract
- The fluid exerts pressure that causes contractions of muscles that change shape and create
movement
Advantages
o Don’t need specialized support because the water they live in provides support
Disadvantages
o Cant move fast
o Only found in water
o Limits size of animal
o No protection
Exoskeleton
- Skeleton occurs on the outside
- Consists of chitin (polysaccharide), which hardens with calcium carbonate
Advantages
o Supports/protects underlying tissues/organs
o Provides place of attachment for muscles making quick movements possible
o Joints are thin and flexible for movement
o Prevents desiccation (drying out)
Disadvantages
o Larger and heavier the exoskeleton which limits the movement
o Limits growth (Chitin can’t expand and animals must shed to grow)
o Impermeable to gases and special respiratory organs are required
Endoskeleton
- Skeleton inside body
- Consist of mainly bone and cartilage
Advantages
o Grow large (bone/cartilage grow with the animal)
o Protects internal organs
o Structural support and shape
o Place of attachment for muscles makes movement possible
o Joints aid flexibility which makes movement efficient
Disadvantages
o Vulnerable to drying out
, Human skeleton
Functions of the skeleton
- Movement
- Protection
- Support
- Mineral storage
- Hearing
- Blood cell formation
Structure of the skeleton
Consists of 206 bone and can be divided into two main sections:
o Axial skeleton
o Appendicular skeleton
Axial Skeleton
Forms the central axis that keeps the body upright. All other parts of the skeleton are attached and it
protects the brain, sense organs, spinal chord and lungs.
Consists of:
→ Skull
→ Vertebral column
→ Rib cage
