For this IBDP Biology blog post, we will be introducing the mechanisms of the skeletal framework within the body, as well as the different types of jointd associated with our movements, let's get to it!
Exoskeleton
Exoskeleton: Internal skeleton surrounding and protecting most of the body surface of animals (insects)
Facilitate movement by:
- Providing an anchorage for muscles
- Acting as levers
In a lever there is an effort force, a pivot and a resultant force
Antagonistic Pairs of Muscles
Antagonist Pair: When one muscle contracts the other muscle relaxes
Skeletal muscles occur in Antagonistic Pairs
- Produces opposite movements in a joint such as in the elbow joint when triceps extend the forearm and the biseps flex the forearm
Human Elbow and Joints
Joint: Point where bones meet
- Joints allow bones to move in relation to each other this is known as articulation
- Articulated joints have a similar structure: cartilage, synovial fluid and joint capsule
Cartilage: Tough smooth tissue that covers the regions of bone in the joint
- Prevents contact between regions of bones that might rub - prevents friction
- Absorbs the shock that might have caused bones to fracture
Synovial Fluid: Fills a cavity in the joint between the cartilages on the ends of bones
- Lubricates joints to help prevent the friction that would have ocurred if the cartliages were dry and touching
Joint Capsule: Tough ligamentous covering to the joint.
- It seals the joint and holds the synovial fluid and helps prevent dislocation
Joint Types
Synovial Joint
- Bone to bone joints
- Self-contained capsule area that contains a lubericant (synovial fluid)
- Ends of bones are coated with cartilage to cushion any bone to bone contact
Hinge Joint
- Allows only two movements: Flexion (bending) & Extension (straightening)
- Example: Knee
Pivot Joint
- Allows rotation movement
Ball and Socket Joint
- Greater range of movement: Flex, extend, rotate and move sideways and back
That's all for this topic! Well done!
Drafted by Venetia (Biology)