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JOINTS. JOINTS. Where 2 or more bones meet They increase mobility The more movement a joint has, the less stability it has (& the greater risk of injury) LIGAMENTS: strong flexible tissue that connect bone to bone
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JOINTS • Where 2 or more bones meet • They increase mobility • The more movement a joint has, the less stability it has (& the greater risk of injury) • LIGAMENTS: strong flexible tissue that connect bone to bone • Not very elastic (take a long time to return to normal shape), can be damaged permanently
TYPES OF JOINTS • FIBROUS: • Think layer of fibrous tissue connecting the edges of the two bones • No movement allowed • e.g. sutures in the skull
TYPES OF JOINTS • CARTILAGINOUS JOINTS: • Bones can be separated by fibrocartilage disc (e.g. intervertebral discs), or by a thick layer of hyaline cartilage (e.g. where ribs & sternum connect) • Limited movement at these joints
TYPES OF JOINTS • SYNOVIAL JOINTS: • Most common & most important for mobility • Features: • Space b/w the bones is called the joint (articular cavity)
SYNOVIAL JOINTS • Smooth white layer of articular cartilage covers the articulating surfaces of the bones. • Cartilage: reduces friction; absorb shock; protect bones; varies in thickness; can wear & tear; overuse = osetoarthritis
SYNOVIAL JOINTS • Articular capsule surrounds the joint (sleeve like) • Flexible to allow movement, but strong to prevent dislocation
SYNOVIAL JOINTS • Inside of the capsule is lined by a synovial membrane that secretes synovial fluid. (like raw egg white • It lubricates the joint cavity, reduces friction and provides nutrients.
SYNOVIAL JOINTS • MENISCI: semi-lunar discs of fibrocartilage • Allow bones of different shapes fit together more tightly • Provides greater cushioning & stability
SYNOVIAL JOINTS • BURSAE: small fluid-filled sacs found where two structures rub against each other • e.g. b/w ligament & bone; b/w tendon & bone • Lined by a synovial membrane, provide lubrication and reduce friction • Found in areas of high stress in the body
TYPES OF SYNOVIAL JOINTS • Gliding joints • Hinge joints • Pivot joints • Condyloid joint • Saddle joint • Ball & socket joint
YOUR TASK • Investigate one type of synovial joint. • Description of the joint • Examples where it’s found in the body • Diagrams and/or video • A fun witty way to remember this joint • All information to be presented to the class, and a copy of your research available to all. due TUESDAY 27th August