Joints (human Skeleton) Flashcards
What are joints
Places in the body where two or more bones articulate (move) with each other
Different types of joints
Fibrous Cartilaginous Synovial - ball and socket Hinge Pivot Plane/ gliding
What can joints be classified according to
To the material bonding them or to their mobility
What are fibrous joints
Held together by fibers, immovable
Eg. Sutures of the cranium
Cartilaginous joints
Held together by cartilage, partly move able
Eg. Pubic symphysis and joints btw vertebrae
Synovial joints and their classification
Held together by a double layered articulate capsule ,
Have a fluid filled cavity surrounding bones
Freely moveable
Classifies according to the kind of movement that takes place in joint
- ball and socket
- hinge
- pivot
- plane/ gliding
This joint is v flexible, allows movement in most directions
E.g a hip joint
Ball and socket
Allows bones to move in one plane of direction
Hinge
Eg knee joint
Allows a bone to rotate
Pivot
Eg atlas and axis vertebrae
Flat bone glides/ slips over another bone
Plane/ gliding joint
Eg carpal bones in wrist
Synovial cavity
Contains synovial fluid
Acts as lubricant reducing friction
Helps absorb shock if joint is compressed
Nourishes cartilage
Articular cartilage
Creates a smooth surface on articulating bones
Prevents friction
Keeps bone ends from being crushed
Articular capsule
Encloses the joint and prevents dislocation
Synovial membrane
Secretes synovial fluid
Examples of joint injuries and diseases
Bunion
Sprain
Dislocation
Arthritis
Bunion
Swelling at base of big toe with calluses and bone spurs
Tight fitting shoes/ inherited
(Enlarged bursa at base of big toe)
BURSAE= flattened sacs lined with synovial membrane found btw ligaments/ muscles/ tendons - prevents them rubbing against bone causing friction
Sprain
Stretched torn ligament
Joint is built to withstand tough treatment. Injury caused when it’s forced beyond limits of movement
Kept still till ligament repairs itself
Ligaments have poor blood supply which means healing is slow
Ankle/knee/ lumbar regions most often sprained
Dislocation
Injury/ disability caused when the normal position of bone is displaced
Ligaments around joint can often be torn during dislocation
Major trauma
Can cut off blood supply
Must be out back into place otherwise can loose limb
Arthritis
Includes many different diseases Results in stiff, swollen, painful and even deformed joints Osteoarthritis Gout Rheumatoid arthritis
OSTEOARTHRITIS
Cartilage in joints breaks down due to wear and tear
Joints become inflexible
Rheumatoid arthritis
Chronic inflammatory condition
Joints become swollen , painful, finally deformed
Auto immune disease where body attacks own tissue
Gout
Build up of Uris acid crystals in joints
Big toe/ thumb (can occur in any other joint)
Results in swollen , v painful joints. Can become discolor red
How do muscles function
Each skeletal muscle has a nerve attached, when nerve impulse sent to muscle - muscle contracts
In skeletal muscle, nerve mostly under voluntary control
When muscle stimulate by a nerve impulse, contract by becoming shorter
Then move back to original position when relaxed
The muscle fibers are pulled back into position by the other muscles that work antagonistic ally
Two types of protein, actin and myosin, filaments slide btw each other making muscle shorter
When nerve impulse comes to muscle along nerve
Antagonistic muscles
Skeletal muscle only exert a force by contracting and relaxing
To reverse a muscular movem in opposite directions requires an antagonistic muscle to pull in that direction by contracting
The antagonistic pair of muscles include the flexor (BENDINGM) and the extensor (EXTENDING)
