UTM Malaysia assignment viewer · Interactive 3D anatomy model with contributor profile
Explore how muscles, bones, joints, tendons, and ligaments work together for movement and postures
Musculoskeletal System Legacy Model
A tendon is a tough, fibrous cord of connective tissue that connects muscle to bone. Its primary function is to transmit the mechanical force generated by muscle contractions to the skeleton, allowing us to move our joints, run, jump, and maintain posture.
Muscles can only pull; they cannot push. To move a bone back and forth, skeletal muscles must work in antagonistic pairs (opposite teams).
When one muscle contracts (the agonist), the opposing muscle (the antagonist) relaxes to allow movement.
Example: To bend your arm, your biceps contract while your triceps relax. To straighten it, the process reverses.
Where bones meet, they require a specialized architecture to move without grinding themselves to dust. Synovial joints (like your knees and shoulders) feature:
Articular Cartilage: A smooth, slippery coating on the bone ends that reduces friction.
Synovial Fluid: A built-in lubricant that cushions the joint.
Ligaments: Tough, fibrous bands of connective tissue that connect bone to bone, keeping the joint stable and preventing it from twisting out of place.
For a muscle to contract, it must receive an electrical command from the nervous system.
A motor unit consists of a single motor neuron and all the specific muscle fibers it activates.
The neuromuscular junction is the chemical bridge where the nerve terminal meets the muscle fiber. The nerve releases a neurotransmitter (acetylcholine), which triggers an electrical wave inside the muscle, causing it to contract. This determines how much force you use, whether you are picking up a feather or lifting a heavy weight.