Muscle, Bone & Joint
The Animations (6)
How a Broken Bone Heals
Follow a break through its four stages — blood clot, soft cartilage callus, hard bony bridge, then the long remodel back to normal — and see what smoking, movement or missing calcium do to it.
Launch animation →How a Joint Works & What Goes Wrong
Bend a healthy joint gliding on smooth cartilage — then wear the cushion away, watch bone grind on bone and spurs form, and see what actually eases an arthritic joint.
Launch animation →Slow vs Fast: Your Two Kinds of Muscle
Recruit slow-twitch fibres for a steady hold and fast-twitch fibres for a sprint — see why one resists fatigue and one delivers power, and why aging steals the fast ones first.
Launch animation →Bone Remodeling & Calcium
Watch osteoclasts tunnel and osteoblasts rebuild — then drop vitamin D and see PTH quietly strip calcium out of your skeleton to defend the blood level.
Launch animation →Gout: How Uric Acid Crystals Attack a Joint
Watch uric acid climb past the point where it dissolves and stab needle-shaped crystals into a joint, igniting a red-hot gout attack — then lower it with allopurinol and watch the crystals melt away.
Launch animation →Muscle Contraction
Release calcium, expose the actin binding sites, and watch myosin heads ratchet through the cross-bridge cycle to slide the filaments and shorten the sarcomere.
Launch animation →The mechanics of movement and the tissue that carries it: the sliding filaments of a muscle contraction, fast and slow fibre types, bone remodelling continuously around its calcium supply, a fracture knitting, and what changes inside a joint in osteoarthritis and during a gout attack.
Every page here is a hands-on animated diagram, not a video — press play, slow it down, break the mechanism on purpose, and read the live values in real clinical units. They explain how a process works; they are not medical advice, and the evidence for any treatment lives on the topic pages each animation links into.