Muscle Contraction and Rigor Mortis

These flashcards cover key concepts related to muscle contraction, relaxation, and the physiological phenomenon of rigor mortis.

Troponin Proteins

Three proteins that return to their original conformation to regulate muscle contraction.

Tropomyosin

A protein that slides back to block the myosin binding site during muscle relaxation.

Cross-Bridges

Connections formed between myosin and actin during muscle contraction.

Rigor Mortis

The stiffness of joints after death caused by prolonged muscle contraction.

Calcium (Ca2+)

An ion that, when it flows into the cytosol after cell death, leads to excessive cross-bridge formation.

ATP (Adenosine Triphosphate)

The energy molecule necessary for muscle contractions and detachment of cross-bridges.

Stiffness Duration

Rigor mortis typically lasts for 6-72 hours post-death.

Muscle Relaxation

Occurs when troponin and tropomyosin block myosin from accessing the binding site.

Cell Death Effects

ATP synthesis stops, calcium is not pumped, and muscles begin to contract uncontrollably.

Breakdown of Rigor Mortis

Occurs as muscle proteins degrade, leading to a release from the contracted state.