lihassäätelyn
Lihassäätely refers to the coordinated control of muscle contraction and relaxation in animals, an essential physiological process that enables movement, posture, and various involuntary functions such as breathing and heart pumping. The primary mechanism of lihassäätely is excitation‑contraction coupling, where a neural impulse travels along a motor neuron, reaches the neuromuscular junction, and triggers the release of neurotransmitter acetylcholine. This signal rapidly depolarizes the sarcolemma (muscle cell membrane), opening voltage‑gated L‑type calcium channels (DHPR) in the transverse tubules. The depolarization induces calcium release from the sarcoplasmic reticulum via ryanodine receptors, raising cytosolic calcium concentration.
Calcium binds to troponin C on the thin filament, causing tropomyosin to shift and expose the myosin‑binding
Lihassäätely involves multiple regulatory layers: neural input (motor units, firing frequency), hormonal modulation (epinephrine, thyroid hormones),