stimulation of the muscle by a nerve ending.
stimulation of the muscle by a nerve ending.
The lymph is circulated via muscle movement. The lymphatic system is not closed and has no central pump; thus transport is slow and sporadic. Lymph movement occurs due to peristalsis (propulsion of the lymph due to alternate contraction and relaxation of smooth muscle), valves, and compression during contraction of adjacent skeletal muscle and arterial pulsation.
During muscle contraction, the Z-lines move closer together as the sarcomeres shorten. This is due to the sliding of actin and myosin filaments past each other, resulting in the contraction of the muscle.
Actin
M-line, causing overlap with the thick filament during muscle contraction. This results in the sarcomere shortening and overall muscle contraction.
Skeletal muscles work together or in opposition Muscles only pull (never push) As muscles shorten, the insertion generally moves toward the origin Whatever a muscle (or group of muscles) does, another muscle (or group) "undoes"
Blood flow due to skeletal contraction is primarily found in the muscles of the limbs, particularly during physical activity. When skeletal muscles contract, they compress nearby blood vessels, which helps to propel blood back toward the heart through the venous system. This process, known as the "muscle pump," enhances circulation and improves oxygen delivery to tissues during exercise. Additionally, it plays a crucial role in maintaining venous return, especially in the legs.
1. All muscles cross at least one joint. 2. Typically, the bulk of muscle lies proximal to the joint crossed. 3. During contraction, the muscle insertion moves toward the origin. 4. All muscles have at least two attachments (origin and insertion). 5. Muscles always pull, they never push.
The three mechanisms that assist blood in returning to the heart are the skeletal muscle pump, the respiratory pump, and venous valves. The skeletal muscle pump involves the contraction of muscles, particularly in the legs, which compresses veins and propels blood toward the heart. The respiratory pump works by creating pressure changes in the thoracic cavity during breathing, helping to draw blood back to the heart. Lastly, venous valves prevent backflow, ensuring that blood flows in one direction toward the heart.
Flexing of the cross bridge (power stroke)
Also known as a wry neck, spasmodic torticollis is a stiff neck due to spasmodic contraction of the neck muscle. The spasm causes the head to be pulled toward the affected side.