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Parachute mitral valve occurs when all the chordae tendineae of the mitral valve attach to a single papillary muscle. [9] [10] [11] This causes mitral valve stenosis at an early age. [10] It is a rare congenital heart defect. [11] Although it often causes mitral insufficiency, it may not present any symptoms. [10]
The papillary muscles are muscles located in the ventricles of the heart. They attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) via the chordae tendineae and contract to prevent inversion or prolapse of these valves on systole (or ventricular contraction).
Kipping pull-ups have lower muscle activation in the upper body but greater activation in the lower body and core; it is possible to perform them faster and complete more repetitions before encountering upper-body fatigue. [14] Kipping pull-ups are considered high risk for injury and are a major cause of shoulder injury in CrossFit athletes. [15]
The chest fly is performed while lying face up on a bench or standing up, with arms outspread holding weights, by bringing the arms together above the chest. This is a compound exercise for the pectorals. Other muscles worked include deltoids, triceps, and forearms. Equipment: dumbbells, cable machine or "pec deck" machine.
The action potential passes along the cell membrane causing the cell to contract, therefore the activity of the sinoatrial node results in a resting heart rate of roughly 60–100 beats per minute. All cardiac muscle cells are electrically linked to one another, by intercalated discs which allow the action potential to pass from one cell to the ...
The moderator band (also known as septomarginal trabecula [1]) is a band of cardiac muscle found in the right ventricle of the heart. [2] [3] [4] It is well-marked in sheep and some other animals, including humans. It extends from the base of the anterior papillary muscle of the tricuspid valve to the ventricular septum. [2]
The skeletal muscle pump. The skeletal muscle pump or musculovenous pump is a collection of skeletal muscles that aid the heart in the circulation of blood. It is especially important in increasing venous return to the heart, [1] but may also play a role in arterial blood flow.
The muscle-up begins with the arms extended above the head, gripping a hold in the overhand pull-up position. The hold is usually on a chin-up bar or gymnastic rings. The body is then explosively pulled up by the arms in a radial pull-up, with greater speed than a regular pull-up. When the bar approaches the upper chest, the wrists are swiftly ...