Sarcomere

sudden cardiac death in young athletes. It affects approximately one in 500 adults in the United States. HCM is a genetically determined heart muscle disease caused by more than 1400 mutations in 11 or more genes encoding proteins of the cardiac sarcomere (Maron & Maron, 2013). HCM is characterized by left ventricular hypertrophy (LVH) of various morphologies with a wide array of clinical manifestations and hemodynamic abnormalities. The age when symptoms develop, the severity of symptoms,…

1. The resting membrane potential is the potential difference across the cell membrane of excitable cells such as nerve and muscle cells. The 3 major factors that establish a resting membrane potential are as follows: (1) Non-diffusible anions: The resting membrane potential is influenced by the presence of large non-diffusible anions (proteins, nucleic acids and organic phosphates) inside a cell. The presence of large non-diffusible anions inside a cell attracts a large number of cations and…

Hamstring Strain Injury & Incidence (20%- 750-1250) Hamstring strain injuries (HSI) pose a significant problem within English professional soccer accounting for 12% of all injuries (25), with over half (53%) affecting the Biceps Femoris Long Head (BFLH) (70). To decelerate the extending knee and flexing hip (5, 31, 70) during kicking and late swing phase of gait (33, 59), the hamstrings must undergo intense eccentric loading in a lengthened position (16). Stretching to 110% of its length in…

The heart is the organ that pumps blood through the body. Together with the circulatory system it makes up the cardiovascular system (Anatomy of the Heart, 2015). The heart is oddly shaped, almost oval at the bottom but with a series of veins and arteries at the top and sides. It definitely is not “heart” shaped. It is made up of four chambers consisting of two atria (upper) and two ventricles (lower). These chambers are separated into right and left side by the septum, which is a wall of muscle…

the thin filament is a complex of actin, troponin, and tropomyosin (3)(4). Using calcium and ATP, the thick and thin filaments interact with each other resulting in a power stroke and a shortening of the sarcomere, the skeletal muscle fiber's contractile unit (4). The shortening of multiple sarcomeres in multiple muscle fibers results in the overall contraction of the muscle. Due to the origin and insertion of the muscles around the knee joint, this contractile force allows extension and flexure…

5. Normal muscle contraction occurs in a series of steps, and they are as follows: First, a motor neuron must have acetylcholine released in the synaptic cleft. The acetylcholine is then able to bind with receptors found in the cell membrane. This binding causes the Ca+/Na+ channels to open. The terminal cisternae then releases calcium into the muscle fiber. Calcium will begin to bind to troponin. The troponin moves tropomyosin out of the way since it blocks the actin’s active site. Next, actin…

tissue, similar to the endomysium of the skeletal muscle which supports the extremely rich capillary network necessary to meet the high metabolism demands of strong and continuous activity by the cardiac muscle. Similar to the skeletal muscle, the sarcomere is the contractile unit of the myocardial cell. Between the ends of the muscle cells there are specialised intercellular junctions that are called intercalated discs. Intercalated discs are irregular transverse thickenings of the sarcolemma…

increase in long-term strength training. This increase in the size of filaments is due to an increase in myofibrillar proteins, for example actin and myosin. The increase in these actin and myosin filaments occurs because additional sarcomeres are added to the current sarcomeres. Additions of these proteins increase the number of myosin cross-bridges, which increases the ability to create force. Resistance training increases the size of both type I and type II muscle fibers, but there is…

abdominal muscles in hyperlordotic postures (Diagram 2). Abdominal muscles are maintained in lengthened position and this will lead to a reduction of force that can be generated secondary to the contact between actin and myosin filaments reduce when the sarcomere is stretched (Rassier et al., 1999). Conversely, hip and back extensors will be shortened. Tight hip flexors and back extensors encourage pelvic innominate inclination at the operated side (Gaunaurd et al., 2011). All these factors will…

the sarcolemma and down the T-tubules surrounding the myofibrils. 4. As the impulse passes through the T-tubules, it causes the Sarcoplasmic Reticulum surrounding the T-tubule to release Calcium ions into the sarcoplasm, eventually reaching the sarcomere. 5. The Calcium binds to troponin located on the actin filament, causing the tropomyosin to move and expose binding sites for myosin. 6. The myosin head now binds to actin and forms a crossbridge. 7. ADP and Pi are released from myosin, which…