Criado por Amelia Claire
mais de 8 anos atrás
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Questão | Responda |
What are the three types of muscle tissue? | smooth skeletal cardiac |
What are the six major functions of skeletal muscle | produce skeletal movement maintain posture and body position support soft tissues guard body entrances and exits maintain body temperature store nutrients |
What are the elements of the skeletal muscle (organ) ? | Epimysium Perimysium Endomysium Nerve Muscle Fascicle Muscle Fibres Blood Vessels |
What are the elements of the Muscle Fascicle (bundle of fibres) | Perimysium Muscle Fibre Endomysium |
What are the elements of the muscle fibre (cell)? | Capillary Myofibril Endomysium Sarcoplasm Myosatellite cell Sarcolemma organelles |
Muscle has three layers of connective tissue: | Epimysium Perimysium Endomysium |
Epimysium | A dense layer of collagen fibres that surrounds the ENTIRE muscle. It separates the muscle from nearby issues and organs. It is connected to the deep fascia. |
Perimysium | Divides the skeletal muscle into a series of compartments. Each compartment contains a bundle of muscle fibres called a fascicle. Also contains collagen, elastic fibres, blood vessels and nerves. Each fascicle receives branches of these blood vessels and nerves. |
Endomysium | Within the fascicle, the endomysium surrounds the individual skeletal muscle cells and loosely interconnect the adjacent cells. Has capillary network, and myosatellite cells to repair damaged muscle tissue. |
Tendons and Aponeuroses | collagen fibres of the epimysium, perimysium, and, endomysium come together to form bundles (tendons) or broad sheets (aponeuroses) that attach muscles to bones, allowing movement. |
What are the distinctive features of skeletal muscle fibres | skeletal muscle cells are multinucleate with hundreds of nuclei just internal to the plasma membrane. they are striated due to arrangements of actin and myosin filaments. |
Sarcolemma | sarcolemma is the plasma membrane of a muscle fibre, surrounding the sarcoplasm (cytoplasm of a muscle fibre) |
Transverse Tubules | T tubules are narrow tubes whose surfaces are continuous with the sarcolemma and conduct electrical impulse to support the whole muscle to contract at the same time. |
Myofibrils | each muscle fibre contains hundreds of myofibrils, encircled by T Tubules. myofibrils are made of bundles of protein filaments called myofilaments; thin filaments (actin) and thick filaments (myosin) and titin. They are anchored to the sarcolemma. |
Sarcoplasmic Reticulum | membranous complex forms a tubular network around myofibril, has a chamber called terminal cisternae. A pair of cisternae and a T tubule = triad. Stores calcium ions for release when needed. |
Sarcomeres | the myofilaments actin and myosin are arranged into repeating functional units called sarcomeres; the smallest functional units of muscle fire, Interactions between actin and myosin within the sarcomere are responsible for muscle contraction |
The A Band | contains overlapping myosin and actin filaments, the myosin filaments are at the centre of the sarcomere, in the A band. The A Band has three subdivisions - the M Line, the H band, and the Zone of Overlap. |
The M Line | The M Line is a subdivision of the A Band. It is in the centre of the A Band, and proteins of the M line connect the central portion of each thick filament to neighbouring thick filaments. Help stabilise position of thick filaments. |
The H Band | The H Band is a subdivision of the A Band. In a resting sarcomere the H band is a lighter region on either side of the M Line. it contains thick filaments but no thin filaments. |
The Zone of Overlap | The Zone of Overlap is a subdivision of the A Band. It is where the thin filaments are located between the thick filaments. Hence, three thick filaments surround each thin filament and six thin filaments surround each thick filament. |
The I Band | The I Band is a region of the sarcomere that contains thin filaments but no thick filaments. It extends from the A band of one sarcomere to the A band of the next sarcomere. Z Lines bisect the I Bands and mark the boundary between adjacent sarcomeres. |
Titin | Strands of elastic protein titian extend from the tips of the tick filaments to attachment sites at the Z Line. Titin helps keep the thick and thin filaments in proper alignment, and aids in restoring the resting sarcomere length after contraction. It resits extreme stretching. |
The Z Line | Each Z Line is surrounded my a meshwork of intermediate filaments that interconnect adjacent myofibrils. The myofibrils bind to the sarcolemma. Because Z Lines of all the myofibrils are alined this way, the muscle has a banded appearance. The striations are visible with a microscope. |
What are the Proteins that make up the Thin Filaments | a single thin filament contains 4 proteins f-actin nebulin tropomyosin troponin |
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