muscle physiology

Question	Answer
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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	Created by Amelia Claire about 8 years ago