Muscular 1 Flashcards
What are the types of muscle tissue?
Skeletal, Cardiac and Smooth
What are the characteristics of skeletal muscle?
longest muscle cells, straited and voluntary
What are the characteristics of cardiac muscle?
straited, involuntary but has branching, the CNS can accelerate/decelerate
What are the 4 major characteristics of muscles?
Excitability(ability to recieve/respond to stimuli, electrical pulse passed through sarcolemma), contractility (ability to shorten), Extensibility (ability to stretch when relaxed), Elasticity (ability to return to original length)
What are the 5 major functions of muscle tissue?
Movement (of body/substances within body-blood, food, waste), Posture (Stabilzes body position with million contractions per second), Regulation of organ volume (Sphincters, valves- heart, stomach), Heat production (Give 85% body heat via release of energy with ATP), Stabilization of joints (via tendons)
What is the skeletal muscle organisation?
Muscle, Fascicle, Muscle fibre, Myofibril, Myofilament (Sarcomere-contractible segments of Myofibril)
What are the connective tissue wrapping and muscle structure?
Allows elastic approach, Endomysium (aerolar CT wrapping of fibres), Perimysium (Wrapping around fascicles), Fascicles (bundle muscle fibres), Epimysium (outer wrapping made of dense irregular CT)
What are the connective tissue components?
Provide strength and support, Fascia broad band of CT, Connective tissue sheaths (cover and strengthen muscle fibres), Tendons
What are muscle fibres?
Elongated cylindrical cells that make up muscles
What is the Sarcolemma?
The muscle cell plasma membrane
What is Sarcoplasm?
Cytoplasm but contains glycosomes and myoglobin
What is multinucleate?
Fusion of smaller cells in embryonic development
What is glycogen and Myoglobin?
Glycogen stores glucose and myoglobin acts like haemoglobin by transporting o2 to muscle
What are myofibrils?
Rodlike contractile, most of muscle volume, densely packed with organelle and mitochondria, have A bands (dark) and I bands (light), contain myofilaments, composed of chain arranged end to end divided by z line
What are myofilaments?
Thread like structures, has 2 proteins (actin-thin and myosin-thick) which slide past eachother for contraction
What is the arrangement of myofilaments?
longitudinally, overlap, repeating units, between z lines in sarcomere, I bands-actin, H zone- myosin, A band-overlapping area, M line- dense region at H zone, Elastin-connects actin to z line and Titin-holds fibres in place and assists in spring back
What is the sarcomere?
contractile unit, made of myofilaments, central is myosin and lateral is actin
What are the 3 stages of sliding filament mechanism?
- Muscle is relaxed, no contact between actin and myosin. 2. Cross bridges form and actin filaments are moved closer together as the muscle fibre contracts. 3. Cross bridges return to original position and attach to new sites to prepare for another pill on actin filaments and further contraction.
What do you need to start a contraction?
Blood and nerve supply (1 artery and 2 veins per muscle, must be able to stretch and shorten with muscle, must have a motor nerve ending , each muscle has 1 nerve), Motor units (3/4 for fine control, hundreds for big control. motor nueron fires all muscle cells contract, strength determined by how many fired at once), Calcium (attacks proteins blocking receptor site, allows cross bridges to form, returns to sarcoplasmic reticulum and changes shape in troponin sites) , Tubules (form triad with 2 SR, continuous with sarcolemma, conduct nerve impulses to myofibril)
What is the Nueromuscular Junction?
Axon terminal that contains synpatic vesicles with nuerotransmitters (Acetylcholine Ach), nerve pulse reach azon, vesicles fuse to flasma membrane and empty Ach into synaptic gap, Ach combines with sarcolemma allowing Na gates to open and muscle contracts
What is the sarcoplasmic reticulum?
Network of tubules surrounding myofibrils, stores and regulates Ca
What is the energy source for muscle contraction?
Requires ATP, fracture energy into ADP and P
