Muscle Study Questions
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Transcript of Muscle Study Questions
Muscle Study Questions
Mader Chapter 71-5 on page 133
1. Name & describe the 3 types of muscles, & give a general location for each type (p. 111)
1. Skeletal – voluntary (attached to skeleton)
2. Cardiac – involuntary (heart)3. Smooth – involuntary (walls of
hollow internal organs)
2. List & discuss 4 functions of muscles. (p 111)
1. Produce movement – picking up an object2. Resist movement – posture, blood pressure
(Newton’s 3rd Law: muscles generate a force (static tension) that exactly opposes and equal but opposite force being applied to a body part
3. Generate heat – contraction of our muscles accounts for > 75% of all heat generated by the body – shivering thermogenesis
4. Stabilizing joints – stabilize & strengthen
3. Describe the anatomy of a muscle, from the whole muscle to the myofilaments w/in a sarcomere. Name the layers of fascia that cover a skeletal muscle & divide the muscle interior. (p 113) A group of many individual cells, all w/same
origin and insertion and all with the same function (p. 115)
Arranged in bundles called fascicles Each bundle is enclosed in a sheath of fibrous
connective tissue called fascia Each fascicle contains 12 to 1000s of individual
muscle cells – called muscle fibers The outer surface of the whole muscle is
covered with several more layers of fascia – at the ends all come together forming tendons
Muscle Cells to sarcomere Tube shaped 3 cm – 30 cm (thigh) Can contain more than one nucleus just
under the cell membrane (skeletal) Nearly entire cell is packed with long
cylindrical structures in parallel called myofibrils
Myofibrils are packed with contractile proteins called actin and myosin
When myofibrils contract the muscle cell also contracts
Myofibrils = muscle fibers Each skeletal muscle fiber is a long,
cylindrical cell w/multiple oval nuclei just beneath the sarcolemma (plasma membrane) surface
Fibers are large, 10 to 100 m in diameter, and up to hundreds of centimeters long
Sarcoplasm, similar to cytoplasm of other cells, but has numerous glycosomes (=organelle full of glycogen) and a unique oxygen-binding protein called myoglobin, similar to hemoglobin
Sarcomere = contractile unit (6)sarco – Gk for “flesh”
Sarcomere / contractile unit (6) A single myofibril within one muscle
cell (in your biceps) can contain > 100,000 sarcomeres arranged end to end.
100,000 sarcomeres all shortening at once produces a muscle contraction
Understanding muscle shortening is simply understanding how a single sarcomere works
Sarcomere = contractile unit
From Z to shining Z
Sarcomere structure
2 kinds of proteins
1) Myosin – thick filaments interspersed @ regular intervals with a different protein
2) Actin – thin filaments that are structurally linked to the Z-line
Myosin filaments are completely contained within the sarcomere
Muscle contractions depend on the interaction of these 2 filaments
4. List the sequential events that occur when a nerve impulse reaches a muscle.1. Nerves activate skeletal muscles2. Activation releases calcium3. Calcium starts the sliding filament
mechanism4. Contraction ends when nerve
activation ends
Sliding filament model of contraction
http://video.google.com/videosearch?ndsp=18&um=1&hl=en&q=sliding%20filament%20of%20contraction&ie=UTF-8&sa=N&tab=iv#
grants.hhp.coe.uh.edu/clayne/6397/Unit3.htm
5. How is ATP supplied to muscles? What is oxygen debt? (p. 114)
1. Lots of mitochondria form ATP by aerobic cellular respiration
2. Muscles contain creatine phosphate (high E storage supply) used to regenerate ATP indirectly
3. ATP produced anaerobically when oxygen supply is limited
Oxygen Debt
Continued intake of oxygen (panting) to complete the metabolism of lactic acid (built up anaerobically)
Lactic acid is transported to the liver and broken down into carbon dioxide and water