Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle –...
Transcript of Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle –...
![Page 1: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/1.jpg)
Muscle Contraction and Movement
Chapter 30
![Page 2: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/2.jpg)
Fig 30.7
![Page 3: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/3.jpg)
Muscles
• Muscles are attached to bones by tendons• Muscles work in antagonistic pairs
– Ex. Biceps and triceps– One muscle contracts while the other relaxes
![Page 4: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/4.jpg)
Fig 30.8
![Page 5: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/5.jpg)
Fig 30.8
![Page 6: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/6.jpg)
Contractile apparatus• Skeletal muscle
– Muscle cell = muscle fiber (a single cell with one nucleus)
– Muscle fibers are made of myofibrils (striated)– Myofibrils are made of units called sarcomeres– Sarcomeres are made of thick and thin filaments– Z line is the end of the sarcomere– Thick and thin filaments slide over one another to
shorten the muscle during contraction
![Page 7: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/7.jpg)
Fig 30.9A
![Page 8: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/8.jpg)
Sliding filament theory
• Links the structure of a sarcomere to its function
• During contraction thin filaments slide over thick filaments
• Thick filaments= myosin and have “heads”• Thin filaments = actin, these slide• Ca and ATP required for sliding and
attachment
![Page 9: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/9.jpg)
Fig 30.9A
![Page 10: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/10.jpg)
Fig 30.9B
![Page 11: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/11.jpg)
QuickTime™ and aCinepak decompressor
are needed to see this picture.
![Page 12: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/12.jpg)
Sliding filament theory
• ATP binds to a myosin head, which is released from an actin filament
• Hydrolysis of ATP cocks the myosin head• The myosin head attaches to an actin
binding site with the help of Calcium• The power stroke slides the thin filament
when ADP and Pi are released from it
![Page 13: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/13.jpg)
Sliding filament theory
• 350 myosin heads per thick filament• Can bind and unbind to thin filament up to 5
times per second
![Page 14: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/14.jpg)
Fig 30.10A
![Page 15: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/15.jpg)
Motor neurons and muscle contraction
• Motor neurons stimulate muscle contraction• Motor neurons are branched and can
stimulate more than one muscle fiber• Motor unit = motor unit and all the muscle
fibers it controls• Neuromuscular junctions = the synapse
between a motor neuron and a muscle fiber
![Page 16: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/16.jpg)
Fig 30.10A
![Page 17: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/17.jpg)
Motor neurons and muscle contraction
• The strength of a muscular contraction is controlled by the number of motor units activated. More motor units = stronger contractions
• Muscles requiring precise control have one motor neuron per muscle fiber
![Page 18: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/18.jpg)
Fig 30.10A
![Page 19: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/19.jpg)
Motor neurons and muscle contraction
• Mechanism of stimulation:– Ap releases acetylcholine into the
neuromuscular junction– Ach depolarizes the muscle cell channels inside
on the sacroplasmic reticulum release Ca so it can reach the contractile apparatus
• Mechanism of relaxation– Motor neuron stops firing– Ca pumped back into the SR
![Page 20: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/20.jpg)
Fig 30.10B
![Page 21: Muscle Contraction and Movementfaculty.uncfsu.edu/ssalek/Biol130/CH 30.pdf• Skeletal muscle – Muscle cell = muscle fiber (a single cell with one nucleus) – Muscle fibers are](https://reader033.fdocuments.in/reader033/viewer/2022051604/600128fc4ad20b5ebd6f59bf/html5/thumbnails/21.jpg)