The Magnificent World of Muscles

What are Muscles for? To provide the ability of locomotion To provide movement for the proper function of organs

Double Muscling It’s a mutation! Good or Bad?

Types of Muscle Skeletal Smooth Cardiac

Skeletal Muscle Muscle attached to skeleton Also called striated muscle The action of the muscle is voluntarily controlled

Skeletal Muscles Skeletal Muscle fibers are striated (striped). I band A band Skeletal Muscle fibers are striated (striped). Striated appearance is due to the alternating: I bands-Light colored A bands-Dark Colored

Smooth Muscle Found on the walls of all the hollow organs of the body (except the heart) General not voluntary Controls functions of: Arterial blood flow Bladder Air through the lungs

Cardiac Muscle Comprises the wall of the heart Not under voluntary control You cannot voluntarily stop and start your heart

Muscle Fibers

How do I make a Muscle? Muscles are composed of many cylindrical muscle fibers. The fibers are bound together into bundles by connective tissue.

Muscle Fibers Muscle fibers are not single cells, they’re fused together. Group of fused muscle cells= Sarcomere vs Cheek cells

Muscle Fibers Contain 4 Parts Sarcolemma The “skin” that holds everything in Myofibrils Stacked lengthwise and run the entire length of the fiber Sarcosome Converts food into energy Sarcoplasmic Reticulum Converts protein into fat

Muscle Fibers Sarcosome

Myofibrils Each myofibril is made up of two types of filaments: Thick filaments Contain the protein Myosin Thin filaments Contain the protein Actin

Sarcomere The Sarcomere is the set of thick and thin filaments between the two Z lines.

Sarcomere cont. The thick filaments produce dark A bands A bands are dissected by the H zone The H zone is the area where the thick filaments do not overlap the thin filaments. The thin filaments extend in each direction from the Z line. Where thin filaments do not over lap thick filaments, they create the light colored I bands. I bands are dissected by the Z line

Sarcomere DRAW THIS!

Funtivities!!! In your Interactive Notebook, draw a sarcomere. Label the following parts: I band A band Z lines H zone Thin filaments Thick filaments

Muscle Contractions

Muscle Contraction Refers to the generation of tension by muscle fibers with the help of motor neurons Locomotion is only possible due to the repeated contraction of muscles at the correct times

Relaxed Muscle Contracted Muscle

Concentric Contraction Muscles shorten while generating force Shortens according to the sliding filament mechanism A biceps curl

Eccentric Contraction Muscle elongates while under tension Usually occur as a “braking” force in opposition of Concentric Contraction Voluntarily or involuntarily protects the joints Aid in giving smoothness to actions Throwing a ball Reducing eccentric braking in pitching practice

Isometric Contraction There is no change in the length of the muscle while generating force Carrying an object in front of you The weight of the object would be pulling downward The muscles in your hands and arms would be opposing the motion upwards Since the arms are neither raising or lowering, the bicep muscle is isometrically contracted

15 Muscular System Fun Facts!

Muscular System Fun Facts! 1. Muscles make up 40% of your body weight. 2. It takes twice as long to gain muscle than it does to lose it.

Muscular System Fun Facts! 3. The smallest muscle is the stapedius which found in the middle ear. 4. The Largest muscle is the gluteus maximus in your buttocks.

Muscular System Fun Facts! 5. The longest muscle is the Sartorius, found in your thigh – up to 12 inches long. 6. It takes 200 muscles to take one step.

Muscular System Fun Facts! 7. Humans are born with all the muscle fibers they will ever have. 8. Arnold Schwarzenegger has as many muscles fibers as the average person, they’re just thicker.

Muscular System Fun Facts! 9. Relative to its size, your tongue is the strongest muscle in your body. 10. It takes 17 muscles to smile and 43 to frown.

Muscular System Fun Facts! 11. Your heart is the only muscle that never gets tired. 12. Eye muscles are the busiest muscles in the body- they move more than 100,000 times a day.

Muscular System Fun Facts! 13. Muscles can contract, pull, and relax but they cannot push. 14. There are approx. 696 muscles in your body- 200 of them are voluntary.

Muscular System Fun Facts! 15. 85% of body heat is generated by muscle contractions. Shivers work to heat up your body.