1. Muscle Contractions By Jarad Settles 5.19.04 Per. CD

2. Types of Muscles b Skeletal The type we can see and feel.The type we can see and feel. Attached to the skeleton and come in pairs, one to move the bone one way and the other the other way.Attached to the skeleton and come in pairs, one to move the bone one way and the other the other way. These muscles are voluntary, which means you control them.These muscles are voluntary, which means you control them. Can do a short twitch or a long one.Can do a short twitch or a long one.

3. Types of Muscles Con’t. b Smooth Muscles Found in your digestive system.Found in your digestive system. –Blood Vessels, Airways, Bladder, and in women, the uterus. Has the ability to stretch and maintain tension for long periods of time.Has the ability to stretch and maintain tension for long periods of time. Involuntary muscles, automatically contract without you thinking about it.Involuntary muscles, automatically contract without you thinking about it.

4. Types of Muscles Con’t. b Cardiac Muscles Only found in your heart.Only found in your heart. Endurance and Consistency.Endurance and Consistency. Can stretch a limited amount like the smooth muscle.Can stretch a limited amount like the smooth muscle. Can contract like the skeletal muscle.Can contract like the skeletal muscle. Twitch muscle.Twitch muscle. Contracts involuntarily.Contracts involuntarily.

5. Muscle Contractions b Bundle of many cells called fibers. Long CylindersLong Cylinders b Fibers are about 1 to 40 microns long and 10 to 100 microns wide. (100 microns = diameter of a strand of hair. 10 microns = a cell in your body.) b A Fiber contains many myofibrils.

6. Muscle Contractions Con’t. b Each muscle fiber contains myofibrils. Cylinders of enzymes.Cylinders of enzymes. b Enzymes are made up of proteins. Enzymes are the cause of all chemical reactions. They allow the cell to carry out chemical reactions quickly.Enzymes are the cause of all chemical reactions. They allow the cell to carry out chemical reactions quickly. b Proteins are chains of amino acids.

7. Muscle Contractions Con’t. b Myofibrils contain two types of filaments. Thick and ThinThick and Thin b Arranged in hexagonal patterns, the filaments run along the axis of the fiber. b Filaments are attached to the Z-Line that runs perpendicular to the long axis of the fiber. b Running down the Z-Line is the T-Tubule.

8. Muscle Contractions Con’t. b Inside the fiber, between T-tubules is a membrane system called the sarcoplasmic reticulum, which releases the calcium ions that make a muscle contract.

9. Triggering a Contraction b Electrical signal travels down a nerve cell causing the release of a chemical message into the synapse (gap between nerve cell and muscle cell). b The neurotransmitter (chemical message) crosses the synapse, binds to a receptor on the cell membrane and causes another electrical signal in the muscle cell. b The signal travels along the muscle cell and enters the cell through the T-tubule. b The signal triggers the release of calcium ions that bind to the molecules located in the grooves of the filaments. b After the signal passes, the ions are stopped from being released and calcium pumps remove calcium from the cytoplasm. b After this process, the muscle relaxes.

10. Contracting a Muscle b Thick and thin filaments do all the work of a muscle. b Thick filaments are made of proteins called myosin and thin filaments are made of the protein actin. b During contraction the myosin grabs onto the actin by forming crossbridges. b The two fibers pull and make the muscle contract.

11. Energy to Make a Muscle Contract b ATP is what muscles use to contract. ATP resets the myosin crossbridges and releases the actin.ATP resets the myosin crossbridges and releases the actin. b The muscle creates ATP by: Breaking down creatine phosphate and adding it to ADP.Breaking down creatine phosphate and adding it to ADP. Then it carries out anaerobic respiration which breaks down glucose, glycogen, and amino acids to form lactic acid to form ATP.Then it carries out anaerobic respiration which breaks down glucose, glycogen, and amino acids to form lactic acid to form ATP.

12. Works Cited b www.howstuffworks.com