Essential Question What is the Muscular system Do

Essential Question: What is the Muscular system? Do Now: In what ways do you use your muscles daily?

Support • Muscles and bones • Muscular system • Three types of muscle http: //www. besthealth. com/besthealth/bodyguide/reftext/images/100085. jpg

Muscular System • Skeletal muscle tissue is made up of elongated cells called Muscle Fibers • Each fiber has dark and light lines called Striation • Fascicles are the dense bundles of muscle fibers • Voluntary Muscles are consciously controlled • Skeletal Muscles • Because most of its movements cannot be consciously controlled, Smooth and Cardiac muscle is referred to as Involuntary Muscles

Skeletal muscle • Allow movement • Voluntary muscle • You can control them • Can only pull bones, not push • Work in pairs – flexor(bends), extensor(straightens) • Actin and myosin cause muscles to work

Smooth muscle • Involuntary • You cannot control them • blood vessels, stomach, other organs • Diaphragm • lowers to increase size of chest cavity • Air moves in due to low pressure

Cardiac muscle • Involuntary • Transmits electrical impulses • Pump blood through heart and rest of body

• Each muscle fiber consists of Myofibrils • Each myofibrils is composed of two proteins: • Myosin- Thick filaments • Actin-Thin Filaments • Where all of the actin are anchored together is the Z-Line • From z-line to the next is considered a Sarcomere

• Neuromuscular junction is to point in which the motor neuron and a skeletal muscle meet • The neurotransmitter released at this junction is Acetylcholine

• Muscle are attached to periosteum by a Tendon • The point where a muscle attaches to a stationary bone is called the Origin • The point where a muscle attaches to a moving bone is called the Insertion • Flexor- Muscle that bends the joint. Bicep • Extensor- Muscle that straightens the joint- Triceps