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