Muscular System Animal movement is based on contraction

Muscular System • Animal movement is based on contraction of muscles working against part of the skeleton

Muscle Tissue • Cells that contract • Three types of muscle tissue: 1. Skeletal 2. Cardiac 3. Smooth

Types of Muscle Tissue • Skeletal: voluntary attached to bones striated: repeating units of contractile proteins, actin and myosin long, cylinders multinucleated many mitochondria

Types of Muscle Tissue • Cardiac: involuntary only in the heart unit contractions due to gap junctions branched striated

Types of Muscle Tissue • Smooth: involuntary walls of organs tapered cells unstriated

Classification of muscle Voluntary Involuntary Skeletal Cardiac Smooth Limbs Heart Viscera Striated Non-striated Note: Control, Location and Structure

Muscle Control Type of muscle Nervous control Type of control Example Skeletal Controlled by CNS Voluntary Lifting a glass Cardiac Regulated by ANS Involuntary Heart beating Smooth Controlled by ANS Involuntary Peristalsis

REMEMBER! • Tendon connects muscle to bone • Ligament connects bone to bone

Tendons • Muscles are attached to TWO different bones by tendons. • When the muscle contracts only ONE bone moves. • The place where the muscle is attached to the stationary bone is called the Origin. • The place where the muscle is attached to the moving bone is called the Insertion.

Muscles Pull NEVER Push!! • Muscles only contract and relax • Contraction (=shortening) of a muscle pulls a bone

Antagonist Muscle Pairs • To make a joint move in two directions, you need two muscles that can pull in opposite directions. • Antagonistic muscles are pairs of muscles that work against each other. • One muscle contracts while the other one relaxes

Muscles work in Antagonistic Pairs Flexor and Extensor Flexor = decreases the angle between two bones Extensor = increases the angle between two bones Extensor Flexor

True or False Muscles cause movement by pushing and pulling on the bones of the skeleton.

True or False Muscles cause movement by pushing and pulling on the bones of the skeleton. FALSE! Muscles NEVER push. They can only pull.

Short Answer List the three types of muscle tissue.

Short Answer List the three types of muscle tissue. Skeletal Muscle Smooth Muscle Cardiac Muscle

Multiple Choice Voluntary muscle tissue is also called A. skeletal muscle. B. smooth muscle. C. cardiac muscle. D. All of the above.

Multiple Choice A muscle that decreases the angle between two bones is called A. an extensor. B. a flexor. C. a tendon. D. an antagonistic pair.

Frontalis Trapezius Sternocleidomastoid Deltoid Pectoralis major Rectus abdominis Biceps brachii Sartorius Rectus femoris Gastrocnemius

Sternocleidomastoid Trapezius Deltoid Triceps brachii Latissimus dorsi Gluteus maximus Biceps femoris Gastrocnemius Sartorius

Skeletal Muscle Organization • Skeletal muscle fibers (= cells) are bundled into packages called fascicle

Skeletal Muscle Organization • Fibers (=cells) are made up of myofibrils that consist of actin (thin filament) and myosin (thick filament)

Sarcomere repeating units of actin and myosin within a myofibril

Myosin (Thick Filament) Actin (Thin Filament)

Sliding Filament Model Mechanism for Muscle Contraction • When the muscle is at rest, a long, rod-like tropomyosin molecule blocks the myosin-binding sites that are instrumental in forming cross bridges. • When another protein complex, troponin, binds calcium ions, the actin binding sites are exposed, cross-bridges with myosin can form, and contraction begins.

Sliding Filament Model (continued) • Ca+ comes from the sacroplasmic reticulum in the plasma membrane around each myofibril

Cross Bridging b/t Actin and Myosin

Sliding Filament Theory Animations • http: //www. blackwellpublishing. com/matth ews/myosin. html • http: //highered. mcgrawhill. com/sites/0072437316/student_view 0/ chapter 42/animations. html#