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

Limbs Heart Viscera

Striated Non-striated

Skeletal Cardiac Smooth

Note: Control, Location and Structure

Muscle Control

Type of muscle

Nervouscontrol

Type of control

Example

SkeletalSkeletal 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

Extensor

Flexor = decreases the angle between two bones

Extensor = increases the angle between two bones

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

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.

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.

Biceps brachii

Deltoid

Frontalis

Gastrocnemius

Pectoralis major

Rectus abdominis

Rectus femoris

Sartorius

SternocleidomastoidTrapezius

Biceps femoris

Deltoid

Gastrocnemius

Gluteus maximus

Latissimus dorsi

Sartorius

Sternocleidomastoid Trapezius

Tricepsbrachii

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 unitsof actin and myosin within a myofibril

Myosin (Thick Filament)

Actin (Thin Filament)

• 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 Mechanism for Muscle Contraction

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/matthews/myosin.html

• http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter42/animations.html#