MUSCLES & MOVEMENT

Section 9.4

Three Types of MuscleCardiac, Smooth, Skeletal

1. Cardiac Muscle

ONLY found in the heartContracts and relaxes involuntarily

(heart beat)Controlled by nerves of the autonomic

nervous system

2. Smooth Muscle

Found in the lining of organsLining of the stomach, the esophagus,

uterusWalls of blood vessels

Involuntary movement

Skeletal Muscle

Attached to the bones of the skeleton via tendons

Tendons – connective tissue that joins the muscle to the bone.

Under conscious (voluntary) control

Muscle Movement

Muscles shorten when they contract and lengthen when they relax

Many skeletal muscles are arranged in pairs that work against each other to make a joint move.

These are called ANTAGONISTIC MUSCLES

Biceps & TricepsWhen the biceps

contracts and the triceps relaxes, the bones forming the elbow joint are brought closer together (bending your arm)

When the biceps relaxes and the triceps contract, the two bones are moved apart (straightening your arm)

Actin and Myosine

Sliding Filament Theory

The Sliding Filament Theory – Student Task

Read about “The Sliding Filament Theory” on page 301.Why is it called a “theory”?Discuss the interaction between myosin and

actin during muscle movement.Discuss ATP and its connection to rigor

mortis

Muscle Contraction

Lesson Assignment

Read about Muscle Fatigue – Page 301Read about Motor System Injuries – Page 303Review content on Page 298 – Page 300

Page 304 = #3, #5, #6