4.2.1 MUSCLE RULES REVIEW QUIZ NEXT CLASS

Types of Muscle There are 3 types of muscle in our bodies Skeletal Smooth Cardiac Each has different characteristics

Skeletal Muscle Voluntary – we control the movement Striated – looks like long fibers Linked to bones by tendons Function – to help us move / move our bones

Skeletal Muscle

Smooth Muscle Involuntary Action – controlled by our CNS Non-striated Found in arteries, veins, intestines, etc. Function : Maintain organ dimensions – stretch and recoil

Smooth Muscle

Cardiac Muscle Involuntary Striated – but, may be branched which is unlike skeletal muscle. Found in walls of the heart Function : To pump the heart!!!! Highly resistant to fatigue w/ lots of mitochondria

Cardiac Muscle

MUSCLE RULE #1 Muscles must have at least two attachments and must cross at least one joint

Muscles always “pull” and get shorter. MUSCLE RULE #2 Muscles always “pull” and get shorter.

MUSCLE RULE #3 The attachment that moves is known as the insertion and the attachment that remains stationary is known as the origin.

MUSCLE RULE #4 Muscles that decrease the angle between ventral surfaces of the body are known as flexors. Muscles that increase the angle between ventral surfaces of the body are known as extensors

MUSCLE RULE #5 Muscles work in opposing pairs.

Muscle striations point to the attachment & show direction of pull MUSCLE RULE #6 Muscle striations point to the attachment & show direction of pull Muscle striations point to the attachments and show the direction of pull.

Naming Skeletal Muscles 1 – Location of the muscle 2 – Shape of the muscle 3 – Size of the muscle 4 – Direction/Orientation of the muscle fibers/cells 5 – Number of Origins 6 – Location of the Attachments 7 – Action of the muscle