Muscular System

Functions of the Muscular System Movement Provides Shape and Form Posture Maintains body temp

Structures of the Muscular System 3 types of muscles Skeletal Smooth Cardiac Skeletal Attaches to bone Also called voluntary Appears striped or striated under the microscope

Cardiac Muscle- Found only in the heart Is an involuntary muscle Requires a continuous supply of Oxygen Smooth Muscle- Unlike the skeletal muscle, the smooth muscle is unmarked Smooth muscle is involuntary Smooth muscle is controlled by the autonomic nervous system

Characteristics of Muscles-All groups Contractility- shortening of a muscle in response to a stimuli Excitability or Irritability- production of electric signals in response to stimuli Extensibility- a muscles ability to be stretched. Elasticity- the muscles ability to return to its original length when relaxed

Other parts to know: Tendons- Fibrous connective tissue attaching bone to muscle Ligaments- attaches bone to bone Joints- where bones are connected Fascia- Connective tissue

Origin vs. Insertion- Origin- part of the muscle that is attached to a fixed structure like a bone Insertion-part of the muscle that is attached to a moveable part

Muscle groups- Head- Functions: Expression Chewing Did you know you only need 17 muscles to smile, but you need 43 muscles to frown? Every 2000 frowns creates one wrinkle!!

Neck- Functions- Moves the head Moving upper rib muscles

Trunk- Functions: Control breathing Movement of the abdomen

Upper Extremities- Functions- Move shoulders and arms Moves the hands and fingers

Lower extremities- Functions- movement of the thigh, leg, ankle, foot and toes Abducts Adduct Flex Extend Intramuscular injections

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Disorders of the Muscular System Atrophy- muscles shrink in size when not used Muscular Dystrophy- muscle cells deteriorate