MUSCULAR SYSTEM HST I

Structure and Function The human body has more than 600 muscles The human body has more than 600 muscles

Characteristics of Muscles Excitability Excitability Contractibility Contractibility Extensibility Extensibility Elasticity Elasticity

Excitability Irritability, the ability to respond to a stimulus such as a nerve impulse Irritability, the ability to respond to a stimulus such as a nerve impulse

Contractibility Muscle fibers that are stimulated by nerves contract, or become short and thick, which causes movement Muscle fibers that are stimulated by nerves contract, or become short and thick, which causes movement

Extensibility The ability to be stretched The ability to be stretched

Elasticity Allows the muscle to return to its original shape after it has contracted or stretched Allows the muscle to return to its original shape after it has contracted or stretched

Skeletal Muscle Makes up more than 40% of a person’s body weight Makes up more than 40% of a person’s body weight Looks striated, or banded, under the microscope Looks striated, or banded, under the microscope Skeletal muscles have three parts Skeletal muscles have three parts Origin is one end of the muscle, attached to the less movable part of the bone Origin is one end of the muscle, attached to the less movable part of the bone Insertion is the other end of the muscle, attached to the more movable part of the bone Insertion is the other end of the muscle, attached to the more movable part of the bone The action, or body, is the thick middle part of the muscle The action, or body, is the thick middle part of the muscle

Skeletal Muscles (cont.) Skeletal muscles attach to bones in different ways Skeletal muscles attach to bones in different ways Tendons-strong tough, fibrous connective- tissue cords Tendons-strong tough, fibrous connective- tissue cords Fascia- a tough sheetlike membrane that covers and protects the tissue Fascia- a tough sheetlike membrane that covers and protects the tissue

Visceral Muscle Lines various hollow organs Lines various hollow organs Makes up the walls of blood vessels Makes up the walls of blood vessels Found in the tubes of the digestive system Found in the tubes of the digestive system Smooth and has no striations Smooth and has no striations Controlled by the autonomic nervous system Controlled by the autonomic nervous system

Cardiac Muscle Found only in the heart Found only in the heart Striated muscle Striated muscle Under involuntary control Under involuntary control Has specialized cells that provide a stimulus for contraction Has specialized cells that provide a stimulus for contraction

Sternocleidomastoid Location: Side of neck Location: Side of neck Function: Turns and flexes head Function: Turns and flexes head

Trapezius Location: Upper back and neck Location: Upper back and neck Function: Extends head, moves shoulder Function: Extends head, moves shoulder

Deltoid Location: Shoulder Location: Shoulder Function: Abducts arm, injection site Function: Abducts arm, injection site

Biceps brachii Location: Upper arm Location: Upper arm Function: Flexes lower arm and supinates hand Function: Flexes lower arm and supinates hand

Triceps brachii Location: Upper arm Location: Upper arm Function: Extends and adducts lower arm Function: Extends and adducts lower arm

Pectoralis major Location: Upper chest Location: Upper chest Function: Adducts and flexes upper arm Function: Adducts and flexes upper arm

Intercostals Location: Between ribs Location: Between ribs Function: Moves ribs for breathing Function: Moves ribs for breathing

Rectus abdominus Location: Ribs to pubis (pelvis) Location: Ribs to pubis (pelvis) Function: Compresses abdomen and flexes vertebral column Function: Compresses abdomen and flexes vertebral column

Latissimus dorsi Location: Spine around to chest Location: Spine around to chest Function: Extends and adducts upper arm Function: Extends and adducts upper arm

Gluteus maximus Location: Buttocks Location: Buttocks Function: Extends and rotates thigh, injection site Function: Extends and rotates thigh, injection site

Sartorius Location: Front of thigh Location: Front of thigh Function: Abducts thigh, flexes leg Function: Abducts thigh, flexes leg

Quadriceps femoris Location: Front of thigh Location: Front of thigh Function: Extends leg, injection site Function: Extends leg, injection site

Tibialis anterior Location: Front of lower leg Location: Front of lower leg Function: Flexes and inverts foot Function: Flexes and inverts foot

Gastrocnemius Location: Back of lower leg Location: Back of lower leg Function: Flexes and supinates sole of the foot Function: Flexes and supinates sole of the foot

Basic Types of Muscle Movement Adduction Adduction Abduction Abduction Flexion Flexion Extension Extension Rotation Rotation

Adduction Moving a body part toward the midline Moving a body part toward the midline

Abduction Moving a body part away from the midline Moving a body part away from the midline

Flexion Decreasing the angle between two bones, or bending a body part Decreasing the angle between two bones, or bending a body part

Extension Increasing the angle between two bones, or straightening a body part Increasing the angle between two bones, or straightening a body part

Rotation Turning a body part around its own axis; for example, turning the head from side to side. Turning a body part around its own axis; for example, turning the head from side to side.

Circumduction Moving in a circle at a joint, or moving one end of a body part in a circle while the other end remains stationary, such as swinging a arm in a circle Moving in a circle at a joint, or moving one end of a body part in a circle while the other end remains stationary, such as swinging a arm in a circle

Body Mechanics Body Mechanics is the way in which the body moves and maintains balance while making the most efficient use of all its body parts. Body Mechanics is the way in which the body moves and maintains balance while making the most efficient use of all its body parts. To prevent injury to yourself and others while working in the health field, it is important to observe good body mechanics To prevent injury to yourself and others while working in the health field, it is important to observe good body mechanics

Four Main Reasons for Using Good Body Mechanics Muscles work best when used correctly. Muscles work best when used correctly. Correct use of muscles makes lifting, pulling and pushing easier Correct use of muscles makes lifting, pulling and pushing easier Prevents unnecessary fatigue, strain and saves energy Prevents unnecessary fatigue, strain and saves energy Prevents injury to self and others Prevents injury to self and others

Eight Basic Rules of Good Body Mechanics 1)Maintain a broad base of support by keeping the feet 8-10 inches apart 2)Bend from the hips and knees to get close to an object, and keep your back straight 3)Use the strongest muscles to do the job (shoulders, upper arms, hips and thighs) 4)Use the weight of your body to help push or pull an object. Whenever possible, push, slide, or pull rather than lift

Eight Basic Rules of Good Body Mechanics 5)Carry heavy objects close to the body 6)Avoid twisting your body as you work. Turn with your feet and entire body when you change direction of movement 7)Avoid bending for long periods 8)If a patient or object is too heavy for you to lift alone, always get help

Related Health Careers Athletic Trainer Athletic Trainer Chiropractor Chiropractor Doctor of Osteopathic Medicine Doctor of Osteopathic Medicine Massage Therapist Massage Therapist Myologist Myologist Neurologist Neurologist Orthopedist Orthopedist Physiatrist Physiatrist Physical Therapist Physical Therapist Podiatrist Podiatrist Prosthetist Prosthetist Rheumatologist Rheumatologist Sports Medicine Physician Sports Medicine Physician