Muscular System  The body has more than 600 muscles that make up 40 to 45% of the body’s weight

Types of Muscle Tissue  Skeletal muscle  Striated  Dark and light bands in fibers  Voluntary  Conscious control over these muscles

Cardiac Muscles  Indistinctly striated  Involuntary

Smooth Muscle  Also called visceral muscle  Unstriated  No dark and light bands  Involuntary

Smooth Muscle Tissue  Located:  Walls of internal organs  Respiratory and digestive tracts  Digestive tract=peristalsis  Wavelike movement  Causes contents to be propelled onward

Muscle Function

 Movement of:  Body  Blood  Food  Waste  Provide and maintain posture  Protect internal organs  Provide heat

How Muscles Are Named

How Muscles are Named MMMMuscle origin PPPPlace where muscle begins EEEEnd where movement does not occurs MMMMuscle insertion PPPPlace where muscle ends EEEEnd where movement occurs

 Size  Maximus  Minimus  Shape  Deltoid  Trapezius  Direction of fibers  Rectus  Oblique  Location  Anterior  Posterior  Bone  Number  Bi  Tri  Quad

Muscle Characteristics  Irritability  Ability to respond to stimulus  Contractibility  Ability to shorten  Extensibility  Ability to stretch and lengthen  Elasticity  Ability to return to original length at rest

Muscle Characteristics  Muscle tone  Partial state of contraction  Balanced muscle tension required to hold body in position

Attachment of Muscle Tissue  Tendons:  While ligaments attach bone to bone, muscles are attached to bones by bands of fibrous tissue called tendons.  Fascia:  A sheet of tough fibrous tissue that wraps around an individual muscle.

Body Movements Caused by Skeletal Muscle  Flexion:  Decrease angle between two bones or bending a limb at a joint  Elbow bent and lower arm brought upward  Plantar flexion: bending foot forward  Dorsiflexion: bending foot toward knee

Body Movements Caused by Skeletal Muscle  Extension  Increase angle between two bones or straightening out a limb  Elbow straightened and lower arm downward

Body Movements Caused by Skeletal Muscle  Abduction  Movement away from body midline  Arm moves outward, away from side of body  Adduction  Movement toward midline of body  Arm moves inward, toward side of body

Body Movements Caused by Skeletal Muscle  Rotation  Circular or semi- circular movement around an axis  Turning head side to side

Body Movements Caused by Skeletal Muscle  Pronation:  Turning hand downward  Supination:  Turning hand upward

Pathology of the Muscular System

Muscle atrophy  Weakening and wasting away of muscle tissue  Occurs with paralysis  Can lead to contractures:  Joint remains in flexed position 

Muscular dystrophy  Gradual atrophy of muscle tissue  Genetic disease  No cure  Treatment:  Braces  Corrective surgery

Muscular Dystrophy

Fibromyalgia  A group of muscle disorders affecting the tendons, ligaments, and fibrous tissues  Myalgia common  Treatment: reduce stress and exercise

Hernia  The abnormal protrusion of a body part into another body area  Result from weakness in or injury to stomach muscles  Treatment: bracing or surgery

Hernia

Poliomyelitis  A viral infection resulting in paralysis of muscles  Prevented by vaccination  No cure

Tetanus  AKA “lock jaw”  Caused by toxin produced by bacterial infection  Produces uncontrolled muscle spasms  Treatment:  antibiotics  antitoxin  Prevention: immunization

Muscle Strain  Torn or stretched tendons and muscles causing pain  It is caused by muscles being used too suddenly or for too long.  Symptoms include pain and swelling from bleeding inside the muscle.  Treatment involves rest, elevation, and alternating hot and cold applications.

Muscle Movement

 Quadriceps  Extends lower leg  Flexes hip

Muscle Movement  Deltoid  Abduct arm

Muscle Movement  Trapezius  Shrug shoulder

Muscle Movement Gastrocnemius Stand on tiptoe (plantar flexion)

Muscle Movement  Sternocleidomastoid  Rotates head

Muscle Movement  External obliques  Bending to the side  Rectus abdominus  Sit up

Muscle Movement  Sartorius  Flexes hip & knee

Muscle Movement  Intercostals muscle  inhaling

Muscle Movement  Biceps brachii  Flexes lower arm

Muscle Movement  Triceps brachii  Extends lower arm  Used for push ups

Muscle Movement  Biceps femoris and Semitendenosis  Hamstrings  Flex lower leg

Muscle Movement  Gluteus maximus  Extend hip

Muscle Movement  Tibialis anterior  Flex foot

Muscle Movement  Flexor carpi  Flex wrist

Muscle Movement  Pectoralis major  Adducts upper arm

Muscle Movement  Latissimus dorsi  Adducts upper arm

The End