Muscular System
Muscle Facts There are over 600 different muscles in the human body Body contains three muscle types: skeletal, cardiac, and smooth Skeletal muscles are voluntary muscles Cardiac and smooth muscles are involuntary
Functions of Muscles Work with bones to create movement Gives body shape and support Protection for vital organs Vital bodily functions (heartbeat, digestion, excretion of waste, etc.) Contractions create heat to maintain a normal body temperature
Skeletal Muscles Make up approx. 40% of body mass Work in pairs Named for shape, location, function Connected to bones by tendons Can grow in size with repeated resistance work Can contract quickly, but get tired easily and must rest
sterno-mastoid Head movement “yes” and “no”
Trapezius (upper back, neck) Pulls head and upper arms back “yes” and “no” movement Work with deltoids to lift arms
Trapezius (developed)
Pectorals (chest) Move arms to center of body Press away
Deltoid (shoulder cap) Lifts arms to shoulder height Named for Greek letter “D”
Biceps Flexes forearm; palm up
Triceps Extends forearm; Fixes elbow when writing
Brachioradialis Flexes forearm, palm down
Latissimus dorsi Pulls arms down and back; give body “V” shape
For real???????
Abdominals Protects internal organs Helps hold body erect
Gluteus maximus Lifts leg backward Helps hold body erect
Hamstrings Flex knee to buttocks
Quadriceps (quads) Four muscles groups Extends lower leg
Sartorius Longest muscle Allows leg crossing
Tibialis Pulls toes toward face
Gastrocnemius (calf) Extends toes
Achilles Tendon Connects calf muscle to heel Named for Achilles of mythological fame
Human Muscular Anatomy
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