1. Muscular System About 650 skeletal muscles in the human body
17 muscles to smile…42 muscles to frown
Largest muscle = gluteus maximus
Longest muscle = sartorius
Smallest muscle = stapedius (inner ear)
Takes >200 muscles to walk

3. -mysium=CT membrane
and tendon sheath
Myofilaments

4. Types of Muscle Skeletal Striated Voluntary Multinucleated Smooth
Nonstriated
Involuntary
Cardiac
Intercalated disks
~ 50% of body weight
Work in groups to perform a function

5. General Functions of Muscular System
Movement
Skeletal muscle contractions move body in whole or part
Heat Production
Muscle cells produce heat via catabolism to maintain temperature homeostasis
85% of body heat comes from muscle contractions
Posture
Continued partial contraction of muscle in order to perform many functions

6. Characteristics of all Muscle
Excitability
Respond to stimuli
Contractility
Actively shorten to exert a pull
Tension that can be harnessed by CT
Extensibility
Continue to contract over range of resting lengths
Ex: smooth muscle can be stretched to several times its original length and still contract on stimulation
Elasticity
Return to original length after contraction

7. Muscle Fiber Arrangement
Parallel
Convergent
Pennate
Bipennate
Sphincter

8. Muscle Attachment Does NOT move when muscle contracts Does move when

9. Naming Muscles Location Function Shape Fiber direction
Number of heads/divisions
Points of attachment
Muscle size

10. Location Function Fiber Direction Shape Frontalis Frontal bone Femoris
Femur
Gluteus
Posterior of hip/thigh
Oculi
Eye
Oris
Mouth
Radialis
Radius
Ulnaris
Ulna
Brachialis
Arm
Abductor
Moves part away from body
Adductor
Moves part toward body
Depressor
Lowers a part
Extensor
Extends a part
Flexor
Flexes a part
Levator
Elevates a part
Rotator
Rotates a part
Fiber Direction
Shape
Oblique
Diagonal to midline
Rectus
Parallel to midline
Sphincter
Circling an opening
Transversus
Right angle to midline
Deltoid
Shaped like delta ∆
Orbicularis
Circular
Platy
Flattened; platelike
Quadratus
Square
Rhomboideus
Diamond-shaped
Trapezius
Trapezoidal

11. Number of divisions Size Bicep Two heads Tricep Three heads Quadricep
Four heads
Size
Brevis
Short
Longus
Long
Magnus
Large
Maximus
Largest
Medius
Moderately sized
Minimus
Smaller

12. Raises eyebrows
Frowning
Mastication
Blinking
Laughing
Whistling, smiling
Puckering
Mastication
Flexes head

13. Moves head
Moves head
Flexes head

14. Superficial Back Muscles
Large, fan-shaped muscles provide force in a wide range of body positions
-EX: leaning back to straight vertical and all points in between.
Shrugging, pulling scapulas together and down
Rotator cuff
muscles
Stabilize shoulder joint, pull arm back
Shoulder movement
Pull the arm down,
Stabilize torso during many movements (EX: bench press)

15. Trunk Muscles - Thorax
Elevate ribs

16. Trunk Muscles Abdomen Flexes trunk Stabilizes Lower back Compresses

17. Upper Arm
Flexes
Upper arm
Extends forearm

18. Flexors

19. Extensors

20. Upper Leg Deep muscle Vastus intermedius Longest muscle Biceps femoris
Semimembranosus
Quadricep
Femoris
Semitendinosus

21. Lower Leg
Plantar flexion

22. Foot

23. Posture
Good Posture – body alignment that favors function with least work
Standing Position
Head and chest held high
Chin, abdomen, buttocks pulled in
Knees slightly bent
Feet firmly on ground 6 in. apart
Poor Posture - puts abnormal strain on ligaments and bones
Maintenance
Tonicity (muscle tone): muscles exert a pull against gravity
Continuous and passive partial contraction of muscles

24. Classification of Muscle Group Actions
Agonist (Prime Mover)
Muscle most responsible for movement
Antagonist
Opposes prime mover
Provides precision and control during prime mover contraction
Relaxes when prime mover contracts
Synergist
Aid prime mover
Contract at same time as prime mover
Fixator
Joint stabilizer
Maintains posture/balance during prime mover contraction