1. Chapter 10
Muscular System

2. Three types of muscles
1) smooth muscles- involuntary muscles example: large and small intestines
2) Cardiac muscles- involuntary muscle example: heart
3) Skeletal muscles- voluntary muscles example: muscles attached to bones

3. Function of Skeletal Muscles
1) Help maintain homeostasis
2) Produce body movements

4. Skeletal Muscles There are more than 600 muscles in the body.
40 to 50 percent of our body is skeletal muscle.

5. Connective tissue components
Endomysium- covers specialized skeletal muscle fibers
Perimysium- binding together fascicles
Epimysium- sheath covering the muscle as a whole

6. Three ways muscles are arranged
1) Size- small to large masses
2) Shape- broad, narrow, long, tapering, short, blunt, triangular, quadrilateral, irregular, flat sheets, or bulky masses
3) Arrangement- parallel to long axis, converge to a narrow attachment, oblique, pennate, bipennate, or curved

8. Attachment of muscles
1) Origin- point of attachment that does not move when the muscle contracts
2) Insertion- point of attachment that moves when muscles contract

9. Muscle actions
1) Prime movers (agonist)- muscle or group of muscles that directly performs a specific movement
2) Antagonist- muscle that, when contracting, directly oppose prime movers; relax while prime mover (agonist) is contracting to produce movement; provide precision and control during contraction of prime movers
3) synergists- muscles that contract at the same time as the prime movers; they facilitate prime mover actions to produce a more efficient movement
4) Fixator muscles- joint stabilizers

10. Lever system Composed of 4 components 1) Rigid bar (bone)
2) Fulcrum (F) around which the rod moves (joint)
3) Load (L) that is moved
4) Pull (P) that produces movement (muscle contraction)

11. Types of levers
1) First class lever- fulcrum lies between pull and the load
Not abundant in the human body; serve as levers of stability

12. Types of levers
2) Second Class lever- Load lies between the fulcrum and the joint at which the pull is exerted
Presence of these levers in the human body is a controversial issue

13. Types of levers
Third-class levers- Pull is exerted between the fulcrum and the load
Permit rapid and extensive movement
Most common type of lever found in the body

14. Naming Muscles 1) Location, function, shape
2) Direction of fibers- named according to fiber orientation
3) Number of heads of divisions
4) Points of attachment- origin and insertion points
5) Relative size- small, medium, or large
Read page 286 on hints on how to deduce muscle action

15. Facial Muscles Occipitofrontals- Raises eyebrows, wrinkles forehead
Orbicularis oculi- closes eyes
Zygomaticus major- Laughing
Orbicularis oris- Draws lips together
Buccinator- Permits smiling (no Coach Bryant does not have this muscle)

17. Muscles for Mastification
Masseter- Closes jaw
Temporalis- Closes jaw

19. Muscles that move head
Sternocleidomastoid- Flexes head, one muscle alone, rotates head toward opposite side
Semispinalis capitis- Extends head; bends it laterally
Splenius capitis- Extends head/ Bends and rotates head toward same side as contracting muscle
Longissimus capitis- Extents head

21. Muscles of the Thorax External intercostals- Elevate ribs
Internal intercostals- Depress ribs
Diaphragm- Enlarges thorax, causing inspiration

23. Muscles of the Abdominal Wall
External oblique- Compresses abdomen/ rotates trunk laterally
Internal oblique- same as external oblique
Transverse abdominis- same as external oblique
Rectus abdominis- same as external oblique

25. Muscles moving on Shoulder Girdle
Trapezius- Raises or lowers shoulder and shrugs them
Pectoralis minor- Pulls shoulder down and forward
Serratus anterior- Pulls shoulder down and forward; abducts and rotates it upward
Levator scapulae- Elevates and retracts scapula and abducts neck.
Rhomboid major and minor- Retracts, rotates, fixes scapula

28. Muscles moving upper arm
Pectoralis major- Flexes upper arm, Adducts upper arm anteriorly
Latissimus dorsi- Extends upper arm, Adducts upper arm posteriorly
Deltoid- Abducts upper arm
Coracobrachialis- Adduction
Supraspinatus- Assist in abducting arm
Teres minor- rotates arm outward

29. Upper arm cont.
Teres major- Assist in extension, adduction, and medial rotation of arm
Infraspinatus- Rotates arm outward
Subscapularis- medial rotation

33. Muscles moving the Forearm
Biceps brachii- flexes supinated forearm
Brachialis- flexes pronated forearm
Brachioradialis- flexes semipronated or semisupinated forearm
Triceps brachii- Extends lower arm
Pronator teres- Pronates and flexer forearm
Pronator quadratus- Pronates forearm
Supinator- Supinates forearm

39. Muscles that move the hand
Flexor carpi radialis- Flexes hand/forearm
Flexor carpi ulnaris- Flexes hand/ adducts hand
Extensor carpi radialis brevis- Extends hand
Extensor carpi ulnaris- Extends hand/ Adducts hand
Flexor digitorum- flexes fingers
Extensor digitorum- extends fingers

45. Muscles that move thigh
Iliopsoas- Flexes thigh
Rectus femoris- Flexes thigh/ extends lower leg
Gluteal muscles (maximus- extends thigh/ medius- abducts thigh/ minimus- abducts thigh)
Tensor fasciae latae- abducts thigh
Adductor group- (brevis/longus/mangus- adducts thigh)
Gracilis- adducts tigh and flexes and adducts leg

48. Muscles that move lower leg
Quadriceps femoris group:
Rectus femoris- Flexes thigh/ extends leg
Vastus lateralis- Extends leg
Vastus medialis- Extends leg
Vastus intermedius- Extends leg
Sartorius- Adducts and flexes leg

49. Muscles moving lower leg cont.
Hamstring group:
Biceps femoris- Flexes leg
Semitendinosus- Extends thigh
Semimembranosus- Extends thigh

56. Muscles move the foot Tibialis anterior- Flexes/ Inverts foot
Gastrocnemius- Extends foot/ Flexes lower leg
Soleus- Extends foot (planter flexion)
Peroneus longus- extends foot
Peroneus brevis- Flexes foot
Peroneus tertius- Flexes foot
Extensor digitorum longus- Dorsiflexion of foot/ extension of toes