The Muscular System

1. The Muscular System

2. Primary Function of the Muscular System • Locomotion • movement of substances through the body • structure and support for organs and tissues

3. Muscle Tissue: 3 Types • Muscle Tissue enables the movement of body structures. Smooth, Cardiac, Skeletal

4. Muscle Types: Smooth Muscle • Smooth muscle is non-striated, and acts in a number of involuntary processes in the body. Some of these processes include:

5. Muscle Types: Smooth Muscle • allows the expansion and contraction of arteries and veins • lines the bladder and reproductive tracts • lines the entire gastrointestinal tract

6. Did you know?... • Tiny smooth muscle fibers in the skin called Arrectorpili are responsible for “goose bumps.”

7. Muscle Types: Cardiac Muscle • Cardiac muscle (heart muscle) is striated but functions involuntarily. It is solely responsible for propelling blood throughout the body.

8. Muscle Types: Skeletal Muscle • Skeletal muscle is striated, and associated with voluntary movement. It also provides structure and support for organs and tissues.

9. Anatomy of skeletal muscles tendon Muscle Fascicle Skeletal muscle Skeletal muscle fiber (cell)

10. How Do Muscles Work? • Individual muscle fibers are composed of small cylindrical structures called myofibrils. The functional component within the myofibril is called the sarcomere. • Within the sacromere, protein filaments called actin and myosin allow the cell to expand and contract in a • 3 step process:

11. 3 Steps • 1) Before the muscle is stimulated, actin and myosin filaments partially overlap one another. • 2) A nerve cell releases a signal which causes the actin and myosin filaments to “slide” along one another and overlap even more. • 3) This contracts the myofibril and subsequently the entire muscle cell. When the nervous signal changes, the filaments relax and return to their original state.

12. Muscle fiber sarcomere Z-line myofibril Actin myosin Myosin molecule of thick myofilament Thin myofilament

13. Sarcomere

14. Actin and Myosin: A Closer Look • Access the website below (skip to sections 6-10) and complete the tutorial. http://www.wiley.com/college/pratt/0471393878/student/animations/actin_myosin/actin_myosin.swf

15. Action Potentials and the Neuromuscular Junction • Impulse arrives at axon terminal Ca+ ions rush in activating synaptic vesicles • Synaptic vesicles fuse with cell membrane of axon terminal • ACh released • ACh binds with motor end plate: deplorization occurs Impulse travels through T-tubules & SR

16. Actin, Myosin, and Action PotentialsPutting it all Together… • Access these online animations to help visualize these processes… The Neuromuscular Junction • http://tinyurl.com/the-neuromuscularjunction Action Potential and Muscle Contraction • http://tinyurl.com/5qox4x Sarcomere Contraction • http://tinyurl.com/sarcomerecontraction

17. Muscle (~35%) Did you Know? If you check out a standard lass, Muscles are a third of her body mass. BODY COMPOSITION

18. The Muscular System: Key Components • Muscles move body parts because they’re attached to bones by strips of dense connective tissue called tendons.

19. Skeletal Muscle: Key Concepts • The place where muscle attaches to a stationary bone is called the “origin.” The place where the same muscle attaches and “pulls” is called the “insertion.” Origin Insertion

20. Skeletal Muscle: Key Concepts • Skeletal muscle can be characterized as either “extensors” (causing a joint to straighten or extend), or a “flexor” (causing a joint to bend or flex).

21. Challenge question • How are tendons different from ligaments?

22. Basic Muscle Groups You Need to Know!

23. Basic Muscle Groups You Need to Know!

24. Basic Muscle Groups You Need to Know!

25. Naming Skeletal Muscles

26. Naming Muscles: By Direction of Muscle Fibers(Relative to the Midline) • RECTUS = parallel to the midline • RectusAbdominus • TRANSVERSE = perpendicular to midline • TransverseAbdominus • OBLIQUE = diagonal to midline • External Oblique

27. Naming Muscles: Location • Structure near which muscle is found • FRONTALIS= near FRONTAL bone • OCCIPITALIS = near OCCIPITAL bone

28. Naming Muscles: Size • Relative Size of Muscle • MAXIMUS = largest • GluteusMaximus • MEDIUS= middle • Gluteus Medius • MINIMUS= smallest • Gluteus Minimus • LONGUS= longest • FibularisLongus • BREVIS = short • FibularisBrevis • TERTIUS = shortest • FibularisTertius

29. Naming Muscles: Number of Origins • Number of tendons of origin • BICEPS= Two • Biceps Brachii • Biceps Femoris • TRICEPS= Three • Triceps Brachii • QUADRICEPS= Four • Quadriceps Femoris

30. Naming Muscles: Shape • Relative Shape of the Muscle • DELTOID= triangular shape Δ • TRAPEZIUS= trapezoid shape  • SERRATUS= saw-toothed ♒ • RHOMBOIDEUS = rhomboid shape  • TERES = round ○

31. Naming Muscles: Action

32. Cateorigizing muscles by the Actions they Facilitate Examples __________ __________ __________ __________ • Prime mover– muscle with the major responsibility for a certain movement • Antagonist – muscle that opposes or reverses a prime mover • Synergist – muscle that aids a prime mover in a movement and helps prevent rotation • Fixator – stabilizes the origin of a prime mover

33. Head & Neck Muscles

34. Frontalis: elevate eyebrows  OrbicularisOculi: close eyelid  Zygomaticus: draw angle of lip upward  Buccinator: draws cheeks against teeth OrbicularisOris: closes mouth  Platysma: draws lower lip down & back  Cranial Aponeurosis: connects frontalis to occipitalis Temporalis: elevates mandible Occipitalis: draws scalp back Masseter: elevates mandible Sternocleidomastoid: Flexes head Draws head toward shoulder Head & Neck Muscles

36. Smiling Muscles OrbicularisOculi Nasalis LevatorLabiiSuperioris LevatorAnguliSuperioris Zygomaticus Risorius Frowning Muscles Frontalis OrbicularisOris Depressor AnguliOris Depressor LabiiInferioris Mentalis Platysma Key Muscles of Facial Expression

37. Erector Spinae: maintain posture of back/extension Spinalis Longissimus Iliocostalis Oblique Muscles: rotation of the vertebrae Semispinalis Multifidus Rotatores Respiratory Muscles Diaphragm External Intercostals Internal Intercostals—deep breaths Abdominal Muscles External Obliques Internal Obliques Transverse Abdominus Rectus Abdominus Muscles of the Axial Skeleton

38. Muscles of the Axial Skeleton

39. Muscles of Scapular Stabilization • Trapezius: • Retraction • Elevation • Depression • Upward Rotation • Rhomboid—retraction • Levator Scapular—Elevation • Pectoralis Major—Protraction • Serratus Anterior—Protraction

40. Anterior Muscles of Shoulder • Deltoid • Flexion/Extension • Abduction/Adduction • Internal’External Rotation • Pectoralis Major • Adduction • Flexion • Extension • Internal Rotation • Biceps Brachii—Flexion

41. Posterior Muscles of Shoulder • Teres Major • Adduction • Extension • Internal Rotation • LatissimusDorsi • Adduction • Extension • Internal Rotation • Triceps Brachii • Adduction • Extension

42. Rotator Cuff Muscles (SITS) • Supraspinatus • Abduction • Infraspinatus • External Rotation • Teres Minor • External Rotation • Subscapularis • Internal Rotation

43. Muscles of the Elbow/Forearm • Triceps Brachii—Extension • Bicep Brachii— • Flexion • Supination • Brachialis—Flexion • Brachioradialis— • Flexion • Pronation • PronatorTeres • PronatorQuadratus • SupinatorLongus

44. Muscles of the Wrist & Hand • Flexor Carpi Ulnaris • Flexor Carpi Radialis • Flexor Digitorum • Extensor Carpi Ulnaris • Extensor Carpi Radialis • Extensor Digitorum Anterior (Palmar) View Posterior (Dorsal) View

45. Muscles of the Hip: Anterior • Medial/Adductor Muscles: • Adductor Magnus • Adductor Longus • Adductor Brevis • Gracilis • Anterior Muscles • Iliopsoas—Flexion • Pectineus— • Flexion • Adduction • Sartorius— • Flexion • Lateral Rotation

46. Muscles of the Hip: Gluteal • Gluteus Maximus—Extension • Gluteus Medius—Abduction • Gluteus Minimus—Abduction • Tensor Fasciae Latae— • Flexion • Abduction ** Gluteus Minimus is under the Gluteus Medius

47. Muscles of Anterior Thigh • “Quadriceps” • Rectus Femoris— • Hip flexion • Knee extension • VastusLateralis—knee extension • VastusMedialis—knee extension • VastusIntermedius—knee extension • Sartorius— • Hip & Knee Flexion • Lateral Hip Rotation **Vastus Intermedius is beneath Rectus Femoris

48. Muscles of Posterior Thigh • “Hamstrings” • Responsible for Knee Flexion & Hip Extension • Semimembranosus • Semitendinosus • Biceps Femoris • Gastrocnemius • Knee Flexion

49. Muscles of the Lower Leg • Anterior Compartment • Tibialis Anterior — Dorsiflexion & inversion • Extensor DigitorumLongus • FibularisTertius — dorsiflexion & eversion • Posterior Compartment • Gastrocnemius — plantarflexion, knee flexion • Soleus — plantarflexion • Lateral Compartment • FibularisLongus — plantarflexion & eversion • FibularisBrevis — plantarflexion & eversion

50. Can you think of different ways in which the muscular system works with other body systems to maintain homeostasis?