The skeleton ….CAN move but only with THIS system…. MUSCULAR

1. The skeleton ….CAN move but only with THIS system…. MUSCULAR

2. Organization of Muscles • 600 Human skeletal muscles • General structural and functional topics • muscle shape and function • connective tissues of muscle • coordinated actions of muscle groups • intrinsic and extrinsic muscles • muscle innervation • Regional descriptions

5. Characteristics of Muscle • Excitability (Contractability) • to chemical signals, stretch and electrical changes across the plasma membran • Contractility -- shortens when stimulated • Extensibility -- capable of being stretched • Elasticity -- returns to its original resting length after being stretched

6. Characteristics of Muscles • Muscle cells are elongated (muscle cell = muscle fiber) • Contraction of muscles is due to the movement of microfilaments • All muscles share some terminology • Prefix myo refers to muscle • Prefix mys refers to muscle • Prefix sarco refers to flesh

7. Muscle Cell =Muscle Fiber= Myocyte • The myocyte is elongated • Their characteristics depend on which type of muscle they are found: skeletal, muscle or cardiac.

14. Muscle is an ORGAN • MUSCLE is an ORGAN- contains, muscle tissue, connective tissue, blood vessels, and nerves

16. Connective Tissues of a Muscle • Epimysium • covers whole muscle belly • blends into CT between muscles • Perimysium • slightly thicker layer of connective tissue • surrounds bundle of cells called a fascicle • Endomysium • thin areolar tissue around each cell • allows room for capillaries and nerve fibers

17. First, Let’s Review Muscle Anatomy

19. Location of Fascia • Deep fascia • found between adjacent muscles • Superficial fascia (hypodermis) • adipose between skin and muscles Superficial Fascia Deep Fascia

20. Muscle Attachments • Direct (fleshy) attachment to bone • epimysium is continuous with periosteum • intercostal muscles • Indirect attachment to bone • epimysium continues as tendon or aponeurosis that merges into periosteum as perforating fibers • biceps brachii or abdominal muscle • Attachment to dermis • Stress will tear the tendon before pulling the tendon loose from either muscle or bone

21. Parts of a Skeletal Muscle • Origin • attachment to stationary end of muscle • Belly • thicker, middle region of muscle • Insertion • attachment to mobile end of muscle

22. Anterior Muscles Acting on the Hip Origin and Insertion: An Example • Iliopsoas muscle • crosses anterior surface of hip joint and inserts on femur • iliacus portion arises from iliac fossa • psoas portion arises from lumbar vertebrae • major hip flexor Iliopsoas

23. Muscle : Levetar Scapulae • Origin-Transverse Process of the cervical vertebrae • Insersion-Medial Angle of the Scapula • Action- Elevates Scapula

24. Look For Medial Angle • This is the left Scapula

26. Skeletal Muscle Shapes • Fusiform muscles • thick in middle and tapered at ends • biceps brachii m. • Parallel muscles have parallel fascicles • rectus abdominis m. • Convergent muscle • broad at origin and tapering to a narrower insertion • Pennate muscles • fascicles insert obliquely on a tendon • unipennate, bipennate or multipennate • palmar interosseus, rectus femoris and deltoid • Circular muscles • ring around body opening • orbicularis oculi

27. Skeletal Muscle Shapes

28. Muscle Actions during Elbow Flexion • Prime mover (agonist) = brachialis • Synergist = biceps brachii • Antagonist = triceps brachii • Fixator = muscle that holds scapula firmly in place • rhomboideus m.

29. Intrinsic and Extrinsic Muscles • Intrinsic muscles are contained within a region such as the hand. • Extrinsic muscles move the fingers but are found outside the region. ( See next slide)

30. These are RELATIVE terms • Intrinsic and Extrinsic Muscles • Intrinsic Muscles- The origin and insertion are both in same region. i.e. hand. • Extrinsic Muscles- The insertion muscle (one that moves) may have its origin in a remote place, that is a place further off….another region. Ex. Some movements of fingers are produced by extrinsic ( origins) in forearm whose long tendons reach the phalanges. Other fingers that are intrinsic rely on origin muscle of metacarpals muscles, muscles right there.

31. Coordinated Muscle Actions

32. Categories of Muscle Action: • The movement produced by a muscle is called an ACTION • There are 4 categories of muscle action. • To show you these 4 categories let’s look at flexion of the elbow.

33. Prime mover or agonist • produces most of force • Example: When flexing the elbow the bracialis is the prime mover • You book calls this muscle the agonist.

34. Synergist • aids the prime mover • stabilizes the nearby joint • modifies the direction of movement • The Biceps Brachi is the Synergist in the elbow muscles group

35. Antagonist • opposes the prime mover • preventing excessive movement and injury

36. Fixator • prevents movement of bone • Rhomboids prevent scapula from being pulled laterally when biceps contract.

37. This would be and …Antagonistic Pair • What about the ….. Biceps-Triceps?

38. How Muscles are Named • Nomina Anatomica • system of Latin names developed in 1895 • updated since then • English names for muscles are slight modifications of the Latin names. • Table 10.1 = terms used to name muscles • levator = elevates a body part • profundus = deepest • quadriceps = having 4 heads

39. Skeletal Muscle Characteristics • Most are attached by tendons to bones • Cells are multinucleate • Striated – have visible banding • Voluntary – subject to conscious control • Cells are surrounded and bundled by connective tissue

40. Day One of Muscle Terminology: The Structure of A Muscle Fiber , How Muscles are Named and Origin and Insertion

41. What Do We Mean By Fascia? Fascia is strong connective tissue which performs a number of functions, including enveloping and isolating the muscles of the body, providing structural support and protection. It is a product of mesenchyme, a type of connective tissue which develops in embryos before differentiating into numerous other structures in the body.

44. Muscles are Named by their….

45. SIZE • major, minor, longus (= long), brevis (= short), • latissimus (= broadest), longissimus (= longest)

46. SHAPE • deltoid (= triangular), quadratus (= square), rhomboid • (= diamond-shaped) • teres (= round), gracilis (= slender), rectus (= straight), • lumbrical (= worm-like)

48. Number of Heads or Bellies biceps (= 2 heads), triceps (= 3 heads), quadriceps (= 4 heads) digastric (= 2 bellies), biventer (= 2 bellies),

49. Position • anterior, posterior, interosseus (= between bones) • supraspinatus (= above spine of scapula), • infraspinatus (= below spine), • dorsi (= of the back), abdominis (= of the abdomen) • pectoralis (= of the chest), brachii (= of the arm) • femoris (= of the thigh), oris (= of the mouth)

50. Depth • superficialis (= superficial), profundus (= deep), • externus (or externi), internus (or interni)