2. Muscular System – SPO #1
Using specimens, models, and/or diagrams, describe and identify the following components of skeletal muscle:
Muscle belly
Epimysium
Perimysium
Fascicle
Endomysium
Muscle Fiber/cell
Tendon

3. Skeletal Muscle Organization & Structure
Skeletal muscle is a bundle of skeletal muscle fibers wrapped in connective tissue layers:
Epimysium
Dense layer of collagen fibers surrounding entire muscle
Perimysium
Fibrous layer dividing skeletal muscle into bundles of fibers called muscle fascicles
Endomysium
Delicate connective tissue surrounding individual muscle fibers/cells

4. Organization of skeletal muscle

5. Organization of skeletal muscle

6. Skeletal Muscle Fiber Structure
Contain hundreds of nuclei
Filled with cylindrical structures called myofibrils:
Packed with myofilaments:
Thin filaments composed mostly of actin
Thick filaments composed primarily of myosin
Banded appearance of myofibrils gives entire fiber a striated look

7. Striations of skeletal muscle

8. Structure of a skeletal muscle fiber
Nuclei
Myofibrils
Sarcoplasm
Mitochondria
Sarcolemma
Skeletal muscle fiber
Myofibril
Sarcoplasmic reticulum
Thick filament
Thin filament
A skeletal muscle contains skeletal muscle tissue,connective tissues, blood vessels, and nerves

9. Attachment of Skeletal Muscle - Tendons
Collagen fibers of connective tissue layers in skeletal muscle extend beyond muscle at end
Bundle of fibers is tendon
Tendon attaches muscle to bone
Sheet of fibers is aponeurosis
Aponeurosis attaches muscle to broader area
Collagen fibers extend into bone matrix

10. Muscle fibers are attached to tendons
Epimysium
Myofibrils
Endomysium
The sliding filament theory explains the physical changes that occur during a contraction
Muscle fiber
Tendon
Perimysium

11. Tension Transmitted to Bone
Myofilaments attached to end of muscle fiber
Muscle fibers attached to tendons attached to bone
Sarcomere contraction reflected out to entire skeletal muscle
Result is movement of bone

12. Skeletal Muscle and Tendon

13. Muscular System – SPO #2
Define the following terms and use them appropriately as they apply to the parts of muscles and the roles that muscles play during a body movement:
Origin
Insertion
Prime mover/Agonist
Antagonist
Synergist
Fixator

14. Skeletal Muscle Functional Terms
Origin:
Where fixed end of skeletal muscle attaches
Insertion:
Where movable end of skeletal muscle attaches
Action:
Specific movement of a skeletal muscle

15. Origin and insertion of skeletal muscles
Origins of biceps
brachii muscle
Action
Insertion of biceps
The names of muscles provide clues to their appearance and/or function

16. Functional Description of Skeletal Muscles
Prime mover or Agonist
Responsible for producing particular movement
Example: biceps brachii in bending elbow
Antagonist:
Opposes action of agonist
Example: triceps brachii in bending elbow
Synergist:
Helps agonist work efficiently by providing additional pull or stability
Example: brachioradialis in bending elbow
Fixator:
Acts to stabilize the origin of the agonist (and the joint it moves over) in order to help the agonist function more effectively
Example: trapezius and rhomboids during flexion of biceps brachii

17. Skeletal muscles may be described by their functions
Agonist, or prime mover,
in bending the elbow
Synergist helps the agonist
and stabilizes the elbow joint
Insertion of
brachioradialis
muscle
Antagonist in
bending the elbow
Origin of
The names of muscles provide clues to their appearance and/or function

18. Biceps brachii

19. During Flexion of Biceps brachii – Trapezius & Rhomboid major act as FIXATORS

20. Muscular System – SPO #3 Describe the following muscle actions:
- Flexion - Extension - Abduction
- Adduction - Rotation - Circumduction
- Pronation - Supination - Inversion
- Eversion - Dorsiflexion - Plantar flexion
- Protraction - Retraction - Hyperextension
- Elevation - Depression
* Refer to APR video for additional examples

21. Specific Flexion Terms
Lateral flexion:
When vertebral column bends to side
Dorsiflexion:
Flexion at ankle joint involving elevation of sole of foot (toes pointing upwards)
Plantar flexion:
Extension at ankle joint (toes pointing downward)

22. Lateral flexion of the head
Broad descriptive terms are used to describe movements with reference to the anatomical position

23. Dorsiflexion and plantar flexion
flexion (ankle
extension)
Dorsiflexion
(ankle flexion)
Broad descriptive terms are used to describe movements with reference to the anatomical position

24. Abduction and Adduction
Refers to movement of appendicular skeleton:
Abduction:
Movement away from longitudinal axis
Spreading fingers or toes (moving away from midline)
Adduction
Movement toward longitudinal axis
Bringing fingers or toes together (moving toward midline)

25. Abuction and adduction
Abduction
Broad descriptive terms are used to describe movements with reference to the anatomical position

26. Circumduction
Tracing large circle with hand while keeping arm straight
Movement occurring at shoulder called circumduction

27. Circumduction
Broad descriptive terms are used to describe movements with reference to the anatomical position

28. Rotation Rotation can be of trunk or limbs:
Trunk directional terms with reference to anatomical position
Left rotation (looking to left)
Right rotation (looking to right)
Limbs
Medial rotation or internal or inward rotation
Anterior surface of limb turned toward trunk
Lateral rotation or external or outward rotation
Opposite movement

29. Rotational movements in the body
Right
rotation
Left
Lateral
(external)
Medial
(internal)
Terms of more limited application describe rotational movements and special movements

30. Movement at Proximal Radio-Ulnar Joint
Rotation of radial head causing rolling of distal epiphysis of radius across anterior surface of ulna:
Pronation
Turning wrist and hand from palm facing front to palm facing back
Supination
Turning wrist and hand from palm facing back to palm facing front

31. Supination and pronation of the arm
Terms of more limited application describe rotational movements and special movements

32. Special Movements Opposition:
Movement of thumb toward palm or pads of other fingers
Inversion and eversion involve twisting motion of foot:
Inversion turning sole inward; eversion turning sole outward

33. Special Movements Protraction and retraction:
Protraction moving body part anteriorly in horizontal plane
Retraction moving body part posteriorly in horizontal plane
Depression and elevation:
Depression moving in inferior direction; elevation moving in superior direction

34. Special movements Opposition Retraction Protraction Eversion Inversion
Terms of more limited application describe rotational movements and special movements
Depression
Elevation

35. Muscular System – SPO #4
Identify the following reasons for naming muscles and site at least one example for each.
Location
Shape
Size of muscle
Direction of muscle fiber
Number of heads
Location of origin and/or insertion
Action

36. The names of muscles provide clues to their appearance and/or function

37. Naming Muscles Skeletal muscles named according to:
Region of body (femoris = thigh)
Position (posterior = back)
Nature of origin (biceps = two heads)
Shape (deltoid = triangle)
Size (maximus = largest)
Action (flexor = bending movement)

38. Muscular System – SPO #5
Using microscope images, models, and/or illustrations, identify and describe the structure of the following types of muscle tissue and the listed components:
Smooth
Cardiac
Skeletal
Striations
Intercalated disc

39. Muscle Tissue One of the four primary tissue types
Specialized for contraction
Three types:
Skeletal muscle tissue
Cardiac muscle tissue
Smooth muscle tissue

40. Types of muscle tissue Skeletal Muscle Tissue Cardiac Muscle Tissue
Smooth Muscle Tissue
Functional Anatomy of Skeletal Muscle Tissue

41. What Type of Muscle Tissue Is It?

42. What Type of Muscle Tissue Is It?

43. What Type of Muscle Tissue Is It?

44. What Type of Muscle Tissue Is It?

45. Muscle Tissue Types Skeletal muscle: Cardiac muscle: Smooth muscle:
Moves the body by pulling on bones of skeleton
Cardiac muscle:
Found only in the heart
Propels blood
Smooth muscle:
Moves fluid and solids along digestive tract
Regulates diameter of small arteries