1. MOVEMENT

2. MAJOR FUNCTIONS
1. SUPPORT
framework for body
2. MOVEMENT
~point of attachment for skeletal
muscles
~joints

3. 3. PROTECTION
~ soft tissues
(brain, spinal
cord, heart, etc.)

4. 4. STORAGE
~ minerals:
(Ca, P, Na, K )
for use when needed…

5. 5. FORMATION OF BLOOD CELLS
~Hematopoiesis:
red marrow produces blood
cells for circulation

6. TWO MAJOR TYPES OF
BONE TISSUE
• COMPACT BONE
–Give bone hard, durable quality
–Outer layers of bone
–Functions served?
–Composed of osteocytes packed into
lacunae.

7. COMPACT BONE

8. • SPONGY BONE
- Less dense than compact bone
– Contains red marrow:
stem cellsblood cell
components
– Yellow marrow:
fat storage centers

11. Types of Joints
• The type of joints that are particularly important for
physical activity and sport are:
– BALL AND SOCKET JOINT - allows a full range of
movement. E.g. the hip and shoulder joints
– HINGE JOINT - movement in one plane: flexion and
extension.

12. – GLIDING JOINT - these occur in the many small bones
of the hand and feet. They allow a slight sliding motion
forwards and backwards and from side to side.
– PIVOT JOINT - allows rotation. E.g. atlas and axis in the
neck.

13. • TASK:
• the picture shows:
• 1: Shoulder joint -ball and
socket
• 2: Elbow joint - hinge joint
• can you name another
ball and socket and hinge
joint?

15. FOUR MAJOR TYPES OF BONES
1. LONG BONES
2. SHORT BONES
3. FLAT BONES
4. IRREGULAR BONES

16. LONG BONES
• Greater in length than width
• Absorb stress from body weight
• Upper/lower appendages

18. Long bone structure
1. Diaphysis- shaft with compact bone &
medullary cavity
2. Epiphysis- ends, articular cartilage & compact
bone covering cancellous bone
3. Epiphyseal line- between epiphysis &
diaphysis- region of bone growth
(epiphyseal plate)
4. Medullary cavity-
central cavity within diaphysis

19. SHORT BONES
• ~ equal length/width
• Wrists, ankles

22. FLAT BONES
• Thin, flat in structure
• Skull, ribs, sternum

24. IRREGULAR BONES
• Variety of shapes
• Vertebral column / bones of face

27. The Muscular System

28. Muscular System Functions
• MOVEMENT
• Maintain Posture
• Stabilize Joints
• Generate HEAT
– 40% body mass
– 80% body heat
– Endothermy!

29. Muscle Tissue
• Tissue Review:
– Cardiac Cardiovascular System
• Involuntary, Striated
– Smooth  Cardiovascular, Digestive,
Reproductive, etc.
• Involuntary, non-striated
– Skeletal* MUSCULAR SYSTEM
• Voluntary, striated

30. Muscles are…
• Excitable (irritable)
• Contractile
• Extensible
• Elastic
• Myo-, Mys, Sarco- (muscle prefixes)

31. Skeletal Muscle Tissue
• MUSCLE CELL STRUCTURE
– Arrangement: large, long FIBERS
• Fiber = muscle cell
– Two major protein filaments present:
• Actin
• Myosin myofilaments

32. Skeletal Muscle Structure
• Striated
– Due to actin/myosin
• Elongated
– Varied lengths
• Multinucleated

33. Muscle Anatomy

35. • http://www.bmb.psu.edu/courses/bisci004a/
muscle/b4muscle.htm

36. Skeletal Muscle Connections
• Direct connection to Bone
• Indirect connection via TENDON
• ORIGIN: bone that does NOT move when
muscle contracts
• INSERTION: bone that MOVES when muscle
contracts

37. Microscopic Structure of
Muscle Fiber
• Cell membrane = Sarcolemma
• Cytoplasm = Sarcoplasm
• Multiple Mitochondria = High E output
• Fiber is filled with long myofibrils
• Myofibrils filled with filaments arranged in
contractile units called SARCOMERES.
– Myosin (thick filament)
– Actin (thin filament)

38. Sarcoplasmic Reticulum
• Specialized ER connected to cell surface by T-
tubules
• Surrounds each myofibril
• At rest, filled with Ca++ maintained by a
calcium “pump”, uses ATP
• When activated, pores open and release
calcium, initiating contraction

40. Actin (thin) filament
Composition
• Long chains of actin globules in double spiral
arrangement
• Each actin contains binding site for myosin
• Tropomyosin spiral around chain
– blocks active site on actin
• Troponin clustered along spiral
– Binding site for calcium!

41. Actin Filament

42. Myosin (thick) filament
Composition
• Contains 2 tails each with globular heads
• Heads have ATP binding sites and ATPase for
splitting ATP
• Heads attracted to active sites on actin
molecules
• Heads form cross-bridges with actin

43. Myosin Filament

44. Multiple Myosin Filaments

45. Sarcomere structure
• Alternating dark and light bands
• Central H-zone contains MYOSIN only
• Lateral A-bands  contain both
ACTIN and MYOSIN filaments
• End in I-bands contain ACTIN only
(with Z-line in center)
Z LINE TO Z LINE = 1 SARCOMERE

46. SARCOMERE STRUCTURE

47. Sarcomere

49. Nerve supply
to Muscle Fiber
• Each muscle fiber served by a motor neuron
• Motor neuron ends in a pad filled with
vacuoles packed with neurotransmitter
• Pad sits above specialized piece of
sarcolemma called motor end plate

51. Neuron pad + motor end plate =
Neuromuscular
junction
(Space between called synaptic cleft )

53. Sliding Filament Theory of
Muscle Contraction
Sequence of Steps:
1. Neuron releases neurotransmitter, acetylcholine
(ACh) into synaptic cleft
2. ACh diffuses to motor end plate
3. ACh binds to receptor on motor end plate
4. Gated channel protein opens, Na+ rushes into cell
interior, upsets RMP!

55. Generation of
Action Potential
• RMP = -70 Mv
• Sudden influx of Na+ generates
Action Potential
• RMP later restored to normal by
sodium-potassium pump

56. 5. Action potential carried along the
sarcolemma to transverse (“T”) tubules
connected to Sarcoplasmic Reticulum
6. SR membrane becomes permeable to
calcium
7. Sarcoplasm is flooded with calcium ions

58. 8. Ca++ binds to troponin
9. Ca/Troponin pulls tropomyosin out of the
way, unmasks active site on actin molecules
10. Myosin heads attach to actin
11. Heads rotate, pull actin in to H-zone
12. Z lines get closer…

63. 13. Myosin splits ATP to recharge
14. Continues until Action Potential is restored
and Ca++ is pumped back into SR
15.All sarcomeres shorten, shortening muscle
cell

64. 16. Shortening cell pulls on tendons attached to
bones, moving bone at articulation
17. Contraction of opposite muscle required to
fully elongate shortened muscle

65. Reminders:
• Refractory Period
• All or None Effect
• Breakdown of ACh by ACh-esterase

66. Disorders/Conditions of the Muscular
System
• Duchenne’s Muscular Dystrophy
– Sex linked inheritance
– Dystrophin protein deficiency
– Tearing of sarcolemma
– Accumulation of CT/fat
– Muscular ATROPHY

67. Tetanus