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.
8. • SPONGY BONE
- Less dense than compact bone
– Contains red marrow:
stem cellsblood cell
components
– Yellow marrow:
fat storage centers
9.
10.
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?
14.
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
17.
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
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
39.
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!
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
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
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
50.
51. Neuron pad + motor end plate =
Neuromuscular
junction
(Space between called synaptic cleft )
52.
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!
54.
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
57.
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…
59.
60.
61.
62.
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
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