2. Contents
Introduction
Structure of bone
Functions of skeleton
Classification
a) Axial
b) Appendicular
The joints
Classification of joints
Disorders of joints
Skeletal muscle
Physiology of muscle contraction
Neuromuscular junction
3. Introduction
Bone tissues makes up about 18% of the total human body weight.
The skeletal system supports and protects the body while giving it shape and form.
Consist of 206 bones.
Composed of:
-Bones
-Cartilage
-Joints
-Ligaments
Osteology
4. Structure of bone
Hardest connective tissue.
Consist of 2 kind of tissue
1. Compact bone: Hard
2. Cancellous bone: Spongy
Microscopic structure of bone
1. Haversian canal
2. Lamellae
3. Lacunae
4. Canaliculi
5. Functions of skeletal
1. Support
2. Boundaries
3. Protection
4. Movement
5. Blood cell production
6. Storehouse
6. Divisions of the Skeletal System
1. Axial skeleton
Skull, Vertebral column, thoracic cage.
2. Appendicular skeleton
Shoulder girdle, pelvic girdle
Upper and lower limbs
7. CLASSIFICATION OF BONE BASED ON SHAPE
• Long Bones
– Greater length than width and are slightly curved for strength
– Femur, tibia, fibula, humerus, ulna, radius, phalanges
• Short bones
– Cube-shaped and are nearly equal in length and width
– Carpal, tarsal
• Flat bones
– Thin and composed of two nearly parallel plates of compact bone tissue enclosing a layer of spongy bone tissue
– Cranial, sternum, ribs, scapulae
• Irregular bones
– Complex shapes and cannot be grouped into any of the previous categories
– Vertebrae, hip bones, some facial bones, calcaneus
• Sesamoid bones
– Protect tendons from excessive wear and tear
– Patellae, foot, hand
8. The Joints
Site at which two or more bones comes together.
Classification:
1. Fibrous joint / Fixed joint
2. Cartilagenous joint
3. Synovial joint
i) Ball and socket joint
ii) Hinge joint
iii) Double hinge joint
iv) Gliding joint
v) Pivot joint
11. Movements of different kinds of joint
Ball & Socket joints – flexion and extension, abduction, adduction, circumduction,
external & internal rotation
Hine joint - flexion and extension only
Double hinge joint - flexion and extension, abduction, adduction, circumduction
Gliding joint – slight movement increasing range of movement in all direction.
Pivot joint – Rotation where they are pivoted
12. Disorders of Joints
Arthritis – Inflammation of joints.
It is of two types:
1. Acute arthritis
- Acute synovitis
- Traumatic synovitis
2. Chronic arthritis
- Tuberculous arthritis
- Rheumatoid arthritis
- Osteoarthritis
- Gout
- Dislocation
- Osteoporosis
14. The Axial skeleton
The axial skeleton consists of :
1. Skull
Cranium: Base and vault
Face: 13 bones form the skeleton of face.
2. Vertebral column
3. Thoracic cage.
16. Vertebral column
Consist of 24 separate movable bones called as Vertebrae.
Divided into 3 groups:
a. Cervical – 7
b. Thoracic – 12
c. Lumbar – 5
Fused bone
Sacrum – 5
Coccyx - 4
17. 1. Cervical vertebrae
They have 2 special features:
A. Transverse process
B. Spinous process
Atlas
First cervical vertebra consist of ring of bone.
Ring is divided into 2 parts.
Anterior – odontoid process.
Posterior – spinal cord.
Axis – Second cervical vertebra
23. Difference between male & female pelvic girdle
Female Male
Bones Lighter & Smaller Heavier & longer
Cavity Shallow and round Deep & funnel shaped
Sacrum More concave Less concave
Pubic arch Bones are movable Bones are immovable
25. Physiology of muscle contraction
SLIDING FILAMENT MECHANISM
The length of skeletal muscle shortens during contraction because the thick and thin filaments slide over one another. The process is
known as the sliding filament mechanism.
The thick filament contains 300 myosin molecules.
It contain two parts: 1. Myosin tail 2. Myosin heads
Myosin tail forms the shaft of the thick filament and heads projects towards the thin filament.
Thin filament contain actin, troponin and tropomyosin.
At the onset of contraction, the sarcoplasmic reticulum release calcium ions into cytosol
There they bind to troponin and cause troponin-tropomyosin complexes to move away from binding site on actin.
Once the binding sites are free, the repeating sequence of events of the contraction cycle occurs that causes the filaments to slide on
each other.
26. Neuromuscular Junction
Connection between large myelinated nerve fibre
and skeletal muscle fibre.
Sarcolemma: membrane through which nerve fibre
passes.
Branches of nerve fibre: Hypolemmal axons.
Axons: Sole feet
Sole feet contain vesicles that contains ACH