SKELETAL SYSTEM

1. Introduction to the Skeletal
System
The skeletal system supports, protects, and enables movement.
It consists of 206 bones in the adult human body.
Bone marrow produces blood cells and stores minerals.
by Sadakat Bashir

2. Functions of the Skeletal System
Support
Provides framework for muscles
and organs.
Movement
Bones act as levers for muscle-
driven motion.
Protection
Encases vital organs like brain and
lungs.
Hematopoiesis
Red marrow produces blood cells.
Mineral Storage
Reservoir for calcium and phosphorus.

3. Bone Structure: Compact vs. Spongy
Compact Bone
Dense and strong outer layer.
Periosteum
Outer membrane with blood vessels
and nerves.
Spongy Bone
Lightweight inner layer with trabeculae.
Endosteum
Inner membrane lining marrow cavity.
Bone Marrow
Red marrow produces blood; yellow
stores fat.

4. Types of Bones
Long Bones
Longer than wide, e.g., femur.
Short Bones
Cube-shaped, like carpals.
Flat Bones
Thin and curved, e.g., skull bones.
Irregular Bones
Complex shapes such as vertebrae.
Sesamoid Bones
Embedded in tendons, like the patella.

5. Bone Growth and Development
Ossification
Bone formation process.
Osteoblasts
Cells building new bone.
Osteoclasts
Cells breaking down old bone.
Growth Plates
Cartilage zones for bone lengthening.
Remodeling
Lifelong replacement of bone tissue.

6. Joints: Connections Between Bones
Fibrous Joints
Immovable, e.g. skull sutures.
1
Cartilaginous Joints
Slightly movable, like vertebral discs.
2
Synovial Joints
Freely movable, e.g., knee and shoulder.
3
Joint Structure
Includes cartilage, fluid, and ligaments.
4

7. Common Skeletal Disorders
Osteoporosis
Low bone density, high fracture risk.
Arthritis
Joint inflammation causing pain.
Fractures
Bone breaks of various types.
Scoliosis
Spine abnormal curvature.
Rickets/Osteomalacia
Soft bones due to vitamin D deficiency.

8. Maintaining a Healthy Skeletal System
Calcium & Vitamin D
Essential nutrients for bone strength.
Weight-bearing Exercise
Stimulates bone growth and density.
Healthy Diet
Provides essential nutrients for bones.
Regular Check-ups
Detect bone issues early.
Avoid Smoking & Excess Alcohol
Both harm bone health.