Skeletal System

Overview

The skeletal system is a dynamic organ system that provides the framework for the human body, supports movement, and protects vital organs. It consists of bones and cartilages, which are constantly forming and changing throughout life.

• Functions: Support, protection, movement, mineral storage, blood cell formation, and energy storage.

• Components: Bones and cartilages.

• Dynamic Nature: Bone tissue is continually remodeled and repaired.

Functions of Bones

Key Roles of Bone Tissue

Bones serve multiple essential functions in the body, contributing to both structure and physiology.

• Support: Provides a rigid framework for the body and supports soft organs.

• Protection: Shields the brain, spinal cord, and vital organs from injury.

• Movement: Acts as levers for muscle action, enabling locomotion and manipulation of the environment.

• Mineral Storage: Stores minerals such as calcium and phosphorus, which are released into the bloodstream as needed.

• Blood Cell Formation (Hematopoiesis): Occurs in the marrow cavities of certain bones, producing red and white blood cells.

• Triglyceride (Energy) Storage: Fat is stored in bone cavities as an energy reserve.

Skeletal Structure: Cartilages

Characteristics and Functions of Cartilage

Cartilage is a specialized connective tissue that provides flexible support and reduces friction in joints. It is avascular and lacks nerves, making it distinct from other connective tissues.

• Avascular: Cartilage contains no blood vessels or nerves.

• Perichondrium: A dense connective tissue girdle surrounding cartilage; contains blood vessels for nutrient delivery.

• Function: Provides support, flexibility, and resilience in various parts of the body.

Skeletal Structure: Types of Cartilage

Classification of Cartilage

There are three main types of cartilage, each with unique properties and locations in the body.

• Hyaline Cartilage: Most abundant type; provides support, flexibility, and resilience. Found in articular surfaces, costal cartilage, nose, and respiratory tubes.

• Elastic Cartilage: Similar to hyaline but contains elastic fibers, allowing greater flexibility. Found in the external ear and epiglottis.

• Fibrocartilage: Contains thick collagen fibers, providing great tensile strength. Found in intervertebral discs and pubic symphysis.

Skeletal Structure: Cartilage Locations

Distribution of Cartilage in the Human Body

Cartilage is found in specific locations, contributing to the structure and function of the skeletal system.

• External Ear: Elastic cartilage

• Nose: Hyaline cartilage

• Articular Cartilage of Joints: Hyaline cartilage

• Costal Cartilage (Ribs): Hyaline cartilage

• Intervertebral Discs: Fibrocartilage

• Pubic Symphysis: Fibrocartilage

• Epiglottis: Elastic cartilage

• Respiratory Tube Cartilage: Hyaline cartilage (e.g., thyroid, cricoid cartilages)

Skeletal Structure: Bones

Overview of Bone Structure

Bones are rigid organs that form the skeleton and are classified by their shape and location. They provide the main support for the body and serve as attachment points for muscles.

• Axial Skeleton: Includes the skull, vertebral column, and rib cage.

• Appendicular Skeleton: Includes the limbs and girdles (shoulder and pelvic).

• Bone Tissue: Composed of compact and spongy bone, with marrow cavities for hematopoiesis and fat storage.

Summary Table: Bones and Cartilages

Additional info:

• The skeletal system is essential for maintaining homeostasis, enabling movement, and protecting internal organs.

• Bone and cartilage development, remodeling, and repair are ongoing processes influenced by genetics, nutrition, and mechanical stress.