Skeletal System Overview

Skeletal System Overview

• The skeletal system comprises all bones in the body, along with connective tissues (tendons, ligaments, and cartilage) that join them.
• Babies have around 300 bones, which fuse to form 206 bones in adults.

Objectives

• After studying this presentation, students should be able to:
  • Describe the function of the skeletal system.
  • Define the axial skeleton.
  • Define the appendicular skeleton.
  • Distinguish different types of bones.
  • Understand the overall shape of the skeleton.

Functions of the Skeletal System

• Protection: Protects vital organs such as the brain (skull), heart and lungs (rib cage), and the spinal cord (vertebrae).
• Support: Provides structural support for the body.
• Movement: Works with the muscular system, enabling movement through muscles attached to bones via tendons. Bones are connected by ligaments. Joints are where bones meet.
• Shape: Gives the body its form.
• Blood Production: Bone marrow produces red blood cells (RBCs)
• Mineral Storage: Stores minerals such as calcium and phosphorus. Excess minerals accumulate in bones and are released when the body needs them.

Bone Composition

• Bones are made of compact and spongy (cancellous) bone.
• Compact bone forms the outer layer that's dense and hard.
• Spongy bone is inside, porous, and full of tiny holes.
• Bone tissue consists of bone cells embedded in a matrix of organic salts (mainly calcium and phosphorus) for strength, and collagenous fibers providing flexibility.

Blood Production

• Blood cells are produced within bone marrow located in some bones.
• Bone marrow produces approximately 206 million RBCs per second to replace those destroyed by the liver.

Mineral Storage

• Bones serve as reservoirs for important minerals like calcium and phosphorus.
• If blood mineral levels are high, excess minerals are stored in bone.
• If blood mineral levels are low, minerals are released from the bones.

Types of Bones

• Long bones: Longer than wide, found in limbs (e.g., femur).
• Short bones: Cube-shaped, found in the wrists and ankles.
• Irregular bones: Varying shapes, located in the spine and face (e.g., vertebrae).
• Flat bones: Thin and flat, protect internal organs or provide muscle attachment points (e.g., skull, ribs).
• Sesamoid bones: Small, embedded within tendons, found in joints (e.g., patella).

Divisions of the Skeleton

• Axial Skeleton: Forms the central axis of the body, supporting and protecting organs of the head, neck, and trunk. Includes the skull, vertebral column, ribs, and sternum.
• Appendicular Skeleton: Includes bones of the upper and lower limbs, along with the girdles (shoulder and pelvic) that connect them to the axial skeleton.

Axial Skeleton Details

• Skull: A bony structure supporting facial features and enclosing the brain (eight cranial bones, fourteen facial bones).
• Vertebral Column: Composed of about 33 irregular bones called vertebrae; divided into five groups (cervical, thoracic, lumbar, sacral, coccyx), based on location within the spine.
• Ribs: Thin, curved bones forming a protective cage around upper-body organs (twelve pairs); categorized as true, false, or floating.
• Sternum: A flat, dagger-shaped bone located in the middle of the chest that anchors the ribs and protects internal organs.

Appendicular Skeleton Details

• Upper Limbs: The arm, forearm, and hand (humerus, radius, ulna, carpal, metacarpal, and phalanges bones).
• Lower Limbs: Thigh, leg, and foot (femur, tibia, fibula, tarsal, metatarsal, and phalanges bones).
• Shoulder Girdle: Two clavicles and two scapulae, attaching upper limbs to the axial skeleton.
• Pelvic Girdle: Two coxal bones, connecting the lower limbs to the axial skeleton.

Skeletal Diseases

• Osteoporosis: A disease characterized by reduction in bone density and quality, leading to fragile bones.
  • Causes: Aging, lack of hormones, genetics, body size, alcohol intake, lack of activity
  • Symptoms: Back pain, loss of height over time, stooped posture, increased risk of bone fractures
  • Treatment: Eating calcium-rich foods, taking vitamin D, exercising, avoiding alcohol and smoking
• Arthritis: Inflammation of the joints.
  • Causes: Reduced cartilage, injury, immune system attack on tissues
  • Symptoms: Pain, limited joint function, stiffness, swelling, redness, tenderness
  • Treatment: Surgeries, home remedies, medications; some forms involve weight reduction.
• Scoliosis: Abnormal spine curvature, varying in severity.
  • Causes: Birth defects, growth spurts, injuries, previous spine surgeries
  • Symptoms: One shoulder higher than the other, uneven hips, rotating spine, back pain, breathing problems
  • Treatment: Bracing, surgical intervention, depending on severity.

This quiz covers the basic components and functions of the skeletal system, including the definitions of the axial and appendicular skeletons. Students will learn about the different types of bones, their roles in protection, support, movement, and shape of the body. Test your knowledge on how the skeletal system contributes to the human body's structure and function.