Skeletal System Bones and Joints-MOD6

PNUR 113 – Module #6: Bones and Joints

Overview

  • Understanding the skeletal system's functions:

    • Framework for the body, supporting and protecting structures

    • Aids in producing body movements

  • Joints represent points where two bones connect, allowing movement (e.g., bending at knees).

Learning Outcomes

  • After completing this module, students will be able to:

    • Describe functions of bones and bone tissue.

    • Identify and explain the locations and functions of red and yellow bone marrow.

    • Discuss bone growth, remodeling, and repair processes.

    • Identify major bones.

    • Describe structure, function, and types of joints (with examples).

    • Explain movements at synovial joints.

    • Differentiate types of arthritis.

    • Discuss maintenance of bone and joint health.

    • Describe age-related changes in the skeleton.

  • Note: These outcomes will inform long answer questions on the exam.

Functions of Bones

  • Framework:

    • Supports body weight against gravity.

  • Protection:

    • Cranium protects the brain.

    • Ribcage protects heart and lungs.

    • Pelvis protects bladder and reproductive organs.

  • Movement:

    • Bones serve as levers, operated by muscle contractions.

  • Storage:

    • Stores mineral salts like calcium and phosphate.

  • Blood Cell Formation:

    • Occurs in red bone marrow.

Skeletal Divisions

  • The adult skeleton consists of 206 bones.

  • Divided into:

    • Axial Skeleton: Forms the head and trunk.

    • Appendicular Skeleton: Includes limbs and girdles.

Bone Shapes

  • Flat Bones: Ribs, cranium, scapula

  • Short Bones: Carpals of wrist, tarsals of ankle, patella

  • Irregular Bones: Vertebrae, facial bones

  • Long Bones: Humerus, femur, and long bones of arms and legs

Bone Marrow Types

  • Red Bone Marrow:

    • Located in spongy bone, generates red and white blood cells.

  • Yellow Bone Marrow:

    • Found in central cavity of long bones, mainly used for fat storage.

Bone Growth and Repair

  • Embryonic skeleton starts as cartilage; can grow in width/length.

  • Ossification:

    • Begins in the second and third month of embryonic life.

    • Cartilage replaced with bone (especially long bones) until puberty when growth plates close.

  • Continuous width growth occurs with weight-bearing exercise.

Cells Involved in Bone Growth

  • Osteoblasts:

    • Build bone by manufacturing matrix and depositing calcium.

  • Osteocytes:

    • Maintain existing bone; do not produce new tissue.

  • Osteoclasts:

    • Resorb bone, critical for remodeling and repair, regulated by hormones.

Calcium Homeostasis

  • Vital for skeletal muscle contractions, nerve function, blood clotting.

  • Vitamin D: Promotes dietary calcium absorption.

  • Calcitonin and Parathyroid hormone: Regulate blood calcium levels;

    • Calcitonin from the thyroid lowers blood calcium.

    • Parathyroid hormone increases blood calcium by resorbing bone.

Skull Anatomy

  • Cranium: Protects the brain—comprised of:

    • Frontal, parietal, sphenoid, temporal, nasal, maxilla, occipital, zygomatic, mandible, vomer, conchae.

    • Bone Functions:

      • Correspond to brain regions for protection.

Vertebral Column

  • Supports trunk/head; protects spinal cord; attachment point for hip bones.

  • Vertebrae: Parts include:

    • Atlas: First cervical vertebra.

    • Different types include cervical (C1-C7), thoracic (T1-T12), lumbar (L1-L5), sacral, and coccygeal vertebrae.

Thorax

  • Ribcage: Comprising sternum and ribs.

    • Supports organs; true ribs (1-7), false ribs (8-12), and floating ribs (11-12).

Appendicular Skeleton

  • Upper Division:

    • Shoulder girdle (clavicle, scapula), arm (humerus), forearm (radius, ulna), wrist (carpals), hand (metacarpals, phalanges).

  • Lower Division:

    • Pelvis (hip girdle), thigh (femur), leg (tibia, fibula), ankle (tarsals), foot (metatarsals, phalanges).

Health and Aging

  • Bones and Arthritis:

    • Osteoporosis leads to bone loss, especially in postmenopausal women.

    • Curvatures of Spine: Kyphosis, lordosis, scoliosis are common spine issues.

Types of Joints

  • Fibrous Joints: Immovable, e.g., skull sutures.

  • Cartilaginous Joints: Slightly movable, e.g., pubic symphysis.

  • Synovial Joints: Freely movable, e.g., shoulder and knee.

    • Movements can include flexion, extension, abduction, adduction, and rotation.

Disorders of Joints

  • Osteoarthritis: Degenerative, primarily in weight-bearing joints.

  • Rheumatoid Arthritis: Autoimmune condition affecting multiple joints, leading to deformation.

    • Difference between OA and RA is crucial to treatment and management strategies.

Final Tips for Study

  • Review bones using provided tables and practice identifying their locations and functions.

  • Understand the role of lifestyle factors in maintaining bone health.

Here are some important terms related to the skeletal system that you should know:

  • Osteoblasts: Cells that build bone by manufacturing matrix and depositing calcium.

  • Osteocytes: Mature bone cells that maintain existing bone tissue.

  • Osteoclasts: Cells that resorb bone, important for remodeling and repair.

  • Red Bone Marrow: Located in spongy bone, responsible for generating red and white blood cells.

  • Yellow Bone Marrow: Found in the central cavity of long bones, primarily for fat storage.

  • Axial Skeleton: The part of the skeleton that forms the head and trunk.

  • Appendicular Skeleton: The part of the skeleton that includes the limbs and girdles.

  • Synovial Joints: Freely movable joints like the shoulder and knee.

  • Osteoporosis: A condition where bones lose density, often seen in postmenopausal women.

  • Arthritis: A disorder affecting joints, with types like Osteoarthritis and Rheumatoid Arthritis.