Untitled Quiz

Introduction to Human Anatomy

• The study of human anatomy covers the structures of the body.
• The objectives for this lecture include identifying parts of the skeletal system, listing cartilage types, describing bone functions, classifying bones by shape and development, and describing bone growth.

Cartilage and Bones

• Skeletal structure is composed of cartilage and bones.
• Cartilage is a semi-rigid connective tissue found in areas requiring flexibility, such as at rib attachments to the sternum and articular surfaces of synovial joints.
• Articular cartilage provides smooth surfaces for gliding.
• Cartilage is avascular; oxygen and nutrients diffuse into cartilage cells.

Types of Cartilage

• Hyaline: translucent, has very fine collagen fibers, for example, the costal cartilage and the auricle.
• Elastic: yellow, rich in elastic fibers, for example, the epiglottis and the auricle.
• Fibrocartilage: white, high collagen content, for example, the intervertebral discs.

Bone

• Bone is the hardest connective tissue in the body.
• Bone continually remodels throughout life.
• Functions: support, protection, assistance with movement, storage for minerals, and blood cell production.

The Bony Skeleton

• The bony skeleton has two parts:
  • Axial Skeleton (80 bones): skull, facial bones, associated bones, hyoid, sternum, thoracic cage, ribs, and vertebral column.
  • Appendicular Skeleton (126 bones): pectoral girdle, arms, pelvic girdle, and legs.

Morphological Classification of Bone

• Bones are classified by shape:
  • Long bones: tubular, examples: humerus, femur.
  • Short bones: cuboid, examples: carpals, tarsals.
  • Flat bones: usually serve protective functions, examples: cranial bones, sternum.
  • Irregular bones: have various shapes, examples: vertebrae.
  • Sesamoid bones: develop in tendons, embedded in tendons near joints, and have a varied appearance, examples: patella.

Structure of Long Bone

• Long bone structure includes:
  • Epiphysis
  • Diaphysis
  • Metaphysis
  • Articular cartilage
  • Medullary cavity/marrow cavity
  • Periosteum
  • Compact bone
  • Spongy bone

Modifications of Bones

• The clavicle is a modified long bone, lacking a medullary cavity.

Types of Bone Growth

• Cartilage Growth: Growth of cartilage occurs first; this is followed by replacement with bone.

• Growth in Length: Occurs at the epiphyseal plate and involves replacement of cartilage with bone.

• Epiphyseal Plate: A layer of cartilage between the epiphysis and diaphysis, found in growing long bones. This plate is responsible for bone growth in length.

Parts of a Growing Long Bone

• Epiphyses: The proximal (top) and distal (bottom) ends of a long bone.
• Diaphysis: The shaft, or long cylindrical part of a long bone.
• Metaphysis: The region connecting the diaphysis and epiphyses. Active in bone growth.
• Periosteum: A tough connective tissue sheath covering the bone surface, except parts covered by articular cartilage. Helps provide nutrients and supports growth and repair.

Function of Periosteum

• Enable bone growth in thickness.
• Protect the bone.
• Assist in fracture repair.
• Help nourish bone tissue.
• Serve as an attachment site for ligaments and tendons.

Blood Supply of Long Bone

• Periosteal Arteries: Supply blood to the outer surface of the bone.
• Nutrient Artery: Enters through the nutrient foramen, a small hole in the diaphysis.
• Metaphyseal Arteries: Supply nutrients to the metaphysis.
• Epiphyseal Arteries: Supply the epiphysis with nutrients.

Direction of Nutrient Foramina

• Arteries in long bones, especially in the diaphysis run in general from the elbow to the knee, from top to bottom in the body.

Bone Formation

• Bone formation begins in the 5th week of fetal life.
• Two types of centers appear for ossification:
• Primary
• Secondary

Developmental Classification of Bone

• Intramembranous Bones: Develop from mesenchymal membranes (e.g., bones of the face, skull).
• Endochondral Bones: Develop from cartilage models (e.g., long bones).

Growth of Long Bone

• Growth in Length: Occurs at the epiphyseal plate, where cartilage is produced and replaced by bone.
• After full height is achieved, the epiphyseal plate transforms into an epiphyseal line.
• Growth in Thickness (Appositional Growth): Occurs through subperiosteal deposition of bone tissue by osteoblasts.
• Concurrently, during this process, old bone is removed by osteoclasts.

Diagrams

• Diagrams illustrated growing long bone sections, cartilage and bone types, bone structures, and blood supply pathways.

Short Essay Topics

• Draw a labeled diagram of parts of a growing long bone.
• Classify bones according to shape.
• List types of bones according to development.
• Justify that the epiphysis is the area for active bone growth.