Ch. 5 - Bone Flashcards
Function of bone
Support (Structural framework)
Protection (i.e. Skull, vertebrae, rib-cage)
Movement (Attachment for muscles)
Mineral homeostasis (Ca++ balance)
Blood cell production (RBC and WBC, red bone marrow)
Fat storage (Yellow bone marrow)
Hyaline cartilage (Functions)
Development and growth of bone (bone replaces cartilage model)
Cushioning of joints (Articular cartilage, Costal cartilage)
Protection in respiratory system
Elastic cartilage
Elastic fibers that stretch and recoil Repeated bending (i.e. Ear Epiglottis)
Fibrocartilage
Collagen fibers resist stretching and compression
Location: Intervertebral discs, Meniscus in knee, Pubic symphysis
Long Bone
Epiphysis (Articulating cartilage, spongy bone)
Metaphysis (Epiphyseal line)
Diaphysis (Medullary cavity, Endosteum, Compact bone, Periosteum)
Flat Bone
Consists of spongy bone sandwiched between compact bone
Bone matrix
25% water
25% collagen (adding flexibility)
50% salts (deposited on collagen fibers making bones hard
Bone cells
Osteogenic cells
Osteoblasts
Osteocytes
Osteoclasts
Osteogenic cells
Stem cells (periosteum, endosteum)
Osteoblasts
Produce new bone tissue
Osteocytes
Maintain bone tissue
Osteoclasts
Break down bone matrix
Periosteum
Membrane around the bone
Outer layer: Connective tissue
Inner layer: Osteogenic cells and osteoblasts
Osteon
Basic bone unit with concentric lamellae, osteocytes, and a central canal with blood and lymphatic vessels
Osteocyte
Basic bone cell, in lacuna, with canaliculi to allow nutrients to pass from the central canal to the outer edges of the osteon
Spongy Bone
No central canal, but still concentric lamellae. Made up of trabeculae, and has osteoblasts on the outer edge
Blood Supply
Blood vessels on either side of the epiphyseal line. In the diaphysis, nutrient blood vessels enter through nutrient foramen. In the epiphysis, blood vessels enter through the sides
Bone Growth
Intramembranous ossification
Endochondral ossification
Intramembranous ossification
Flat bones form between two membranes (From the outside in). Mesenchyme becomes osteogenic cells which become osteoblasts… Osteoblasts stay on the outside producing bone matrix inside
Endochondral ossification
A cartilage model of the bone forms (Bone tissue replaces the cartilage)
Center of ossification
Intramembranous ossification
Mesenchyme cells cluster and become osteogenic cells
Osteogenic cells develop into Osteoblasts
Osteoblasts produce bone matrix
Calcification
Intramembranous ossification
Osteoblasts become osteocytes that lie in lacuna Matrix hardens (calcification)
Formation of Spongy bone
Intramembranous ossification
Trabecula grow to form spongy bone
Formation of compact bone
Intramembranous ossification
The periosteum develops on the surface
Osteoblasts put down compact bone tissue
Endochondral ossification
- Mesenchyme cells become chonroblasts
- Hyalin cart. surrounded by perichondrium
- Growth of model bone
2.
- Primary ossification center forms
- Chondrocytes begin calcification
- Bone collar forms (periosteum)
- Growth into and up diaphysis
- Blood vessels grow into model
Spongy bone continues to form
The medullary cavity forms (osteoclasts)
4.
Periosteum forms compact bone
Secondary centers of ossification in epiphysis
5.
Bone spreads through the epiphysis and the diaphysis
6.
Cartilage remains in the bone (Epiphyseal plate, Articulating surfaces)
Bone Growth (Length)
From normal cartilage on the articulating surface, to proliferation area, to hypertrophy area (mature chondrocytes), to the calcification area (bone formation), to the bone
