SPECIALIZED CONNECTED TISSUE:BONE
Clara CorpuzEmsi Cipriano
Jacob Dela Cruz
BONE TISSUE Bone Matrix: consists of cells, fibers
and ECM made up of type 1 collagen Highly vascular + Mineral deposition: Bone →
Calcified Bear more wt Withstand stress Provide attachment sites for
muscles and organs Hematopoiesis Storage of Ca+2 and phosphate
BONE MATRIX Bone Matrix: consists of cells, fibers
and ECM made up of type 1 collagen Organic components: sulfated
glycosalmiglycans and hyaluronic acid → larger proteoglycan aggregrates Mineralization: Glycoproteins osteocalcin and
osteopontin bind to calcium Sialoprotein binds osteoblasts to ecm through integrins
of plasma membrane Inorganic components:
Calcium + phosphate = hydroxyapatite crystals + collagen fibers = bone hardness durability strength
BONE CELLSOsteoprogenitor cells:
undifferentiated, pleuropotential stem cells
Osteoblasts: @ surface of the bone that synthesize, secrete bony matrix; active
Osteocytes: mature form of osteoblasts; maintain the structural integrity of the matrix
Osteoclasts: resorb bone during remodeling
PROCESS OF BONE FORMATION
Endochondrial OssificationIntramembranous Ossification
Endochondral OssificationHyaline Cartilage → Interstital and
Appositional Growth → Chondrocytes divide and enlarge → Cartilage Calcify → diffusion of nutrients ↓ chondrocytes die fragmented → calcified matrix → Periosteum → osteoprogenitor cells (arise from endosteum) and bv invades → Osteoblasts
Mesenchyme + Osteoblasts + Bv = Ossification center
Long bones: primary ossification center in diaphysis → secondary in epiphysis → Osteoid Matrix → bone (x epiphyseal plate region)
INTRAMEMBRANOUS OSSIFICATIONNo cartilageforms the mandible, clavicles,
and flat bones of the bodyMesenchyme → Osteoblasts →
osteoid → calcified → osteocytes w/ lacunae
Two Kinds of Bone
Compact bone
Spongy Bone
Spongy BoneAlso called cancellous or
trabecular boneNo formal osteonsTrabeculaeForms most of the structure of
short, flat, and irregular bones, and the epiphyses of long bones.
Spongy bone (Trabeculae)Latticework of thin plates of bone
oriented along lines of stressContains red bone marrow
(hemopoiesis)Found in ends of long bones and
inside flat bones such as the hipbones, sternum, sides of skull, and ribs.
Red bone marrow in spongy bone
Slide Observed under LPO
Two Kinds of Bone
• Compact Bone
• Spongy Bone
Histology of Bone Tissue
Compact Bone• The structural unit of compact bone
is the osteon or Haversian system.• Each osteon is an elongated cylinder
running parallel to the long axis of the bone.
• It actually contains canals and passageways that provide access for nerves, blood vessels, and lymphatic ducts.
• Each columns is made up of concentric rings or lamellae along the calcified matrix.
Concentric layers or rings along the calcified matrix.
Tiny cavities inside the lamellae. This is the space where the osteocyte are found.
It is the central canal that is surrounded by concentric lamellae.
Tiny hair-like channels that are branching.
Compact Bone
• Connects two Haversian canals.
• Canals lie at right angles to long axis of bone.
• Connect the vascular supply of the periosteum to those of the central canal and medullary cavity.
Volkmann’s canal
Histology of Bone Tissue
Canaliculi
Haversian canal
Circumferencial lamellae
Osteocyte surrounded by lacuna
Interstitial lamellae
Haversian system/Osteon
OIODecalcifiedhuman bone
REFERENCESDifiores’ Atlas of Histology 11th
Ed.http://www.freezingblue.com/
iphone/flashcards/printPreview.cgi?cardsetID=266224
http://www.wisegeekhealth.com/what-is-spongy-bone.htm
http://www.gla.ac.uk/t4/~fbls/files/fab/tutorial/generic/bone2.html