1.2.1 Compact Bone

What is the endosteum?

Thin vascular membrane of connective tissue that lines the surface of the bony tissue that forms the medullary cavity of long bones.

What is the central canal?

A circular channel running vertically in the center of an haversian system of mature compact bone, containing blood and lymphatic vessels and nerves. AKA haversian canal

What is an osteocyte?

A mature bone cell that maintains the daily activities of bone tissue.

What is the volkmann canal?

A minute horizontal passageway of which blood vessels and nerves from the periosteum penetrate into compact bone. AKA perforating canal

What is spongy bone?

A network of irregularly-shaped sheets and spikes of bone (trabeculae). The trabeculae are only a few cell layers thick. The spaces between the trabeculae contain red or yellow marrow, depending on a person's age.

What is the nutrient artery?

Arteries that are accompanied by one or two veins, sends branches upward and downward to the bone marrow, which spread in the medullary membrane, and adjoining canals. Nutrient arteries are the most apparent blood vessels of the bones.

What is compact bone?

Bone tissue that contains few spaces between osteons; forms the external portion of all bones and the bulk of the diaphysis (shaft) of long bones; is found immediately deep to the periosteum and external to spongy bone.

What is the circumferential lamella?

Calcified extracellular matrix *surrounds the entire bone.*

What is the concentric lamella?

Calcified extracellular matrix that *surrounds the current osteon*

What is the periosteum?

Dense layer of vascular connective tissue enveloping the bones except at the surfaces of the joints.

Interstitial lamella Calcified extracellular matrix found in compact bone from a previous osteon.

Identify

Lacunae Found between lamellae, and consist of a number of *oblong spaces.* In an ordinary microscopic section, they appear as fusiform *opaque spots.* Each lacuna has a branched cell, termed an osteocyte. Lacunae are connected to one another by small canals called canaliculi. A lacuna never contains more than one osteocyte.

Identify

Marrow that is part of the spongy bone.

Identify

Canaliculi Microscopic canals that connect lacunae of compact bone. The radiating processes of the osteocytes project into these canals.

Identify.

Central canal. A circular channel running longitudinally in the center of an osteon (haversian system) of mature compact bone, containing blood and lymphatic vessels and nerves. *Also called a haversian canal.*

Identify.

Osteon. The fundamental functional unit of most compact bone. Osteons are rough cylindrical structures that repeat and are typically several millimeters long and around 0.2mm in diameter. *AKA haversian system* Consist of concentric lamellae arranged around a central canal.

Identify.

What are trabeculae?

Irregular latticework of thin plates of spongy bone tissue. Fibrous cord of connective tissue serve as supporting fiber by forming a septum extending into an organ from its wall or capsule.

What is red marrow?

Marrow that contains hemopoietic cells, which produce RBC

What is yellow marrow?

Marrow that contains stromal cells which produce mostly fat, cartilage, and bone

What is the medullary cavity?

The central cavity of bone shafts where red bone marrow and/or yellow bone marrow is stored. AKA marrow cavity