Anatomy and Physiology (Tortora) Chapter 6

Osteogenic cells

.undergo cell division and develop into osteoblasts

Calcium

99% stored in bone

Calcitriol

Active form of vitamin D. Stimulated by the parathyroid hormone

Yellow bone marrow

Adipose tissue. Stores fat. Found in the medullary cavity. Contain small blood vessels that provide nutrients to osteocytes

Mesenchyme

An embryonic connective tissue that develops into connective and skeletal tissues, including blood and lymph. Irregularly shaped cells embedded in semifluid ground substance

Fracture

Any break in the bone

Circumferential lamellae

Arranged around the entire inner and outer circumference of the shaft of a long bone. They develop during initial bone formation

Hemopoiesis

Blood cell production, which occurs in red bone marrow after birth

Osteoblasts

Bone building cells, synthesize and secrete collagen fibers and other components needed for bone formation, initiate calcification. Become trapped in their secretions and become osteocytes

Osseus tissue

Bone tissue

Resorption

Breakdown of bone extracellular matrix

Haversian canal

Central canal of an osteon (also called osteonic cannal)

Concentric lamellae

Circular plates of mineralized extracelluar matrix, increasing in diameter, and surrounding a small network of blood vessels and nerves

Calcification

Deposition of mineral salts, primarily hydroxyapatite, in a framework formed by collagen fibers in which the tissue hardens. Also called mineralization

Epiphysis

End of a long bone, usually larger in diameter than the shaft

Ossification

Formation of bone. Also called osteogenesis

Neighboring osteocytes communicate via this

Gap junctions

Extracellular matrix

Ground substance and fibers between cells of the connective tissue

Appositional growth

Growth due to surface deposition of material, as in growth in diameter of cartilage and bone

Interstitial growth

Growth from within, as in the growth of cartilage

Fibrocartilaginous callus

Happens in the reparative phase. A mass of repair tissue consisting of collagen fibers and cartilage that bridges the broken ends of the bone

Bony callus

Happens in the reparative phase. Fibrocartilage is converted to spongy bone and it gets a spiffy new name (cause we need another name to learn)

Red bone marrow

Highly vascularized connective tissue located in microscopic spaces between trabeculae of spongy bone tissue. Have small blood vessels that provide nutrients to osteocytes

Osteoclasts

Huge cells concentrated in the endosteum. Break down of bone extracellular matrix (called resorption). Have ruffled border. Help regulate blood calcium level

Articular cartilage

Hyaline cartilage attached to articular bone surfaces

Epiphyseal plate

Hyaline cartilage in the metaphysis of a long bone. Site of LENGTHWISE growth of long bones. Also known as the growth plate

Secondary ossification center

In the epiphysis in long bones. Appears after primary ossification center. Spongy bone remains in the interior, exterior is similar to primary ossification center.

Volkmann's canal

Interosteonic canal. Perforating canal. Go transverse through the osteon. Vessels and nerves go through them from the periosteum to the central canal. Also connects with blood vessels and nerves of the medullary cavity

Bone formation

Intramembranous ossification, endochondral ossification

Trabeculae

Irregular latticework of thin plates of spongy bone tissue.

Zone of hypertrophic cartilage

Large, maturing chondrocytes arranged in columns

Zone of resting cartilage

Layer nearest the epiphysis. Consists of small, scattered chondrocytes. Cells anchor epiphyseal plate to the epiphysis of bone

Lacunae

Located between the concentric lamallea. Hold one or two osteocytes

Cortical/ compact bone

Made of osteons

Collagen

Main structural protein found in skin. Big in bones, too- lose it and bones become brittle and lose their flexibility.

Fracture hematoma

Mass of blood (usually clotted) that forms around the site of a bone fracture

Periosteum

Membrane that covers bone and consists of connective tissue, osteogenic cells, and osteoblasts. Essential for bone growth, repair, and nutrition

Phosphorus

Needed for bone growth. Works with Ca to form bone

Bone remodeling

Ongoing replacement of old bone tissue by new bone tissue

Zone of calcified cartilage

Only a few cells thick. Mosly has dead chondrocytes. Calcified extracellular matrix. Becomes the "new diaphysis" that is firmly cemented to the rest of the diaphysis of the bone

Parafollicular cell

Produces calcitonin, which helps regulate the levels of calcium and phosphate in the blood by inhibiting bone resorption and by accelerating the uptake of calcium and phosphates into the bone matrix

Metaphysis

Region of long bone between diaphysis and epiphysis that contains the epiphysisial plate in a growing bone

Primary ossification center

Region where bone tissue will replace most of the cartilage- first area of bone to start ossifiying

Epiphyseal line

Remnant of the epiphyseal plate in the metaphysis of the long bone

Bone resorption

Removal of minerals and collagen fibers from bone by osteoclasts

Osteons

Repeating structural unit of compact bone

Endochondral ossification

Replacement of cartilage by bone

Tensile strength

Resistance of material to breaking under tension by pulling (as opposed to compression)- think pulling taffy

Parathyroid hormone

Secreted by parathyroid gland. Increases blood calcium level and decreases blood phosphate level

Calcitonin

Secreted by the parafollicular cells of the thyroid gland. Inhibits activity of osteoclasts, speeds up blood calcium uptake by bone, accelerates blood calcium deposition of bones

Diaphysis

Shaft of a long bone. Contains compact bone, a very small amount of spongy bone, the medullary cavity, and yellow bone marrow. Also has the nutrient foramen and arteries and veins. Surrounded by periosteum. Has the endosteum (lining of the medullary cavity)

Zone of proliferating cartilage

Slightly larger chondrocytes stacked like coins. They undergo interstitial growth, divide, and secrete extracellular matrix. Chondrocytes divide to replace those that die at the diaphyseal side of the epiphyseal plate

Medullary or marrow cavity

Space within the diaphysis of a bone that contains yellow bone marrow.

Trabecular bone

Spongy bone, contains trabeculae

Interstitial lamellae

The area between osteons. They contain lacunae with osteocytes and canaliculi

Intramembranous ossification

The method of bone formation in which the bone is formed directly in mesenchyme arranged in sheetlike layers that resemble membranes

Endosteum

c.t that lines medullary cavity

bones thin

due to loss of the mineral calcium.

Canaliculi

tiny channels that connect lacuana allow osteocyte and recieve nutrients

bones brittle

to the loss of collagen