Bones and Bone Structure

Flashcards about Bones and Bone Structure.

Skeletal System

Bones of the skeleton, cartilages, ligaments, and other connective tissue.

Primary Functions of Skeletal System

Support, storage of minerals and lipids, blood cell production, protection, and leverage.

Bones classified by their shape

Sutural, irregular, short, flat, long, and sesamoid.

Foramen

Natural opening in the body.

Diaphysis

Shaft, longest part of the long bone, wall of compact bone, contains medullary cavity (marrow cavity).

Epiphysis

Wide part at each end of long bone, mostly spongy bone (Trabecular bone).

Metaphysis

Between epiphysis and diaphysis, where they meet.

Dipole

Layer of spongy bone within the cranium filled with trabeculae.

Types of specialized bone cells

Osteocytes, osteoblasts, osteoclasts, and osteogenic cells (aka osteoprogenitor cells).

Bone Tissue

Dense, supportive connective tissue (spongy and compact bone), contains specialized cells, solid extracellular matrix with collagen fibers.

Organic matrix (osteoid)

Mainly collagen fibers, part of bone tissue.

Inorganic matrix

Mainly hydroxyapatite, gives bones their hardness, part of bone tissue.

Hydroxyapatite

Ca10(PO4)6(OH)2, gives bone hardness due to deposits of calcium salts.

Osteocytes

Mature bone cells, within lacunae organized around blood vessels.

Lacunae

Small openings with osteocytes inside.

Osteon

Basic functional unit of compact bone.

Canaliculi

Narrow passageways that allow for exchange of nutrients and gases.

Lamellae

Layers within lamellae.

Osteogenic cells (aka osteoprogenitor cells)

Stem cells of bone tissue that become osteoblasts.

Osteoblasts

Build bone tissue.

Osteocytes

Mature bone cells.

Osteoclasts

Break/dissolve bone tissue.

Concentric lamellae

Surround central canal, type of lamellae.

Circumferential lamellae

At outer and inner bone surfaces, type of lamellae.

Periosteum

Covers outer surfaces of bones, consists of outer fibrous and inner cellular layers.

Bone Matrix

Major component of compact bone, interacts with calcium hydroxide to form crystals of hydroxyapatite.

Spongy Bone

Open network of trabeculae, lacks osteons, gets blood supply by diffusion.

Red bone marrow

Fills spaces between trabeculae in spongy bone, forms blood cells (WBC, RBC).

Yellow bone marrow

Stores fat (aka adipocytes), found in other sites of spongy bone.

Periosteum

Membrane that covers outside bones (except within joint cavities), isolates bone, participates in growth and repair.

Endosteum

Incomplete cellular layer that lines medullary cavity (inside), contains osteogenic cells, lines medullary cavity of long bones.

Ossification (osteogenesis)

Bone formation.

Endochondral ossification

How most of our bones form. (bone grows in length)

Intramembranous ossification

How our flat bones form (skull, face, and clavicle). (bone grows in width)

Calcification

Deposition of calcium salts, makes bones harder and stronger, occurs during ossification.

Interstitial growth

Growth in length, part of Endochondral ossification.

Appositional growth

Growth in width, part of Endochondral ossification.

Epiphyseal closure

Moment when you stop growing in height, epiphyseal plate becomes epiphyseal line.

Intramembranous ossification

Produces dermal bones such as mandible (lower jaw) and clavicles (collarbones).

Mesenchymal cells

Connective tissue in adults.

Cholecalciferol

Becomes calcitriol and increases calcium levels in our body.

Calcitonin

Decreases calcium levels, the opposite (antagonistic) effect to calcitriol.

Osteopenia

Losing your osteocytes (mature bone cells), inadequate ossification (due to aging).

Minerals

Calcium and phosphorus are required in the diet + calcium = hydroxyapatite ( gives bones its hardness).

Magnesium

Required for bone mineral density, helps in converting vitamin D to its active form (D3 → cholecalciferol).

Iron

Used for blood because of hemoglobin → transports oxygen and carbon dioxide.

Vitamin D3

Fat soluble, only vitamin we can make.

Open Fracture

Pierces the skin.

Close Fracture

Does not pierce the skin.

Greenstick

Common in children,type of fracture.

Osteoporosis

Severe loss of bone mass, bones become brittle (prone to fracture).