CH 6 Bones and Bone Structure

Comprehensive vocabulary flashcards covering skeletal system functions, bone classification, surface markings, histology, growth, remodeling, and pathology based on the lecture notes.

Skeletal System Functions

Provides support, stores minerals and lipids (calcium salts/energy in yellow marrow), produces blood cells (RBC/WBC in red marrow), protects soft tissues, and provides leverage for muscle-generated forces.

Femur

Classified as a long bone, it is the largest and heaviest bone in the human body.

Sutural Bones

Also known as Wormian bones, these are flat, oddly shaped bones found between the flat bones of the skull, resembling a jigsaw puzzle.

Irregular Bones

Bones with complex shapes such as those found in the vertebrae and pelvis.

Short Bones

Bones with a boxlike appearance, including the carpal bones (wrists) and tarsal bones (ankles).

Sesamoid Bones

Small, round, and flat bones found near joints of the knees, hands, and feet; the patella is a universal example.

Sulcus

A narrow groove marking the surface of a bone.

Fossa

A shallow depression on the surface of a bone.

Trochanter

A large, rough projection found on the femur where muscles or ligaments attach.

Condyle

A smooth, rounded articular process used for forming joints.

Diaphysis

The extended tubular shaft of a long bone.

Epiphysis

The expanded area at the ends of a long bone, consisting mostly of spongy bone.

Metaphysis

The narrow zone where the diaphysis and epiphysis interconnect.

Diploe

The layer of spongy bone sandwiched between layers of compact bone in the cranium.

Bone Matrix Composition

Consists of $\frac{2}{3}$ calcium phosphate, which provides hardness to withstand compression, and $\frac{1}{3}$ collagen fibers, which provide flexibility and strength against twisting.

Hydroxyapatite

Crystals formed by the combination of calcium phosphate, calcium hydroxide, and calcium carbonate: $(Ca_3(PO_4)_2 + Ca(OH)_2 + CaCO_3 \rightarrow \text{hydroxyapatite})$.

Osteogenic Cells

Mesenchymal stem cells that differentiate into osteoblasts and are crucial for fracture repair; located in the periosteum and endosteum.

Osteoblasts

Cells which produce new bone matrix through the processes of osteogenesis or ossification.

Osteocytes

Mature bone cells that reside in lacunae; they maintain protein and mineral content and can convert back to osteoblasts for bone repair.

Canaliculi

Narrow passageways extending through the matrix that allow osteocytes to communicate and access nutrients from blood vessels.

Osteoclasts

Large multinucleate cells (50+ nuclei) that remove and recycle bone matrix through a process called osteolysis.

Osteon (Haversian System)

The basic functional unit of compact bone, where osteocytes are arranged in concentric layers called lamellae around a central canal.

Perforating Canals

Horizontal canals that supply blood to osteons deeper within the bone.

Trabeculae

The meshwork of supporting bundles of fibers (struts and plates) that forms the matrix of spongy bone.

Periosteum

A membrane with fibrous and cellular layers that covers the superficial layer of compact bone, isolating it from surrounding tissues and providing a route for vessels and nerves.

Endosteum

An incomplete cellular layer lining the medullary cavity and covering the trabeculae, active during bone growth, repair, and remodeling.

Endochondral Ossification

The replacement of a hyaline cartilage model with bone during development.

Appositional Growth

Bone growth in width where layers of circumferential lamellae are added to the outer surface by osteoblasts from the periosteum.

Intramembranous Ossification

The process where bone forms within mesenchymal or fibrous connective tissue, typically producing dermal bones like the mandible and clavicles.

Calcitriol

A hormone produced in the kidneys that increases calcium and phosphate ion absorption in the digestive tract.

Parathyroid Hormone (PTH)

A hormone from the parathyroid glands that stimulates osteoclasts and increases blood calcium ion levels.

Calcitonin

A hormone from the thyroid gland that decreases blood calcium levels by inhibiting osteoclast activity.

Gigantism

A condition caused by the overproduction of growth hormone before puberty.

Acromegaly

A condition where growth hormone levels rise after epiphyseal closure, causing bones to grow thicker, particularly in the face, jaw, and hands.

Marfan Syndrome

A disorder involving excessive cartilage formation at epiphyseal cartilages, resulting in tall height and long, slender limbs.

Osteopenia

Inadequate ossification resulting in thinner, weaker bones as a part of the natural aging process, usually starting between ages 30 and 40.

Osteoporosis

A severe reduction in bone mass that compromises normal function, often accelerated by a decline in estrogen after menopause.

Greenstick Fracture

A fracture where one side of the bone shaft is broken while the other is bent; typically occurs in children.

Colles Fracture

A break in the distal portion of the radius, often resulting from cushioning a fall.

Pott's Fracture

Also called a bimalleolar fracture, it affects both the medial malleolus of the distal tibia and the lateral malleolus of the distal fibula.