Anatomy and Physiology: Skeletal System and Bone Structure

Comprehensive vocabulary flashcards covering skeletal system organization, bone classifications, bone histology, cellular components, and osteogenesis.

Diffusion

The movement of molecules from a region of high concentration to a region of low concentration until there is equal distribution or equilibrium.

Red Bone Marrow

The specialized bone marrow tissue in the skeletal system where blood cells are produced.

Yellow Bone Marrow

Bone marrow characterized by the presence of adipose tissue (fat cells) that stores fat and can serve as an energy source.

Erythrocytes

Biconcave, anucleated red blood cells that transport blood gases ($O_2$ and $CO_2$) and constitute greater than $99.9\%$ of all blood cells.

Leukocytes

White blood cells that function in body defense and fighting infections, categorized into granular and agranular forms.

Granular Leukocytes

A classification of white blood cells containing visible granules in their cytoplasm; includes neutrophils, basophils, and eosinophils.

Agranular Leukocytes

A classification of white blood cells containing little to no granules in their cytoplasm; includes monocytes and lymphocytes.

Thrombocytes

Blood platelets that function in blood clotting and, alongside white blood cells, account for less than $0.1\%$ of blood cells.

Heparin

An anticoagulant molecule, often referred to as a blood thinner, that acts to prevent blood from clotting.

Hematopoiesis

The physiological process of blood cell production that occurs in the red bone marrow.

Femur

The longest and largest long bone in the human body, situated in the thigh region.

Carpal Bones

A collection of $8$ short bones that make up the human wrist.

Tarsal Bones

A collection of $7$ short bones that compose the ankle region.

Cervical Vertebrae

A series of $7$ irregular bones ($C_1$ through $C_7$) located posteriorly in the neck region.

Thoracic Vertebrae

A series of $12$ irregular vertebrae ($T_1$ through $T_{12}$) positioned in the chest (thorax) region.

Lumbar Vertebrae

The $5$ large, irregular vertebrae located in the lower back or abdominal region.

Floating Ribs

Rib pairs $11$ and $12$, which attach posteriorly to the vertebrae but lack anterior attachment to cartilage or the sternum.

Cartilage

A semi-rigid connective tissue located in areas of skeletal movement that provides flexibility and smooth articulating surfaces.

Orthopedist

A physician specializing in diagnosing and treating disorders and injuries associated with the musculoskeletal system.

Patella

The kneecap; a universal example of a sesamoid bone located within joints of the knee.

Foramen

A rounded hole or opening through a bone that serves as a passageway for nerves and blood vessels.

Canaliculi

Narrow bone passageways that facilitate the exchange of nutrients, waste, and metabolic gases between cells.

Trochanter

A large, rough bone projection found on the femur that serves as an attachment site for muscles, tendons, and ligaments.

Diaphysis

The central tubular shaft of a long bone, composed primarily of compact bone and housing the medullary cavity.

Epiphysis

The expanded superior and inferior ends of a long bone, composed predominantly of spongy (trabecular) bone.

Metaphysis

The narrow transitional zone of a long bone where the diaphysis meets the epiphysis.

Medullary Cavity

The internal central space within the shaft (diaphysis) of a long bone, also referred to as the marrow cavity.

Diploë

The internal layer of spongy bone situated between the compact bone layers of the cranium.

Periosteum

A membrane covering the outer surface of bones (except at joints) consisting of an outer fibrous layer and an inner cellular layer.

Osteogenic Cells

Mesenchymal stem cells that undergo cell division and differentiate into osteoblasts.

Osteoblasts

Immature bone cells responsible for synthesizing and secreting the organic components of the bone matrix.

Osteocytes

Mature, non-dividing bone cells located within lacunae that maintain the protein and mineral content of the matrix and assist in bone repair.

Osteoclasts

Large, multinucleated cells that secrete acids and enzymes to dissolve bone matrix during the process of bone resorption.

Osteoid

The unmineralized organic bone matrix produced by osteoblasts that has not yet undergone calcification.

Osteon

The basic structural and functional unit of mature compact bone, absent in spongy bone.

Lamellae

Layers of matrix within compact bone organized into concentric, interstitial, and circumferential arrangements.

Osteogenesis

The process of bone formation, synonymous with ossification, which begins during the $6^{\text{th}}$ or $7^{\text{th}}$ week of embryonic development.

Endochondral Ossification

An osteogenic pathway through which the long bones (such as the humerus and femur) and the base of the skull are formed.