Comparative Vertebrate Anatomy - Bones

Vocabulary practice flashcards generated from lecture notes on comparative vertebrate anatomy, bone classifications, skeletal divisions, microscopic structure, and bone pathology.

Hematopoiesis

The process of blood cell formation that occurs within the marrow cavities of bones.

Calcium Hydroxyapatite

The inorganic component of bone that comprises $60\%$ of its dry weight.

Collagen

The primary organic component of bone that provides structural strength.

Axial Skeleton

The division of the skeleton that forms the longitudinal axis of the body, consisting of the skull, vertebral column, ribs, and sternum.

Appendicular Skeleton

The division of the skeleton comprising the bones of the limbs and the girdles that attach them to the axial skeleton.

Ligaments

Fibrous connective tissue structures that connect bone to bone.

Tendons

Fibrous connective tissue structures that attach muscle to bone.

Sutures

Specialized fibrous joints that connect the individual bones of the skull.

Coronal Suture

The skull suture located between the frontal bone and the parietal bones.

Sagittal Suture

The skull suture located between the two parietal bones.

Lambdoid Suture

The skull suture located between the parietal bones and the occipital bone.

Squamousal Suture

The skull suture located between the parietal bone and the temporal bone.

Fontanel

A membranous gap between the bones of an unclosed skull.

Anterior Fontanel

The diamond-shaped fontanel situated at the junction of the coronal and sagittal sutures between the frontal and parietal bones.

Posterior Fontanel

The triangular fontanel located at the junction of the sagittal and lambdoid sutures between the parietal and occipital bones.

Sphenoidal Fontanel

The anterolateral fontanel located at the junction of the frontal, parietal, temporal, and sphenoid bones.

Mastoid Fontanel

The posterolateral fontanel located between the parietal, occipital, and temporal bones.

Cervical Vertebrae

The seven vertebrae ($C1-C7$) that support the head and allow rotation and nodding, featuring transverse foramina for arteries.

Atlas (C1)

The first cervical vertebra, specialized to support and articulate with the skull for head movement.

Axis (C2)

The second cervical vertebra, specialized to act as a pivot for head rotation.

Thoracic Vertebrae

The twelve vertebrae ($T1-T12$) that feature facets for rib articulation, serving to anchor ribs and protect thoracic organs.

Lumbar Vertebrae

The five largest and strongest vertebrae ($L1-L5$), possessing short, blunt spinous processes that bear body weight and provide flexibility to the lower back.

Sacrum

A triangular bone formed by five fused sacral vertebrae ($S1-S5$) that connects the spine to the pelvis and transmits weight to the lower limbs.

Coccyx

A bone composed of $3-5$ fused small vestigial vertebrae that serves as an attachment site for ligaments and pelvic floor muscles.

Compact Bone

Bone tissue that is dense, smooth, and homogeneous.

Spongy Bone

Bone tissue characterized by small needle-like pieces of bone and open spaces giving it a spiky, sponge-like appearance.

Diaphysis

The elongated shaft that makes up most of a long bone's length, composed of compact bone surrounded by periosteum.

Epiphysis

The expanded end of a long bone, consisting of a thin outer layer of compact bone enclosing spongy bone and capped with articular cartilage.

Periosteum

A fibrous connective tissue membrane that covers and protects the exterior of the diaphysis.

Epiphyseal Line

A calcified remnant of the hyaline cartilage epiphyseal plate found in adult long bones after longitudinal growth has stopped.

Medullary Cavity

The central cavity within the diaphysis of a long bone that holds red marrow in young children and yellow adipose marrow in adults.

Osteocytes

Mature bone cells entrapped within the bone matrix inside tiny cavities called lacunae, responsible for maintaining matrix mineral concentration.

Lacunae

Tiny cavities within the bone matrix that house mature osteocytes.

Lamellae

Concentric rings or layers of calcified bone matrix surrounding a central canal.

Osteon

The primary structural unit of compact bone, consisting of a central Haversian canal surrounded by concentric lamellae.

Canaliculi

Extremely tiny canals radiating outward from central canals to lacunae, forming a transport network for nutrients through the bone matrix.

Osteogenic Cells

Mesenchymal stem cells located in the deep layers of the periosteum and marrow that differentiate into osteoblasts.

Osteoblasts

Bone-building cells responsible for bone matrix synthesis during ossification and growth.

Osteoclasts

Large bone cells responsible for bone resorption and breakdown of old or damaged bone matrix.

Ossification

The developmental process of bone tissue formation from pre-existing cartilage or membrane templates.

Osteoarthritis

A chronic degenerative joint disease common in elderly individuals, characterized by breakdown of articular cartilage and growth of marginal bone spurs.

Rheumatoid Arthritis

A chronic inflammatory autoimmune disorder typically presenting between ages $40-50$ in which the body's immune system attacks its own joint tissues.

Osteoporosis

A bone-thinning condition in which bone resorption outpaces sluggish osteoblast activity, resulting in fragile and easily fractured bones.