Bones and Skeletal Tissues Flashcards

A comprehensive vocabulary flashcard set covering the concepts, cell types, structural anatomy, ossification processes, and disorders of bones and skeletal tissues from Chapter 06.

Skeletal cartilage

Highly resilient, molded cartilage tissue consisting primarily of water, which contains no blood vessels or nerves.

Perichondrium

A layer of dense connective tissue surrounding cartilage that helps resist outward expansion and contains blood vessels for nutrient delivery.

Chondrocytes

Cartilage cells encased in small cavities called lacunae within a jelly-like extracellular matrix.

Hyaline cartilage

The most abundant type of cartilage that provides support, flexibility, and resilience, containing collagen fibers only.

Elastic cartilage

Cartilage type that is similar to hyaline cartilage but contains both collagen and elastic fibers; located in the external ear and epiglottis.

Fibrocartilage

Cartilage containing thick collagen fibers that provide great tensile strength; located in the menisci of the knee, pubic symphysis, and intervertebral discs.

Appositional growth

Cartilage or bone growth in which new matrix is laid down on the external surface by cells in the perichondrium or periosteum.

Interstitial growth

Cartilage growth in which chondrocytes within lacunae divide and secrete new matrix, expanding the cartilage from within.

Hematopoiesis

The process of blood cell formation occurring in the red bone marrow of certain bones.

Osteocalcin

A hormone produced by bones that helps regulate insulin secretion, glucose homeostasis, and energy expenditure.

Axial skeleton

Bones forming the long axis of the body, consisting of the skull, vertebral column, and rib cage.

Appendicular skeleton

Bones of the upper and lower limbs and the girdles that attach limbs to the axial skeleton.

Long bones

Bones that are longer than they are wide, containing a medullary cavity extending the length of the shaft.

Short bones

Cube-shaped bones, such as wrist and ankle bones, as well as sesamoid bones that form within tendons.

Flat bones

Thin, flat, and slightly curved bones, such as the sternum, ribs, and most cranial bones.

Irregular bones

Bones with complicated shapes, such as the vertebrae and hip bones.

Compact bone

The dense outer layer on every bone that appears smooth and solid.

Spongy bone

Internal bone tissue made up of a honeycomb of small, needle-like or flat pieces called trabeculae.

Diaphysis

The tubular shaft that forms the long axis of a long bone, consisting of compact bone surrounding a central medullary cavity.

Epiphyses

The bone ends of long bones, consisting of compact bone externally and spongy bone internally.

Periosteum

A white, double-layered membrane covering external bone surfaces (except joints), consisting of an outer fibrous layer and an inner osteogenic layer.

Endosteum

A delicate connective tissue membrane covering internal bone surfaces, trabeculae of spongy bone, and canals passing through compact bone.

Osteoprogenitor cells

Mitotically active stem cells located in the periosteum and endosteum that differentiate into osteoblasts or bone-lining cells.

Osteoblasts

Bone-forming cells that secrete unmineralized bone matrix called osteoid.

Osteoid

Unmineralized bone matrix secreted by osteoblasts, composed of ground substance and collagen fibers.

Osteocytes

Mature bone cells located in lacunae that no longer divide, functioning to maintain the bone matrix and act as stress or strain sensors.

Bone-lining cells

Flat cells on bone surfaces that assist in maintaining the bone matrix; called periosteal cells externally and endosteal cells internally.

Osteoclasts

Giant, multinucleate cells derived from hematopoietic stem cells that function in bone resorption.

Osteon

The structural unit of compact bone, consisting of an elongated cylinder parallel to the bone long axis made of concentric matrix rings called lamellae.

Central canal

A canal running through the core of an osteon that contains blood vessels and nerve fibers.

Perforating canals

Canals lined with endosteum running at right angles to central canals, connecting blood vessels and nerves of the periosteum, medullary cavity, and central canal.

Canaliculi

Hairlike canals that connect lacunae to each other and to the central canal, allowing communication and nutrient relay between osteocytes.

Hydroxyapatites

Inorganic mineral salts, mainly calcium phosphate crystals, that make up 65% of bone by mass and provide hardness and resistance to compression.

Ossification

The process of bone tissue formation, also referred to as osteogenesis.

Endochondral ossification

The bone formation process where bone develops by replacing previously formed hyaline cartilage models.

Intramembranous ossification

The bone formation process where bone develops directly from fibrous connective tissue membranes formed by mesenchymal cells.

Wolff's law

The law stating that bones grow or remodel in response to demands or mechanical stresses placed on them.

Parathyroid hormone

Hormone produced by parathyroid glands in response to low blood calcium levels that stimulates osteoclasts to resorb bone, releasing calcium into the blood.

Comminuted fracture

A bone fracture where the bone fragments into three or more pieces; common in older adults.

Greenstick fracture

An incomplete bone fracture where one side of the shaft breaks and the other side bends; common in children.

Osteomalacia

A condition in adults where bones are poorly mineralized because calcium salts are not adequately deposited, causing soft and weak bones.

Rickets

Osteomalacia in children caused by vitamin D deficiency or insufficient dietary calcium, resulting in bowed legs and bone deformities.

Osteoporosis

A group of diseases in which bone resorption exceeds bone deposit, leading to a decline in bone mass while matrix remains normal.

Paget's disease

A bone disorder characterized by excessive and haphazard bone deposit and resorption, producing poorly mineralized Pagetic bone with a high spongy-to-compact bone ratio.