Osteology and the Skeletal System

Vocabulary flashcards covering bone structure, osseous cells, mineral regulation, bone disorders, and fracture healing based on the lecture notes.

Osteology

The study of bones.

Skeletal system

Body system composed of bones, cartilages, and ligaments.

Roles of the skeleton

Support, protection, movement, electrolyte balance, acid-base balance, blood formation, and hormone secretion.

Osseous Tissue (Bone)

Connective tissue with the matrix hardened by calcium phosphate and other minerals.

Mineralization / calcification

The hardening process of bone.

Flat bones

Thin, curved plates that protect soft organs.

Long bones

Bones that are longer than they are wide; act as rigid levers to muscles and are crucial for movement.

Short bones

Bones that are equal in length and width.

Irregular bones

Bones with elaborate shapes that do not fit into other categories.

Compact bone

Dense outer layer of bone that encloses the marrow.

Spongy (cancellous) bone

Loosely organized bone tissue, covered by more durable compact bone.

Periosteum

External sheath covering most of bone.

Articular cartilage

Layer of hyaline cartilage that covers joint surface; allows joint to move more freely.

Nutrient foramina

Minute holes in the bone surface that allow blood vessels to penetrate.

Endosteum

Thin layer of reticular connective tissue lining marrow cavity and all internal bone surfaces.

Osteogenic cells

Stem cells found in endosteum and inner layer of periosteum.

Osteoblasts

Bone-forming cells that secrete the bone matrix.

Osteocytes

Former osteoblasts that have become trapped in the matrix they deposited.

Canaliculi

Little channels that connect lacunae.

Lacunae

Tiny cavities where osteocytes reside.

Osteoclasts

Bone-dissolving cells found on the bone surface.

Bone marrow

A soft tissue inside the bone that produces blood cells.

Ossification (osteogenesis)

The formation of bone.

Intramembranous ossification

Process that produces the flat bones of the skull, most of the clavicle, and part of the mandible.

Achondroplastic dwarfism

Condition caused by a mutant dominant allele where long bones stop growing in childhood, resulting in a normal torso, short limbs, and failure of cartilage growth in the metaphysis.

Mineral deposition (mineralization)

Crystallization process in which calcium, phosphate, and other ions are taken from the blood and deposited in bone.

Ectopic ossification

Abnormal calcification of tissues.

Calculus

A calcified mass in an otherwise soft organ.

Mineral resorption

The process of dissolving bone and releasing minerals into the blood.

Hypocalcemia

Calcium deficiency that causes excessive excitability of the nervous system and muscles.

Hypercalcemia

Calcium excess that causes nerve and muscle cells to be less excitable than normal.

Calcitriol

A form of vitamin D produced by the sequential action of the skin, liver, and kidneys.

Calcitonin

Hormone produced by parafollicular cells (C cells) of the thyroid gland; lowers blood calcium levels by inhibiting osteoclasts and stimulating calcium uptake by bones.

Orthopedics

Branch of medicine treating disorders and injuries of the skeletal system and tissues related to movement.

Stress fracture

A break caused by abnormal trauma to a bone.

Pathological fracture

A break in a bone weakened by disease.

Stages of fracture healing

1. Hematoma formation, 2. Fibrocartilaginous callus formation, 3. Bony callus formation, 4. Bone remodeling.

Closed reduction

Procedure in which the bone fragments are manipulated into their normal positions without surgery.

Open Reduction Internal Fixation (ORIF)

Procedure involving surgical exposure of the bone and the use of plates, screws, or pins to realign the fragments.

Osteoporosis

Severe loss of bone density causing bones to easily fracture.

Osteopenia

Measurable decline in bone density that may advance to osteoporosis.