Chapter 6: Calcium Homeostasis and Bone Fractures

Vocabulary flashcards covering hormonal calcium homeostasis, cellular mechanisms, fracture repair steps, and specific clinical bone fracture classifications.

Chlorcalciferol

The initial form of vitamin D synthesized by living skin cells in the stratum spinosum and stratum basale before being processed by the liver and kidneys.

Calcitriol

The activated form of vitamin D produced by the kidneys that signals the digestive tract to absorb calcium.

Parathyroid Hormone

A hormone released by the parathyroid glands in response to low blood calcium levels that stimulates osteoclasts, prompts kidneys to reabsorb calcium, and triggers calcitriol release.

Calcitonin

A hormone secreted by C cells of the thyroid gland during high calcium levels that inhibits osteoclasts, stimulates osteoblasts, and increases calcium excretion in urine.

Osteoclasts

Bone cells that break down and chew away at bone matrix, releasing calcium and phosphate into the bloodstream.

Osteoblasts

Bone-building cells that deposit calcium salts into the bone matrix to store minerals and strengthen bone.

Osteoprogenitor Cells

Stem cells located within the periosteum and endosteum that divide and differentiate into osteoblasts to facilitate bone repair.

Fracture Hematoma

A localized blood clot that develops at the site of a bone break immediately following extensive bleeding.

External Callus

A visible thickened collar of cartilage and bone forming around the outside of a break during repair that undergoes remodeling over time.

Transverse Fracture

A fracture that breaks completely across the long axis or shaft of a bone, typically caused by a perpendicular blow.

Spiral Fracture

A fracture produced by a sudden twisting force that causes the break to extend diagonally along the length of the bone.

Displaced Fracture

A fracture in which the broken bone fragments shift out of their normal anatomical alignment and must be set back into place.

Compression Fracture

A fracture characterized by crushing force on the vertebrae, commonly occurring from high-impact falls onto the back.

Greenstick Fracture

A partial fracture where only one side of the bone shaft breaks while the other side bends, commonly occurring in children due to bone flexibility.

Comminuted Fracture

A fracture in which the bone shatters into three or more individual pieces and fragments.

Epiphyseal Fracture

A break occurring at the growth plate cartilage that requires careful management to prevent shortened or uneven limb growth.

Pott's Fracture

A specialized fracture that occurs at the ankle.

Colles' Fracture

A break involving the distal portion of the radius in the wrist region, most commonly caused by bracing a fall with outstretched hands.

Closed Fracture

A fracture, also called a simple fracture, that remains internal with no piercing or breaking of the overlying skin.

Open Fracture

A fracture, also called a compound fracture, in which the bone projects through the skin, introducing risks of uncontrolled bleeding and infection.