Intro to Ossification
What is ossification?
The process by which bone forms
What two methods of bone formation involve the replacement of a preexisting connective tissue with bone?
Intramembranous ossification and endochondral ossification
What’s the difference between a closed (simple) fracture and an open (compound) fracture?
A closed fracture does not break the skin, while an open fracture has bone ends protruding through the skin.
How does mechanical stress increase bone strength?
By increasing deposition of mineral salts and the production of collagen fibers.
There is a condition in which bones become weak and brittle, what is it called?
osteoporosis
Name one situation in which bone formation occurs.
Bone formation occurs in the initial formation of bones in an embryo and fetus
What bone formation process forms most of the bones in the body?
Endochondral ossification
What’s the difference between a greenstick fracture and a comminuted fracture?
A greenstick fracture involves a partial break with bending on the other side (common in children), while a comminuted fracture involves the bone being splintered or crushed into pieces.
The first step of the repair of a bone fracture is a fracture hematoma. What is it?
It is a mass of clotted blood that forms around the site of a bone fracture when blood vessels crossing the fracture line are broken.
The loss of what mineral is the principal effect of aging on bones?
Calcium
What happens during bone remodeling?
Bone remodeling involves bone resorption and deposition, where old bone tissue is replaced by new bone tissue
What type of bone formation involves the bone forming directly with the mesenchyme, arranging in sheet-like layers that resemble membranes? Provide two examples of bones that form like this.
Intramembranous ossification; Flat bones of the skull and mandible
What’s the difference between a stress fracture and an impacted fracture?
A stress fracture results from microscopic fissures due to repeated activities like running, while an impacted fracture occurs when one end of the bone is forcefully driven into the other.
What is a fibrocartilaginous callus, and what role does it play in bone repair?
It is a mass of repair tissue made up of collagen fibers and cartilage that bridges the broken ends of the bone.
What is another effect of aging that makes bones more brittle and susceptible to fracture?
Decreased production of collagen fibers
What is bone resorption, and what does it involve?
Bone resorption is the breakdown of the extracellular matrix of bone. It involves the removal of minerals and collagen fibers from bones.
What’s an embryonic connective tissue from which all other connective tissue arise?
Mesenchyme
How does a Pott’s fracture differ from a Colles’ fracture?
A Pott’s fracture involves the distal end of the fibula with serious injury to the tibial articulation, while a Colles’ fracture affects the distal end of the radius with the fragment displaced posteriorly.
What is a bony callus, and how does it contribute to bone healing?
It is the hardened structure that forms when fibrocartilage is converted into spongy bone, helping to stabilize and strengthen the fracture site.
What are the four factors that affect bone growth?
Minerals, vitamins, hormones, and weight-bearing exercise.
At any given time, what percentage of bone mass is undergoing remodeling?
Approximately 5% of bone mass is remodeling at any given time.
What is endochondral ossification?
The process in which bone forms within hyaline cartilage that develops from mesenchyme
What makes a comminuted fracture harder to treat compared to a greenstick fracture?
A comminuted fracture involves multiple bone fragments, making treatment more complex, while a greenstick fracture is a partial break with less severe displacement.
What happens during the bone remodeling phase of fracture repair?
The repair process makes the fracture line undetectable through bone resorption and deposition, but a thickened area may remain on the surface of the bone.
Which vitamins affect bone growth?
A, C, D, K, B12