anatomy - broken bones and repair

After age ~30, ______ > Ossification *resporption - osteoclasts break down tissue and release minerals from hydroxyapatite Result: bones slowly get less dense and weaker (______). Osteoporosis is most common in postmenopausal women.

Bone resorption, osteoporosis

4 steps on how the body heals from fractures, the bone will heal regardless of whether is is set in place. If it isn't set, it will heal crooked and your bone will be forever curved.

1.Hematoma forms 2.Fibrocartilage callus forms 3.Bony callus forms 4.Bone remodels to a permanent patch

(compression fracture) -Part of bone is______ -Almost always happen in a _____ -Caused by osteoporosis (bones cannot support normal amount of weight because they have low mineral density) -Seen almost exclusively in ______

"crushed" or caved in, vertebra, geriatric patients

Trabeculae

("lines" of spongy bone) remodel to run parallel or perpendicular to stress)

(bone repair) 4. Bone remodels to a permanent patch (8-10 weeks)

-Compact bone settles around edges -Dead cells are removed by osteoclasts -Bone eventually reaches full strength again (usually)

(bone repair) 2. Fibrocartilage callus forms (~48 hours)

-Fibroblasts and osteoblasts migrate to damaged site, make fibrocartilage (cartilage matrix + bone matrix + collagen) -Capillaries begin redeveloping -Phagocytes(a type of white blood cell)remove some debris

types of fractures

-Stress fracture -Greenstick fracture -Compression fracture -Complete fracture: Transverse, Oblique, Spiral -Comminuted fracture

(broken bones) Breaks can be one of two things: _____ do not pierce the skin _____ do pierce the skin

Closed fractures, Open fractures

What is the difference between a break, a crack, and a fracture?

NOTHING. They all mean the same thing - the bone's integrity has been compromised.

(bone remodeling) Bones are constantly broken down and rebuilt. -______: Build bone (_______) -_______: Break bone apart (______) Each year, about ________. This is a delicate process! _______ _____: Wolff's Law states that bone grows and remodels in response to the forces that are placed upon it in a healthy person. After an injury to a bone, placing specific stress in specific directions to the bone can help it remodel and become normal, healthy bone again. More Stress = Stronger Bone!

Osteoblasts, ossification, osteoclasts, bone resorption, 10% of skeleton is replaced, Osteoporosis, osteopetrosis, wolff's law

______ - binds to and activates _____ on ______ membranes and increases osteoclast activity. a. Estrogen ______ RANK ligand production -leads to less osteoclast activity, less resorption b. Estrogen ________ osteoprotegerin (_____) production. OPG binds to RANK Ligand and blocks it from binding to RANK receptors -leads to less osteoclast activity, less resorption In menopause, estrogen production dramatically decreases. Thus, osteoclast activity and bone resorption increases.

RANK Ligand, RANK receptors, osteoclast, downregulates, unregulates, OPG

(bone repair) 3. Bony callus forms (3-4 weeks)

The fibrocartilage slowly starts to ossify as more and more osteoblasts arrive at the fracture site. The break is full of new immature spongy bone.

(complete fracture) -Bone breaks all the way through -3 "subtypes" -_____ (perpendicular angle) -______ (nonperpendicular angle) -______ (break at rotating angles) aka Torsion fracture (Spiral fracture of humerus(from arm wrestling!!)- Usually happens in LONG BONES)

Transverse, Oblique, Spiral

(bone repair) 1.Hematoma forms (6-8 hours after)

When a bone breaks, blood vessels surrounding and inside it also break. This will lead to swelling in the area called a hematoma. Many bone cells near the break, deprived of their normal blood flow, die.

Osteoporosis

bone diesease wheredensity and quality of bone are reduced. Risk of fracture increases.

Osteopetrosis

bone diseasethat makes bones abnormallydence and prone to fractures

pictures are

fair game

(stress fractures) -Also called a _____. -Comes not from one severe trauma event, but _____. -Common in _____ -Most common in ______ (tibia, femur, metatarsals)

hairline fracture, extended overuse, athletes, weight-bearing bones

(comminuted fracture) -Bone breaks into _____ -General from high-speed or high-trauma events -Often requires screws or plates to hold bone together

many fragments

(greenstick fracture) -Come from an incomplete fracture through the bone. -Bone breaks much like a "green stick": A piece splinters off, but _____. -Happen almost exclusively in ______ (more cartilage, less ossification)

part stays intact, patients under 10yo