Systems path exam 1 NOT FINISHING!!!!!!!

What is diaphysis?

shaft of bone

What is metaphysis?

Neck of a bone (contains growth plates)

What is epiphysis?

End of a long bone (articular cartilage)

What is characteristics compact bone?

Densely packed, tightly organized

What are some characteristic of spongy bones?

Sparsely packed, random, arranged along lines of stress

What are the cellular (organic)components of a bone?

- osteoblast

- osteoclast

- osteocytes

- Osteoprogenitor cells

What are the proteins of a bone?

Collagen, Osteoid

What are the minerals of bones

• Hydroxyapatite

• Calcium

• Phosphorus

Components of woven bone?

• Immature osteoid

• Highly cellular

• Disorganized

• Abnormal in adults

What are components of lamellar bones?

• Mature

• Less cellular (more matrix)

• Organized along stress lines

• Normal in adults

What type of bone cells are stem cells and differentiate into osteoblasts?

Osteoprogenitor Cells

What are the bone forming cells?

Osteoblast

What do the osteoblast mature into?

osteocytes

What are mature bone cells called?

osteocytes

What type of bone cells maintain the bony matrix, Wolff's law, and Skelton replacement?

Osteocytes

What bone cells are responsible for bone resorption?

osteoclasts

Osteoclast mature from the same stem cells as _____________.

Macrophages

True or false: Before the age of 30 there is a net equilibrium in bones remodeling

True

A slight shift towards bone loss after age _____ often occurs.

30

Osteoclast precursor has _________ receptor

Rank

What do RANK ligands bind to?

RANKL from osteoblast

What is Dysostosis?

developmental anomaly of bone or cartilage

What are some characteristics of congenital disorders?

- dysostosis

- localized abnormality

- mutations

- supernumerary digit

- Klippel-Feil Syndrome, Congenital Kyphosis

Dysostoses

Skeletal disorder that results from abnormal bone patterning, genetic or environmental. Extra digits or fusion of digits

What is kipper-feil syndrome?

Congenital fusion of ≥2 cervical vertebrae

Idiopathicl: 1/40,000

What is another disorder also associated with klippel-feil syndrome.

Sprengle's deformity

What is Sprengel's deformity?

Fused scapula

Congenital failure of scapula to descent

Elevation of the scapula, and limited humeral abduction

What malformations are common with klippel-feil syndrome?

renal & cardiac malformations are common as well

What is congenial kyphosis?

An severe kyphotic curve

What type of Congenital Kyphosis

Is worse?

Type 1

What are some characteristics of congenital kyphosis?

Failed development

- severe

- deformity

- possible cord compression

What are some characteristic of type 2 congenital kyphosis?

Failed segmentation (Type II)

• Mild compared to type I

• Mild Deformity

Surgical fusion

Dysplasia?

mutations interfere with growth & bone remodeling

How is dysplasia related to the congenital disorders?

- Effecting multiple bones or entire skeleton

- not pre-cancerous

What are some example of congential disorders that are associated with dysplasia?

Achondroplasia, Cleidocranial dysplasia,

Osteogenesis imperfecta, Osteopetrosis

Type I spondylolisthesis

Genetic Etiology

What is cleidocranial dysplasia?

- Absent/ under-developed clavicles (dental abnormalities)

- delayed closure of cranial sutures

- short stature

What gene is affected by Cleidocranial Dysplasia?

RUNX2 gene

What is RUNX2 gene important for?

function during skeletal formation & bone maintenance

What is Achondroplasia?

Most common cause of dwarfism and most common skeletal dysplasia

Height of Individuals with dwarfism?

Adult Height ≤4' 10"

True or false: achondorplasia is the only cause of dwarfism.

False (Hypopituitary, Turner Syndrome, malnutrition, osteogenesis imperfecta)

How doe achondroplasia affect the foramen magnum and spinal stenosis?

Increase stenosis

What are some spinal abnormalities of individuals with achondroplasia?

• Bullet vertebrae

• Stenosis

What are the effects of a bullet vertebrae?

• hyperlordosis & kyphosis

• scoliosis

What undergoes stenosis with individuals with achondroplasia?

1. foramen magnum

• brain stem, may be lethal

2. lumbar spinal canal

• radiculopathy

What congenital disorder is trident hand associated with?

Achondroplasia

What causes achondroplasia happen?

• Inhibited Endochondral growth

• ↓ cartilage synthesis

• short / bowed long bones

• frontal bossing, midface hypoplasia

What gene is associated with achondroplasia?

FGFR3

True or false: achondroplasia is most commonly inherited.

False (90% are spontaneous -- MC from sperm (dad), 10% are autosomal dominant)

What is Thanatophoric Dwarfism?

- Extremely rare form of dwarfism, more severe than achondplasia.

- small thorax. Short long bones

- fatal (still birth, perinatal respiratory failure)

Other names of Osteogenesis Imperfecta (OI)

"brittle bone disease" or Type I Collagen Disease

What causes osteogenesis imperfecta?

weak connective tissue due to altered type 1 collagen ( weak foundation for hydroxyapatite deposition)

What features are often affected by Osteogenesis Imperfecta?

Bones, eyes, teeth, inner ear bones, skin, joints

What are the different types of Osteogenesis Imperfecta?

Type I = normal lifespan

Type II = lethal in utero

What is a very common sign of osteogenesis imperfecta?

Blue Sclerae - Translucent (visualize underlying choroid blood vessels)

What are some childhood signs of brittle bone syndrome?

• fractures, bowing, scoliosis

• hearing loss

• dwarfism

What condition does the zebra stripe sign refer to?

Osteogenesis imperfecta

What is the main cause of osteogenesis imperfecta?

Mutated Type I collagen (inherited)

•α1 or α2 chains

• premature breakdown & structural weakness

• autosomal dominant

• 1 in 20,000

__________ is associated with normal bone strength, but frequently with stenosis of the foramen magnum and lumbar spinal stenosis

Achondroplasia

__________ frequently involves localized abnormalities in development of the clavicles and teeth

Cleidocranial dysplasia

Individuals born with ________ will be affected by an incomplete formation of one or more vertebral bodies.

type I congenital kyphosis

What does Radiolucent mean?

- Areas appearing darker on x-ray

- Due to lower density of structure

- Ex. Cartilage, foramen, gas in GI tract, bone destroying tumor, osteoporotic bone (with reduced density)

What does Radiopaque/Radiodensity mean?

- Areas appearing brighter/whiter on x-ray

- Due to higher density of structure

- Ex. Bone, metal

What is another name for osteopetrosis?

"marble bone disease"

What is osteopetrosis?

• Skeletal sclerosis (↑ density of bone)

• fractures: brittle

• Bony stenosis = cranial nerve palsies

• Deranged hematopoiesis

• fatigue & infections

What is a chalk stick pathological fracture associated with?

Osteopetrosis

What is an Erlenmeyer flask deformity associated with?

Osteopetrosis

What is the root of the problem of Osteopetrosis?

- ↓ osteoclast activity

- loss of hematopoietic bone marrow

- ↓ Ca++ intake and/or stem cell transplant

What can a decrease in osteoclast activity?

- impaired acid production in osteoclasts

- Inability to remodel & resorb bone

- Leads to dense & thick, but brittle bone

True or false: osteopetrosis is an inherited condition.

True

What is used to measure bone mineral density and can determine risk of fracture?

DEXA scan

What is indicated if the DEXA scan is 2.5 standard deviations below?

Osteoporosis

What is indicated if the DEXA scan is between 1-2.5 standard deviations below?

Osteopenia

What type of osteoporosis comes after another disease or issue?

Secondary osteoporosis

What type of osteoporosis often affects the senile and those that are postmenopausal?

Primary osteoporosis

What often decreases osteoblast activity in people with osteoporosis?

Senile (old age)

True or false: osteoclast activity remains normal in individuals with osteoporosis?

True

What is linked to an increase in osteoclast activity with women that suffer from osteoporosis?

Postmenopausal (decrease in estrogen)

Women that have an increased age, that live a sedentary lifestyle are most at risk of what condition?

Osteoporosis

Distorted eating,malnutrition, and malabsorption can also lead to what?

Osteoporosis

Vertebral body compression Fx and Femoral neck fracture are all consequences of what condition?

Osteoporosis

True or false: x-ray is the best way to diagnosis a patient with osteoporosis.

False (nor sensitive enough)

Physical activity, Dietary calcium & Vitamin D, and Antiresorptive pharmacologic agents are all ways to prevent what condition?

Osteoporosis

What is the childhood vitamin D deficiency?

Rickets

What condition involve undermineralized bone, weak & bowing bones, and poor growth plates?

Rickets

What conditions if from failed osteoid formation and failed deposition of bone in the growth plates?

Rickets

Who is most affected by rickets?

Children

Deficiency (dietary or UV), malabsorption, and chronic renal disorders (↓ conversion to active vitamin D) all cause what condition?

Rickets and osteomalacia

What condion deals with Undermineralized bone and bone that is Weak & prone to fracture (in adults) ?

Osteomalacia

Failed remodeling and underminaralized matrix accumulation can cause what?

Osteomalacia

Who is most at risk for osteomalacia?

Adults (Less severe than in children)

Primary hyperparathyroidism is most common caused by a ________.

Adrenoma

Renal failure, which leads to hypocalcemia and a ↑ PTH all are associated with ______.

Secondary Hyperparathyroidism

_____ osteoclast activity and _____ renal tubule resorption of Ca++ is caused from primary hyperparathyrodism.

Increase, increase

True or false: Hyperparathyroidism (Primary) is asymptomatic

True

Kidney stones (MC), bone pain, peptic ulcers,

depression, demineralization/pathologic Fx are all linked to ______.

Hyperparathyroidism (Primary)

unique skeletal changes and adiographic features are linked to what?

Hyperparathyroidism

What is the most common non malignant cause of hypercalcemia?

Salt and pepper skull

Salt & Pepper Skull, rugger-jersey spine, and subperiosteal resorption is associated with what condition?

Hyperparathyroidism