Bones

Front 1

Osteoblasts are what shapes

Back 1

cuboidal mainly but can be columnar

Front 2

Osteocytes

Back 2

mature osteoblasts trapped in lacunae

Front 3

osteoclasts

Back 3

Large multinucleated cells for bone resorption

Front 4

what is the clear region in osteoblasts lining a bone

Back 4

depositing of osteoid and other proteins

Front 5

calcium homeostasis is regulated by what three hormone

Back 5

PTH, calcitonin, calcitriol (Vitamin D)

Front 6

PTH does what to calcium levels and stimulates what

Back 6

stimulates bone resorption, so calcium in serum goes up

PTH can, when given as a drug (Forteo recombinant human PTH), act to build bond as a treatment for osteoporosis- this is counterintuitive and is not well understood by researchers.

Front 7

How does PTH stimulate bone resorption?

Back 7

Binds to osteoblasts which secrete Osteoclast stimulating factor and then binds to receptors in osteoclasts

Front 8

Calcitonin comes from where?

Back 8

parafollicular cells of the thyroid

Front 9

calcitonin prevents what

Back 9

bone resorption and builds bone and keeps calcium levels low in serum

Front 10

Vitamin D does what

Back 10

Increases Ca and phosphate absorption in the gut, which increases bone resorption. Reduced excretion of calcium in kidneys

Front 11

Calcitriol (vitamin D) leads to?

Back 11

Bone resorption, reduction excretion of Ca in kidneys
absorptions of ca and phosphate

Front 12

What does estrogen do to bone density

Back 12

It inhibits resorption and is stored in testes and adrenals for men

Front 13

Bone is mainly made of what collagen?

Back 13

Type I

Front 14

Collagen and ground substance become mineralized with calcium and phosphate in the form of what?

Back 14

Hydroxyapatite

Front 15

osteocalcin?

Back 15

bone specific vitamin K dependent calcium binding protein

Front 16

Bone morphogenic proteins (BMP) are significant why?

Back 16

cause differentiation of mesenchymal cells into osteoblasts (may be used by surgeons to repair bone defects)

Front 17

additional proteins in matrix?

Back 17

Type V collagen, osteonection, osteopontin, sialoproteins
Glycosaminoglycans-Hyaluroinc acid chondroitin sulfate and keratin sulfate

Front 18

Bone is a mineral resevoir for what?
is it well vascularized
red marrow is the site for what

Back 18

Calcium and Phospahte
yes unlike cartilage
hematopoiesis

Front 19

Bone is made of what components

Back 19

bone tissue, hematopoitic tissue, adipose tissue, blood vessels, nerves and hyaline cartilage

Front 20

what is the periosteum

Back 20

CT that surrounds bone (long bones)

Front 21

Periorsteal nerve would cause pain when what happens?

Back 21

broken bone

Front 22

In flat bones, the outer layer of compact bones is called?
the inner spongy bone is called?

Back 22

Plates

Diploe

Front 23

Red bone marrow

Back 23

site for developing blood cells
located in sternum and iliac crest in adults
site for biopsy or bone marrow transplant

Front 24

Yellow marrow replaces what in adults

Back 24

most red marrow
can convert back to red marrow in times of anemia

Front 25

Spongy bone is also called what

Back 25

cancellous or trabecular

Front 26

Haversian systems are found where?

Back 26

compact bone and thicker trabeculae of spongy bone

Front 27

Osteon

Back 27

Concentric lamellae and Haversian Canal

Front 28

Volkmanns canal are related to Haversian canals how?

Back 28

the run perpendicular to the them

Front 29

Interstitial lamellae are what?

Back 29

Lie between complete lamellae and are remnants of bone remodeling

Front 30

Inner circumferential lamellae are near what
Outer circumferential lamellae are near what?

Back 30

endosteum

periosteum

Front 31

Periosteum has 2 layers composed of

Back 31

outer fibrous layer of Dense CT
Inner layer that is composed osteoprogenitor cells that can become osteoblasts

Front 32

endosteum

Back 32

thin layer of osteoprogenitor cells that lines internal surfaces(beginning of spongy bone)

Front 33

What are sharpeys fibers

Back 33

collagen fibers at the site of tendon insertion to a bone

Front 34

collagen fibers run which direction compared to bone surface

Back 34

parallel

Front 35

Osteocytes entend what ?

Back 35

cytoplasmic processes into canaliculi (only on EM slide)

Front 36

haversian systems are also called what

Back 36

osteons

Front 37

gap junction are present where in bone

Back 37

osteocyte processes

Front 38

canaliculi

Back 38

small canals allowing cytoplasmic processes of osteocytes in lacunaw to make contact with other cells via gap junction

Front 39

haversian systems are lined with

Back 39

endosteum, running along long axis of bone. contains blood vessels, nerves and CT

Front 40

characteristics of Primary bone and secondary bone

Back 40

Primary bone is woven with many cells and a matrix
secondary bone is mature with concentric lamellae and interstitial lamellae

Front 41

Primary bone is in adults mainly where?

Back 41

tooth sockets or sutures of flat bones

Front 42

In a mallery Azan stain light is what and dark blue is what?

Back 42

calcified cartilage
bone

Front 43

Howships lacuna

Back 43

depression in bone from osteoclasts also called resorption bay

Front 44

osteoprogenitor cells are what?

Back 44

basophilic

Front 45

Osteoclasts are derived from fusion of what

Back 45

monocytes and create multinucleated cells

Front 46

Clear zone around osteoclasts does what?

Back 46

forms a microenvironment. Secretes H and Cl (via H ATPase) to dissolve inorganic matrix
Secretes lysomal enzymes to degrade organic matrix

Front 47

the organic bone matrix is made of what

Back 47

collagen type I fibers and proteoglycans, and glycoproteins (sialoprotein and osteocalcin)
Inorganic:

Front 48

the inorganic bone matrix is made of what

Back 48

calcium and phosphorous in the form of hydroxyapitate

Front 49

Osteomalacia

Back 49

Mineralization of bone matrix is impaired (soft bones) Because of VITAMIN D deficiency
in children leads to rickets

Front 50

Osteogenesis inmperfecta

Back 50

Brittle Bone Disease
Disorder of TYPE I COLLAGEN
fractures after minor trauma

Front 51

Osteoporosis

Back 51

ratio of mineral to organic matrix is normal but have thinner spiculaes than normal

Front 52

what happens is you have a vitamin C deficiency

Back 52

poor bone growth and fracture repair BECAUSE OF IMPAIRED COLLAGEN SYNTHESIS

Front 53

process of intramembranous ossification

Back 53

Best example is the flat bones of skull.
Begins by a condensation of mesenchymal cells

Groups of mesenchymal cells within the membrane differentiate into osteoblasts. This site of osteoblast formation becomes a primary ossification center.

Osteoblast lay down bone matrix. Matrix encapsulates osteoblasts and calcifies. Cells become osteocytes located in lacunae. Spicules of woven bone form and these grow together forming trabeculae.
Compact bone forms outer plates. Inner bone around the developing marrow cavity becomes spongy bone

Front 54

endochondral ossification

Back 54

Mainly long and short bones
Endochondral ossification consists of two phases:
Hypertrophy and degeneration of chondrocytes
Osteogenic bud of osteoprogenitor cells and blood vessels penetrates the space left by the dead chondrocytes
Formation of the primary ossification center (prenatal)

Bone collar forms around diaphysis by differentiation of osteoblasts from the inner perichondrium, followed by deposition of bone matrix. This process, bone collar formation, is actually a form of intramembranous bone formation, i.e. bone formation within the perichondrium.

Cartilage hypertrophy, degeneration, and calcification occur in area surrounded by the bone collar
Osteogenic bud of blood vessels and osteoprogenitor cells penetrates bone collar and enters space left by degenerating cartilage
Osteoblasts differentiate and secrete bone matrix on a scaffold of remaining calcified cartilage
Primary ossification center expands to occupy the whole diaphysis

A secondary ossification centers arise later in the epiphyses (postnatal). This secondary center again forms by endochondral ossification

Front 55

what are the 5 layers of epiphyseal plates

Back 55

Zone of Reserve- hylaine cartilage
Zone of proliferation - condrocytes proliferate and START to form columns
Zone of hypertrophy- Condrocytes ENLARGE, matrix is compressed into lines between COLUMNS OF CONDROCYTES
zone of calcification-cartilage calcifies and first area to be basophilic
Zone of resorption- nearest diaphysis, comes in contact withmarrow cavity, blood vessels invade

Front 56

Bone remodeling unit cutting cone

Back 56

Osteoclasts are big open end
progressively smaller cone is closing cone of osteoblast

Front 57

Pituitary dwarfism

Back 57

Deficiency of growth hormones

Front 58

Gigantism

Back 58

Excess growth hormone with epiphyseal plates still open

Front 59

Acromegaly

Back 59

thickening of bones becauses growth plate closed

Front 60

Process of fracture repair

Back 60

1. blood clot forms at site
2. CT of periosteum and endosteum proliferate
3. Hyaline cartilage forms
4. Primary bone forms at site by endochondral and intramembranous
5. Bone callus temporaryily unites fracture
6. Osteoporgenitor cells from periosteum divide and become osteoblasts they invade the callus and deposit new bone
7. Remodeling occurs with healing