B6,052 Prework 1: Bone Architecture

Question 1

function of hydroxyapatite crystals in bone

Answer 1

prevents:
-diffusion of metabolites
-interstitial growth
both of these occur in cartilage (which is avascular)

Question 2

canalicular system

Answer 2

tiny canals extending from one lacuna to another

Question 3

gap junction

Answer 3

facilitates communication between osteocytes (mature bone cells) responsible for the maintenance of bone

Question 4

vascularity of bone

Answer 4

bone cells must be in close proximity to capillaries

Question 5

composition of bone

Answer 5

cells, fibers, and ground substance

Question 6

types of bone cells

Answer 6

bone lining cells (osteoprogenitor cells)
osteoblasts
osteocytes
osteoclasts

Question 7

how does bone elongation occur

Answer 7

proliferation of cartilage

Question 8

is bone dead?

Answer 8

no!!!!!!!!!!!!!!!!

BONE IS NOT DEAD!

Question 9

why is bone not dead

Answer 9

10% remodeling occurs annually

highly vascular and blood vessels are accompanied by sympathetic and pain fibers

Question 10

names for denser outer bone

Answer 10

compact
lamellar
Haversian
cortical

Question 11

names for spongy bone

Answer 11

cancellous

trabecular

Question 12

description of trabecular bone

Answer 12

3 dimensional lattice of branching bony spicules

forms trabeculae around marrow spaces

Question 13

epiphysis

Answer 13

end of long bone

Question 14

metaphysis

Answer 14

growth area between shaft and head of long bone

Question 15

diaphysis

Answer 15

shaft portion of long bone

Question 16

periosteum

Answer 16

dense connective tissue surrounding bone
has osteogenic potential
made up of osteoprogenitor cells

Question 17

where is periosteum absent

Answer 17

articulating surfaces and at the attachments of tendons and ligaments

Question 18

endosteum

Answer 18

lines marrow cavity
also has osteogenic potential
osteoprogenitor cells line the inside of the marrow cavity

Question 19

bone pattern of skull

Answer 19

external and internal tables (compact bone)
inner diploe (cancellous bone)

Question 20

factors determining the set point of peak bone mass

Answer 20

• genetics
• nutrition (ca, vit D)
• physical activity (mechanical loading, muscle strength)
• hormonal status
• age
• overall health

Question 21

genetic factors that may impact PBM

Answer 21

polymorphisms in vit D receptor, LRP5/6 (males)

RANK, OPG, RANKL

Question 22

effects of menopause on peak bone mass

Answer 22

decreased serum estrogen
increased IL-1, IL06, TNF levels
increased RANK, RANKL
increased osteoclastic activity

Question 23

effects of aging on peak bone mass

Answer 23

decreased replication of osteoprogenitor cells
decreased synthetic activity of osteoblasts
decreased biologic activity of matrix bound growth factors
reduced physical activity