chapter 6

Question 1

what are the two groups that the bones of the skeletal system divided into

Answer 1

axial skeleton and appendicular skeleton

Question 2

axial skeleton

Answer 2

bones that form the long axis of body
ex) skull, vertebral column and ribcage

Question 3

appedicular skeleton

Answer 3

bones of upper and lower limbs
ex) scapula, hip bones

Question 4

long bones

Answer 4

longer than they are wide
ex0 humerous, femur, radius, ulna

Question 5

short bones

Answer 5

cube shaped bones in wrist or ankle
sesamoid bones within tendons
ex) patella

Question 6

flat bones

Answer 6

thin, flat, slightly curvy
ex) sternum, ribs scapulae and most skull bones

Question 7

irregular bones

Answer 7

complicated shapes
ex) vertebra

Question 8

what are the 6 functions of bones

Answer 8

support, protection, anchorage, mineral storage, blood cell formation and triglyceride(fat) storage

Question 9

where s fat stored in bones

Answer 9

yellow marrow

Question 10

yellow marrow

Answer 10

in the medullary cavity of long bones
can convert to red marrow if necessary

Question 11

what are two types of bone textures

Answer 11

compact bone and spongy bone

Question 12

compact bone

Answer 12

dense outer layer feels smooth and solid

Question 13

spongy bone

Answer 13

inner layer that possesses a honey comb of flat pieces called trabeculae
contains red marrow

Question 14

Diaphysis

Answer 14

this tubular shaft forms the long axis of bone
consists of compact bones surrounding medullary cavity

Question 15

epiphyses

Answer 15

the ends of the long bone
external layer is compact bone internal layer is spongy bone

Question 16

where is the epiphyseal line

Answer 16

between the diaphysis and the epiphysis which is a remnant of the epiphyseal plate

Question 17

periosteum

Answer 17

covers the external surfaces of bone except for the articular surfaces
is a double layered membrane

Question 18

outer fibrous layer

Answer 18

composed of dense irregular connective tissue

Question 19

inner osteogenic layer

Answer 19

comprised of stem cells that give rise to other bone cells
contains many nerve fivers including blood vessles
* anchoring point for tendons and ligaments **

Question 20

endosteum

Answer 20

delicate connective tissue membrane coverinf internal bone surface
covers trabeculae of spongy bone
lines canals that pass through compact bone
contains osteogenic cells that can differenciate into other bone cell types

Question 21

Red marrow

Answer 21

produces blood cells
found within the trabecular cavities of spongy bone
adult long bones have little red bone marrow
found n heads of femur and humerous, flat bones and ireegular bones

Question 22

what are the 4 major types of bone cells

Answer 22

osteogenic cells, osteoblasts, osteocytes and osteoclasts

Question 23

osteogenic cells

Answer 23

also called osteoprogenitor cells
mitotically active stem cells n periosteum and endosteum ‘these cells can differentiate into osteoblasts when stimulated to do so

Question 24

osteoblasts

Answer 24

Bone forming cells
these cells secrete unmineralized bone matrix

Question 25

osteoid

Answer 25

includes collagen and calcium binding proteins

Question 26

osteocytes

Answer 26

mature bone cells located in the lacunae monitor or maintain the bone matrix act as stress or strain sensors respond to mechanical stress and communicate with osteoblasts and osteoclasts so bone remodling can occur

Question 27

osteoclasts

Answer 27

cells involved in breaking down bone have ruffed border that increases surface area for enzyme degradtion of bone

Question 28

osteon

Answer 28

structural unit of compact bone elongated cylinder parallel to long axis of bone hollow tubes of bone matrix

Question 29

central canal

Answer 29

core of osteon contains blood vessels and nerve fibers

Question 30

perforating canals

Answer 30

connect vessels and nerve =s of periosteum, medullary cavity and central canal

Question 31

what to the organic components of bone include

Answer 31

cells of the osteiod

Question 32

osteoid

Answer 32

made of ground substance and collagen fibers provides tensile strength and flexibilty to bone

Question 33

hydroxyapatites

Answer 33

mineral salts maes up 65% of bone by mass mainly tiny calcium phosphate crystals in and around collagen fibers responsible for hardness and resistance to compression

Question 34

what structures posses osteogenic cells

Answer 34

red marrow endosteum, periosteum and central canal

Question 35

ossification (osteogenesis)

Answer 35

the process of bone formation

Question 36

when does ossification occur

Answer 36

during the prenatal period during postnatal growth during bone remodeling and repair

Question 37

endochondral ossification

Answer 37

occurs when the hyaline cartilage is replaced by newly forming bone forms most of the human skeleton

Question 38

intramembrous ossification

Answer 38

occurs when fibrous membrane is replaced by bone forms clavicle and cranial bones

Question 39

interstitial(longitudanal growth)

Answer 39

bone lengthens during growth requires presence of epiphyseal cartilage in the epiphyseal plate

Question 40

appositional growth

Answer 40

bone increases in thickness during growth

Question 41

growth hormone

Answer 41

stimulates epiphyseal plate activity during infancy and childhood

Question 42

thyroid hormone

Answer 42

regulates growth hormone to ensure proper proportions during bone growth

Question 43

epiphyseal plate

Answer 43

cartilage

Question 44

testrosterone and estrogens

Answer 44

levels of testosterone and estrogen promote adolecent growth spurts at the begining of puberty

Question 45

what controls bone remodeling

Answer 45

based on mechanical stress and gravity

Question 46

parathyroid hormone

Answer 46

(PTH) secreted by paraphyroid glands on the posterior aspect of the thyroid stimulus for release: low blood calcium levels removes calcium from bone regardless of bone integrity

Question 47

calcitonin

Answer 47

secreted by parafollicular cells of thyroid gland stimulus for release: high blood calcium levels Effect: lowers blood calcium levels

Question 48

nondisplaced fracture

Answer 48

ends retain normal position

Question 49

displaced fracture

Answer 49

ends out of normal allignment

Question 50

complete fracture

Answer 50

broken all the way through

Question 51

incomplete fracture

Answer 51

not broken all the way through

Question 52

open fracture

Answer 52

skin is penetrated

Question 53

closed fracture

Answer 53

skin is not penetrated

Question 54

what re two ways to treat and repair a fractured bone

Answer 54

reduction and immobolization

Question 55

bony callus

Answer 55

soft callus is converted to bony hard callus of spongy bone

Question 56

bone remodeling

Answer 56

occurs for several months compact bone is laid down excess material is removed

Question 57

when would a parathyroid hormone be released

Answer 57

low blood calcium levels