block 5 lecture 3 building the skeleton

Question 1

what do bones do?

Answer 1

protect organs, provide support for limbs, haematopoeisis

Question 2

what signals determines the form of the skeleton?

Answer 2

genetic and functional signals

Question 3

what are the two embryonic sources of the skeleton?

Answer 3

mesoderm and neural crest cells

Question 4

what models do the long bones and ribs form in?

Answer 4

cartileginous models

Question 5

bones of the skull and face form in a membrane derived from what?

Answer 5

neural crest

Question 6

what days of the embryo do you get the development of somites?

Answer 6

21-25

Question 7

what do vertebrae develop from in the embryo?

Answer 7

somites

Question 8

what group of genes determine the shape of the individual vertebrae?

Answer 8

hox genes

Question 9

what are the structures described as during limb development?

Answer 9

paddle-like structures

Question 10

which limbs develop first?

Answer 10

for limbs

Question 11

how do you form digits?

Answer 11

programmed cell death, cells in the paddle like structures die

Question 12

what sends signals to the developing limb bud to identify elements of the limbs?

Answer 12

epithelium surrounding the limb

Question 13

signalling from the route of the limb to the tip of the limb is done by what?

Answer 13

apical epidermic ridge

Question 14

what is the signalling of limbs from side to side done by?

Answer 14

epidermic cap - zone of polarizing activity

Question 15

what are the two types of ossification?

Answer 15

endrochondral ossification in cartilage and intramembranous ossification

Question 16

what is the ossification center at the end of bones called?

Answer 16

epiphysis

Question 17

which end is the epiphysis located?

Answer 17

articular end

Question 18

what is the physis? and its other name?

Answer 18

epiphysial growth plate

the thin cartilage that separates the the epiphysis from bone, where growth occurs for length

Question 19

what is the metaphysis?

Answer 19

broad part of the bone at the end of the shaft

Question 20

what is the long part of the shaft of the bone called?

Answer 20

diaphysis

Question 21

in endochondral ossification do genetic signals form?

Answer 21

cartilaginous models

Question 22

how does cartilage ossify in endochondral ossification?

Answer 22

invaded by blood vessels

Question 23

where does ossification begin along the shaft in in endochondral ossification?

Answer 23

middle

Question 24

what is between the end of the long bone and the shaft?

Answer 24

epiphysial plate

Question 25

how do bones increase in lengthin endochondral ossification?

Answer 25

cartilage at the epiphysial plate expands and drives the epiphys and diaphysis away

Question 26

what is the epiphysis covered with?

Answer 26

articular cartilage that the bone was formed in

Question 27

what stops the bone growingin endochondral ossification?

Answer 27

sex hormones are released during puberty which stops the cartilage from growing and ossifies the cartilage

Question 28

what is the cell of cartilage?

Answer 28

chondrocyte

Question 29

what are chondrocytes derived from?

Answer 29

chondroblasts

Question 30

how are chondroblasts converted to chondrocytes?

Answer 30

the chondroblasts secrete a matrix which inttumes its self

Question 31

what are the holes chondrocytes sit in called?

Answer 31

lacuna

Question 32

how do bones grow in diameter?

Answer 32

laying cells on the outersurface under the peristoneum

Question 33

how do the cells of bone act to make the bone bigger?

Answer 33

they proliferate forming layers and expand

Question 34

what is the outer shell of long bones called?

Answer 34

cortex

Question 35

what is at the end of long bones under the joints surface?

Answer 35

spongy network

Question 36

features of the cortex of long bones?

Answer 36

compact

not porus

Question 37

what are the long tubes forming in the compact regions of long bones called and what do they contain?

Answer 37

osteons and they contain minerals and collagen

Question 38

shape of osteocytes?

Answer 38

they have long processes which penetrate the bone and have a central nucleus

Question 39

how do bones adapt?

Answer 39

the processes of osteocytes stretch and contract which send signals to osteoblasts to deposit bone

Question 40

how is bone removed?

Answer 40

acid secretion by osteoclasts

Question 41

what is the formation when the cortex is first laid down?

Answer 41

woven

Question 42

what is different about the layers of collagen in an osteon? and what is good about this?

Answer 42

the different layers go in different directions, strength

Question 43

where is cancellous bone found?

Answer 43

ends of long bones

Question 44

what is the woven structure of bone converted to?

Answer 44

lamellar

Question 45

what is osteoporosis?

Answer 45

deposition and resorption is out of balance

Question 46

what are the types of joints?

Answer 46

fibrous - sutures and between long bones
cartileginous - ribs
synovial

Question 47

what is the synovial membrane?

Answer 47

thin sheet of connective tissue that secrets synovial fluid

Question 48

what are synovial joints supported by?

Answer 48

ligaments

Question 49

what are the five stages of healing?

Answer 49

haematoma, subperiostel and endosteal cell proliferation, callus, consolidation and remodelling