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Flashcards in exam 3 chp 9 Deck (68)
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1

what is the endchondral ossification- replacing of bone?

splanchnchondrocranium

2

what is the intramembranous ossification- composed of membrane bones?

splanchnomembranocranium

3

the cartilagenus skeleton develops from?

visceral or brachial arches

4

humans have how many arches?
and start with how many?

5 arches with 5th disappearing in 1.5 days and they start with 6

5

which arch forms the palate, maxilla, meckel's cartilage, incus and malleous (bones of ear)?

first arch (mandibular arch)

6

which arch forms the stapes, cranial half of the hyoid, and the lesser horn?

the second arch (reichert's cartilage)
cranial half of hyoid is not attached to any bone
lesser horn is still on hyiod bone

7

which arch forms the caudal half of the hyoid, and the greater horn?

third arch

8

the fourth and six arches form what?

cartilages of the larynx
-no ossification occurs here

9

what is the region in front of the incisive fissure and between canines?

premaxillae

10

maxillae and the premaxillae unite to form?

maxilla

11

the bones in upper and lower jaw, premaxillae, and maxillae are what types of splanchnocranium bones?

splanchnomembranocranium

12

the bones whose ossification center begins in the 7th week of developmennt, ossify outside of meckel's cartilage, and forms the ramus of the mandible?

dentary bones

13

3 characteristics of the fetal skull?

-thin bones, large head
-very large in proportion to body
-hard for baby to hold up when born

14

the notochord offers support of the axial skeleton and is replaced by?

vertebral column

15

what is the modified tissue in the intervertebral disc?

nucleus pulposus

16

when the vertebral column is developing from somite mesenchyme sclerotomes, the caudal part is? and the cranial part is?

caudal- proliferates creating a densely packed area
cranial- loosely packed

17

two parts of intersegmental dvelopment?

1. muscle attachment
2. nerve emergence

18

what begins at the 7thweek and starts in the cranial vertebrae and continuing into the caudal part

chondrification

19

the cartilaginous vertebral body that replaces the notochord and has 2 chondrification centers?

centrum

20

what is the medial growth on each side around the neural tube, and has one chondrification center in each side?

vertebral arches

21

vertebral arches do not unite to form the _______ ________ until the 3rd month after birth?

spinous process

22

ossification of the vertebral column begins at 9 weeks and by what month all ossification centers except two are present?

the 5th month all but 2 are present

23

what are the two ossification centers still not present by the 5th month?

Sacral region
Coccygeal region

24

what are the three ossification centers in the vertebrae?

one in centrum
one in each half of the vertebral arch

25

what are the five ossification centers of a vertebrae present at puberty?

1 at tip of spinous process
1 at each tip of transverse process
2 on the rim of epiphyseal center

26

the process by which dense mesenchymal precursors of the skeleton are converted into cartilage is known as?

chondrification

27

what develops from the mesenchyme and cartilage of the costal processes?

ribs
each rib has one chondrification center
ossification appears in 9th week

28

the sternum unites and fuses with the ends of ribs at what week?

the 6th week

29

mesenchymal bands of the sternum are called?

sternal bars

30

smaller cartilages anterior to the sternal bars fuse with sternum become the?

Manubrium