Flashcards in exam 3 chp 9 Deck (68)
what is the endchondral ossification- replacing of bone?
what is the intramembranous ossification- composed of membrane bones?
the cartilagenus skeleton develops from?
visceral or brachial arches
humans have how many arches?
and start with how many?
5 arches with 5th disappearing in 1.5 days and they start with 6
which arch forms the palate, maxilla, meckel's cartilage, incus and malleous (bones of ear)?
first arch (mandibular arch)
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
which arch forms the caudal half of the hyoid, and the greater horn?
the fourth and six arches form what?
cartilages of the larynx
-no ossification occurs here
what is the region in front of the incisive fissure and between canines?
maxillae and the premaxillae unite to form?
the bones in upper and lower jaw, premaxillae, and maxillae are what types of splanchnocranium bones?
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?
3 characteristics of the fetal skull?
-thin bones, large head
-very large in proportion to body
-hard for baby to hold up when born
the notochord offers support of the axial skeleton and is replaced by?
what is the modified tissue in the intervertebral disc?
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
two parts of intersegmental dvelopment?
1. muscle attachment
2. nerve emergence
what begins at the 7thweek and starts in the cranial vertebrae and continuing into the caudal part
the cartilaginous vertebral body that replaces the notochord and has 2 chondrification centers?
what is the medial growth on each side around the neural tube, and has one chondrification center in each side?
vertebral arches do not unite to form the _______ ________ until the 3rd month after birth?
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
what are the two ossification centers still not present by the 5th month?
what are the three ossification centers in the vertebrae?
one in centrum
one in each half of the vertebral arch
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
the process by which dense mesenchymal precursors of the skeleton are converted into cartilage is known as?
what develops from the mesenchyme and cartilage of the costal processes?
each rib has one chondrification center
ossification appears in 9th week
the sternum unites and fuses with the ends of ribs at what week?
the 6th week
mesenchymal bands of the sternum are called?