embryo 2

Question 1

sources of bone forming tissue

Answer 1

mesoderm

neural crest

Question 2

Mesoderm/Neural crest cells revert to ________ state

Answer 2

mesenchymal

Question 3

Mesenchymal cells will differentiate into ________ and _______ to eventually form bone

Answer 3

osteoblasts or chondroblasts

Question 4

during intremembranous ossification: At first, bone is arranged in ______ , which will reorganize as ______

Answer 4

spicules, osteons

Question 5

joint formation begins when as condensed mesenchyme appears in _______

Answer 5

joint interzones

Question 6

what will form the tissue that unites the bones of a joint

Answer 6

Mesenchyme

Question 7

3 types of joints

Answer 7

• Fibrous (ex: sutures)
• Cartilaginous (ex: costochondral joints, symphyses)
• Synovial (ex: knee joint)

Question 8

during formation of synovial joints, Mesenchymal cells surrounding joint interzone form _______ and _______

Answer 8

form fibrous joint capsule & reinforcing ligaments

Question 9

Condensed mesenchyme in joint inter zone gives rise to

Answer 9

Ligaments inside joint capsule, synovial membrane, menisci

Question 10

Paraxial mesoderm (sclerotome) forms all of the ________ except for the _____ and portion of the ______

Answer 10

axial skeleton, sternum and portion of the skull

Question 11

forming vertebrae and IV disc starts with what

Answer 11

Sclerotome cells surround neural tube and notochord

Question 12

Each sclerotome segment has a _______ portion cranially and a ______ portion caudally

Answer 12

less dense, dense

Question 13

half of dense forms what and other half combines with less dense and forms what

Answer 13

IV disc, vertebrea bodies

Question 14

______ are formed from sclerotome of paraxial mesoderm. Grow out as lateral extensions of costal processes developing from thoracic vertebrae & wrap around anteriorly

Answer 14

Ribs

Question 15

________forms where costal process meets vertebra

Answer 15

Synovial joint

Question 16

Sternum is induced to form by ribs at ventral midline from ________

Answer 16

lateral plate somatic mesoderm

Question 17

Develops as two sternal bars that will fuse cranially to caudally during _____ week

Answer 17

10th

Question 18

Primary curvatures

Answer 18

(develop during fetal period): thoracic & sacral

Question 19

secondary curvatures

Answer 19

(develop after birth): cervical (once can hold head up) & lumbar (once begins walking)

Question 20

Neurocranial bones form from what and what are by what ossification process(s)

Answer 20

paraxial mesoderm and neural crest cells

intramembranous and endochondral ossification

Question 21

visocranium bones form from what and by which ossification process(s)?

Answer 21

neural crest cells from first 2 pharyngeal arches, ONLY by intramembranous

Question 22

_______ forms by endochondral ossification (base of skull: sphenoid, clivus, petrous portion of temporal bone) (red + blue = chondrocranium)

Answer 22

“Chondrocranium”

Question 23

_______: forms by intramembranous ossification (all other parts of neurocranium)

Answer 23

“Membranous neurocranium”

Question 24

Fontanelles

Answer 24

enlarged membranous spaces where 2+ bones meet

Question 25

Sutures:

Answer 25

Fibrous joints uniting the flat bones of the skull | During fetal period, are membranous and flexible joints

Question 26

Craniosynostosis

Answer 26

Premature closure of suture(s)

Question 27

Scaphocephaly

Answer 27

(premature closure of sagittal suture)

Question 28

Brachycephaly

Answer 28

(premature closure of coronal suture)

Question 29

Lateral plate mesoderm -->

Answer 29

mesenchyme --> pectoral & pelvic girdles, limb bones, sternum (= appendicular skeleton + sternum)

Question 30

Paraxial mesoderm (sclerotome) -->

Answer 30

mesenchyme -->vertebral column, ribs, + portion of neurocranium (occipital & parietal bones, petrous portion of temporal bone, posterior half of sphenoid bone)

Question 31

Neural Crest -->

Answer 31

mesenchyme --> bones of face (viscerocranium) + portion of neurocranium (frontal bone, squamous portion of temporal bone, anterior half of sphenoid bone), hyoid bone

Question 32

skeletal muscle derived from what

Answer 32

-Derived from paraxial mesoderm

Question 33

cardiac muscle derived from what

Answer 33

Derived from intraembryonic splanchnic mesoderm surrounding developing heart

Question 34

smooth muscle derived from what

Answer 34

Of G.I. tract: Derived from intraembryonic splanchnic mesoderm surrounding gut tube

Question 35

which smooth muscle is derived from ectoderm

Answer 35

Sphincter pupillae m. & dilator pupillae m. of iris: neuroectoderm Myoepithelial cells of mammary, salivary & sweat glands: surface ectoderm

Question 36

skeletal muscle formation steps

Answer 36

paraxial mesoderm -> somites -> somites differentiate into sclerotome, MYOTOME, and dermatome

Question 37

_______ (paraxial mesoderm) give rise to most of the axial skeleton & associated musculature + overlying dermis of back

Answer 37

Somites

Question 38

limb skeletal muscle. _________ separates paraxial mesoderm from lateral plate somatic mesoderm

Answer 38

Lateral somitic frontier

Question 39

Some VLL ______ myoblasts will migrate across the frontier into lateral plate somatic mesoderm to form skeletal muscle of the limb

Answer 39

(ventrolateral lip)

Question 40

Each myotome divides into ______ and ______

Answer 40

``` epaxial group (dorsal) hypaxial group (ventral) ```

Question 41

Muscle tendons (or aponeuroses) form from ______ near myotomes

Answer 41

sclerotome cells

Question 42

Limb musculature is derived from the _____ of somite myotomes that migrates into lateral plate mesoderm

Answer 42

VLL

Question 43

limb bud

Answer 43

Core of mesenchyme, lined by surface ectoderm

Question 44

limb elongation: __________ sends signaling factors to nearby mesenchyme of ________ (keeps cells undifferentiated and rapidly dividing to form more limb tissue)

Answer 44

AER (apical ectodermal ridge), progress zone

Question 45

Limb buds initially grow straight out laterally, followed by: UL _____ rotation by 90° & LL _____ rotation by 90°

Answer 45

lateral, medial

Question 46

By the end of 6th week, mesenchyme is condensing to form digital rays =

Answer 46

outlines of future digits

Question 47

Organized ______ of cells in AER divides paddle into 5 digits

Answer 47

apoptosis

Question 48

Meromelia

Answer 48

: absence of part of a limb

Question 49

Amelia:

Answer 49

absence of entire limb

Question 50

Polydactyly:

Answer 50

extra digits

Question 51

Syndactyly:

Answer 51

fewer digits