BONE DEVELOPMENT ACH Flashcards
(102 cards)
1
Q
when is the critical period for the development of skeleton, muscles and limbs
A
week 4
2
Q
when does neural tube begin to close
A
week 4
3
Q
where are somitomeres derived from
A
paraxial mesoderm
4
Q
what induces formation of the somitomeres
A
neural tube
5
Q
how does somitomere development progress and what regulates it
A
rostal to caudal
6
Q
what do somitomeres become when they are compacted and bound by epithelium
A
somites
7
Q
how many pairs of somites
A
42-44
8
Q
pairs 1-7 of somites
A
do not compact
9
Q
what do the 1-7 somites contribute to
A
head and neck structures
10
Q
what do mesodermal cells from somites give rise to
A
dermomyotome
11
Q
what does dermomyotome give rise to
A
dermatomes
12
Q
dermatomes
A
skin, dermis, subcutaneous tissue
13
Q
myotomes
A
skeletal muscle of trunk and limbs
14
Q
sclerotome
A
bone
15
Q
what makes up mesenchyme
A
multipotent cells
16
Q
where is mesenchyme derived from
A
mesoderm or neural crest
17
Q
notochord leads to..
A
neural plate and neural tube development
18
Q
neural tube develops to..
A
somites
19
Q
intramembranous ossification
A
mesenchymal cells differentiate directly into osteoblasts
20
Q
where does intramembranous ossification occur?
A
flat skull bones
21
Q
endochondral ossification
A
mesenchymal cells are transformed into chondroblasts that lay down hyaline cartilage
22
Q
what causes primary ossification centers to form?
A
periosteal capillaries bring in osteogenic cells into the diaphysis
23
Q
what do osteoblasts do?
A
lay down minearlized matrix that replaces cartilage
24
Q
what continues to lay down cartilage until we’re about 20
A
growth (epiphyseal) plate
25
which direction do growth plates grow
diaphysis toward epiphysis
26
where do secondary ossification centers form?
ephiphyses (ends)
27
when do most secondary ossification centers form?
postnatally
28
abnormality of conversion of cartilage into bone. Most common form of dwarfism.
achondroplasia
29
what bones does achondroplasia affect?
long bones
30
enlargement of head, hands, and feet due to excess growth hormone secreted by pituitary after closure of epihyseal plates
acromegaly
31
excess growth hormone before growth plates close (during childhood)
gigantism
32
autosomal dominant disorder due to mutation in gene for fibrillin that affects connective tissue - results in long thin limbs
marfan syndrome
33
extreme bone fragility, spontaneous fracture may even occur in utero, defect in type I collagen gene
osteogenesis imperfecta
34
hip joint gets flattened due to misgrowing of cartilage in the hip - head of femur can slip out
congenital hip dysplasia/dislocation
35
mesenchyme between hyaline cartilage models is replaced by fibrous tissue or fibrocartilage
fibrocartilaginous joints
36
where are fibrocartilaginous joints
sutures in the skull
37
where chondroblasts condense around ends of bones and across space to form articular surfaces and joint capsules
synovial joints
38
what can cartilage between epiphyses remodel into?
menisci
39
where does myotome originate from?
paraxial mesoderm
40
what do myoblasts give rise to
myotubes
41
what do myotubes develop
myofilaments
42
what do the myofilaments do for skeletal muscle
give skeletal muscle fibers their striation
43
what cells reside in the muscle and can make new myocytes in response to exercise
satellite cells
44
where does smooth muscle of the gut, respiratory and mesenteries originate from?
splanchnic mesoderm of lateral plate
45
what gives rise to smooth muscle in the walls of the vascular system of the head, limbs and body wall
somatic mesoderm
46
what gives rise to myoepithelial cells of the mammary and sweat glands and smooth muscle of the iris
ectoderm
47
where does cardiac muscle originate from
splanchnic mesoderm
48
T/F. cardiac myblasts fuse.
False. They develop into individual cells.
49
type of ossification that forms the vertebral column
endochondral
50
what do sclerotomes split into?
dense-caudal
51
what separates the two parts
intersclerotomic (von Ebner's) fissure
52
what is resegmentation
caudal part of one segment fuses with the rostral part of segment below so each vertebra is intersegmental
53
what fuse to form the spinous processes
sclerotome forms vertebral arch. left and right arches fuse
54
what is nucleus pulposis derived from/
notochord
55
what is annulus fibrosis derived from
sclerotome
56
where do arteries exit
loose cephalic (at the level of the body)
57
where do spinal nerves exit
at the level of the disc
58
condition that results from failure of the neural tube to close
spina bifida
59
least severe form of spina bifida. often marked by tuft of hair but no obvious symptoms.
spina bifida occulta
60
spina bifida form in which meninges protrudes through defect in spinal cord or skull
meningocele
61
spina bifida form in which meninges and spinal cord protrude through the defect
meningomyelocele
62
form of occult spinal dysraphia in which neural ectoderm fails to completely separate from the surface ectoderm. spinal cord may be tethered.
Congenital dermal sinus
63
caused by failure of ossification center on one side of vertebral body.
congenital scoliosis
64
shortened neck due to non-segmentation of cervical vertebrae. limited movement of neck and low hairline.
congenital brevicollis (Klipper-Feil sequence)
65
concave chest caused by issues with sternal bars fusing and forming cartilage models of manubrium, sternum, and xiphoid
pectus excavatum
66
chest pushes outward
pectus carinatum
67
what do ribs develop from
costal processes of thoracic vertebrae
68
what forms from rib development?
costovertebral synovial joints
69
rib that can compress neurovascular structures supplying upper limb.
cervical rib C7 - occurs in thoracic outlet syndrome
70
what do myotomes divide into?
epimere and hypomere
71
what do myoblasts in the epimere form?
deep back muscles (erector spinae)
72
what innervates epimere muscles
dorsal primary rami
73
what do myoblasts in the hypomere form
intercostal muscles
74
what supplies the hypomere muscles
ventral primary rami
75
underdevelopment or absense of pectoralis muscles, usually unilateral
poland syndrome
76
poor development of abdominal muscle wall causing skin to wrinkle, often accompanied by urinary tract abnormalities, delays in sitting and walking
prune belly syndrome
77
spasm or shortening of one side of sternocleidomastoid muscle so head is twisted to one side
congenital torticollis
78
when do limbs between to develop
week 4
79
what limb develops first
upper limbs
80
what genes control positioning of limbs
homeobox genes
81
what mesoderm contributes to limb components
somatic and somititc mesoderm
82
somites for upper limbs
C5-T1
83
somites for lower limb
L2-S2
84
core of limb bud is..
mesoderm
85
outside of limb bud is..
ectoderm
86
when the ectoderm thickens what's formed?
apical ectodermal ridge (AER)
87
what does the AER secrete
FGF
88
what does FGF do?
stimulates growth and development of mesenchyme
89
what do cells further from AER become
cartilage and muscle
90
what happens to form the digits
apoptosis in certain areas of AER
91
specialized mesenchymal cell that responds to FGFs from AER
zone of polarizing activity (ZPA)
92
what does ZPA do
secretes factors that determine axis...like sonic hedgehog gene
93
what does the sonic hedgehog protein do?
determines anterior and posterior axis (thumb vs. little finger, great toe vs baby toe)
94
when do limbs rotate
week 8
95
which way do the thumbs rotate
90 degrees laterally
96
which way do the toes rotate
90 degrees medially
97
absence or malformation of one or more limbs
amelia
98
partial absence of one or more limbs, shortened limb with/without hand or foot attached, limbs resemble flippers
meromelia or phocomelia
99
drug that was teratogenic that was prescribed for morning sickness
thalidomide
100
duplication of digits, most common is little finger
polydactyly
101
failure of apoptosis that results in webbed fingers and or toes
syndactyly
102
fusion of adjacent digits but nothing in the middle.. leads to unusual positioning of the foot
clubfoot
