1 and 2: development Flashcards
Mesoderm becomes what? (4)
gonads, kidneys, circulatory system, somites
Gastrulation happens in what day of development?
16-18
you can start driving a car from 16-18, ‘gas’ time
what direction in the bilaminar disk does the primitive streak form?
from caudal (tail end) to cranial.
Where is hensen;’s node in relation to the primitive streak?
anterior to it
Where do the cells that become mesoderm come from, and how do they migrate?
they come from the epiblast layer and they migrate, using the primitive streak, into the layer between the epiblast and hypoblast
(in order of what develops first to what develops last,) name the five main parts/types of mesoderm:
extraembryonic mesoderm, lateral plate mesoderm, intermediate mesoderm
paraxial mesoderm,
notochord
What days does neurulation BEGIN?
days 19-20
what does the eem or extraembryonic mesoderm become?
amnion, yolksac, etc
what does LPM, or lateral plate mesoderm become?
heart, vessel, gut wall
Love Plasma! Mmmmm! -says the vampire
what does the IM, intermediate mesoderm become?
kidney, gonads
IM sports: drink lots of water and dont get hit in the balls
what does the PM, paraxial mesoderm become?
skin, bone, muscle
PM nighttime “go to sleep and dont move a muscle”
What part of the PM becomes dermis of skin?
dermatome (derma, skin)
What part of the PM becomes skeleton (axial)?
sclerotome (sclera means white, and bones are white)
What part of the PM becomes limb and axial muscles?
myotome (myo, muscle)
somites develop in what day of development?
day 17, from paraxial mesoderm
What Weeks does neurulation happen in?
Week 3-4,
my brain is mush at 3-4 pm
what developmental week does folding happen in?
Week 4
how many sets of somites will develop?
44 but you dont keep all of them
What are the two parts of the LPM?
somatic and splanchnic mesoderm
what does the somatic mesoderm become?
limb skeleton
soma means body, and you can move your body without limb skeleton. “it’s what makes your ‘soma’ tick!”
What does the splanchnic mesoderm become? (4)
blood cells, heart (muscle), walls of GI (smooth muscle), and walls of respiratory system (smooth muscle)
“bleeding hearts always go with their gut! take a breather!”, explains nick. (splains nic)
two main kinds of bone development?
intramembranous ossification and endochondral ossification (cartilage mediated)
when does membranous ossification of neurocranium start and how long does it last?
9th week, (months 3-9 fetal period)
What are the somite-like structures in the cervical region?
8 somitomeres that condense down to 4
what do the somitomeres in the cervical region become? (3) and what innervates the structures?
occipital bone (partly), intrinsic mm. of the tongue, palatoglossus m., and it receives innervation from hypoglossal
Neural crest cells contribute to the formation of the facial bones by first developing….what?
the branchial arches.
the skull base is formed with what type of ossification?
endochondral ossification
the skull (calvaria and not base) is formed with what kind of ossification?
intramembraneous ossification
the frontal part of the skull is from what cell origins?
Neural crest cell
the posterior portion of the skull is from what cell origin?
mesodermal origin
the body and ramus of mandible is from what cell origin, and how is it formed?
neural crest cell origin, intramembraneous ossification
the condyle, coronoid, and symphysis of the mandible is from what cell origin, and how is it formed?
neural crest cell origin, endochondral ossification
when does the the lip fusion occur? (mid facial development)
weeks 4-5
usually dinner is at five and you gotta have lips before you eat dinner at 5
consequences of Fetal Alcohol Syndrome?
Cleft lip and palate
failure of neural tube closure causes?
anencephaly, exencephaly, spina bifida
When does human limb development begin?
5 weeks (finishes up at 8 weeks), you can see limb buds at 31-32
limbs develop from what mesoderm? (2)
paraxial and lateral plate mesoderm
limb bones and connective tissue comes from what mesoderm?
lateral plate mesoderm
limb bones form by what kind of ossification?
endochondral ossification
What signaling causes interdigit area (webbing) to go away through apoptosis?
BMP signaling
What must occur to correctly orient the lower limbs?
limb torsion, (because lower limbs grow outward but they have to face forward)
Type of myoblast that can actually divide and can aid in repair?
satellite cells
What protein is expressed after limb bud outgrowth and localizes to the AER?
Fgf8
What happens if you remove AER?
limb development arrests at the stage it was removed
Digit identity is patterned by what protein?
SHH
How is Anterior posterior (pinky to thumb) patterning of digits regulated?
SHH is more concentrated towards the posterior of limb bud which causes pinky development, and the decreasing concentration leads to the more anterior digits. Pinky (v),…. index (ii) and thumb (i)
insufficient apoptosis signaling in digit formation leads to?
syndactyly (fused digits)
Dorso-ventral patterning of limb is regulated by?
Dorsally: WNT-7a and “radical fringe” expressed which induces LMX-1 in the mesoderm.
Ventrally: Engrailed-1 expression inhibits wnt7a and r-Fng.
AER is the border between the two.
What molecular signals distinguish forelimb from hindlimb?
upper limb/forelimb: TBX5
lower/hindlimb: TBX4
what genes act as switches and control pattern formation during development?
Homeotic/HOX genes (it’s the reason why limbs form at the correct axial level)
How is HOX code used for limb patterning?
Proximo-distal patterning
knock out of Hox11d leads to ?
no radius or ulna
What is amelia and what causes it?
failure of developing an entire limb, caused by loss of AER and FGF8 signaling
How does thalidomide (drug) affect limb development?
it prevents limb angiogenesis in the proximal limbs so it “withers away” and no limb forms
What is phocomelia and what causes it?
partial loss of limb, caused by FGF/HOX/angiogenesis (thalidomide) disruption
what is polydactyly, and what causes it?
duplication of digits, caused by disrupted Shh/Gli3 function, usu Auto Dominant but Auto Rece. with ellis van creveld syndrome
What inheritance is Ellis van creveld?
Auto Recessive
Common signs of Ellis van creveld sydrome?
DENTAL DEFECT
skeleton defect
polydactyly
Prune belly sign?
no abdominal muscles
Cause of torticollis or wry neck?
Sternocleidomastoid muscle too short
