Term
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Definition
-thick layerof cells develop between layers of the trophoblast (externally) + yolk sac/embryonic disc/ amniotic cavity (interally) -spaces develop and join together to form a cavity →extraembryonic coelom |
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Term
| Formation of coelom splits mesoderm into 2 layers: name them and thier functions. |
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Definition
1. extraembryonic somatic mesoderm (lining trophoblast)
-covers amnion
2. extraembryonic spanchnic (visceral) mesoderm
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Term
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Definition
-is formed by 2 layers: extraembryonic somatic mesoderm and 2 layers of the trophoblast (cyto and synchatio) -wall of the chorionic sac
1. contains embryo, amniotic cavity, yolk sac
-connected by connecting stalk (primordium of the umbilical cord)
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Term
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Definition
-primary chorionic villi will form
-formed by projections of cytotrophicblast into syncytiotrophoblast
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Term
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Definition
-thickening of the hypoblast at cranial end of embryonic disc
-it’s a marker, it indicates where the mouth will form |
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Term
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Definition
-germ layer formation
-conversion of bilaminar disc to a trilaminar disc
-beginning of morphogenesis
**develepment of shape
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Term
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Definition
1. ectoderm
-nervous system, epidermis
2. mesoderm
-connective tissue, cartilage and bone, organs, muscle, blood vessels
3. endoderm
-epithelial linings of digestive system, respiratory system, ect. |
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Term
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Definition
-beginning of gastrulation
-thickening of the epiblast
*linear
*caudal
*midline
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Term
| mesenchyme forms a tri laminer disc, name each stage |
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Definition
-Epiblast→ectoderm(outer)
-mesoderm(jam)
-hypoblast→endoderm(inner)
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Term
| the disc remains in bi-laminar parts at which pars? |
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Definition
Disc remains bi laminar in 2 parts:
1. orophyryngeal membrane
-site of prechordial plate
2. cloacal membrane
-site of future anus
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Term
| Where is the cardiogenic area located? |
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Definition
Cardiogenic Area:
-above oropharyngeal membrane
-future site of the heart
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Term
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Definition
-from mesenchyme that migrates cranially from Hensen’s node
-in the middle layer
-linear and extends to the oropharyngeal membrane
-becomes the notocord |
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Term
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Definition
-Vertebral column is going to form around the notochord
-degerates where it is replaced by the vertebral bodies
-remains as the center of the IVD (intervertebral discs)-Called Nucleus Pulpolsus
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Term
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Definition
-formation of the neural tube
-primordium of the CNS
-notochord induces overlying ectodermo form →neural plate
-neuroplate is made of neuroectoderm
-neuroplate invaginates
-neuro fold fuse
-zip up and zip down
-neural tube formed
-ends of neural tube remain open
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Term
| name the two ends of the neural tubes |
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Definition
1. rostral neuralpore (top)
2. caudal neuropore (bottom)
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Term
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Definition
-derivitives of neural crest:
a. ANS ganglia
b. Spinal DRG
c. Schwann cells
d. 2 layers of the meninges →arachnoid and pia matter
e. cranial nerves V,VII,IX,X
f. pharyngeal arches
g. adrenal medulla
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Term
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Definition
-mesoderm on either side of notochord forms 3 longitudinal columns:
(medial to lateral)
1. Paraxial mesoderm (next to)
2. Intermediate mesoderm (middle)
3. Lateral mesoderm
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Term
| the blocks form from the paraxial mesoderm on which day? |
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Definition
-blocks start to form from the paraxial mesoderm (DAY 20 **MUST KNOW THIS!)
-formation cranial→caudal
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Term
| when is the somite period? |
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Definition
-somite period is day 20-30 (**Must KNOW THIS)
-38 pairs form
-by week 5 42-44 pairs form
-can determine age of embryo
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Term
| somite formation breaks up into 3 parts, name them! |
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Definition
-Each somite breaks up into 3 parts:
1. sclerotome→vertebrae +ribs
2. myotome→most skeletal muscles
3. dermatomes→dermis of skin
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Term
| Develepment of Intraembryonic Coelom |
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Definition
| -space develops in lateral mesoderm + join to form a cavity→intraembryonic coelom (primitive body cavity) |
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Term
| -formation of coelom splits mesoderm: name them |
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Definition
1. intraembryonic somatic mesoderm
2. intraembryonic splanchnic mesoderm
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Term
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Definition
| somaticpleure (embryonic wall) |
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Term
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Definition
| splanchnopleure (gut wall) |
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Term
| intraembryonic coelom forms? |
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Definition
-gives rise to :
1. pericardial cavity
2. pleural cavity
3. peritoneal cavity
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Term
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Definition
| -angiogenesis (blood vessel formation) |
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Term
| formation of the cardiac system |
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Definition
*1st begins in extraembryonic membrane
*2nd begins in embryo
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Term
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Definition
| -ALANTOIS (finger like outpouching form caudal yolk sac) |
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Term
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Definition
-primitive heart forms in cardiogenic area
-hooks up with blood vessels
-starts to beat day 21 or 22
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Term
| which system is our first functional system? |
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Definition
| -Cardiovascular system→1st functional System |
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Term
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Definition
| a. core of cyto into syncytio |
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Term
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Definition
-secondary villi (week 3)
a. core of mesenchyme into cyto
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Term
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Definition
teritiary villi (week 3)
a. blood vessels form mesehchyme to form →arterio-venous capillary network
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Term
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Definition
Cytotrophoblastic shell (week 3)
-formed by cytotrophoblastic cells penetrating thru top of the villi.
-anchors chorionic sac to the endometrium
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