Vetan Topic 2 and 4 Flashcards
What are the five processes that take place during early developmental stages?
- growth
- morphogenesis
- patterning
- cytodifferentiation
- tissue interaction
It refers to the increase in the number or size of cells that results in the increase in mass of the organism.
growth
Process which refers to the entire group of processes that mold the external & internal
configuration of the embryo. This involves a change in the shape or location or even
death of a cell or tissue.
morphogenesis
elongation of epithelial cells. Ex. elongation of epiblasts during gastrulation.
epithelial expansion
programmed degeneration & eventual death of
cells in areas called necrotic zones
normal cell death or apoptosis
outward folding or outpocketing of the epithelium. Ex. development of optic vesicle from neural tube
evagination
downward migration of epithelium with secondary, tertiary branches given off from the main branch. Ex. development of lung and duct system
of major salivary glands.
budding and branching
separation of an invaginated epithelium from the original epithelium; the second stage in more complex morphogenetic reorganization. Ex.
formation of neural tube
vesicle formation
infolding or depression of epithelium to form a pit or groove; often the first stage in more complex morphogenetic reorganization. Ex. formation of neural tube
invagination
focal thickening of surface ectoderm, often in response to an underlying mesenchymal aggregation
placode formation
grouping of mesenchymal cells to form a densely
packed subpopulation within a mesenchymal tissue. Ex. formation of enamel organ
and vertebra.
mesenchymal aggregation
migration of epithelial cells to the underlying area to form mesenchymal cells. Ex. formation of mesoderm
delamination
is the establishment of invisible blueprint of cell
subpopulations that serves as a guide in the formation of a particular tissue or organ
patterning
complex tortuous process by which each cell or cell line attains and expresses a stable phenotype or a process by which a cell becomes specialized
and the final product is a differentiated cell
cytodifferentiation
is a process in which the presence of one tissue
or structure induces or causes the development of another tissue or structure
tissue interaction or tissue induction
period or the time during which each organ system in the body is being formed and obligatory inductive tissue interactions and morphogenesis are occurring
critical period
genes that cause congenital defects
deleterious genes
Causes of congenital malformation or defect?
- Hereditary or genetic factors
- Environmental factors
What are the teratogens transmitted directly to the embryo through the maternal-placental fetal interaction? (4)
- radiation
- viruses
- steroid hormones
- low molecular weight compounds
induces birth defects during closure of neural tube resulting in eye, brain and heart defects
hypervitaminosis A
occurs in the epiblast of the embryonic disk, a
relatively small area of the blastocyst when compared to the extraembryonic trophoblast
formation of the primitive streak
defines the longitudinal axis of the embryo and indicates the start of germ layer formation.
primitive streak
The primitive streak presents at its
cranial end the primitive (Hensen’s) node that presents a central deep hole called
primitive pit
What is the process of epiblast migration to form endoderm and mesoderm is called?
involution
closely adjacent to the overlying ectoderm of the
embryonic disk and the trophoblast
somatic mesoderm
closely related to the underlying
embryonic endoderm and hypoblast
splanchnic visceral mesoderm
somatic mesoderm and the embryonic ectoderm and trophoblast eventually combine to
form the?
somatopleure
It is the central pale oval area of blastoderm
area pellucida
the dark area peripheral to the area pellucida
area opaca
What is the rod-shaped aggregate of epiblast cells located cranial to the primitive streak?
notochord
What is the ultimate fate of the notochord?
nucleus pulposus of intervertebral discs
In birds, when the primitive streak has completely regressed, the epiblast cells on the surface of the embryonic disk constitute what germ layer?
ectoderm
Five characteristics of neurulation.
i. Formation of the central nervous system
ii. Formation of the head process
iii. The initial development of the gut
iv. Formation of somite
v. Initial development of the heart
it is the result of the thickening of the surface ectodermal cells along the dorsal midline of the embryonic disk overlying the notochord
neural plate
neural plate becomes depressed
to form _______ and the edges of the neural plate becomes raised or elevated to form
NEURAL FOLDS
neural groove
first part of the gut tube that is formed is the
foregut, whose most rostral tip eventually becomes the?
pharynx
What is the future of the foregut?
pharynx
These are blocks of mesoderm derived from paraxial mesoderm located just lateral to the notochord
somites
less-developed somites
somitomeres
somites which forms skeletal musculature.
myotome
somites which forms most of the axial skeleton: vertebrae, ribs and bone of the skull
sclerotome
somites that migrates to form the skin dermis
dermatome
cardiogenic mesoderm on either side forms endocardial tube and the two endocardial tubes fuse to form a single?
cardiac tube
The fused endocardial tubes and cardiogenic plates become the ______ which is composed of epimyocardium
cardiac tube
it holds the cardiac tube in place
dorsal mesocardium
The fused ventral parts of splanchnic mesoderm
become the _______ ________, which degenerates almost as soon as it is formed, giving
way for the R and L pericardial coeloms to fuse and communicate.
ventral mesocardium
subcephalic pocket created during the formation of the head process forms bilateral margins designated as the?
lateral body folds
