Concepts and Mechanism of Development Flashcards
4 developmental processes
Growth
Cytodifferentiation
Morphogenesis
Patterning
4 developmental processes are all ___ and usually ___
interrelated
interdependent
increase in the size of a part or the entirety of the organism by increasing cellular size (hypertrophy) and/or number of cells (hyperplasia)
Growth
growth is not proportionate in all body parts
Allometric growth
growth rate of all body parts of the body occurs at the same rate as the overall growth of the body
Isometric growth
mechanism by which tissues and organs are shaped
Morphogenesis
process whereby embryonic cells organize into tissues and organs
consequence of regional gene expression
Patterning
formation of the cranio-caudal axis comes with ___, whereas the proximo-distal axis is ___ until limb formation
gastrulation
delayed
process whereby specialized cell types from less specialized
Cytodifferentiation
an event preceding cell differentiation
cell commitment
*cell commitment
divided into labile, reversible phase referred to as
cell specification
*cell commitment
followed by an irreversible one called
cell determination
process when embryonic stem cells commit to one specialized function
cell determination
process in which cells develop their specialzed shapes and function
cell differentiation
a cell is fixed and it will irrevocably differentiate
cell determination
ability of the cells to produce all the differentiated cells in the body
totipotency
developmental potential
potency
having equal effects or capacities
equipotent
cells individually give rise to all cells of the embryo proper
cellular totipotency
ICM and epiblast, retain the ability to form all tissues of the embryo proper but lose competence to form extra embryonic tissues
pluripotency
cells within each of these somatic germ layers
multipotent
tissues specific progenitor or precursor cells
unipotent
fully matured and no longer divide
terminally differentiated
process by which tissue interact with other tissues in the body
failure to interact may result to non development of a certain tissue or organ
tissue interaction
occur by ___ - interaction at close range between two or more cells
induction (proximate interaction)
the group that controls the differentiation of the other group
-optic vesicle induce the lens formation from the surface ectoderm
inducing cells
the dependent group
when the optic vesicle was removed, no lens was formed
induced cells
ability to respond to a specific inductive signal
competence
genetically programmed death of cells in the interdigital zone/necrotic zone for the normal development of the digits
apoptosis
principal intracellular mediators of apoptosis
caspases
those carried in the genes which are either caused by a single or multiple genes
intrinsic/hereditary factors
*Congenital malformations
caused by an extra 21st chromosome (trisomy 21) - may result to heart defects
down syndrome
those caused by teratogens
extrinsic/non hereditary factors
those agents that caused induced birth defects
teratogens
targets the ectoderm, hence defects arise from this germ layer
virus-rubella (german measles)
medicines for virus-rubella (german measles)
-thalidomide (Thalomid), angiotensin-
converting enzyme (ACE) inhibitors, statins, the acne
medication isotretinoin and lithium.
The teratogens that enter the the mother via the ____ or ____, the actual teratogenic effect can either be modified to lessen the effect or to be more embryopathic as a product of maternal metabolism
digestive tract or placenta
the most critical period of most structures is during ___ and ___ - at this stage the issues are the most sensitive to disruption by exogenous factors
blastula and gastrula
____ and ____ are sensitive to teratogenic insult throughout prenatal and even postnatal in most species
This is due to late development of the neurons in the cerebrum and cerebellum
CNS and heart
At neurula stage few organs will be affected
Oftentimes, an induced lesion in one system will result in the ____ in other organs
secondary malformations
____, ____ and ____ (behavioral teratogens) cause irreversible defects in cognitive and motor dev’t.
tranquilizers, sedatives and anticonvulsants
