Craniofacial Developmental Disorders Flashcards
what is the definition of induction?
The process by which one tissue or cell influences another to differentiate/develop
(the process by which an undifferenciated cell is instructed by specific organisers to produce a morphogenic effect)
what is the definition of proliferation?
controlled cellular growth and accumulation of by products
what is the definition of differentiation
change in identical embryonic cells to become distinct structurally and functionally
what is the definition of morphogenisis?
development of specific tissue structure or differing form due to embryonic cell migration or proliferation and inductive interactions
what is the definition of maturation?
attainment of adult function and size due to proliferation, differentiation and morphogenesis
what weeks does the embryonic period of prenatal development take place?
beginning of the 2nd - the end of the 8th
what does the embryonic pattern arise from?
Arises from the spatial and temporal regulation of induction, cell proliferation, differentiation, morphogenesis and maturation
These processes cause the structure of the implanted blastocyst to become, with further development, an embryo
what is cytodifferentiation?
the development of different cell types
what is histodifferentiation?
the development of different histologic tissue types within a structure
what is morphodifferentiation?
the development of the differing morphology, which makes up its structure or shape, for each organ or system
what process increases the complexity of the structure and function of cells, during the embryonic period?
morphongenesis, the process of development of specific tissue structures or shape
At what week does a blastocyst take on distinct human characteristics and is now a recognisable embryo?
the 8th week of prenatal development (the end of the embryonic period)
what happens during the second week of prenatal development?
the blastocyst is implanted into the uterine wall
blastocyst grows by increased proliferation of the embryonic cells, with differentiation occurring resulting in changes in cellular morphogenesis
The increased number of embryonic cells creates the embryonic cell layers (germ layers) within the blastocyst
what are the 3 germ layers?
the mesoderm, endoderm and ectoderm
in the second week what is developed from the blastocyst?
a bilaminar embryonic disc - epiblast and hypoblast (2 layers)
in the third week, with the layers present the bilaminar disc has thickened into what?
a trilaminar embryonic disc
the epiblast layer is now considered the ectoderm and creation of the new embryonic cell layers (mesoderm and endoderm)
what happens during the 4th week of prenatal development (within the embryonic period)
the trilaminar embryonic disc undergos folding
This (for the first time) establishes the axis, which places forming tissues types into their proper positions for further embryonic development as well as producing somewhat a tubular embryo
what are dynamic interactions?
interactions that happen quickly
what are reciprocal interactions?
one is in control of another
what are sequentially interactions?
the timing of events
what are the 2 general types of phenomena that tissue interactions are associated with?
instructive and permissive
what is the instructive phenomena of tissue interactions?
the ability of one tissue to determine specific patterns of morphogenesis and differentiation that will develop in associated tissue
what is the permissive (or facilitative) phenomena of tissue interactions?
the ability of an interacting tissue to provide certain conditions that is necessary for its committed partner tissue to progress to full expression of its pre-determined phenotype
what are the future structures of the ectoderm?
epidermis; sensory epithelium of the eyes, ears, nose, nervous system, and neural crest cells; mammary and cutaneous glands
what are the future structures of the mesoderm?
Dermis, muscle, bone, lymphatics, blood cells and bone marrow, cartilage, reproductive and excretory organs
what are the future structures of the endoderm?
organs of the GI and respiratory systems (linings), liver and pancreatic cells
what is the origin of the ectoderm?
the epiblast layer
what is the origin of the mesoderm?
migrating cells from the epiblast layer
what is the origin of the endoderm?
migrating cells from the epiblast layer
what is the process that establishes the three distinct embryonic cell layers?
gastrulation
what does teratogenic mean?
able to disturb the growth and development of an embryo or fetus
what drugs are known teratogens involved in congenital malformations?
ethanol, tetracycline, phenytoin sodium, lithium, methotrexate, aminopterin, diethylstilbestrol, warfarin, thalidomide, isotretinoin (retinoic acid), androgens, progesterone
what chemicals are known teratogens involved in congenital malformations?
methylmercury and polychlorinated biphenyls
what ainfections are known teratogens involved in congenital malformations?
rebulla virus, syphilis spirochete, herpes simplex virus, human immunodeficiency virus (HIV)
