Odontogenesis: cellular and Molecular Flashcards
number of chromosomes in people
22 pairs of autosomes
1 pair of sex chromosomes
Germ cells
Gametes (spermatozoa and ova)
what do gametes hold
1 chromosome from each pair of chromosomes
DNA that encodes a protein product
Gene
Genomic DNA is converted to mRNA in the nucleus
Transcription
mRNS serves as a template for making a protein out of amino acids in the cytoplasm
Translation
Different versions of the same gene
Allele
Genetic makeup of an individuals (what alleles do they carry)
Genotype
Observable characteristics from the genotype and envrionment
pHenotype
A change in nucleotide sequence of a gene
Mutuations
Mutation in germline is what
Heritable and passed to offspring
A hereditary disease that affects bones and teeth
Osteogenesis imperfecta (OI)
what is mutatated in Osteogenesis Impoerfectta
COL1A1 (type I collagen)
what type of mutation is Osteogenesis imperfecta
Autosomal dominant
what is the result of an autosomal dominant mutation
1 mutant allele is enough to cause OI phenotype
Shows up in nearly every generation (50% of chance in offspring)
what kind of disease is Supernumerary incisor
Autosomal recessive
what is needed for autosomal recessive diseases to show in the phenotype
2 mutant alleles to change phenotype
how does Autosomal recessive diseases show
not every generation, as both parents need to at least be a carrier of the gene
the processes of a generalized cell become specialized for a job
Cell differentiation
what changes in cell differentiation
size, shape, products, activities, divisions
what is the product that initiates differentiation
induction
an agent that procides cell with a signal to differentiate
Inducer
what must a cell be to respond to an inducer
must be competent to receive the signal
the ability of a cell to receive and respond to a molecular signal
Competence
what is needed for cellular competence
Receptors
Internal machinery
what inducer binds to cell surface BMP receptor type I or II
Bone Morphogenetic protein (BMP)
what inducer binds to intracellular vitamin D receptor
Vitamin D
What inducer binds to cell surface LRP6 and Frizzled Receptor
WnT signal
what is cell signaling
Transfer of information to cuase change in cell gene expression and function
what are some cell signals
Signals
Growth factors
Inducer
Ligand
types of cell signaling receptors
Membrane
Intracellular/nuclear
what happens in cell signalling
Inducing signal comes from outside cell
Cell is competent to receive it
Intracellular changes
Cell function changes
Effects of cell signaling
Cell Differentiation
Cell Proliferation
Cell Migration
what is cell signalling
Secreted chemical signal directs changes in target cells that express receptors
what controls gene expression
Transcription factors
what are transcription factors
Proteins that control whether genes will be transcribed into mRNA
how many genes can one TF control
tens to hundgreds of genes
what do TF do for target genes
can activate or repress expression
what are Pleiotropic effects
1 mutations causes lots of systems to be affected
Amino acids in the DLX family
214 amino acid TF
what does a a mutation in DLX3 lead to
Pleiotropic effects
what does DLX3 regulate
Hair folicle differentiation (BMP signaling)
Enamel genes (Amelogenin, Enamelin, Kallikrein 4)
Bone (formation, resporption, hemostasis)
what mainly happens in weeks 0-4 of development
mostly proliferation and migration
what happens in week 4 to 8
cell differentiation
Morphogenesis
Formation of major external and internal structures
Morphogenesis
what happens in week 8 to 40
Growth and maturations
what are the 2 stages of prenatal development
Embryo(0-8 week)
Fetus(8-40 week)
the inner cell mass of the Blastocyst stage
Embyroblast
what does the Embryobalst form
All tissues of the embryo
what are the cells of the embryoblast
Embryonic stems
the outer cells of the blastocyst
trophoblast layer
when is the Morula
3-4 days
what does the Blastocyst form
day 5-13
what are the layers of the Bilaminar embryo
Ectoderm- dorsal
Endoderm- ventral
what do he ectoderm cells look like
Columnar cells
What do the endoderm cells look like
More cuboidal
how does the mesoderm form
Ectodermal cells converge to the midline to form the primitive streak
Extoderm migrate through the streak between the ectoerm and endoderm to create the mesoderm
what is the conversion to a trilaminar embryo
Gastrulation
when does gastrulation occure
3rd week
what layers make up the buccopharyngeal membrane
Extoderm and endoderm without any mesoderm
what eventually forms the notocord
Cephalic (more rostal) migrating cells
when does Rostro-caudal(front back) folding occure
week 4
why does Rostro-caudal folding occur
directed growth at both ends
when does lateral (side to side) folding occure
week 4
what happens in lateral fodling
middle parts grow upwards and close to form the neural tube and neural crest cells
lateral parts of the ectoderm grow downwards to sournd the endoderm
what does Rostral-caudal folding form
A mouth
The primitive oral cavity
Stomatodeum
what defines the most rostral boundry of the primitive gut
Buccopharyngeal membrane
what origin are neural crest cells
Extoderm
where are neural crest cells formed
Adjacent to neural tube to separate from the neural plate when the neural tube closes
when does the neural tube close
day 22/end of 3rd week
what do the Neural crest cells do
Migrate and differentiate extensively
what do Cranial Nueral crest cells undergo
Epithelial- mesenchymal transformation
other name for Crnail neural crest cells
Ectomesenchymal cells
why are Cranial neural crest cells also called ectomesenchymal cells
Act like mesenchyme to form the connective tissues of the head
what part of Cranial neural crest cells is important to dentist
Create the connective tissue of teeth and supportive tissues
why are neural crest cells important
Become some of the craniofacial bones Cranial and sensory ganglia and nerves Adrenal medulla dentin Periodontal ligaments Alveolar bonds
where do skeletal bones come from
Mesoderm