01 Embryology dev/fertilization Flashcards
Embryo is what time period?
Fertilization to 9 weeks
Fetus is what time period?
9 weeks to birth
Neonate is what time period?
birth to 1 month
Infant is what time period?
1 month to 2 years
Cleft palate issues are primarily what?
cosmetic
The 2nd largest effect of cleft palate is?
Speech
Meiosis is a specialized process of what?
cell division, because it results in a split/division of chromosomal material
the process of cell division that leads to a sperm or a egg
Meiosis results in a __________ number
haploid
A gamete is what type of cell?
sexual germ cell
what does the haploid number mean?
it’s division of half, 23 pairs (46 chromosomes in every cell)
What is the developmental timeline?
zygote –> blastomere –> morula –> blastocyst –> gastrulation –> embryonic disc
what is a zygote?
it is a one simple nucleated cell (46 chromosomes)
it forms during the first 24 hours
sperm meets egg (gametes)
what is a blastomere?
once the cell makes it’s first division
continues for 72 hours (it is not cell differentiated)
biggest of the 2 cells divide into 3, and so on
continues
Meiosis creates _____ –> _____ create the zygotes –> and from here on out cell division is going to be mitosis
gametes; gametes
What is mitosis?
- Regular/basic cellular division that creates another cell exactly like it
- It takes place in every cell
the complicated process of cell division can be broken into two major categories
segmentation and cell differentiation
Segmentation is what?
- Once cell divides, and makes another cell just like it
- Duplication of the chromosomes and the division of cytoplasm
- Process continues throughout the lifespan of any organism
What are examples of segmentation?
- Blastomere
- Morula
The morula forms when?
- after 72 hours
- it floats in the fluid of the uterus
- It does not have a wrapping yet
What is cell differentiation?
- Programmed to differentiate and divide the chromosome
- so the chromosomal content of a cell is the map that change the cells
When does cell differentiation begin to occur?
between 3-6 days when the blastocyst attaches to the uterine wall
What is a blastocyst?
it develops at roughly 6 days
it also develops 1. Trophoblast 2. Inner cell mass
What the trophoblast?
- the wrapping
- This is due to cell differentiation in the blastomere itself—the wrapping comes from the organism not the uterus
later, the trophoblast becomes what? and the inner cell becomes what?
- the trophoblast becomes the umbilical chord and placenta
- the inner cell mass becomes the embryo
After the blastocyst forms the trophoblast and inner cell mass what happens next? what day does it happen?
Gastrulation and it occurs between the 9th and 10th day
What happens in gastrulation? Why is it important?
This is when the inner cell mass turns inside out
If gastrulation fails a mother will have a miscarriage
Lots of cell differentiation occurs and is much more susceptible to damage
At about 12 days what happens?
The embryonic disc forms, it is an organized group of cells
In the embryonic disc this is the first time the organized differentiation = tissues. What are the three tissue layers?
- Ectoderm
- Mesoderm
- Endoderm
What does the ectoderm form?
Outerlayer of inner cell mass that contacts air (skin hair, teeth) AND the nervous system (both peripheral and central)
everything that communicates with the environment
What does the mesoderm form?
creates the connective tissues of the body; the structural element—bones, cartilage, and blood vessels)
What does the endoderm form?
the inner skin that lines the digestive tract, thoracic cavity,
Organs are tend to be a cross section of what two layers?
Endoderm and mesoderm
chromosome–>_______–> DNA –> ______
genes; nucleotide pairs
what are chromosomes?
they are made up of genes
they are different in size and shape
you HAVE to get this order right because they hod the genes!
What are genes?
- A region of DNA that controls a hereditary characteristics
- It corresponds to a sequence used in a production of a specific protein or RNA
- blue print for our behaviors and physical characteristics
What is the function of the genes?
genes carry a trait and some are switches that turn it on or off
DNA
They are made up of Nucleotide Pairs
Nucleotide Pairs
- A set number and order that makes up a specific strand of DNA
- Highly regulated pairs
What are the 4 amino acids in a nucleotide pairs
- Thymine
- Adenine
- Guanine
- Cytosine
In a nucleutide pair what goes with what?
T and A ; G and C
Nucleotide pairs make the codes that provide instruction for what?
- shape/form: your physical appearance and function
- Code for behavior, outward appearance, etc.
Genetic instruction govern _______
function
- these strands that make up the genes that code the function for an organism
- Ex. Brain function = too much dopamine, adrenaline, hormones etc.that regulate your personality or digestive system
What is the karyotype
it is a a picture of someone’s chromosomes–different pairs
Autosomes are the first _______ pairs
22 different pairs–many disorders originate here
Sex chromosomes are
the last pair
what is the waist of a chromosome called? the long arm? the short arm ?
Centromere
long arm: q
short arm: p
Chromosome _____ has the most genes and chromosome_____ has the least # of genes
1 vs. y
which is why most disorders are linked to boys because is the information is missing, it’s really missing there’s not back up like two x’s for girls
Genes appear as bands on the chromosomes the
dark band shows what in comparison to light bands
dark band: high concentration of genes
light band: low concentration of genes
What is a anomoly?
there’s a difference
what is a syndrome?
a single cause, with multiple constellation of symptoms that trace bak to a single cause
What is a sequence error?
When one anomaly is due to another anomaly
it’s a chain of events
ex. pierre robant sequence
T/F during continued growth of the embryo the pieces are already in place for normal or abnormal development
True
Mutation is what?
an error in replication
it is In the duplication of the chromosomal genetic material = mutation
It can happen anywhere in the process of utero development and across all aspects of cell function
a mutation in early process of development is devastating
What are the various types of mutation?
Spontaneous: the parents are normal but offspring is not (most common)
inherited factor: one of the parents are normal, but the other isn’t so offspring will inherit it
Teratogen: mutation due to poison or disease
Name the typical mutations at a chromosomal level
- Monosomy
- Trisomy
- Deletion
- Inversion
- Translocation
- Dysmorphology
what is monosomy vs. trisomy
Monosomy: one of the chromosomal pairs will not be a pair (so only 22 pairs will be present)
Trisomy: the chromosome pair is present but they have an extra copy of one of the chromosomes (ex. downs)
what is deletion vs. inversion
deletion: the chromosome pair is present but on one of the chromosomes has a genetic deletion
(Note: deletions can have sone or no effects)
Inversion: the genetic the material is there but it is turned 180 degrees around (it is rendered useless because order and number are wrong
what is translocation? and what types of variable expression does it have?
A piece of information that is not on the correct gene, it’s some place else
it has variable expression:
- phenotype-
- genotype-the construction of the chromosome
T/F The exact same mutation in two people does not have the same results
True
What is incomplete penetration
There is an individual carrying the gene for the condition but no expression of the gene in the phenotype
what is dysmorphology?
it’s the wrong shame of the gene
this is expression in the genotype and phenotype
It has nothing to do with the genetics of the parents it’s just that something looks wrong
What is autosomal dominance vs recessive genes
Dominant: The abnormality can be carried on; and it most cases it is. The normal donor does not override the abnormal gene
Recessive: does not show up in the offspring unless both parents carry the traits
What is x-linked vs. multifactorial?
x linked are carried by the moms (ex. fragile x syndrome)
multifactorial: Some interaction between the chromosomal genetic function and the environment
In a chromosome analysis you are looking at what?
- Looking at karyotype and make up of genes
- Find a piece of a gene that is missing, inverted, etc. from the chromosomal pair
- These different proteins will attract or reflect exposure to different chemicals
Clefting can be ______ or ________
spontaneous mutation or part of a syndrome
Describe Spontaneous mutation of clefting
- Usually caused by mutated genes, not very often an inherited factor
- The chance of transmitting the gene (IF I carry the gene) to the child is only 5% more than a normal
Describe syndromic clefting
This will be passed along if part of a craniofacial syndrome
More information is tampered with, it’s more complication
