Embryology Flashcards
Name the 5 subsets of teratogens
physical
chemical
nutritional
hormonal
infection
What is the cell mass known as in 0-3 weeks
conceptus
what is it called during the 3-8 week period
embryo
what is the embryo called from 9 weeks to term
fetus
what is an example of a chemical teratogen
smoking or alcohol consumption
What are the 6 stages of embryogenesis
gametogenesis
fertilisation
cleavage
gastrulation
morphogenesis
organogensis
What happens during cleavage
rapid cell division (no increase in cell size just smaller cells as they divide)
What is fertilisation
formation of a diploid zygote
What is gastrulation
the conversion of a bilaminar disk to a trilaminar embryo
name the three layers formed after gastrulation
endoderm ectoderm and mesoderm
what does the endoderm go on to produce
digestive system, liver, pancreas and lungs
what does the ectoderm form
skin nervous system hair and nails
what does the mesoderm form
circulatory system, skeletal and muscular and epithelial layer of the lungs
what is the primitive streak
the first evidence of gastrulation
What does the trophoblast differentiate into
cytotrophoblast and syncytiotrophoblast
The ventral epiblast and dorsal hypoblast are differentiated from what
embryoblast
What is the chorionic cavity formed from
extra embryonic mesoderm cavities
Why do the maternal blood vessels rupture
because of the trophoblast embedding in the uterine epithelium
What makes up the blastocyst
blastocele (cavity), embryoblast (inner cell mass) and trophoblast (outer cell mass)
Around when does the blastocyst come in contact with the uterine wall and implantation occur?
Day 6
What is compaction
where the blastocysts are stacked closely with each other
Once cell division creates 16 blastomeres, the cell mass is called?
morula
What is the zona pellucida
glycoprotein covering the oocyte for protection
What attracts the sperm to the ampulla
progesterone and the warmer temperatures
What is an ectopic pregnancy
Where the embryo implants outwith the uterine cavity causing an expansion to where the tubes might burst causing a haemorrhage
What is capacitation
once the head of the sperm comes in contact with the ZP it releases acrosomes (enzymes) allowing the permeability of the ZP to change and allow better fertilisation with the oocyte
What is body folding
the connection of the different layers of the embryo (mesoderm ectoderm and endoderm) to form a 3D morphology/body plan of the embryo
What produces the zona pellucida
follicular cells
what is organogenesis
the formation of organs and organ systems
What is the spermatogonial phase
the mitotic division of the sperm cell into two daughter cells
What is the spermatocyte phase
meiosis I and II that eventually produces the four haploid daughter cells (spermatids)
What is the spermatid phase
the spermatids differentiate into mature sperms and morphology
When does spermatogenesis begin
at puberty
meiosis 2 occurs regardless of whether fertilisation occurs
false
meiosis 2 occurs only when fertilisation has occurred
When does meiosis 2 occur of the oocyte
after capacitation occurs
‘A mature haploid male or female germ cell which is able to unite with another of the opposite sex in sexual reproduction to form a zygote’
A zygote
B embryo
C gamete
D fetus
C gamete
Which phase of spermatogenesis involves cell division by mitosis?
A capacitation
B spermatid phase
C spermatocyte phase
D spermatogonial phase
D spermatogonial phase
When is meiosis complete during oogenesis?
A fertilisation
B at puberty
C just before ovulation
D at birth
A fertilisation
What does fertilisation achieve?
A Stimulates the oocyte to complete meiosis II
B Restores a diploid complement of chromosomes (Zygote)
C Forms a genetically unique human
D Determines sex of the embryo
Initiates cleavage
all of the above
A B C and D
The blastocyst must undergo what process before implantation can take place?
A Capacitation
B Acrosome Reaction
C Hatching
D Cleavage
C Hatching
What structure forms the embryonic part of the placenta?
A Embyroblast
B Trophoblast
C Yolk sac
D Decidua basalis
B Trophoblast
Which germ layer would form the following;
A skin
B lining of GI tract
C bone
A ectoderm
B endoderm
C mesoderm
Define the following
A. perimetrium
B. myometrium
C. endometrium
A. the lining surrounding the uterus
B. the smooth muscular and thickest layer of the uterus
C. the inner-most lining of the endometrium (this lining gets shed if there is no implantation each cycle)
