deck_15305702 Flashcards
(93 cards)
1
Q
What is a fetus?
A
an orgnaism that breathes no air, does not use the digestive tract and lives in a sterile environment
2
Q
what is a newborn?
A
an air-breathing organism with a functional GI tract that quickly becomes a colonized by microbial flora
3
Q
what does the ovaries produce?
A
oocytes, progesterone and estrogen
4
Q
what are oocytes?
A
female haploid gametes
5
Q
what is another name for the Uterine tube?
A
fallopian tube
6
Q
what does the uterine tube receive from the ovaries?
A
oocytes
7
Q
where is the site where sperm fertilizes the oocyte?
A
Uterine tube
8
Q
Where is the site where the embryo develops
A
uterus
9
Q
where is the site where the placenta and membranes develop
A
uterus
10
Q
what is a placenta?
A
site where the maternal and embryonic vasculatures exchange substances
11
Q
what does unique mean
A
crossing-over between maternal and paternal chromatids during prophase I to end up with “mixed” chromatids
12
Q
what does “mixed” mean
A
some paternal, some maternal genes
13
Q
where does fertilization occur?
A
in the ampulla of the uterine tube
14
Q
what does ovulation mean?
A
release of a secondary oocyte from ovarian follicle
15
Q
the ovulated secondary oocyte together with zona pellucida, is externally covered with what
A
cumulus oophorus
16
Q
cumulus oophorus will rearrange and form what?
A
corona radiata
17
Q
what happens when the zona pellucida is penetrated by a sperm cell and “injects” its genetic material?
A
it becomes impenetrable and other sperm cells cannot penetrate
18
Q
what are cells that surround the oocyte, found outside of the zona pellucida?
A
corona radiata
19
Q
what are gametes?
A
a haploid germ cell
20
Q
what are sperm?
A
gamete from testes
21
Q
what are oocytes?
A
gamete from ovaries
22
Q
what is fertilization?
A
fusion of the pronucleus of the 2 gametes
23
Q
what is the zona pellucida?
A
protein coat that surrounds an oocyte as well as the early embryo
24
Q
what is a zygote?
A
a fertilized, diploid oocyte, has not yet divided
25
what is an embryo?
multicellular organism, prior to fetal stage (period from fertilization - end of week 7)
26
what is a fetus?
multicellular organism, from end of embryonic stage to birth
27
what is a neonate?
newborn
28
what is extraembryonic
cells from during development that do not become part of the neonatal organism, but involute or contribute to the fetal membranes
29
what is morula?
approximately 16-cell stage (12-32 cells) of an embryo, no blastocoel
30
what is blastocyst?
a spherical mass of cells that is composed of a trophoblast that surrounds a fluid cavity (blastocoel) and an inner cell mass (embryoblast)
31
what is cleavage?
cell division in the early embryo -> each division does not increase the size of the embryo, instead each division results in a smaller and smaller cells
32
what is a blastomere
a cell that is totipotential and is present during very early develop, product of cleavage
33
what does totipotential mean
a cell that can become any cell
34
what does implantation mean?
occurs when an embryo contacts and then becomes surrounded by the endometrium of the uterus
35
what is a trophoblast
layer of cells on the outside of the sphere (blastomere)
36
what are embryoblast (inner cell mass)
surrounded by the trophoblast, these cells develop into the embryo
37
what is blastocoel?
the fluid filled cavity within the sphere
38
T or F: the epithelial cells of the uterine tube are equipped with cilia that "wave" in a single direction
true
39
ciliary movement increases by what?
as progesterone levels increase
40
when does progesterone secretion peak?
shortly after ovulation
41
what are the important roles early in development for the zona pellucida
- barrier that ensures that only one sperm fertilizes an oocyte
- porous - allows communication between the embryo and the maternal reproductive structures
- protects the embryo from immunologic defenses
- acts as a signal to help with differentiation of trophoblast cells
- prevents premature implantation of the embryo
- prevents the blastomeres from dissociating
42
what happens when the embryo implants too early?
it could result in an ectopic pregnancy
43
what day will the embryo "hatch" out of the ZP
day 6
44
what are the small apical processes on the endometrial epithelium that contacts with the trophoblast of the blastocyst
pinopods
45
once the trophoblast contacts the endometrial epithelium and invades, it forms two layers which are? which one is inner and which one is outer?
cytotrophoblast - inner layer
synctiotrophoblast - outer layer
46
what are the important functions of synctiotrophoblast?
- invasion into the endometrial stroma and formation of villi
- secretion of human chorionic gonadotrophin (hCG)
47
what does human chorionic gonadotropin do?
it prevents the shedding of the endometrium by maintaining ovarian secretion of steriod hormones
48
what is the hormone detected in pregnancy tests?
hCG
49
as the synctiotrophoblast invades into the stroma, the inner cell mass (embryoblast) differentiates into 2 distinct layers which are?
epiblast and hypoblast
50
what will line the blastocystic cavity and form the primary yolk sac?
hypoblast
51
Hypoblast is also known as?
primary endoderm
52
what is coelom?
a fluid-filled cavity (blastocystic cavity)
53
what is gastrulation?
the process of forming 3 embryonic germ layers
54
what are the 3 embryonic germ layers?
ectoderm, endoderm, mesoderm
55
list the embryonic germ layers from exterior to interior?
ectoderm, mesoderm, endoderm
56
what does cephalad mean?
towards the head region
57
what does caudad mean?
towards the tail region
58
implantation of the embryo is complete at about day what?
day 10
59
when implantation is complete, stromal cells undergo what? and is now known as what?
decidualization and decidual cells
60
what do decidual cells do?
they accumulate glycogen and lipids throughout the uterus
- The decidual cells that the syncytiotrophoblast contact undergo apoptosis, releasing stored nutrients needed for embryonic growth
61
the epiblast enlarges and gives rise to ?
amnioblast
62
what are ambioblast
cells that surround the developing amniotic cavity
63
what extends around the entire interior surface of the blastocoel
hypoblast
64
what cells begin to form and migrate between the hypoblast-derived cells and the cytotrophoblast
extraembryonic mesoderm
65
blastocoel turns into what?
primary umbilical vesicle/primary yolk sac
66
what forms the bilaminar disk
hypoblast and epiblast
67
what is extraembryonic coelom
the cavity between the extra-embryonic mesodermal cells
68
as the extraembryonic coelom enlarges and develops, it will develop into what?
chorionic cavity
69
extraembryonic coelom completely surrounds the rest of the embryo everywhere except for?
the junction of the amniotic cavity and the rest of the chorionic sac, this is the connecting stalkw
70
what later develops into the umbilical cord
connecting stalk
71
what are the two layers of extraembryonic mesoderm, separated by the fluid in the extraembryonic coelom?
extraembryonic splanchnic mesoderm and extraembryonic somatic mesoderm
72
what does the extraembryonic splanchnic mesoderm surround
umbilical vesicle
73
where is the extraembryonic somatic mesoderm?
found just underneath the cytotrophoblast, inner lining of the chorionic sac
74
what is chorion
the wall of the chorionic sac
75
what are "little lakes" or lacunar networks
where syncytiotrophoblast contacts endometrial blood vessels, the blood vessel deteriorates and blood pools
76
what appears at the end of week 2
prechordal plate
77
what is the prechordal plate?
Thickened area of columnar cells that acts as an organization area, found in the cephalad region of the hypoblast
78
what does induction mean in this case?
signaling “episodes” by key areas of the embryo that stimulate differentiation and development of local structures
79
what is the organizer of the head and mouth region, and helps to induce the formation of structures found at the cephalad pole of the embryo
hypoblast
80
what is the process by which the 3 germ layers of the embryo are established
gastrulation
81
what are the 3 germ layers
- ectoderm
- mesoderm
- endoderm
82
during gastrulation, bilaminar embryonic disc becomes what?
trilaminar embryonic disc
83
at the beginning of the 3rd week, formation of the ?
primitive streak appears
84
what is the primitive streak
thickened linear band in the median plane of the dorsal aspect of the embryonic disc
85
where does the primitive streak initiates
the caudal region of the epiblast
86
cells at the cephalad end of the primative streak proliferate to form a ?
primitive node
87
a narrow groove develops in the primitive streak called
primitive groove
88
the primitive groove is continuous with a small depression in the primitive node known as the ?
primitive pit
89
Cells leave the deep surface of the streak and form ?
mesenchyme
90
what is mesenchyme
embryonic connective tissue which forms the supporting tissues of the embryo
91
what forms the intraembryonic or embryonic mesoderm
mesoblasts
92
cells from the epiblast, as well as from the primitive node and other parts of the primitive streak displace the hypoblast and form what
embryonic endoderm (roof of the umbilical vesicle)
93
what forms the embryonic ectoderm
cells in the epiblast
