Lect 8. Fertilization and Implantation Flashcards
(107 cards)
1
Q
Entering the Oviduct
After ovulation the oocyte is technically in ____
A
the peritoneal cavity
2
Q
Entering the Oviduct
To enter the uterine tube, ____ “sweep” follicular fluid and oocyte to enter infundibulum and ampulla of oviduct and toward the uterus
A
fimbriae of the oviduct
3
Q
Entering the Oviduct
To enter the uterine tube, fimbriae of the oviduct “sweep” ____ to enter infundibulum and ampulla of oviduct and toward the uterus
A
follicular fluid and oocyte
4
Q
Entering the Oviduct
To enter the uterine tube, fimbriae of the oviduct “sweep” follicular fluid and oocyte to enter ____ and toward the uterus
A
infundibulum and ampulla of oviduct
5
Q
Entering the Oviduct
To enter the uterine tube, fimbriae of the oviduct “sweep” follicular fluid and oocyte to enter infundibulum and ampulla of oviduct and toward ____
A
the uterus
6
Q
Entering the Oviduct
Approximately 1 % of spermatozoa ejaculated into the vagina make their way through ____
A
cervix
7
Q
Entering the Oviduct
Contractions of _____ (2) propel spermatozoa closer to oocyte
A
uterus and uterine tube
8
Q
Entering the Oviduct
→ IDENTIFY
A
9
Q
Entering the Oviduct
→ IDENTIFY
A
10
Q
Entering the Oviduct
→ IDENTIFY
A
11
Q
Entering the Oviduct
→ IDENTIFY
A
12
Q
Process of Fertilization
After several hours in the uterus and oviduct, spermatozoa become ___.
A
capacitated
13
Q
Process of Fertilization
After several hours in the uterus and oviduct, spermatozoa become capacitated.
They undergo ____, releasing enzymes that assist them in passing through the zona pellucida.
A
the acrosome reaction
14
Q
Process of Fertilization
After several hours in the uterus and oviduct, spermatozoa become capacitated.
They undergo the acrosome reaction
→ The role of acrosome reaction?
A
releasing enzymes that assist spermatozoa in passing through the zona pellucida.
15
Q
Process of Fertilization
→ How many spermatozoa successfully pass through the zona pellucida?
A
A single spermatozoa successfully passes through the zona pellucida, fuses with oocyte and its nucleus enters the oocyte.
→ Fertilization has occurred!
16
Q
When does fertilization occur?
A
When a single spermatozoa fuses with oocyte and its nucleus enters the oocyte.
17
Q
Process of Fertilization
The oocyte releases ___ that make the zona pellucida impermeable and de- activate spermatozoa receptors.
This prevents polyspermy.
A
cortical granules
18
Q
Process of Fertilization
→ Identify
→ Its role?
A
cortical granules
→ that make the zona pellucida impermeable and de- activate spermatozoa receptors.
→ prevents polyspermy.
19
Q
Process of Fertilization
The secondary oocyte to complete the second phase of meiosis.
→ This creates ___
A
the haploid secondary oocyte and 2 additional polar bodies.
20
Q
Process of Fertilization
Sperm penetration triggers ___
A
21
Q
How does the fusion of pronuclei occur after fertilization?
A
Haploid female pronucleus and haploid male pronucleus each replicate their DNA, creating 2 chromatids for each chromosome
→ fuse to become a new diploid individual
22
Q
Fusion of the Pronuclei
Pronuclei fuse to become ___
A
a new diploid individual
23
Q
Fusion of the Pronuclei
Pronuclei fuse to become a new diploid individual; chromosomes arrange themselves in (1)____ (which phase?) and single-celled zygote undergoes (2)___ and its first mitotic division
A
- metaphase
- cleavage
24
Q
Fusion of the Pronuclei
Pronuclei fuse to become a new diploid individual; chromosomes arrange themselves in metaphase and ____ undergoes cleavage and its first mitotic division
A
single-celled zygote
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**Fusion of the Pronuclei**
Pronuclei fuse to become a new diploid individual; chromosomes arrange themselves in metaphase and single-celled **zygote** undergoes **cleavage** and its first \_\_\_\_
mitotic division
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**Fusion of the Pronuclei - Pronuclear stage**
→ Identify
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**Zygote and Morula**
Cleavage creates (1)\_\_\_\_ after about 30 hours and (2)\_\_\_ after about 40 hours
* 2-celled zygote
* 4-celled zygote
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**Zygote and Morula**
Cells of zygote undergo (1)\_\_\_, keeping inner cells away from external environment
**compaction**
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**Zygote and Morula**
Cells of zygote undergo **compaction**, keeping ____ away from external environment
inner cells
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**Zygote and Morula**
Cells of zygote undergo **compaction**, keeping inner cells away from \_\_
external environment
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**Zygote and Morula**
Cells of zygote undergo **compaction**, keeping inner cells
away from external environment
→ during divisions, do cells enlarge?
NO!
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**Zygote and Morula**
Cells of zygote undergo **compaction**, keeping inner cells
away from external environment
→ during divisions, cells do not enlarge, so the whole assembly is roughly same size as \_\_\_\_
the original secondary oocyte
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**Zygote and Morula**
After 3 days zygote has about 16 cells and is called (1)\_\_\_\_,
**morula**
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**Zygote and Morula**
What does a morula contain?
**inner cell mass** and **outer cell mass**
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**Zygote and Morula**
→ identify
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**Blastocyst**
After 4 days, (1)\_\_\_\_ deteriorates, allowing fluid to penetrate morula
zona pellucida
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**Blastocyst**
After 4 days, zona pellucida deteriorates, allowing fluid to penetrate \_\_\_\_
morula
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**Blastocyst**
After 4 days, zona pellucida deteriorates, allowing fluid to penetrate morula
→ fluid forms (1)\_\_\_ and the whole cell cluster is now called (2)\_\_\_
1. blastocyst cavity
2. blastocyst
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**Blastocyst**
After 4 days,
(1)\_\_\_\_ is now called the **embryoblast** and will create (2)\_\_\_
1. Inner cell mass
2. the structures of the embryo
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**Blastocyst**
After 4 days,
(1)\_\_\_\_ called **trophoblast** will become (2)\_\_\_\_ surrounding and nurturing the developing embryo and fetus
1. Outer cell mass
2. the placenta and membranes
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**Blastocyst**
After 4 days,
Outer cell mass called **trophoblast** will become the placenta and membranes surrounding and nurturing \_\_\_
the developing embryo and fetus
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Name of this cell?
**Early blastocyst**
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**Blastocyst**
**→ identify**
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Name of this cell and identify
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**Implantation**
**→** Where does fertilization occur?
Fertilization occurs in the ampulla of oviduct
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**Implantation**
Fertilization occurs in the ampulla of oviduct
→ ___ has entered the uterus after 4 days
blastocysts
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**Implantation**
If the developing embryo implants in the uterus
→ trophoblast cells begin producing \_\_\_\_
**human chorionic gonadotropin** (hCG)
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**Implantation**
If the developing embryo implants in (1)\_\_\_
→ (2)\_\_\_ begin producing **human chorionic gonadotropin** (hCG)
1. the uterus
2. trophoblast cells
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**Implantation**
3 roles of **human chorionic gonadotropin** (hCG)
1. prevents corpus luteum from degenerating
2. keeps progesterone levels high
3. preventing degeneration of the follicular layer of endometrium
50
**Implantation**
3 roles of **human chorionic gonadotropin** (hCG)
1. prevents ___ from degenerating
2. keeps ___ levels high
3. preventing degeneration of ___ of endometrium
1. corpus luteum
2. progesterone
3. the follicular layer
51
**Implantation**
3 roles of **human chorionic gonadotropin** (hCG)
1. prevents corpus luteum from \_\_\_
2. keeps progesterone levels ___ (low/high)
3. preventing degeneration of the follicular layer of \_\_\_
1. degenerating
2. high
3. endometrium ((en-doh-MEE-tree-um) **The layer of tissue that lines the uterus**.)
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**Implantation**
→ IDENTIFY
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What's happening here?
Ovulation
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What does a pregnancy test measure?
levels of **human chorionic gonadotropin** (hCG) in urine
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Eventually the placenta will produce enough ___ to maintain pregnancy
progesterone
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**Tissues that Support and Nurture the developing Embryo and Fetus**
The **trophoblast** must grow into the uterus and create a surface for \_\_
gas and metabolite exchange
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**Tissues that Support and Nurture the developing Embryo and Fetus**
The **trophoblast** must grow into the uterus and create a surface for gas and metabolite exchange.
→ This must happen while keeping ____ separate
the embryo's and mother's blood supplies
58
**Tissues that Support and Nurture the developing Embryo and Fetus**
The **trophoblast** must grow into the uterus and create a surface for gas and metabolite exchange.
→ This must happen while keeping the embryo's and mother's blood supplies separate
→ What are the 2 things result from this process?
The **placenta** and **umbilical cord**
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**Tissues that Support and Nurture the developing Embryo and Fetus**
When a zygote splits or 2 zygotes implant simultaneously, ___ will develop.
twins
(Different types of twins have their membranes in different permutations.)
60
**Embryoblast and Trophoblast**
Blastocyst has 2 distinct cell populations
→ What are they?
1. **Embryoblast** (inner cluster of cells)
2. **Trophoblast** (outer cell layer)
61
**Embryoblast and Trophoblast**
The role of trophoblast
nourishing and protecting growing fetus
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**Embryoblast and Trophoblast**
As blastocyst implants into ____ , around day 7, trophoblast differentiates into 2 different regions
**follicular layer of the endometrium**
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**Embryoblast and Trophoblast**
**\_\_\_** is layer of cuboidal cells surrounding developing the embryo
**Cytotrophoblast**
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**Embryoblast and Trophoblast**
At the place where the blastocyst implants group of (1)\_\_\_ begin burrowing into endometrium
→ in the process, they lose (2)\_\_\_\_ and form a large multi-nucleated mass, **syncytiotrophoblast**, that burrows into endometrium
1. trophoblast cells
2. cell membranes
65
**Embryoblast and Trophoblast**
At the place where the blastocyst implants group of trophoblast cells begin burrowing into endometrium
→ in the process, they lose cell membranes and form a large multi-nucleated mass called \_\_\_
**syncytiotrophoblast**
66
**Embryoblast and Trophoblast**
→ IDENTIFY
67
**Embryoblast and Trophoblast - day 7**
→ IDENTIFY
68
**Expansion of the Syncytiotrophoblast**
By day 8, blastocyst migrates deeper into the endometrium; the deeper it goes the more it encounters \_\_\_\_
uterine glands and vessels
69
**Expansion of the Syncytiotrophoblast**
**Hypoblast** and **epiblast** have formed (1)\_\_\_ with a tiny (2)\_\_\_ developing within the epiblast layer
1. bilaminar embryo
2. amniotic cavity
70
**Expansion of the Syncytiotrophoblast**
**\_\_and**\_\_have formed bilaminar embryo with a tiny amniotic cavity developing within the epiblast layer
**Hypoblast** and **epiblast**
71
**Expansion of the Syncytiotrophoblast**
**Hypoblast** and **epiblast** have formed **bilaminar embryo** with a tiny **amniotic cavity** developing within \_\_\_
1. the epiblast layer
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**Expansion of the Syncytiotrophoblast - DAY 8**
**→ IDENTIFY?**
73
**Implantation and the Trophoblast**
As syncytiotrophoblast erodes glands and vessels in endometrium, small, blood-filled ____ form in syncytiotrophoblast, around 9 days into development
**trophoblastic lacunae**
74
**Implantation and the Trophoblast**
As ___ erodes glands and vessels in endometrium, small, blood-filled **trophoblastic lacunae** form in syncytiotrophoblast, around 9 days into development
syncytiotrophoblast
75
**Implantation and the Trophoblast**
As syncytiotrophoblast erodes glands and vessels in endometrium, small, blood-filled **trophoblastic lacunae** form in syncytiotrophoblast, around 9 days into development
→ Allows ___ to reach and nurture developing embryo; however, it is not very efficient yet since there is no organized flow
maternal blood
76
**Implantation and the Trophoblast**
\_\_\_ has formed to separate cytotrophoblast on one side from the bilaminar embryo and primary yolk sac on the other
**Extraembryonic mesoderm**
77
**Implantation and the Trophoblast**
**Extraembryonic mesoderm** has formed to separate ___ on one side from the bilaminar embryo and primary yolk sac on the other
cytotrophoblast
78
**Implantation and the Trophoblast**
**Extraembryonic mesoderm** has formed to separate cytotrophoblast on one side from (1)\_\_\_ and (2)\_\_\_ on the other
1. the bilaminar embryo
2. primary yolk sac
79
**Implantation and the Trophoblast - DAY 9**
→ identify
80
**Formation of the Chorionic Cavity**
During 10th to 12th days after fertilization
→ ____ enlarge to surround the embryo as it moves even deeper into the endometrium
Trophoblastic lacunae
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**Formation of the Chorionic Cavity**
During 10th to 12th days after fertilization
→ Fluid-filled spaces (Trophoblastic lacunae) start to develop in the extraembryonic mesoderm
→ will form \_\_\_
**extraembryonic coelom**
82
**Formation of the Chorionic Cavity**
By day 13, ___ has begun to send cellular projections into the syncytiotrophoblast
cytotrophoblast
83
**Formation of the Chorionic Cavity**
Extraembryonic coelom enlarges, separates (1)\_\_\_
→ space is called (2)\_\_\_\_.
1. the embryo and cytotrophoblast
2. chorionic cavity
84
**Formation of the Chorionic Cavity**
What is chorion?
Outer lining of cytotrophoblast, syncytiotrophoblast, and trophoblastic lacunae
85
**Formation of the Chorionic Cavity**
Outer lining of cytotrophoblast, syncytiotrophoblast, and trophoblastic lacunae is called \_\_\_
chorion
86
**Connecting Stalk and Umbilical Cord**
By 14th day, (1)\_\_\_\_suspended within the chorionic cavity by its attachment to the bilaminar embryo; remnants of primary yolk sac are located on opposite side of (2)\_\_\_
1. **secondary yolk sac**
2. cytotrophoblast
87
**Connecting Stalk and Umbilical Cord**
By 14th day, **secondary yolk sac** suspended within (1)\_\_\_ by its attachment to the bilaminar embryo
→ remnants of (2)\_\_\_ are located on opposite side of cytotrophoblast
1. the chorionic cavity
2. primary yolk sac
88
**Connecting Stalk and Umbilical Cord**
By 14th day, (1)\_\_\_\_suspended within the chorionic cavity by its attachment to the bilaminar embryo; remnants of primary yolk sac are located on opposite side of (2)\_\_\_
1. **secondary yolk sac**
2. cytotrophoblast
89
**Connecting Stalk and Umbilical Cord**
day 14
Bilaminar embryo is suspended within the chorionic cavity by (1)\_\_\_\_ of extraembryonic mesoderm
→ connection between embryo and trophoblast will become (2) \_\_\_
1. connecting stalk
2. umbilical cord
90
**Connecting Stalk and Umbilical Cord**
Bilaminar embryo is suspended within the chorionic cavity by **connecting stalk** of (1)\_\_\_\_
→ connection between (2)\_\_\_\_ will becom the **umbilical cord**
1. extraembryonic mesoderm
2. embryo and trophoblast
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**Formation of the Chorionic Cavity - day 10 - 12**
**→ IDENTIFY?**
92
**Formation of the Chorionic Cavity - day 10 - 12**
**→ IDENTIFY?**
93
**Formation of the Chorionic Cavity - day 13**
94
**Connecting Stalk and Umbilical Cord - DAY 14**
**→ IDENTIFY**
95
**Placenta**
What will create **secondary villi?**
Extraembryonic mesoderm that underlies cytotrophoblast will invade the core of each villus to create **secondary villi**
96
**Placenta**
Blood vessels will develop within extraembryonic mesoderm to connect villi, connecting stalk, and the embryo; once blood vessels present within villi, they are termed \_\_\_
**tertiary villi**
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**Placenta**
What will create **tertiary villi?**
Blood vessels will develop within extraembryonic mesoderm to connect villi, connecting stalk, and the embryo
→ once blood vessels present within villi, they are termed **tertiary villi**
98
**Placenta**
Syncytiotrophoblast leaves ___ that anchor the placenta to the uterus
placental lobes, **cotyledons**
99
**Placenta**
The role of **cotyledons**
placental lobes that anchor the placenta to the uterus
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**Placenta**
\_\_\_ leaves placental lobes, **cotyledons**, that anchor the placenta to the uterus
Syncytiotrophoblast
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**Placenta**
In each cotyledon, cytotrophoblast leaves gaps for uterine arteries and veins to reach \_\_\_; these fill with maternal blood and closely associate with tertiary villi
**intervillous spaces**
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**Placenta**
In each cotyledon, cytotrophoblast leaves gaps for (1)\_\_\_ to reach **intervillous spaces**
**→** these fill with (2)\_\_\_\_ and closely associate with tertiary villi
1. uterine arteries and veins
2. maternal blood
103
**Placenta**
In each cotyledon, cytotrophoblast leaves gaps for uterine arteries and veins to reach **intervillous spaces**
**→** these fill with maternal blood and closely associate with \_\_\_
tertiary villi
104
**Placenta**
Placenta is the whole assembly of ___ and \_\_\_\_
trophoblast
intervillous spaces
105
**Placenta**
→ Identify
106
Placenta
→ IDENTIFY
107
Placenta
→ IDENTIFY
