Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

GIGU Exam 2 > Fertilization And Implantation > Flashcards

Fertilization And Implantation Flashcards

1
Q

When does fertilization occur

A

Day 15-16 of menstrual cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where does fertilization happen

And what causes follicular rupture in ovary

A

Ampulla of oviduct

LH surge = ovum + corona radiate around it is ejected into peritoneum ——> oviduct moved by fimbriae—> ampulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How many sperm enter vagina and how many make it to ampulla and how many are infertile

A

300 million
200
<20 million

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Key thing that helps move sperm

A

Myometrium contractions as a result of increased estrogen near the ovulation period
+ increased progesterone to downregulate immune system (to help sperm survive)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How are sperm in the 1epididymus and 2when ejaculated and then 3when entering vagina

A
  1. Surface molecules surround the head
  2. The surface proteins are coated with seminal plasma protein to mask sperm receptors
  3. Capacitation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Capacitated sperm is what

A

The spermatic enters the vagina and the seminal plasma coating and surface proteins are removed exposing surface receptors for 1. sperm to bind to Zona pellucida

  1. Increase Ca+2 into cell during acrozomal reaction
    * this process is slow
  2. Cause hyperactivation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What signals capacitation

A

Ovulation signals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Capacitation is low, what do incapacitated sperm do

A

They can bind to epithelial cells in ISTHMUS of oviduct
They unbind when they become capacitated
= to expend spree life and wait for ovulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does hyper activation of sperm help with

A

This occurs when a sperm is capacitated and gets signals from oocyte
= whip-like, higher f movement of flagella
= help sperm unbind to epithelial cells, or to move through all the membranes of the oocyte, increase mobility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How many barriers does the sperm need to go through in fertilization

A

Corona radiata (expanded cumulus)
Zona pellucida
Plasma membrane of oocyte

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the cumulus composed of and what does the sperm use to break this

A

Made of hyaluronic acid broken down by Hyaluronidase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What comprises the zone pellucida and what does the sperm use to break it down

A

Made up of glycoproteins ZP1, ZP2, ZP3, ZP4

The sperm have ZP3 receptors that bind to the ZP3 = ACROSOMAL REACTION

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What 3 things happen during the acrosomal reaction

A
  1. Inner sperm PM fuses with outer acrosomal membrane of sperm to release acrosomal vesicle contents
  2. Acrosomal contents digest Zona pellucida
  3. Sperm enters through hole made in Zona pellucida
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Cortical reaction -what triggers it

A

Happens with the fusion of the sperm and egg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Cortical reaction steps

A
  1. Ca+2 released
  2. ZP proteins are altered = prevent other sperm to bind
  3. Hyaluronic acid, proteoglycans, proteinases released and hydrated
  4. Zona pellucida has now formed a physical barrier = X Polyspermy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does release of Ca+2 do

A

Stimulated completion of meiosis 2
-Breakdown MAPK proteins
-2nd polar body released
Alters ZP proteins

17
Q

When is the egg activated

A

When the sperm DNA condenses

18
Q

What happens after sperm DNA has condensed and the egg is activated

A
  1. Pronucleus forms around the female egg chromosomes
  2. The male and female chromosomes both replicate
  3. The pronuclei move together
  4. The pronuclei fuse = first embryonic cleavage *beginning of embryonic development
19
Q

What is cleavage

And what is the egg at day 3,4,6-8

A

Cell division without growth
Day 3 = 16 cell(blastomeres) morula
Day 4 = early blastocyst
Day 6-8 = implantation

20
Q

What happens in blastocyst compaction and blastocele development

A

Compaction of morula : increase adhesion cell-cell(desmosomes +TJ) =

  1. trophoelctoderm forms, - cells move to outside sphere
  2. Na+ transport forms the blastocele
21
Q

Inner cell mass

A

In the blastocele DAY 5

They form the embryo proper - pluripotent

22
Q

Steps in blastocyst hatching

A

*before implantation
Zona pellucida detaches and oocyte comes out
1. Trophoblasts secreation proteases that digest ZP
X hatching - infertility, premature hatching - abnormal implantation

23
Q

Blastocyst after hatching

A

Synthesis and secretion of molecules to promote pregnancy and implantation and placenta development
+ immunosuppressive factors (platelet-activating factor, hCG, prostaglandin E2, IL1,6

24
Q

How does the sperm enter the PM

A

Spree have a protein called Izumo binding to Izumo R on oocyte
Entire sperm enters
DNA in spree condenses and forms male pronucleus
Then the release of Ca+2

25
Q

Blastomeres are known as

A

Totipotent = can give rise to any cell, an entire offspring

26
Q

What secretes hCG and when can it be seen

A

Trophoblasts and syncytiotrophoblasts

Seen after day 8 post ovulation

27
Q

hCG function

A
  1. Prevents involution of the corpus luteum
    - Prevent menstruation
    - increased secretion of progesterone and estrogen
  2. Autocrine growth factor
    - stimulates trophoblast growth and development
    - stimulate placenta growth
28
Q

3 stages of implantation

A

Apposition
Attachment
Invasion

29
Q

Apposition

A

Contact between endometrium and trophoblast of oocyte in a crypt of the endometrium
The inner cell mass rotates to face the endometrium attachment

30
Q

Attachment stage

A

Trophoblasts adhere to luminal endometrium and interact with surface proteins
= initiates changes in endometrial stroma (DECIDUATION)

31
Q

DECIDUATION - part of attachment stage

A

Stroma of the endometrium changes due to invasion and progesterone

  1. Increased vascular permeability
  2. ICM made
  3. stromal cells get more enlarged + glycogen filled
32
Q

Invasion stage

A

Degradation of endometrial cells
Trophoblasts fuse with stroma layer, as syncytiotrophoblasts form and protrude through the BM to the stroma
1. Paracrine and autocrine factors degrade stroma and ECM
2. Finger like projections reach maternal BVs
3. Epithelium is restored eventually
*most done by the syncytiotrophoblasts

33
Q

4 functions of the syncytiotrophoblasts

A
  1. Express adhesive proteins, bind to ECM and when invading (Cadherins and integrity’s)
  2. Breakdown of ECM (and stroma): secretion of matrix metal lop rotate and hydrolysis enzymes
  3. hCG secretion : maintains corpus luteum = secrete progesterone
    + make progesterone independent of corpus luteum (WEEK10)
  4. Phagocytosis + placental transfer of gas, nutrients, wastes
34
Q

what happens after DECIDUATION

A

When the stroma cells have changed and become decidual cells, the endometrium is ready for implantation
= the decidual cells around the embryo prevents it from moving and prevents embryo from invading into myometrium - hemorrhage

35
Q

Ectopic Pregnancy

A

The egg is fertilized in the oviduct in most cases, (any place but the uterus) and there is no stroma = no decidualization = implantation causes rupture of tissues- hemorrhage

36
Q

When does Placentation occur

A

DAY 9

37
Q

What happens during placentation

A

Spaces occur in the syncytiotrophoblasts
= lacunae that later fill with maternal blood and endometrial secretions
——> then primary, secondary (forming chorionic membrane), the tertiary villi form

GIGU Exam 2 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions