Implantation Flashcards

1
Q

Implantation

outline the process of implantation

think what the blastocyst adheres to for first step

for the second step, think what the trophoblast cells do to become 2 separate groups of cells and name these groups.

A
  1. Blastocyst adheres to endometrium
  2. At same time, trophoblast (non-embryo) cells divide and differentiate into 2 separate groups:
    - cytotrophoblast (inner layer of cells in blastocyst
    - syncytiotrophoblast (expanding multi-nucleated syncytium)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

implantation

What 2 things does the syncytiotrophoblast release?

think enzymes and what they digest in the uterus

think of the name of a hormone which can be detected in pregnancy testing

A
  • Enzymes to digest endometrium of uterine wall
  • human chorionic gonadotropin (HCG), which is detected in pregnancy testing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

implantation

Give 3 features of the cytotrophoblast

think trophoblast, syncytiotrophoblast and a type of villi

A
  1. inner layer of trophoblast
  2. forms syncytiotrophoblast
  3. forms chorionic villi
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

implantation

what hormones does the syncytiptrophoblast produce

A
  • progesterone
  • human chorionic gonadotropin (hCG)
  • human placental lactogen (HPL)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Prologation of the corpus luteum

outline how hCG prolongs the corpus luteum and luteal phase of the menstrual cycle

for first step, think syncytiotrophoblast producing a hormone, what day it does this and then where it passes into

for second step, think what hCG binds to and on what cells

for third step, explain what hCG binding to this thing maintains and what this causes.

A
  1. hCG produced by syncytiotrophoblast approx. day 6-7 and then passes into maternal blood circulation
  2. hCG binds to LH receptors on luteal cells (in corpus luteum) in ovary
  3. This maintains progesterone release from corpus luteum; progesterone will actively promote survival of corpus luteum by autocrine stimulation (positive feedback loop)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

abnormal implantation sites

What is the most common site of implantation in the female?

think a place on the wall of the uterus

A
  • the upper posterior wall of the body of the uterus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

abnormal implantation sites

what are 5 abnormal implantation sites

think tubes, a pouch, intestines, ovaries, cervix opening

A
  • uterine tube
  • rectouterine pouch
  • intestinal mesenteries
  • ovary
  • Cervical internal os
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

week 2: the bilaminar disc

What happens to the embryoblast (inner cell mass of blastocyst) in week 2 and what is these two layers together known as?

for first part think 2 tissue layers

for second part think bi…. disc

A

Splits into:
- epiblast tissue layer
- hypoblast tissue layer

Known as the Bilaminar disc

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

Week 2: the bilaminar disc

What does the epiblast layer form?

think embryo and amnioblasts

A

forms:
- Embryo proper

  • Amnioblasts lining the amnion (amniotic sac)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

week 2: the bilaminar disc

what does the amniotic cavity do after forming inside epiblast and why is this important?

think what the cavity fills with for first part

for second part think about support the fetus

A
  • fills with amniotic fluid
  • important for physically supporting/protecting the embryo/fetus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

week 2: the bilaminar disc

What does the hypoblast layer form and why is this important?

think yolk sac for first part

think nutrition before a certain point for second part

A
  • Primary yolk sac (exocoelomic cavity)
  • Important as an initial source of nutrition for embryo before placenta is functional
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The embryo at the start of week 3

What is the embryo surrounded by at the start of week 3, what is the primary yolk sac replaced by and what are 3 other features of the embryo at the start of week 3?

think

A
  • surrounded by chorionic cavity and embryonic tissues of the developing placenta
  • primary YS is replaced by secondary YS

3 features are:

  • connecting stalk marks where umbilical cord will be in future
  • 2 distinct epiblast and hypoblast cell layers
  • epiblast layer undergoes gastrulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Gastrulation

In Gastrulation, what is the first stage and why is this important? (hint: there are 2 parts to the first first stage)?

A
  1. primitive streak appears in midline at caudal (tail) end of epiblast
  2. Epiblast cells then migrate towards primitive streak
  • important of establishing left and right sides of the embryo
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Gastrulation: formation of the primary germ layers

Where do epiblast cells migrate towards and what do they undergo?

A
  • migrate toward primitve streak
  • undergo epithelial-to-mesenchymal transition
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Gastrulation: formation of the primary germ layers

what do the first cells through the primitive streak do and what do they form

think hypoblast and endoderm

A

displace hypoblast and form endoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

gastrulation formation of the primary germ layers

what do cells in the middle of the primative streak form

A

the mesoderm

17
Q

grastrulation: formation of the primary germ layer

what do the last epiblast layer cells into the primitive streak form

A

form the ectoderm

18
Q

fates of the ectoderm

What does the ectoderm differentiate into?

A
  • neuroectoderm (nervous system)
19
Q

fasts of the ectoderm, mesoderm, endoderm

what does the mesoderm form

think words starting with D.S.S.B.C.B.H

A

forms:

  • dermis of skin
  • skeletal muscle
  • smooth muscle
  • bone
  • cartilage
  • blood vessels
  • heart
20
Q

fates of the ectoderm, mesoderm and endoderm

what does the endoderm form

think epithelial linings of systems and certain organs

A

forms epithelial linings of digestive and respiratory systems as well as internal organs

21
Q

folding of the embryo

Why does longitudinal folding of embryo occur after gastrulation in week 4?

think rapid enlargement of one of the ends of the embryo

A
  • due to rapid enlargement of the cranial end of the neural tube to form the brain, so embryo bends so head and tail ends are brought closer together
22
Q

folding of the embryo

what happens to amniotic cavity to encourage longitudinal folding in week 4 of development

think amniotic cavity expanding and pushing in to encourage something

A

amniotic cavity expands and pushes in at either end of the embryo to encourage folding

23
Q

folding of the embryo

Why does lateral folding of embryo occur in week 4 of development after gastrulation has happened and why is this important

think enlargement of something

think importance of forming a type of wall

A
  • due to enlargement of somites (mesoderm)
  • important for forming the abdominal wall
24
Q

folding of the embryo

waht does the amnitic cavity do to surround the embryo

think pinching of connection of different places

A

it pinches off the connection of the embryonic gut tube (endoderm) to the yolk sac