Embryology, Growth and Development Flashcards

1
Q

label the parts of the female reproductive system

A
  • drawn out
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2
Q

what are sex cells called

A

gametes

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3
Q

how many ovaries do females have

A

2

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4
Q

after how many days after menstruation does an ovary mature a females’ gamete and prepare its release

A

14

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5
Q

difference between the secondary and primary oocyte

A

secondary = have only done 1st meiotic division,

primary = gives rise to the secondary oocyte and polar bodies

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6
Q

what is ovulation

A

when the secondary oocyte (mature egg) is released from ovary

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7
Q

explain how oocyte and sperm reach each other to fertilize

A

the oocyte leaves the ovary
finger like projections push it into the uterine
then it enters the ampulla (where fertilization occurs)
the muscular contractions in the uterus and uterine tube help push sperm to the oocyte

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8
Q

what are the muscular contractions in the uterine tube and uterus caused by

A

hormones like oxytocin released during sex

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9
Q

what is semen

A

prostaglandins from liquid secretions that support sperm

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10
Q

what is the fertilization window

A

6 days before ovulation and 1 day after
- b/c sperm can live up to 6 days and can only be fertilized for 24 hours after

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11
Q

what are the three prenatal development periods

A

germinal, embryonic and fetal

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12
Q

what is the germinal period

A
  • first 2 weeks of development
  • when cells multiply and primitive germ layers form (which become body tissues)
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13
Q

what is the embryonic period

A
  • 3 to end of week 8
  • embryo forms - organ systems develop
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14
Q

what is the fetal period

A
  • 9th week till birth
  • so organ systems can grow and mature
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15
Q

what are the 2 terms used for timing of developmental events

A

clinical/medical events = date since last period (clinical age of unborn kid)

embyrologists = post-ovulatory age - 14 days less than clinical age (POINT OF FERTILIZATION) = we use this

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16
Q

describe the 6 steps of fertilization

A
  1. sperm penetrate the corona radiata of secondary oocyte
  2. the zona pellucida have ZP3 receptors that allow species-specific binding
  3. after several sperms bind to the zp3 receptors it starts an acrosomal reaction
  4. the acrosomal reaction breaks up the zona pellucida because it releases digestive enzymes
  5. one sperm then makes it through to the plasma membrane and binds to the integrin 6ab1 and causes depolarization
  6. this sperm enters the oocyte and its tail disintegrates so only head is left
  7. female nucleus undergo second meiotic division –> forms ovum and 2nd polar body
  8. female pronucleus and male pronucleus form
    - sperm head
    - ovum + second polar body
  9. fusion of haploid pronuclei = single nucleus –> zygote (diploid)
17
Q

how can you stop multiple sperm from fertilizing the oocyte?

A

fast block to polyspermy:
- depolarization
- through the integrin receptor the sperm binds to the receptor and the fast electrical charge on plasma shocks the other sperm from entering

slow block to polyspermy:
- when calcium moves out of the cell which causes the oocyte to shrink an the zona pellucida to denature –> this means he ZP3 also denatures and sperms can bind to it anymore

18
Q

explain day 1 to 6 when the egg is fertilized

A

day 1:
first cleavage = 2 cells

day 2:
2nd cleavge = 4 cells

day 5:
morula - when there are 12 or more cells

day 6:
blastocyte - Fluids will be secreted and push the cells to the side creating a fluid-filled cavity with all the cells pushed into a single layer around the outside

19
Q

What happens during hatching and when?

A

when - from day 5 to 6

what - the zona pellucida will break free at the point of hatching

20
Q

describe and label the parts of the blastocyte

A

Trophoblast layer = Thin layer of cells that forms structures like placenta and extra embryotic membranes

inner cell mass (aka embryo proper) = becomes a developing embryo

blastocele - fluid-filled cavity

21
Q

where does the blastocyst move after the cleavages and formations have occurs

A

uterine cavity and implants itself to the uterine wall

22
Q

how does the blastocyst get its energy after being implanted?

A

before implantation:
cells were living off of og cell cytosol nutrients and secretions by the uterus wall called uterus milk (glycogen rich)

now:
As it gets bigger diffusion can not be relied on and it needs to make a connection with moms circulatory system for nutrients

23
Q

define totipotent

A

One single cell can divide and differentiate into every single cell type in the body

ex.
Single cell, zygote, morula

24
Q

define pluripotent

A

They’ve started to differentiate so they cant form all different cell types anymore
- Already in a specific cell line
- Morula stage

25
Q

what happens between day 8-12 (implantation and formation of placenta)

A
  • As the blastocyst enters the cavity it orients itself with the inner cell, ass towards the wall of the endometrium and implants itself to the endometrial wall
  • The inner cell mass starts to differentiate into 2 diff cell types
    = syncytiotrophoblasts and cytotrophoblast
26
Q

what is the endometrium?

A
  • Inside the uterine cavity the wall closest to the cavity
  • this layer of uterus changes in thickness with each menstrual cycle
  • When blastocyst reaches uterine cavity endometrium is hella thick and vascular so it has a lot of blood supply
27
Q

what do the synctiotrophoblast and cytotrophoblast do?

A

syncytiotrophoblasts:
- job is to invade uterine wall and digest some blood vessels found in the uterine endometrium

cytotrophoblast:
- They provide layer of seperation between embryo proper and maternal blood supply

28
Q

differentiated cell synctiotrophoblast release hormone called

A

“human chronic gonadotropin” into maternal blood supply
- Use this in pregnancy tests
- Helps maintain thickened and vascular wall of endometrium of uterus

29
Q

what happens during day 14-20 (implantation and formation of placenta)

A
  • Synctiotrophoblasts continue to invade uterine wall
  • Changes in placenta and embryo proper
  • Blastocyst is in uterine wall and covered by uterine wall cells
  • Syncytiotrophoblasts and cytotrophoblasts are changing to make placenta
  • Starting to make a connecting stalk - which later becomes the umbilical cord
30
Q

define implantation

A

burrowing the blastocyte into uterine wall

31
Q

define placenta

A

exchange of nutrients and waste between the mother and embryo

32
Q

define Syncytiotrophoblasts

A

multinucleated cell invades endometrium

33
Q

define cytotrophoblasts

A

remains close to the embryonic tissue

34
Q

define lacunae

A

syncytiotrophoblast surrounds maternal blood vessels and inject their walls which makes pools of blood

35
Q

what happens at 1 month

A

cytotrophoblasts provides a protective barrier between maternal and embryonic blood - they dont mix
- embryo makes its own blood now + circulatory system
- Cytotrophoblast’s finger like projections form cytotrophoblast chords that surround syncytiotroblasts and lacuna
- connecting stock has formed

36
Q

what happens when the placenta matures

A
  • Finger like projections are now chorionic villi and are gonna fill the blood vessels from the fetus
  • New blood comes in from maternal arterioles and leaves through maternal venules
  • Hella gas exchange occurs
  • Chorion is the chorionic barrier - the final division between maternal and embryonic blood
  • cytotrophoblast cells have disintegrated by now only syncytiotrophoblast left
37
Q

at 1 month describe the Umbilical cord - 2 types of blood vessels

A
  • Umbilical arteries (blood away from the heart) and veins (Carrying blood to heart)
  • Maternal blood supplies their oxygenated blood to baby via umbilical cord
  • With deoxygenated blood umbilical veins go up into chronic villi, pick up oxygen in capillary beds from lacunal blood and come back in the form of umbilical veins