Brainscape's Knowledge GenomeTM

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


See full index

BMS Final > Human Embryogenesis (Pinhal-Enfield) > Flashcards

Human Embryogenesis (Pinhal-Enfield) Flashcards

1
Q

When is the embryogenic period & hallmarks

A

1-8 weeks

Organogenesis & high teratogen susceptibility

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

When is the fetal period and what are hallmarks

A

9-38 weeks

Differentiation, growth, weight gain

Lower teratogen susceptibility

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

What happens during ovulation?

A

Oocyte discharges from ovary & migrates into uterine tube during ovulation

Ovulated oocyte is surrounded by shell with layers (follicle)

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

Capacitation

A

Spermatozoa conditions in female tract to fertilize oocyte, but need to undergo Capacitation to fertilize

(It’s a biochemical step that allows sperm to fertilize)

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

Where does fertilization occur

A

Ampulla of the uterine tube (this is where the oocyte & capacitated sperm meet)

Sperm can live in female tract for several days; an oocyte that’s not fertilized degenerates within 24 hours of ovulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Implantation of early embryo is during _____

A

Endometrial secretory phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

If pregnancy occurs, the corpus lute up is maintenance by ______ which is secreted by trophoblast a of placenta

A

Human chorionic gonadotropin (hCG)

**if pregnancy doesn’t occur, corpus lute up degerates & decline of progesterone leads to endometrium shedding & beginning of new cycle

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

3 oocyte shell layers from inside to out

A

Plasma membrane

Zona pellucida

Plasma membrane

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

Corona radiata

A

Outer crown of follicular cells around oocyte

Protection, energy, support for oocyte

Chemoattractant for sperm

Aka cumulus oophorus

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

Zona pellucida

A

Intermediate glycoprotein layer

Made up of “zone proteins” (ZP)

ZP3 binds sperm

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

Plasma membrane is the ____ layer that a sperm needs to penetrate during fertilization

A

Last

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

How and when are sperm modified?

A
  • sperm modified by secretions in female tract
  • modifications can take several hours; mandatory ripening process (Capacitation)

-modifications in sperm intracellular signaling & sperm tails become hyper-activated & more motile

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

What is removed from sperm during Capacitation

A

Glycoproteins & plasma proteins removed from tip of sperm head

Now, membrane overlying acrosome more fluid for enzyme release during fertilization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

3 phases of fertilization

A
  1. Penetration of corona radiata
  2. Penetration of zonal pellucida
  3. Plasma membrane fusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Phase 1 of fertilization

A

-capacitated sperm penetrate the corona radiata via whipping sperm tail

***only 300 of 300 million ejaculated sperm penetrate the corona radiata

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

Phase 2 of fertilization

A

Sperm heads bind to ZP3 sperm receptors in zone pellucida and release acrosome like enzymes that dissolve the zone pellucida & allow sperm to penetrate the zone pellucida

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Phase 3 of fertilization

A

Oocyte & sperm plasma membranes fuse

  • sperm nucleus enters oocyte while its plasma membrane melds with oocyte plasma membrane
  • oocyte meiosis II completion & formation of haploid definitive oocyte (& polar body)
  • female gamete (ovum) and male gamete (sperm) fuse their haploid (n) pro nuclei & form a diploid (2n) zygote
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How does oocyte block polyspermy in order to stop fertilization by more than one sperm?

A

Upon sperm contact with oocyte plasma membrane
–> oocyte plasma membrane depolarizes & there is an intracellular Ca 2+ tsunami that induces cortical reaction

Zone pellucida is impermeable to other sperm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Dizygotic twins

A
  • aka fraternal
  • toe oocyte said are simultaneously ovulated & each fertilized by separate sperm
  • 70% of twin pregnancies (1%)
  • genetic content different
  • separate amniotic cavity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Monozygotic twins

A
  • identical
  • 30% of pregnancies
  • single oocyte fertilized by single sperm; splits into 2 within first week
  • timing or split determines if twins have shared or split amniotic cavities
  • earlier the split: more independent their support structures will be
  • genetic contact same
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is cleavage and what does it result in?

A
  • cleavage is a series of symmetrical mitotic cell divisions during week 1
  • cleavage divisions occur ~20 hours apart and result in BLASTOMERES
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

BLASTOMERES

A
  • result of cleavage

- daughter cells that are smaller with each successive division, encased by the zone pellucida in the early embryo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

BLASTOMERES up through the 8 cell stage are _____

A

Totipotent; they can give rise to all embryonic & extraembryonic tissues

**beyond the 8 cell stage, the cells become more differentiated and committed to becoming a particular cell type (no longer Totipotent)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Morula

A

By day 4, 32 cell

-solid ball of compacted cells migrating in the uterine tube toward the uterus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How do the cells of the morula segregate & begin to establish polarity?

A

Inner cell mass (ICM)/embryo last –> fetus

Outer cell mass (OCM)/trophoblast –>placenta

26
Q

How does blastocyst form

A

Fluid from uterine cavity penetrates zona pellucida to surround cells of the morula’s ICM

By 4.5 days after fertilization, penetrating fluid pools and forms blastocyst cavity of the blastocyst

27
Q

Embryoblast/ICM cells are _____

A

Pluripotent (give rise to any/all embryonic cells but not placenta)

Pluripotent embryoblast/ICM cells have potential as embryonic stem cells (ES cells)

**totipotent up until 8 cell stage, then becomes morula –>blastocyst (pluripotent here….as becomes fetus becomes multi potent and unipotent

28
Q

When does implantation occur?

A

~6 days after fertilization during the secretory phase of the endometrium. (Day 20 of 28 day cycle)

29
Q

_______ drive blastocyst implantation

A

Trophoblasts

30
Q

How do Trophoblasts drive blastocyst implantation?

A

Trophoblasts @ embryonic pole of blastocyst secrete enzymes that degrade the zona pellucida

–>blastocyst “hatches” thru the zona pellucida on day 5 & implants into endometrium

Trophoblasts @ embryonic pole embed into uterine wall, eventually form fetal components of placenta & secrete hCG which induces corpus luteum to continue secretion of progresterone for endometrium maintenance

31
Q

With implantation, pregnant uterine endometrium undergoes _______ reaction with increased glandular activity

A

Decided reaction

32
Q

Ectopic pregnancy

A

Blastocyst normally implants into anterior or posterior uterine body wall

—> ectopic is occurs outside this region

95% occur in uterine tube (in ampulla, where fertilization taking place)

33
Q

In week 2, embryoblast of the blastocyst forms ____

A

2-layered/bilaminar disc

*busy time for Trophoblasts, hypoblast, aminoblasts, in forming extraembryonic support

34
Q

Embryoblast different ion forms the

A

Bilaminar embryonic disc

35
Q

Epiblasts differentiate into ________

A

Cells of the embryo proper and amnioblasts

(Amniotic cavity)

Amniotic fluid: fetal urine, oligohydramnios (not enough), polyhyrdaminios (too much)

36
Q

Hypoblasts proliferate & migrate to line inner trophoblast surface of blastocyst cavity

This becomes the ……

A

Yolk sac

  • ventral to bilaminar disc and eventually regresses
  • early exchange/hematopoiesis/germ cells to gonads
37
Q

Hypoblasts give rise to tissue that makes up ____

A

Connecting stalk

–>becomes umbilical cord & connects the embryo/fetus to the placenta

38
Q

Trophoblasts invade uterine endometrium (and along with hypoblast derived tissue) contribute to formation of _____

A

Fetal part of placenta

***maternal part of placenta develops from trophoblast altered endometrium

39
Q

Chorion frondosum

What is it and what makes it up

A

Fetal part of placenta

made up of Trophoblasts and hypoblasts

40
Q

Decidua basalis

A

Maternal part of placenta

Made up of uterine endometrium

41
Q

What does fetal blood carry

A

Waste to placenta from umbilical arteries (2)

Nutrients from placenta to umbilical vein (1)

42
Q

What does maternal blood carry

A

Nutrients to placenta from spiral arteries

Waste from placenta to uterine veins

*waste-nutrient exchange and separation of fetal and maternal blood @ placental barrier

43
Q

What are Trophoblasts, hypoblasts, amnioblasts, doing during week 2?

A

Forming extraembryonic support

44
Q

During week 3, the epic last of the bilaminar embryo forms trial minor sic in process called

A

GASTRULATION

45
Q

Week 3 is a busy time for epic lasts in formation of

A

Intraembryonic germ layers

46
Q

GASTRULATION occurs with ____ formation

A

GASTRULATION occurs with primitive streak formation in the epic last of the bilaminar desk

47
Q

3 primary germ layers of the trial minor embryo:

These originate from ____

A

Ectoderm, mesoderm, endoderm

These layers originate from epic last

48
Q

Epiblast cells migrate to the ______ where they detach and invaginate through it during ____

A

Epiblast cells migrate to the primitive streak where they detach and invaginate through the primitive streak during GASTRULATION

Invaginated epic lasts migrate & form a flat disc-like embryo with 3 layers (trilaminar)

49
Q

Epiblast cells that intercalated among hypoblast cells displace & replace hypoblast cells to form

A

Endoderm

50
Q

Epiblast cells settle between the endoderm and epiblast to form

A

Mesoderm (these cells migrate laterally and carnially)

51
Q

Epiblast cells that remain behind are

A

Ectoderms

52
Q

Ectoderm does what

A

Communication w external environment

Nervous system, epidermis, sensory receptors, some glands

53
Q

Mesoderm does what

A

Support through muscles and connective tissues

Skeletal, muscular, urogenital, cardiovascular systems

54
Q

Endoderm does what

A

Digesting, breathing, secreting (many hands)

Epithelial of urinary bladder, GI-respiratory, some glands

55
Q

2 sites in embryo where ectoderm and endoderm adhere tightly together without migration of intervening mesoderm

A
  1. Buccopharyngeal membrane

1. Cloacal membrane

56
Q

Buccopharyngeal membrane

A

Lies at cranial end of embryo & future location of oral cavity

57
Q

Cloacal membrane

A

Lies at caudal end of embryo as future location of anus

58
Q

What happens when primitive streak doesn’t regress

A

Primitive streak regresses by end of the 3rd week as the notochord mesoderm forms

Teratomas form when primitive streak fails to regress & contain multiple tissue types derived from pluripotent epiblast cells

59
Q

Week 1 of prenatal development beings/ ends with:

A

Begins with fertilization & ends with blastocyst implantation

60
Q

Week 2 of prenatal development forms

A

Bilaminar disc & supportive extraembryonic structures (including placenta)

61
Q

Week 3 of prenatal development results in

A

GASTRULATION of epiblast

Forms trilaminar embryo with 3 primary germ layers

BMS Final (3 decks)

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