Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Y3 repro > applied embryology > Flashcards

applied embryology Flashcards

1
Q

What are the pre-requisits for a pregnancy to occur

A

functioning gametes - viable sperm and mature egg

patent reproductive pathway - vagina, cervix, uterus and fallopian tubes

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

release of the egg for fertilisation

A

ovulation - can survive for 1 day once released

picked up by the fimbrial end of the fallopian tube where it waits to meet the sperm

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

sperm reaching the egg for fertilisation

A

sperm released into the vagina

has to travel up through the cervix, uterine canal and fallopian tube to reach the egg in order to fertilise it

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

what happens during fertilisation

A

sperm enters the egg and unites with its nucleus

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

what follows fertilisation

A

organised series of cell division

cell numbers increase and form an early blastocysts ~day 5

embryo then implants into the womb

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

what is the outer layer surrounding the egg called

A

zona pellucida

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

what helps the sperm get into the egg

A

cap on the sperm head (acrosome) releases hydrolytic enzymes

helps it dissolve the zona pellucida and fet into the perivitelline space

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

what is the perivitelline space

A

the space between the egg and the zona pelludica

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

what occurs in the perivitelline space during fertilisation

A

sperm binds to the protein receptos an the plasma membrane of the egg and sperm fuse

sperm then releases its nucleus whih enters the egg

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

what happens once a sperm has released its nucleus into the egg

A

cortical reaction - egg plasma membrane becomes a tough wall and doesn’t let any more sperm in

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

what happens if multiple sperm enter the egg

A

abnormal fertilisation

these eggs aren’t capable of further cell division or pregnancy

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

what is the first stage in the egg following fertilisation called

A

pronuclei stage

2 nuclei in the fertilised egg (1 from egg and 1 from sperm)

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

what stages occur during day 1-5 following fertilisation

A 
day 1 - pronuclei forms 
2 - 1st cell division 
3 - cell division continues
4 - formation of Morula 
5 - blastocyst forms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is a morula

A

cells continue to divide and numbers increase rapidly until you cannot count them but they form into a ball of cells - morula

this then organises into a blastocyst embryo

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

organisation of cells in the blastocyst

A

2 cell groups:
outer layer - trophoblast, placenta forms from this
inner layer - inner cell mass, this is where the embryo develops

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

what layer of the blastocyst invades the maternal endometrium

A

trophoblast

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

what are the 4 steps for implantation to occur

A

hatching
apposition
adhesion
invation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is hatching

A

blastocyst has to come out of the zona

trophoectoderm cells produce protease to dissolve the zona in preparation for implantation

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

what is apposition

A

first connection between blastocyst and endometrium

apposes to microvilli like structure (pinopodes) expressed on receptive endometrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how does the maternal endometrium become receptive

A

under hormonal preparation which happens in every monthly cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is adhesion

A

earliest implantation sign

trophoblast of the blastocyst adheres to the epithelial layer of the maternal endometrium
embyronic tissue starts to actively secrete hCG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is invasion

A

trophoblast proliferation and differentiation
crossing of the epithelial BM and invasion of endometrial stroma to form the placenta

uterine spiral arteries remodelled by the invasive trophoblast - placentation starts

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

what happens with inability to hatch

A

infertility

premature hatching can result in abnormal implantation in the uterine tube - ectopic

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

what regulates apposition and adherence

A

a number of growth factors and cytokines

this all has to happen in sync as well as with hormones for the implantation to happen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
decidualisation prior to invasion
pre-requisite for trophoblast invasion and placentation involves transformation of stromal cells of maternal endometrium every month under the effect of progesterone
26
what changes occur to the endometrium under the effect of progesterone prior to invasion
stromal cell differentiation - elongated fibroblast cells converted into decidual (rounded epithelial cells) angiogenesis - increased vascular permeability increased macrophages, lymphocytes and decidual leukocytes (uterine natural killer cells) for maternal immune tolerance
27
why are the changed in the endometrium important for invasion
transform the endometrium into a vascular receptive tissue for blastocyst invasion
28
describe placentation
invading trophoblast forms 1y chorionic villi with infiltration of extra-embryonic mesoderm these become 2y villi when capillaries form they become 3y villi invasion of cytotrophoblast remodels spiral arteries to increase blood flow
29
what are the 2 cell layers of the trophoblast
inner part close to the inner cell mass = cytotrophoblast outer part = syncytiotrophoblast these are the parts which will develop into villi
30
placentation - what is the main function of villi
establish the connection with the maternal circuation
31
what is the mature placenta formed from
chorionic villi intervillous space placental septae cotyledons - subunits of the placenta
32
what are the functions of the placenta
``` immunological barrier gas exchange nutrient exchange waste excretion endocrine functions - secreted hCG ```
33
what is embryogenesis
first 8wks of embyro development post-fertilisation
34
embryoblast development
wk2-3 - formation of bilaminar disc and development of amniotic sac, yolk sac, extraembryonic mesoderm and chorionic cavity wk3-4 - differentiation of bilaminar disc into trilaminar structure - 3 germ layers (endoderm, mesoderm, ectoderm), through gastrulation and neural tube formation wk5-8 - organogenesis
35
what are the different parts of the blastocyst and what are the cell types
inner cell mass (embryoblast) - pluripotent cells bilaminar disc - epiblast (undergoes gastrulation) and hypoblast (forms extraembryonic mesoderm) blastocele - fluid filled cavity inner layer cytotrophoblast forms chorionic villi
36
inner cell mass differentiation
inner cell mass differentiates into bilaminar epiblast (columnar epithelial cells) and hypoblast 2 cavities form - yolk sac on side of hypoblast and amniotic cavity on side of epiblast
37
epiblast differentiation/gastulation
3 germ layers form - ectoderm, mesoderm, endoderm (day 13-16) gastrulation starts with a groove appearing in the caudal end of epiblast (primitive streak) newly formed trilaminar disc w/ 3 layers is called gastrula and forms the different organ systems
38
how is the endoderm formed
epiblast cells migrate into the hypoblast layer displacing them
39
how is the mesoderm formed
further epiblast cells migrate through primitive streak between the epiblast and the hypoplast/endoderm to form the mesoderm
40
how is the ectoderm formed
remaining epiblast becomes the ectoderm
41
what forms from the ectoderm
``` epidermis CNS PNS hair and nails neuroendocrine organs (adrenal medulla, pituitary) enamel of teeth ```
42
what forms from the mesoderm
``` dermis MSK structures CVS kidneys ureters trigone of bladder gonads (not germ cells) adrenal cortex visceral and parietal linings (pleura, pericardium, peritoneum) ```
43
what forms from the endoderm
``` lining of GI tract parenchyma of liver pancreas thyroid parathyroid tonsils and thymus bladder (not trigone) ```
44
what are the 3 major subunits of the mesoderm
paraxial - forms MSK structures intermediate - forms kidney, ureter and gonads lateral plate
45
what is a dizygotic pregnancy
≥2 eggs fertilising and implanting | non-idential
46
what is a monozygotic pregnancy
1 embryo splitting timing of embryo splitting determines nature of pregnancy identical twins
47
what type of twins are more common
non-identical
48
what is the risk of multiple pregnancy
natural conception - 1-2% | fertility treatments have increased the rates, target to keep <10%
49
DCDA twins
division day 1-4 post fertilisation | 20%
50
MCDA twins
division day 5-8 post fertilisation 75% seen in fertility treatment
51
MCMA twins
division day 7-14 post-fertilisation 5% high risk twins - shared placenta, higher incidence of fetal death
52
conjoined twins
division >14 days post fertilisation | <1%
53
how is the urinary system linked to the gonads
kidney and ureter and repro system develop from the urogenital ridge in the intermediate mesoderm (same origin) urogenital ridge differentiates into gonadal ridge medially which gives rise to gonad and nephrogenic cord laterally (forms kidney and ureter) urinary system develops ahead of repro system from wk4
54
development of urinary system
kidney, ureter, bladder and urethra kidney and ureter develop from 3 overlapping system in nephrogenic cord portion of urogenital ridge (pronephros, mesonephros and metanephros) kidney develop in pelvis and then ascend into abdo with final position by wk12 bladder and urethra formed from urogenital sinus (part of cloaca) which also gives rise to parts of female and male repro tract
55
what are the 3 stages of development of the kidneys and ureter
pronephros - non-functional mesonephros - functional but transient metanephros - kidneys
56
where does the kidney form from
metanephric mesenchyme
57
what forms the ureter
ureteric duct
58
what is the cloaca
common temporary outlet for digestive, urinary and genital tract in embryonic life nephric duct drains into this
59
what is the nephric duct
connects pronephros, mesonephros and metanephros
60
what are 6 examples of renal anomalies
``` renal agenesis horseshoe kidney pelvic kidney duplex kidney duplex ureter and calyceal system ```
61
what is renal agenesis
no kidney one of the metanephric ducts or none develop gives rise to a unilateral kidney system complete renal agenesis = no kidney
62
what is a pelvic kidney
kidneys have failed to ascend from the pelvis to the abdomen
63
what is a horseshoe kidney
fusion of the kidneys during ascent | get stuck so cannot ascend any further
64
where is the cloaca located and what are its coverings
caudal end of the enfolded yolk sac covered in cloacal membrane which is formed by the fusion of the ectoderm and endoderm
65
what does the urorectal septum form
cloaca is divided by the urorectal septum to form: urogenital sinus anal canal
66
what does the urogenital sinus form
bladder and urethra
67
what forms the trigone of the bladder
mesonephric duct below the ureteric bud is incorporated into the bladder as the trigone
68
where does the indifferent gonad develop
in the gonadal ridge
69
what is the gonadal ridge related to
closely related to the mesonephros
70
where do the primordial germ cells originate from
do not originate in the gonadal ridge they migrate to the gonads from the endoderm lining of the yolk sac via the hindgut at wk6
71
what forms the primitive sex cords
epithelium of gonadal ridge
72
what forms the indifferent gonad
combination of germ cells and primitive sex cords indifferent gonad is capable of developing into a testis/ovary
73
what determines whether the indifferent gonad becomes a testis/ovary
Y chromosome contains SRY gene SRY produces testis determining factor protein acts on the indifferent gonad to promote the formation of the testis in rare cases following a translocation error, a male can be born w/ 46 XX karyotype
74
development of the ovary
migrating germ cells enter the ovary primitive sex cords extends into the medulla but degenerate 2y sex cords (cortical cords) develop and surround the germ cells --> ovarian primordial follicles ovarian follicle pool established at 20wks gestation
75
development of the testis
migrating germ cells enter the testis primitive sex cords extend into medulla and forms testis cords which transform into future seminiferous tubules and rete testis sertoli cells are derived from surface epithelium under effect of AMH Leydig cells are produced from intermediate mesoderm and produce testosterone from wk8 onwards
76
where do the testis develop
posterior abdo wall and then descend through the deep inguinal ring ~7mths into the scrotal sac
77
why do the testis have to descend
scrotal sac temp is lower than body temp required for proper spermatogenesis
78
what % have undescended testis
2-3% | can be in the abdo area or somewhere in the inguinal canal
79
what is cryptochordism when is it checked for what is the management
undescended testis checked for in all male infants early corrective surgery to prevent effects on fertility later on
79
what is cryptochordism when is it checked for what is the management
undescended testis checked for in all male infants early corrective surgery to prevent effects on fertility later on
80
what are the 2 sets of genital ducts
mesonephric duct next to the gonad | paramesonephric duct laterally
81
what is AMH and why is it important
Anti-Mullerian hormone presence/abscence determines which of the genital ducts develops and which regresses males - presence of AMH causes paramesonephric ducts to regress and these don't form any part of the adult
82
where do the mesonephric duct and paramesonephric duct open into
urogenital sinus
83
which ducts remain in males and females
Mesonephric - Male | paramesonephric - female
84
what do the mesonephric ducts drian
aka Wolffian ducts drain mesonephros into the cloaca
85
what does the mesonephric duct form
in both males and females it forms the trigone part of the bladder?
86
persistence of mesonephric duct in males
persists under the effect of testosterone forms epididyms, vas deferens and seminal vesicles
87
regression of mesonephric duct in females
remnants might remain as epophoron, paraophoron (small cysitc structures lateral to ovary) and gartners duct cyst
88
what is gartner's duct cyst
benign lesions on lateral vaginal wall
89
female reproductive tract development
absence of AMH paramesonephric ducts continue to develop, mesonephric ducts regress paramesonephric ducts grow medially and fuse - fused portions canalises to form uterus and upper 2/3 of vagina unfused portions give rise to fallopian tubes paramesonephric ducts fuse w/ urogenital sinus at the sinus tubercle, point of fusion --> hymen
90
what forms the lower 1/3 of the vagina
urogenital sinus
91
development of external genitalia
on either side of the cloacal membrane folds develop - urogenital folds these fuse anteriorly --> genital tubercle lateral to this are the labioscrotal swellings as the cloaca is split by the urorectal septum the anus is separated off
92
male external genitalia development
genital tubercle elongates to form the penis labioscrotal swelling folds fuse posteriorly - form scrotum urogenital folds fuse posterior to anteriorly to form penile urethra (spongy urethra) glans penis will canulate at the tip to form the final part of the urethra
93
female external genitalia
urogenital folds form labia minora labioscrotal folds form labia majora genital tubercle forms clitoris
94
male repro tract anomalies
penile - micropenis, hypospadia testicular - absence, undescended (cryptochordism) absence of vas deferens - CF absence of seminal vesicles
95
how does a micropenis occur
tubercle doesn't elongate fully
96
what is hypospadias
development problem causing urethral opening to be abnormally located e.g. undersurface of penis
97
female repro tract anomalies
common - 4-7% no one agreed classification system (ASRM, ESHRE/ESGE) association w/ renal tract anomalies uterine vaginal MKRH syndrome
98
uterine anomalies
underdevelopment - uterine agenesis, unocornuate uterus fusion - didelphys uterus, bicornuate resorption - septate uterus, arcuate uterus
99
how do uterine anomalies occur
paramesonephric ducts on one or either side don't develop properly - agenesis or unicornuate ducts don't fuse correctly in the middle (no fusion - didelphys, part fusion - bicornuate) fused part of ducts doesn't undergo canalisation, remains as fibromuscular band (uterine septum), septation can be partial or complete
100
vaginal anomalies
vaginal septa - longitudinal or transverse imperforate hymen vaginal agenesis - absent or underdeveloped uterus and vagina
101
MKRH syndrome
Mayer Rokitansky Küster Hause aka Mulleria agenesis syndrome failure of paramesonephric ducts to develop normally - absence of all female repro tract

Y3 repro (47 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions