Embryology Unit 3

fimbriae

egg is swept into the oviduct by —

ampulla

fertilization occurs in — of oviduct

24

cleavage occurs — hours after fertilization in the ampulla, the egg continues to the uterus

rotational, meridional, equatorial

mammalian zygotes undergo — cleavage where the first cleavage is — division and the second is both (prev) and —

asynchronous

mammalian blastomere division is —, the number of cells does not increase exponentially

8

zygotic genes in humans are activated by the # cell stage

compaction, E-cadherin, tight, gap

—: blastomeres huddle together and express — allowing for the formation of — and — junctions, this allows for flattening, congregation, communication, and cooperation of cells

morula

compacted 8-cell stage forms the 16-cell — →smaller internal cells surrounded by larger external cells

trophoblast, ICM

in the morula the external cells are — cells and the inner cells from the — (this is the first differentiation event in mammalian development)

Nanog, Oct4, Sox2

ICMs express what 3 genetic markers making them pluripotent and different from trophoblasts?

GATA3

Trophoblasts have what genetic marker that distinguishes them from ICMs?

blastocyst, blastocoel

the inner cell mass is positioned on one side of the embryo and is called the —, the internal empty cavity is called the —

decidua, mucus

during the peri-implantation period there is a restructuring of the maternal anatomy to accommodate the growing embryo, the trophoblasts of the embryo induces formation of maternal —, which is a thick layer of — membrane that lines the uterus during pregnancy

transient, DVE, signaling

what is mouse anterior visceral endoderm? AVE is a local — grouping of cells that develop from the — and act as a temporary — center to set up the A-P axis. the AVE cells are integrated into developing tissues

BMP, Wnt, Nodal

What are the major signaling pathways that establish the A-P axis in mammalian embryos?

body patterning, polarity

Hox genes are involved in — — by specifying A-P — and codes for multiple TF varients

ribs

Hox10 KO in mice causes the lumbar vertebrae to develop —

lumbar

Hox11 KO causes sacral vertebrae to become — vertebrae

conceptus

the embryo is classified as — from zygote to birth

preimplantation embryo

the embryo is classified as — — before implantation

embryo

—: 8 weeks of development after fertilization

fetus

—: from week 9 to birth

fertilization

before 1965, conception was considered to start at —

implants

after 1965, conception was redefined to be when the embryo — in the uterine wall

14

gastrulation begins at day # and is when twinning is no longer possible (some say this is when the embryo is considered an individual person)

embryogenesis, organogenesis, weight

1^st trimester- fertilization to week 12, — and fetal development

2^nd trimester – week 13-27, — and growth

3rd trimester – week 28 until birth, the baby is just growing/putting on —

primordial follicle

— —: an oocyte surrounded by a partial or complete layer of squamous follicular cells

Primary follicle

— —: follicle with a single layer of cuboidal granulosa cells

secondary follicle

— —: follicle with multiple layers of granulosa cells and oocyte is surrounded by zona pellucida

Graphian

— follicle is the most mature follicle

granulosa

— follicular cells: cumulus cells that form tight adhesions with oocyte

corona radiata

— —: innermost layer of cumulus cells

theca, estrogen

— cells: produce androgen precursor needed for —production

granulosa

during ovulation, the oocyte with the corona radiata is ejected to the uterus, — cells remain behind and make progesterone

LH, FSH

ovulation is regulated by — and —

meiosis 2

LH stimulates ovulation, — — and puberty

granulosa, EGFR, GVBD, adhesions

During ovulation: LH binds to — cells (EGF receptors) → release of EGF-like peptides→ LH/— stimulates — causing break down of the nuclear membrane advancing the oocyte to metaphase 2 →cumulus granulosa cells lose — and become loosely linked to the oocyte allowing the oocyte to be ejected

immune system

the luteal phase causes deactivation of the — — in the uterine lining

corpus luteum

the ejected oocyte leaves behind the — — which produces progesterone

24-48

male ejaculation releases ~40 million sperm, they reach the oviduct in #(range) hours

PLC

sperm activates development during fertilization by releasing — in the oocyte

90

first cell division (cleavage) occurs about # minutes after pronuclei meet

fertilization, cleavage, MZT, independently, compaction, visible

first 5 days of human embryogenesis:

day 1: —

day 2: first —, — occurs as early as 4-8 cell stage 

day 3: ~8 cells embryo is acting —

day 4: —, blastomeres flatten to form spherical shape

day 5: cell layers are —, trophoblast, ICM, and blastocoel

hatching, trophoblast, Na+, water

on day 6, — occurs, embryo leaves the zona pellucida: — cells pump — out causing — to fill the blastocoel

ovulation, reproductive, thickening, restructuring, uNK

preparation for pregnancy involves: —

sperm interactions with — tract environment

during the luteal phase of the uterine cycle there is a — of the endometrium and a local — of the immune cells in the uterus

progesterone secretions promote — cell maturation protecting the embryo from the mother’s immune system

cooperative

implantation is a — event between the embryo and mother

apposition

—: step 1 of implantation, positioning of the blastocyst appropriately for implantation with the ICM facing the uterine wall

adhesion, attachments, L-selectin, Muscin 1, LIF

—: blastocyst forms — with uterine epithelial cells, microvilli on uterine wall have — ligands that allow for positioning and adhesion to occur

— is down regulated by — to promote the attachment site

progression, penetrate, cytotrophoblasts

—: trophoblast cells — epithelial layer and embed in uterine wall, — develop from original trophoblast cells and produce lamellipodia that allow the embryo to move in

decidulization, histocompatibility, syncytiotrophoblasts, corpus luteum

—:restructuring the uterine environment in order to intake the embryo, trophoblasts change their — proteins to hide from the mother’s immune system, — arise from the first cell divisions and secrete hormones that allows the — —to be maintained and activates MMP secretion

uNK, neutrophil, communication

how is the blastocyst not rejected and destroyed by the maternal immune system? progesterone secretions activate — cells that release cytokines that block — invasion, maternal and fetal cells — to prevent rejection of embryo

prechordal plate, thickening, brain, eye, allantois

about 21 days post fertilization, the — — forms and is indicated by anterior mesodermal —, this structure later becomes anterior structures including the —, skull, and — muscles

the allantoic bud forms the — that later becomes the umbilical cord

arteries

during gastrulation, syncytiotrophoblasts remodel uterine — to create placental blood supply

infertility, aneuploidy, twinning, disorders, disruptors

alterations to normal pregnancy include: —, —, —, developmental —, developmental —

motility, hormone

male infertility can be caused by sperm —, — issues, testicular disorders

age, PCOS, thyroid

female infertility can be caused by —, —, endometriosis, — disorders, hormonal issues

aneuploidy

when a person has 2 few or 2 many chromosomes due to miotic nondisjunction, increases in likelihood with maternal age. likely due to protein breakdown at centromeres

twinning

—: first the egg is fertilized, then there is early blastomere separation either before or after formation of trophoblast or amnion

genetic, congenital, chromosomal, pleiotropic, ART, environmental, stochastic

developmental disorders can be caused by — mutations such as: — anomalies leading to a particular syndrome, caused by a — or — event, or the use of —; — mechanism and — events can also play a role

brains, adhesion, oxidative

fetal alcohol syndrome: children present with dramatically smaller —, can deter cell — and increase — stress

endocrine, chemicals, synthetic, block

some developmental disruptors are — disruptors, which is when — disrupt the normal processes directed by hormones, these (prev) act like — hormones and can enhance the effect of the endogenous hormone or — natural hormone activity

BPA, meiosis, reversion

— used in the production of plastics, top 50 chemicals, disrupts — and causes sex — in frogs

Santiago Ramon y Cajal

the father of modern neuroscience, worked with Golgi and won a Nobel prize for their work on the structure of the nervous system

silver, Cajal, reticular, individual

Golgi developed — staining to allow for visualization of neurons, — used that to disprove — theory and showed that neurons are —, specialized cells of the nervous system

arborization

the idea that neurons are single cells with branching structures

network

neural dendrites develop an exquisite branching — throughout the body

neural tube, brain, neural crest, migration

what are the 3 main processes of neural arborization? — — formation, — growth, — — cell —

neurulation, ingressing, anterior, posterior, BMP, epidermis

— first step after gastrulation, at the anterior most portion cells are — even before gastrulation, the groove closes — to —, neural tube closure is governed by ventral — from —

elongation, invagination, convergence, closure, signaling

overview of primary neurulation in chicks: — and folding of neural plate, — of neural plate, — of neural folds, — of neural tube this all allows the formation of the notochord as a — center

elongation, surface area, autonomously, presumptive neural

the first step of primary neurulation in chicks is —: there is an increase in the — — of tissue, cell proliferation occurs —; — — crest cells undergo proliferation

folding, MHP, notochord, midline

the secondary step of primary neurulation in chicks is —: as the tissue bends the — forms, folding of the neural plate makes contact with the —, the floor plate of the neural groove establishes the — axis

elevation, folds, MHP, apical, actin/myosin, faster

the third step of primary neurulation in chicks is — of neural —: the floorplate/— undergoes — constriction by decreasing the (prev) surface area by constricting the —/— filaments in their cytoskeleton, in the neural groove cell proliferation is — than in the MHP

convergence, neural folds, DLHP

the forth step of primary neurulation in chicks is —: tissues of the — — are pushed together by —

Closure, fuse, cadherins, tube, crest

the fifth step of primary neurulation in chicks is —: the neural crest cells — together, — play a critical role in the closure and separating of tissue, neural — forms and neural — cells disperse to form neurons, melanocytes, adrenal cells

posteriorly, ingression, aggregate, cavitation

Secondary neurulation occurs — and involves — of mesenchymal cells that — together to form a solid cord of cells in the tail bud region and — (hollowing out the medullary cord) will occur forming the secondary neural tube that fuses with the primary neural tube

morphogen, BMP, DLHP, apical, Noggin, BMP, DLHP, SHH, Noggin

neurulation signaling uses — gradients: in the outer ectoderm — blocks — and — constriction, in the neural fold — inhibits — so that constriction can occur/— can be expressed, cells closest to the notochord express — and blocks —, the notochord expresses signals allowing MHP to form

BMP, SHH

DLHP exists only where there is low — and —

transition

the notochord is a signaling center and is a — structure

neural, inhibit

SOX are transcription factors that are — markers, the both turn on neural markers and — other fates

caudal epiblast, neural tube, Tbx6

Formation of neural tube: — — contains precursor cells for neural ectoderm and paraxial mesoderm, Sox-2 expressing precursor cells become — —, ingressing cells (that do not express Sox-2) express — to become paraxial mesoderm

extra neural tubes

if Tbx6 is inhibited, the cells form — — —

bidirectionally

anterior to posterior neural tube development can occur —

multiple, both

neural tubes have — closure points during development, the neural tube is “zipped up” in — directions

defects

failure to close the neural tube properly results in neural tube —

5

humans have # neural tube closure points

anencephaly

(NTD) when the brain is exposed to amniotic fluid and the neural tissue degrades

craniorachischisis

(NTD) complete neural tube failure to close

spina bifida

(NTD) spinal cord exposed and degrades, often results in paralysis at the waist down

zinc, p53

— depletion leads to widespread DNA fragmentation and apoptosis and deficiency may lead to stabilization of — which induces widespread apoptosis

synthesis, methylation, unknown, prevented, epigenetic

folate is known to be necessary for DNA — and regulating DNA —, the mechanism of folate activity in neural tube closure is —, but an estimated 25-30% of NTDs can be — with supplemental folate, DHFR and MTHFR convert folate to 5-methylTHF which is thought to have an — effect

segmented, swelling

hindbrain rhombomere formation develops in — pattern this is demonstrated from periodic — in the rhombencephalon

territories, transcription factors, neurons

the different patterns of rhombomeres represent separate — from which different nerves originate and the patterning is governed by a unique combination of — — in each region dictating what types of — develop

sensory

anterior and posterior signaling gradients form sections of interneurons for — processing

complex differential, sensory, motor

dorsal-ventral patterning in spinal cord uses — — transcription factor expression that causes different neuron development. in the dorsal region: — neurons form in the dorsal horn

in the ventral region: — neurons form in the ventral horn

forebrain, midbrain, hindbrain

the primary vesicles of the brain are the —, — , and —

telencephalon, diencephalon

the forebrain becomes the secondary vesicle of the — and —

mesencephalon

the midbrain becomes the secondary vesicles of —

metencephalon, myelencephalon

the hindbrain becomes the secondary vesicles —, and —

volume, plateaus, exponentially

the human brain has a high brain —, far exceeding that of lower primates, brain growth in primates quickly —, but in humans it grows — the first few years of life

gyrencephalic, speed

the human brain is —, meaning that it has folds that increases the outer surface area, this may occur due to the — of development