COT Quiz 1 - BU MAMS

Embryonic Period

0 to 8 weeks (of fertilization age)

Period of Early Embryo

0 to 3 weeks (of fertilization age)

Period of Embryonic Organogenesis

3 to 8 weeks (of fertilization age)

Fetal Period

8 weeks to 38 weeks (of fertilization age)

Carnegie Stages

23 stages that cover the first 8 weeks post ovulation, based on morphological development

Carnegie Stage 1

zygote, two pronuclei visible

Carnegie Stage 2

morula, blastomeres form via mitosis

Carnegie Stage 3

blastocyst; embryoblast and trophoblast are present

Carnegie Stage 4

implantation begins

Carnegies Stages 1-4

week 1 to early week 2, ~0.1 mm in size

Carnegie Stage 5

embryo is fully implanted in endometrium; bilaminar disc & primitive yolk sac

Carnegie Stage 6

amniotic cavity, primitive yolk sac, and chorionic cavity are present; bilaminar disc; primitive streak is visible & gastrulation begins

Carnegie Stages 5-6

week 2; formation of bilmainar disc and ~0.1-0.2 mm in size

Carnegie Stage 7

gastrulation continues, mesoderm forms, trilaminar disc

Carnegie Stage 8

notochord present and formation of neural folds / grooves with primitive pit; trilaminar disc

Carnegie Stage 9

1-3 somites stage; head fold, early heart, & early gut tube

Carnegie Stages 7-9

week 3, trilaminar disc, 0.4 mm-2.5 mm in size

Teratogen

substance that can cross the placental membrane and disrupt embryonic development

2 Weeks After Onset of Last Period

day 1 for fertilization

Endometrium

mucosa in uterus, site of implantation (epithelium + underlying loose connective tissue)

Myometrium

thick layer of smooth muscle in uterus

Perimetrium

layer of the uterus that is connective tissue (mostly serosa / some adventitia)

Menstrual Phase Days 0-4

superficial / functional layer is shed

Proliferative Phase Days 4-14

functional layer thickens

Secretory Phase Days 14-28

functional layer becomes engorged with blood & glycogen

Ovulation (Day 14)

happens on day 14 of 28-day cycle

Ampulla

enlarged region of the uterine tube where fertilization most commonly takes place

Zona Pellucida & Corona Radiata Cells

oocyte is ovulated with these two ?cells

Cell Cleavage

rapid cytokinesis without cell growth (zona pellucida restricts embryo size); blastomeres become smaller with each division & happens day 1

Morula

solid ball of 16+ cells, happens ~day 3 of development

Blastocyst

inner and outer cell masses are apparent; “hatches” out of the zona pellucida (degrades)

Embryoblast

inner cell mass of blastocyst that gives rise to definitive embryo

Trophoblast

outer cell mass that invades endometrium and contributes to placenta

Epiblast

columnar dorsal layer; adjacent to amniotic cavity

Hypoblast

cuboidal ventral layer; adjacent to primitive / primary yolk sac (forms first)

Cytotrophoblast

cells surrounding the developing embryo

Syncytiotrophoblast

cells lose their membranes and become part of an interconnected syncytium

Decidua Basalis

endometrium deep to the site of implantation (parental contribution)

Chorionic Villi

Extraembryonic mesoderm containing blood vessels from embryo

Primitive Streak

formed on dorsal surface of epiblast (facing amniotic cavity) & elevated primitive node at cephalic end surrounding primitive pit

Gastrulation

epiblast gives rise to three primary germ layers

Epithelial-to-Mesenchymal Transition (EMT)

cells delaminate from the epiblast and undergo a transition

Epithelium, Lamina Propria, Muscularis Mucosae

layers of mucosa

Muscularis Externa (Inner Circular & Outer Longitudinal)

layers of muscularis

Tunica Intima, Tunica Media, Tunica Adventitia

layers of blood vessels

Mesothelium

outer surfaces of an organ

Endothelium

epithelium of blood (and lymphatic) vessels

GI Epithelium

region where epithelium is simple columnar epithelium

Skin

Stratified Squamous Keratinized Epithelium

Oral Cavity, Vagina

Stratified Squamous Non-keratinized Epithelium

Pectinate Line

the point of transition from simple columnar epithelium to stratified squamous nonkeratinized epithelium

Lamina Lucida, Lamina Densa, Lamina Reticularis

layers of basement membrane

Terminal Web

anchor for actin filaments inside microvilli

Villi

structures composed of goblet cells and enterocytes (simple columnar epithelial absorptive / secreting cells in small bowel); center composed of connective tissue (lamina propria)

Glycolipids

specific to the extracellular face; all cells have ___ on their surface

Polarity

functional property controlled by microtubules by delivering newly synthesized proteins to appropriate poles

Symmetric Division

to produce two cells equal to the parent cell, cells undergo:

Asymmetric Division

to produce a further differentiated cell, cells undergo:

Zona Occludens (Tight Junction)

binds extracellularly with claudins

Zonula Adherentes (Adhering Junction)

binds to actin; cadherin proteins

Macula Adherentes (Desmosome)

binds to intermediate filaments; desmoglein proteins

Nucleolus

production of ribosomes

Rough Endoplasmic Reticulum

organelle that produces transmembrane proteins, or proteins for exocytosis

Golgi Apparatus

addressing of protein storage vesicles; does not stain

Smooth Endoplasmic Reticulum

organelle where diffusible molecules (steroid hormones) are synthesized; also site of P-450-based detoxification in liver

Lysosome

vesicles containing acid hydrolases for enzymatic digestion

Peroxisome

vesicles containing oxidases (since oxidative reactions might be damaging if carried out freely in the cytoplasm); not distinguishable from lysosomes in normal EMs of human tissue

Residual Body

“undigestible” material; may remain in cytoplasm as “lipofuscin granules”; accumulates in long-lived cells

Primary Cilium

flow-sensing function and has “9+0” microtubules; one is present in almost all cells

Metaplasia

term to describe epithelium that is changing in form / classification (includes adaptive and oncogenic phases)