Embryology Flashcards
what animals have zonary placentae
Carnivores, manatees
What degree of placental interdigitation do cats and dogs have
Endothelialchorial: no uterine connective tissue intervenes between syntrophoblast and endothelium of maternal vessels (be able to draw this)
What stage are the areas above Henson’s node in
Neurlation
What is the diverse migratory cell population that becomes melanocytes, creaniofacial cartilage and bone, smooth muscle among other things
Neural crest
The spaces within the lateral plate are enclosed and form what (space between splanchnic and somatic layers)
coelom
what degree of placental interdigitation do pigs, cows, and horse have
epitheliochorial: fetal and maternal epithelia interdigitate (be able to draw this)
What is restriction
options narrowing
What does dermatome become
dermis
What does umbilical (mamals)/ allantoic (birds) systems do
Oxygen exchange
What do cardinal veins do
drain blood from the body of the embryo
What does chorion do
Site of gas exchange (white skin like stuff when you make hard boiled eggs just inside of the shell)
Definition of mesenchyme
Cells from mesoderm or neural crest that are loosely arranged, tells epithelium what to do, precursor to muscle and connective tissue
What do chorioamniotic folds create
amnion and chorion
What does Myotome become
skeletal muscle
What is differentiation
expression of mature stage
What animals have discoid placentae
humans, rodents, insectivores
What does the somatic layer of lateral plate mesoderm form
Body wall
What animals have diffuse placentae
Pigs, horses
What degree of placental interdigitation do primates have
Hemochorial: chorion is bathed in the maternal blood (be able to draw this)
What does yolk do to the symmetry of developing animals
Reduces symmetry
Why do birds have more yolk
No direct contact with mother
in mammals during blastulation, an inner cell mass separates from the trophoblast and creates what
blastocoele
What are epigenetic factors
Compounds that mark DNA and determine what, where, and when genes should be expressed. (Google: 1 molec bio: 0)
Notochord produces proteins that inhibit ectoderm from becoing epidermis, what does this form
neural ectoderm
What is the morula
Mass of blastomeres at 64 cell stage
In birds during blastulation, the hypoblast delaminates from the epiblast creating what
Blastocoele
What does the mesoderm become
Connective tissue, muscle, cardiac tissue, bones
What stage are the areas below Hensen’s node in
blastulation
What is the outer layer of the blastula
epiblast
Definition of morphogenetic movement
movement of cells in early embryo that change shape or form of differentiating cells
Definition of embryo
development from fertilization until organs develop
What does vitteline system do
To and from yolk, nutrients
Gastrulation converts ___ (two things) into ___ (three things)
Hypoblast and epiblast into ectoderm, endoderm, and mesoderm
What is the enlarged cranial end of primitive streak known as
Hensen’s node
Definition of induction
interaction at close range between 2+ embryonic cells with different properties, and one group is altered
What does Ectoderm become
Neural tissue and skin
What was the point of the Kriegerish (Archer anyone?) experiment with the duck and chicken leg mesenchyme/epithelium
Mesenchyme is what determines what the epithelium becomes
What are the two layers of lateral plate mesoderm
somatic and splanchnic
What is the purpose of the yolk sac in mammals
serves as nutritive functions via the vitteline vessels in early development, more important in horses
Where do the amnion and chorion come from
Somatopleure
what determines the morphological pattern of cleavage and the morula
the amount and distribution of yolk in the zygote
Where does involution occur during gastrulation to form the primary germ layers
Hensen’s node
What is teratology
scientific study of congenital abnormalities and abnormal formations
What is primary induction
influence of notochord and prechordal mesoderm on overlying mideline ectoderm causing it to form neural ectoderm
what is the precursor to the central nervous system
neural tube
What does Endoderm become
respiratory and GI tract
What does the yolk sac come from
splanchnopleure
What does retinoic acid do
Establish identity of location along cranial-caudal axis
What is the trophoderm
another name for chorion
What is a congenital defect
Defect present before birth
what is a fetus
Development from when organs are created but not completely developed
Definition of paracrine factors
Cell chemical signals that act on nearby cells
What are three primary germ layers
Ectoderm, mesoderm, and endoderm
what does sclerotome become
vertebrae, ribs, and scapulae
What is the area of contact between fetal and maternal tissues in mammals
Placenta
What happens during gastrulation
Primitive streak forms,
what is deciduous placenta
Vessels rupture at birth (pig)
What degree of placental interdigitation do sheep and goats have
Syndesmochorial: Chorion is in direct contact with uterine connective tissue (be able to draw this)
What are the four main things that happen during neurulation
Primary induction, Neural tube closure, formation of neural crest, segmentation of mesoderm into somites
What is the allantois
outpocketing of hindgut in between amnion and chorion
Definition of critical period
Organ systems become established, inductive interactions occur, organ is most susceptible to disruption
In mammals during blastulation, what does the trophoblast do
facilitates absorption of nutrients
What is the primitive streak
Cranial to caudal groove of epiblast cells
What direction does Henson’s node develop during gastrulation
Cranial to caudal
What separates branchial archs
pharyngeal pouches (openings of foregut)
What is the relationship between branchial arch and aortic arch
Each branchial arch contains a specific aoric arch, cranial nerve
What are the three fates of somites
Sclerotome, myotome, and dermatome
What do branchial arches form
Major structures of the head
What is the inner layer of the blastula
hypoblast
What animals have cotyledonary placentae
ruminates
What does the amniotic cavity do
provides cushion
What stage are the areas at Hensen’s node in
gastrulation
What is determination
Options closed, fate has been determined
What are 3 characteristics of blastulation
- Cells divisions are asynchronous 2. Blastocoele forms 3. Beginning of cell determination
Describe the difference between yolk distribution influence in mammals and birds on the morula
Mammals: uniform distribution of daughter cells Birds: Large amount of asymmetrically distributed yolk, flat embryo
Name at least 4 of the 6 shared features of all vertebrate embryo
- Dorsal hollow neural tube, enlarged rostrally 2. notochord ventral to neural tube 3. Series of paired mesodermal somites 4. Ventral endodermal gut tube 5. Coelom lined by lateral plate mesoderm 6. Ventral heart and bilateral aortic arches that empty into dorsal aorta
What is non-deciduous placenta
diffuse and cotylendory, fetal side peels away without hemorrhage (cats, dogs)
What does splanchnic layer of lateral plate mesoderm form
circulatory system
where does primates extra embryoic mesoderm come from
Trophoblast
