[LE2] Lecture 11 Flashcards by Genella Alessandra Roallos

Four structures develop by enfolding within the embryo:

Yolk sac - envelopes the yolk
Allantois - reservoir of waste
Amnion - encloses embryo and provides fluid for embryo to float
Chorion - surrounding these 3

How well did you know this?

Not at all

Perfectly

In the blastulation process, walang blastula ang mammals, they only have ____________

(only mammals have blastocysts, and all others have blastula)

a) allantois
b) allantoic cavity
c) hemotropic
d) blastocyst

blastocyst

How well did you know this?

Not at all

Perfectly

Main difference is that ____________ is sandwiched between epiblast and hypoblast, whereas __________ is where the epiblast and hypoblast make the cells clump together on the implanted side

Also, Blastocoele is outside

a) yolk sac, isolecithal
b) blood vessel
c) blastula, blastocyst
d) digestive function of allantois

blastula, blastocyst

How well did you know this?

Not at all

Perfectly

Composite structures contribute very little to the structure of the embryo but form an important part of it and serve vital functions. They are devoted to the ________ and ______________ of the embryo

a) ectoderm, somatic
b) uterine glands
c) care and maintenance
d) stalk, vesicle

care and maintenance

How well did you know this?

Not at all

Perfectly

Extraembryonic membranes develop by folding off of the embryo during the _________ stage

a) vascular
b) neurula
c) amnion
d) yolk sac

neurula

How well did you know this?

Not at all

Perfectly

__________________ = ectoderm and somatic mesoderm

a) chorion
b) amnion
c) somatopleure
d) splanchnopleure

Somatopleure

How well did you know this?

Not at all

Perfectly

They are avascular (meaning they do not have blood or less blood than in splanchnopleure)

a) chorion
b) chorioamniotic cavity
c) chorion & amnion
d) non-invasive

Chorion & Amnion

How well did you know this?

Not at all

Perfectly

_________________ = endoderm and splanchnic mesoderm (vascular)

a) chorion
b) amnion
c) somatopleure
d) splanchnopleure

Splanchnopleure

How well did you know this?

Not at all

Perfectly

This is where your blood islands will be forming over the area opaca

a) vascular
b) neurula
c) amnion
d) yolk sac

Yolk sac

How well did you know this?

Not at all

Perfectly

Area opaca and Vitelline veins enter the body through the _________________ before it goes to the sinus venosus, and that is how blood is formed in chick embryo

a) immunologic
b) ductus venosus
c) blood vessel
d) cotyledons

ductus venosus

How well did you know this?

Not at all

Perfectly

Acts like the embryonic kidney, in chicks because they do not have a way to remove waste materials

a) embryo
b) circulatory
c) implantation
d) allantois

Allantois

How well did you know this?

Not at all

Perfectly

First fetal membrane to be formed

a) discoid placenta
b) yolk sac
c) deciduate
d) 1 layer

YOLK SAC

How well did you know this?

Not at all

Perfectly

[YOLK SAC]

Derived from ____________ and ______________ mesoderm (splanchnopleure)
Derived from the ___________ mass

a) endoderm and splanchnic
inner cell
b) EPITHELIOCHORIAL PLACENTA
c) Albumen and chalazae

endoderm and splanchnic
inner cell

How well did you know this?

Not at all

Perfectly

[YOLK SAC]

Continuous with _________ splanchnopleure
Connects to the midgut via the ___________

a) conceptus, placenta
b) urachus ligament
c) midgut, yolk sac
d) allantoic cavity

midgut, yolk sac

How well did you know this?

Not at all

Perfectly

[YOLK SAC]

Supplied by __________ vessels

a) placentome
b) vitelline
c) somatopleure
d) yolk sac

vitelline

How well did you know this?

Not at all

Perfectly

Yolk sac is important in egg laying vertebrates. Early nutrition for the embryo (2 to 3 weeks in humans), later shrinks and become non functional as the ___________________

a) blastocyst
b) endoderm
c) ectoderm
d) Meckel’s diverticulum

Meckel’s diverticulum

How well did you know this?

Not at all

Perfectly

The yolk is the source of ___________ in chickens or animals that is laid outside for development

(need nila yolk kasi outside the mother’s body na, hindi na makapagsusupply yung mother to the chick ng nutrients)

a) chorion
b) allantois
c) uterine glands
d) nutrients

nutrients

How well did you know this?

Not at all

Perfectly

But in humans or placental, the yolk is only in early nutrition,
- once we are implanted, the ___________ will be used for nutrient exchange
- _________ is barrier between the maternal and fetal side, it is also the site for nutrient exchange between mother and embryo

(once nageexchange na, there is no need na for the yolk so it shrinks na and becomes nonfunctional)

a) placenta
b) gravity
c) amniotic sac
d) protection

placenta

How well did you know this?

Not at all

Perfectly

The yolk sac forms an early temporary __________ in horse and dog

placenta

How well did you know this?

Not at all

Perfectly

The next to develop after yolk sac
Present in amniotes and absent in anamniotes

AMNION

How well did you know this?

Not at all

Perfectly

Amnion is one of the characteristic of ____________ (birds, reptiles, and mammals have the extraembryonic membrane)

amniontes

How well did you know this?

Not at all

Perfectly

Amphibians encloses the entire yolk within its body, but in chicks they develop only on _____ of the yolk and yolk sac encloses them

top

How well did you know this?

Not at all

Perfectly

Amnion is derived from outer surface ________ and inner _________ mesoderm (somatopleure) formed by convergence of the head, lateral and tail folds at the dorsal midline of the embryo

ectoderm
somatic

How well did you know this?

Not at all

Perfectly

Amnion is filled with _______________ in which the embryo floats

amniotic fluid

How well did you know this?

Not at all

Perfectly

Amnion will provide amniotic fluid to protect the embryo from _____________________

mechanical damage

Fluid is secreted initially by the amniotic ____________ and later is augmented by fluids from the kidney, oral glands and respiratory tract of the embryo

ectoderm

As the amnion enlarges, it encompasses the embryo on the ventral side, merging around the _______________ in mammalian fetus

umbilical cord

With embryo growth, the amnion obliterates the ___________ cavity

chorionic

Near birth, the amniotic fluid can contain fetal feces called ____________.

meconium

FUNCTIONS OF THE AMNION:

1. Mechanical protection 2. Allows free movement of the embryo which aids in neuromuscular development 3. Antibacterial 4. Allows fetal growth 5. Prevents adhesion of the fetal membranes

Hydrostatic pressure provides a _________________ environment in which the fragile embryo can develop without harm normal day to day knocks

shock-absorbing

- Inside the eggs, they rotate everyday - If there is no rotation the embryo will stick to the __________ - Kapag embryo is sticking to the __________, kapag nagrotate, the embryo hindi siya magiging upright and it would be squished by the yolk by the gravity

chorion

_____________ and _________ keeps the embryo upright even when rotating or turning

Albumin and Chalaza

If nastuck sa isang position where the embryo is under the yolk, the embryo will be squished by yolk kasi may ________

gravity

Amnion provides embryo first line of ___________ because this is the immediate membrane that we have.

protection

- It is the Outermost, the boundary of fetus; for example, from the eggshell or in mammals the one enclosed in the placenta - Barrier from the maternal to fetal site

Chorion

Chorion is derived from outer surface ________ and inner ________ mesoderm (somatopleure)

ectoderm somatic

Outer sac that forms the outer boundary of the entire conceptus (fetus With fetal membranes)

Chorion

Appropriates within its limit the extraembryonic coelom, which is also known as the ______________________

chorioamniotic cavity

Chorion fuses with the allantois to form the _____________________ that mediates gas and water exchange

chorioallantoic membrane

Allantois starts small but grows depending on how much ___________________ is produced

nitrogenous waste

Allantois is derived from ___________ and ___________ mesoderm (splanchnopleure)

endoderm splanchnic

Ventral _____________ of the hindgut splanchnopleure

diverticulum

Yolk sac is connected to _________ then the Allantois is connected to __________

midgut hindgut

Consists of a narrow proximal part, the allantoic _______ and a dilated part, the allantoic _________

stalk vesicle

[ALLANTOIS] Grows to fill the entire extraembryonic coelom, with fluid-filled ________________

allantoic cavity

Outer surface of the allantois binds to the inner surface of _________ and the outer surface of __________

chorion amnion

[ALLANTOIS] Highly ________ and provides the functional vessels of the placenta via the umbilical vessels

vascular

[ALLANTOIS] Develops an extensive ____________ system connected to that of the embryo and driven by the new embryonic heart

circulatory

When the allantois is fully developed it completely surrounds the _________

embryo

[ALLANTOIS] _________ the connecting stalk that suspends the embryo in the chorionic cavity

Invades

Remnants of the allantois become the _______________ that connects the belly button to the bladder

urachus ligament

The developing embryo uses oxygen and produces carbon dioxide

Respiratory function of allantois

It is unable to carry out this function itself and hence the ___________ oxygenates the blood and eliminates the carbon dioxide

allantois

It removes the wastes that result from the embryo's metabolism and deposits it in the allantoic cavity

Excretory function of allantois (main function)

It provides the means for the embryo to access the albumen and the calcium of the shell

Digestive function of allantois

1. Appears in the chick embryo at about ____ hours of incubation - Amnion is at the ____ hours of incubation

2. At __ to __ days of incubation, the chorion is closely apposed to the inner shell membrane externally and allantois internally

7 to 8

3. Enclose the yolk by the _____ day of Incubation

6th (yolk sac)

4. Appears on the _________ of incubation

3rd day (72 hours) Allantois is at 72 hours of incubation

(A) The chorion amniotic fold di pa nacocover the entire ______ yet

embryo

(B) _______ is already developing but it is not yet connected to the hind gut via the allantoic stalk and chorion and amnion is already enclosed, and ________ will already be providing the fluid

allantois amnion

yolk sac

(D) then it will become the ________________ where the nitrogenous waste will be going

allantoic cavity

MAMMALIAN EMBRYO: _________ is vestigial Type of ovum is __________

Yolk sac isolecithal

Chorion and allantois form the ____________________ that becomes the wall of the chorionic vesicle

chorioallantoic membrane (or wall) (CAM)

- The chorionic vesicle contains the ____________ - The CAM forms the fetal __________ in mammals

conceptus placenta

Placenta is either ___________, ____________, _______________ that will merge with the maternal site

chorioallantoic, chorioamniotic, or choriovitellinic

- Placenta is not only coming from the fetus, it is also coming from the ___________ site - The basic components is that there is 3 layers from the mother before the blood and 3 layers from the embryo before it is their blood

maternal

A membranous structure formed by apposition of the fetal chorioallantoic membrane and the maternal endometrium (deciduas)

placenta

Area(s) of apposition between uterine lining and fetal membranes are where _____________ are exchanged for sustaining pregnancy

metabolites

Before placental formation, the food of embryo is ______________ (aside from the yolk) that diffuses through the chorion and amnion

uterine milk - from secretions of uterus

After placental formation, the embryonic food is uterine milk plus ____________ nutrition through the maternal blood circulation

hemotropic

FUNCTIONS OF PLACENTA: 1. Selectively mediates _______________ exchange between fetus and mother

physiological

FUNCTIONS OF PLACENTA: 2. Secretes hormones like _________________________

chorionic gonadotrophin

- Placenta is an _______________ barrier - Fetus is foreign body in the womb, so it needs to have an _______________ barrier so that the antibodies of the mother will not attack the baby

immunologic

_________________ hormone is the one detected in pregnancy test

Gonadotrophin

FUNCTIONS OF PLACENTA: 3. Acts as a barrier to prevent ________ of fetal and maternal blood

mixing

[yolk sac] Choriovitellinic: Chorioallantoic: Chorioamniotic:

Choriovitellinic: Very large and fuses broadly with the chorion Chorioallantoic & Chorioamniotic: Remains rudimentary

[blood supply] Choriovitellinic: Chorioallantoic: Chorioamniotic:

Choriovitellinic: Chorion gets supply from yolk sac Chorioallantoic & Chorioamniotic: Chorion fuses with allantois to provide circulation

[animal group] Choriovitellinic: Chorioallantoic: Chorioamniotic:

Choriovitellinic: Primitive type found in marsupials Chorioallantoic: All eutherian mammals except man and primates Chorioamniotic: Man and primates

Chorioallantoic membrane except in primates and man, which is chorioamniotic Connects with the embryo through the umbilical cord

1. Fetal placenta (parts of placenta)

Endometrium of maternal uterus

2. Maternal placenta

There are three layers of fetal extraembryonic membranes in the chorioallantoic placenta of all mammals, all of which are components a the mature placenta:

1. Endothelium lining allantoic capillaries 2. Connective tissue in the form of chorioallantoic mesoderm 3. Chorionic epithelium, the outermost layer of fetal membranes derived from trophoblast

There are also three layers on the maternal side, but the number of these layers which are retained - that is, not destroyed in the process of placentation varies greatly among species. The three potential maternal layers in a placenta are:

1. Endothelium lining endometrial blood vessels 2. Connective tissue of the endometrium 3. Endometrial epithelial cells

All the 6 layers are intact (3 from fetal and 3 from maternal)

EPITHELIOCHORIAL PLACENTA

The ectoderm of the chorion is in contact with the __________ of endometrium

epithelium

Species:

○ Horse, pig and cow ○ Partially in sheep and goat

Only 5 intact layers (3 from fetal and 2 from maternal)

SYNEPITHELIOCHORIAL (SYNDESMOCHORIAL) PLACENTA

The ectoderm of chorion contacts with the connective tissue of ____________

endometrium

The epithelium of ___________ degenerates

endometrium

● Newer publications classifies this only as a subcategory of epitheliochorial ● Species: partially in the _________________

sheep and goat

Only 4 intact layers intact (3 from fetal and 1 from maternal)

ENDOTHELIOCHORIAL PLACENTA

The ectoderm of the chorion contacts with the endothelium of ________- (endometrial) blood vessels

uterine

The epithelium and _____________ of the endometrium degenerate

connective tissue

Species:

carnivores (dog, cat and other canine/feline species)

Only 3 intact layers from fetal placenta

HEMOCHORIAL PLACENTA

The ectoderm of chorion contacts with ________ in the uterine (endometrial) blood vessels

blood

All the 3 layers of ________ placenta degenerate

maternal

Species:

rodent, monkey, man

Hemochorial is divided into 3 types depending on how many layers you have on your chorion:

Hemomonochorial Hemodichorial Hemotrichorial

One layer only called syncytiotrophoblast a) Hemomonochorial b) Hemodichorial c) Hemotrichorial

a) Hemomonochorial

1 layer of syncytiotrophoblast, 1 layer cytotrophoblast a) Hemomonochorial b) Hemodichorial c) Hemotrichorial

b) Hemodichorial

1 layer of cytotrophoblast, 2 layer of syncytiotrophoblast a) Hemomonochorial b) Hemodichorial c) Hemotrichorial

c) Hemotrichorial

Endothelioendothelial has endothelium and another endothelium that is fused together - Only _________ remaining

2 layers

[Hemoendothelial] - Only ___ remaining

DIFFUSE PLACENTA: _____ are distributed throughout the chorionic vesicle except the undilated ends

Villi

Species:

horse and pig

Equine placenta is ____________________ (microplacentas are distributed diffusely)

microcotyledonary

Syndesmochorial is also ________________

cotyledonary

COTYLEDONARY: Villi form tiny oval or round areas called _______________ all over the external surface of the chorionic vesicle, except the undilated ends

cotyledons

Cotyledons attach to specific areas, the _________, in the endometrium of the uterus

caruncles

A cotyledon and caruncle attached to it combine to form the _____________

placentome

Then _____________ enter placentome so that there will be an exchange between mother and baby

blood vessel

A discrete area of Integration between a maternal caruncle and a fetal cotyledon

placentome

Species:

ruminants

_________________ are zonary

Endotheliochorial

Villi are concentrated in a wide zone that forms a belt around the _________________

chorionic vesicle

Types: Complete - ___________ Incomplete - _________

Complete - dog and cat Incomplete - bear, skunk, mink, weasel, ferret and racoon

In dogs, they eat ___________ to open them because baby cannot open them if they do not open, the baby would drown and die

placenta

Some Dogs and cats that are too domesticated, they would just give birth and go away, so yung baby na comepletely covered ng ________________, di na nabubuksan and magddrown na lang. If too domesticated na sila, you need to check if manganganak na sila and help yung baby ibreak yung amniotic sac

amniotic sac

_______________ is discoid

Hemochorial

This is the only one connected to the maternal site

DISCOID PLACENTA

Villi that are concentrated in oval-shaped disks

DISCOID PLACENTA

Types: ○ Single - ___________ ○ Double- __________

human and rodents monkeys

Uterine endometrium is sloughed off during parturition

DECIDUATE PLACENTA

Species:

carnivores, primates, human and rodents

Ruminants are partially ____________

deciduate

Uterine endometrium that remains intact during parturition

ADECIDUATE PLACENTA

Species:

horse and pig

- 6 layers ____________ diffuse - 4 layers ________ for zonary - 3 layers ________ for discoid

epitheliochorial endochorial hemochorial

- Syndesmo is also said to be epitheliochorial din - So syndesmochorial for _______________

cotyledonary

PIG EXTRAEMBRYONIC MEMBRANE

Epitheliochorial, Diffuse, Deciduate Placenta

HORSE EXTRAEMBRYONIC MEMBRANE

Epitheliochorial, Diffuse, Adeciduate Placenta

RUMINANT EXTRAEMBRYONIC MEMBRANE

Cows: Epitheliochorial, Cotyledonary, Deciduate Placenta Sheep and goat: Syndesmochorial, Cotyledonary, Deciduate Placenta

DOG AND CAT EXTRAEMBRYONIC MEMBRANE

Endotheliochorial, Zonary, Deciduate Placenta

HUMAN EXTRAEMBRYONIC MEMBRANE

Hemochorial, Discoid, Deciduate Placenta

Refers to the attachment of the trophoblast (ectoderm) of the chorion to the epithelium of uterine endometrium

IMPLANTATION

The site of implantation in the uterus is the ________________ on ventral side of uterus, opposite the mesenteric attachment

antimesometrial

Following the rupture of zona pellucida, the blastocyst is initially free in the uterine lumen, nourished by ______________

uterine glands

Implantation of the mobile blastocyst is a gradual process beginning with apposition leading to ___________ (or invasion in the case of the human and guinea pig)

adhesion

Approximate implantation times are: ○ 1 week -________ - Then placenta starts to from - You need 14 days before a pregnancy can be positive ○ 2 weeks - _______ ○ 3 to 5 weeks - _______ ○ 3 to 8 weeks-________ ○ Delayed up to 4 months - ____________

human dog, cat, sheep cattle deer and bear

The trophoblasts do not grow into the epithelium of the uterine endometrium and can be physically separated from the latter Occurs in most large domestic animals

NON INVASIVE

The trophoblasts invade and partially destroy the epithelium of the uterine endometrium.

INTERSTITIAL (INVASIVE)

Later, adjacent endometrial tissues may close over and form a nest over the embryo (_________)

nidation Interstitial is what we see usually in humans

SEQUENCE OF IMPLANTATION

1. Attachment and adhesion - It will find somewhere it could attach 2. Invasion and penetration - Invading the endometrium and penetrate it 3. Decidual reaction - Create the decidua or the different layers that would enclose the embryo

[LE2] Lecture 11 Flashcards

(146 cards)