Chapter 7,8,9

Question 1

How long does it take for a developing mammalian embryo to reach the uterus?

Answer 1

3 days

Question 2

What supplies the nutrition of embryo prior to its implantation to endometrium?

Answer 2

Own yolk, and reproductive tract secretions

Question 3

Serves as the protection for the developing embryo against maternal immune system

Answer 3

Zona pellucida

Question 4

Serves to nourish the developing embryo after it hatches from zona pellucida before it attaches to epithelium of uterus.

Answer 4

Secretions of uterine glands

Question 5

The process wherein the developing embryo attaches or adheres to the epithelium of the uterus

Answer 5

Implantation/nidation

Question 6

Apposition, Adhesion and Firm attachment

Answer 6

3 stages of implantation

Question 7

Blastocyst implants itself interstitially by passing through the uterine epithelium and becoming completely cut off from the uterine lumen. This is true in primates, guinea pigs and human.

Answer 7

Interstitial/Invasive Implantation

Question 8

blastocyst remains small and becomes lodged in the fold of the uterine lumen, where it implants itself. Example of this form of implantation are
rodents.

Answer 8

Eccentric Implantation

Question 9

Blastocyst elongates and enlarges until it fills a good part of the uterine cavity. This form of placentation occurs in ungulates, carnivores, swine,sheep, cattle and horse

Answer 9

Centric/Superficial Implantation

Question 10

Blastocyst implants in the endometrium on the same side as the attachment of the mesometrium.

Answer 10

Mesometrial Implantation

Question 11

implantation occurs at a site opposite to the attachment of the mesometrium

Answer 11

Anti-mesometrial Implantation

Question 12

Implantation occurs when the probability that
offsprings are born at a time of year favorable for survival. E.g. for Mink, ferrets, roe deer, bears, badgers and seals

Answer 12

Seasonal or Obligative Implantation

Question 13

The dam ensures that it does not have to support two litters contemporaneously
* Rodents and insectivores

Answer 13

Facultative or lactational Implantation

Question 14

Implantation and subsequent embryonic development in an extra-uterine location

Answer 14

Ectopic pregnancy

Question 15

These are the sites of ABNORMAL implantation

Answer 15

Ovary, uterine tube, peritoneal cavity

Question 16

This is a natural placement or orientation and spacing of the embryos that occur in the uterus of the dam.

Answer 16

Embryo orientation and spacing in – utero

Question 17

True or false in cattle When single oocyte is fertilized, the blastocyst attaches to the middle or upper third of the uterine horn adjacent to the ovulating ovary.

Answer 17

TRUE

Question 18

True or false in sheep When two blastocysts are derived from one ovary, one blastocyst usually migrates to the contralateral
(opposite) horn where it becomes implanted.

Answer 18

TRUE

Question 19

True or false in Horses blastocyst will only implant at the left horn close to the body of the uterus.

Answer 19

False, blastocyst will implant on either left or right side of the horn.

Question 20

True or false for litter bearing or Polytocous animals blastocyst are evenly spaced within the uterine horns.

Answer 20

TRUE

Question 21

These are tissues derived from the developing embryo that enclose and contribute
to the support of the developing embryo.

Answer 21

Extra embryonic membranes

Question 22

What are the 4 EEM’s?

Answer 22

Yolk sac, allantois, amnion and chorion

Question 23

Where are the amnion and chorion derived from?

Answer 23

Somatopleure (fused mesoderm and ectoderm)

Question 24

Where are the allantois and yolk sac derived from?

Answer 24

Splanchnopleure (fused mesoderm and endoderm)

Question 25

Is a small membranous structure in egg with scant yolk material like mammals, performs a variety of critical biological functions during early gestation.

Answer 25

Yolk sac

Question 26

Provides the nutrition and gas exchange between the mother and developing embryo

Answer 26

Yolk sac

Question 27

Takes place in yolk sac before the liver and bone marrow eventually take over. It is the provision of oxygen to organs.

Answer 27

Primitive hematopoiesis

Question 28

Remnant of yolk sac after birth

Answer 28

Meckel’s diverticulum

Question 29

Blood supply is provided by which vessel during the 6th day of incubation?

Answer 29

Vitelline vessels

Question 30

the outermost membrane surrounding the embryo in mammals, birds and reptiles, also involved in gas and nutrient exchange due to its vascularity

Answer 30

CHORION

Question 31

Serves as the cushion to protect the embryo

Answer 31

Chorionic fluid

Question 32

the fetal part of placenta

Answer 32

chorion

Question 33

the maternal component of placenta

Answer 33

decidua basalis

Question 34

Membranous sac that intimately encloses the embryo when first formed. It is which serves to provide a protective environment for the developing embryo or fetus.

Answer 34

AMNION

Question 35

In the early weeks of pregnancy is mostly water that comes from the body. After about 20 weeks of pregnancy, the baby's urine makes up most of the fluid.

Answer 35

Amniotic fluid

Question 36

A hollow sac-like structure filled with clear fluid that forms part of a developing amniote's conceptus. Helps the embryo exchange gases and handle liquid waste

Answer 36

ALLANTOIS

Question 37

Are the continuation of the sinus venosus of the heart.

Answer 37

Allantoic veins

Question 38

Shape of allantois for cattle, sheep and pigs

Answer 38

Anchor shaped

Question 39

Shape of allantois for dogs, cats and horses

Answer 39

Tube-shaped

Question 40

the connecting stalk between the fetus and the placenta

Answer 40

UMBILICAL CORD

Question 41

True or false in cattle, sheep and pigs, the umbilical cord ruptures as the fetus passes through the birth canal.

Answer 41

True

Question 42

True or false in horses, dogs and cats, the umbilical cord normally does not break as a result of the action of the dam after the fetus has been born

Answer 42

False - It breaks

Question 43

A structure formed by the apposition of the fetal and maternal tissues

Answer 43

Placenta

Question 44

The formation, type and structure, or arrangement of the placenta

Answer 44

Placentation

Question 45

Its function is to transfer nutrients and electrolytes, respiratory gases, and water from maternal tissue to a growing embryo, and in some instances to remove waste from the embryo

Answer 45

Placenta

Question 46

2 Types of Placenta

Answer 46

Choriovitelline and Chorioallantoic.

Question 47

when the fused vascular choriovitelline membranes become attached to the endometrium. - common in marsupials.

Answer 47

choriovitelline placenta

Question 48

becomes attached to the endometrium. ⁻ definitive form of placentation in higher mammals. ⁻ it may be preceded by and co‐exist with a temporary choriovitelline placenta

Answer 48

chorioallantoic placenta

Question 49

Characterized by uniform distribution of villi on the outer surface of the chorion * Occurs in horses and pigs

Answer 49

Diffuse Placenta

Question 50

are unique to the mare Principal source of the equine chorionic gonadotrophin (formerly known as the pregnant mare serum gonadotrophin)

Answer 50

ENDOMETRIAL CUPS

Question 51

Chorionic villi are restricted to cotyledons * Occurs in ruminants * 90-100 in sheep, 70-120 in cattle

Answer 51

COTYLEDONARY

Question 52

the maternal contact sites

Answer 52

Caruncles

Question 53

the cotyledon-caruncle complex

Answer 53

Placentome

Question 54

Chorionic villi are confined to a girdle-like structure around the middle of the chorionic sac * Occurs in carnivores

Answer 54

ZONARY

Question 55

Chorionic villi are restricted to disc-shaped areas on the chorionic sac * Occurs in humans, monkeys and rodents

Answer 55

Discoidal

Question 56

microcotyledons are distributed diffusely

Answer 56

MICROCOTYLODENARY

Question 57

Loose apposition * Separation is easily achieved at parturition without damage to maternal tissue. * Horses, ruminants and pigs

Answer 57

APPOSED, NON-DECIDUATE

Question 58

* Intimate connection is formed between maternal and embryonic tissue. * Some maternal tissue is lost with the fetal tissue at birth. * Humans, dogs, cats and rodents

Answer 58

CONJOINED, DECIDUATE

Question 59

- trophoblast or chorionic epithelium and uterine epithelium remain in close contact but both retain their original layer. - marsupials ,ungulates and lemur. - all 6 layers are intact

Answer 59

Epithelio-chorial

Question 60

chorionic villi erode the uterine wall, so that the uterine epithelium is ruptured and the chorionic villi comes in contact with the connective tissue of the uterine wall. ⁻ ruminants ⁻ only 5 intact layers (3 from fetal and 2 from maternal).

Answer 60

Syndesmo-chorial

Question 61

both uterine epithelium and connective tissue is eroded so that the chorionic villi comes in contact with endothelium of maternal blood vessel. ⁻ dogs ,cats and other carnivores. ⁻ 4 intact layers (3 from fetal and 1 from maternal).

Answer 61

Endothelio-chorial

Question 62

⁻ uterine epithelium, connective tissue and endothelium all are eroded and the chorionic villi baths in the maternal blood. ⁻ human, primates and rodents. ⁻ only 3 intact layers: fetal/ all maternal layer's degenerate

Answer 62

Haemo-chorial

Question 63

⁻ foetal capillaries lie freely in maternal blood. ⁻ Rabbit.

Answer 63

Haemo-endothelial

Question 64

- the nutritional material supplied to the embryo from the circulating maternal blood.

Answer 64

Haemotrophe