Vetan Topic 3

Question 1

referred to as the development of two (2)
or more embryos in a dam that normally gives birth to one offspring per gestation

Answer 1

embryonic duplication or twinning

Question 2

They are twins having the same genetic composition. Derived from a single zygote that eventually divides or duplicates itself.

Answer 2

Free Symmetrical Monozygotic Twins/ Identical Twins

Question 3

This type of twins originated from a single zygote (monozygotic) that resulted from incomplete separation of blastomeres later in embryonic development (primitive streak stage)

Answer 3

Conjoined or Fused Symmetrical Twins

Question 4

fusion is at the sternal region of the thorax, facing
each other, often with partially fused hearts

Answer 4

thoracopagus twins

Question 5

fusion is at the abdomen, often with partially fused
intestines

Answer 5

abdominopagus twins

Question 6

fusion is back to back at the pelvis
or sacrum

Answer 6

pygopagus

Question 7

fusion is in the head region

Answer 7

cephalopagus

Question 8

twins resulting from duplication of future axial structures which may occur during the primitive streak stage

Answer 8

abnormal twins or monsters

Question 9

two pairs/four of thoracic limbs

Answer 9

tetrabrachius

Question 10

two faces

Answer 10

diprosopus

Question 11

2 pairs/four pelvic limbs

Answer 11

tetrascelus

Question 12

two tails

Answer 12

dicaudatus

Question 13

two heads

Answer 13

dicephalus

Question 14

consist of separate twins one is normal and the other is rudimentary that survives by being attached to the blood supply of fetal membranes
of the normal twin

Answer 14

free, asymmetrical twin

Question 15

Mummified fetus is common in what domestic animals?

Answer 15

cows

Question 16

type of twins occur after gastrulation when specific fields (limb field, heart field, eye field, etc.) are becoming organized.

Answer 16

conjoined, asymmetrical twins

Question 17

an extra pelvic limb is attached to the back of the animal

Answer 17

notomelus twins

Question 18

attached twins of unequal size (heteropagus ) and consist of one reasonably normal individual called the autosite, with an extra body part called the parasite attached to it

Answer 18

conjoined, asymmetrical twins

Question 19

This type of twinning results when two (or more) zygotes develop separately and independently with separate fetal membranes and placenta, during the same pregnancy.

Answer 19

Free Symmetrical Dizygotic or Fraternal Twins

Question 20

composite structure that contribute very little to the structure of embryo but form an important part of it and serve vital functions

Answer 20

extraembryonic (fetal) membranes

Question 21

What is the first fetal membrane to be formed?

Answer 21

Yolk Sac

Question 22

derived from inner cell mass and develops early from hypoblast and extraembryonic splanchnic mesoderm

Answer 22

yolk sac

Question 23

In human embryos 2 – 3 weeks old, the yolk sac is the source of early nutrition but later shrinks and become non-functional as the?

Answer 23

Meckel’s diverticulum (outpocketing of small intestine)

Question 24

By what day of incubation does the yolk sac completely encloses the yolk?

Answer 24

6

Question 25

a short stump of splanchnopleure formed by the folding of the body and closure of the gut tube which connects the yolk sac to the embryo

Answer 25

yolk stalk

Question 26

Amnion is absent in what animals?

Answer 26

fishes and amphibians

Question 27

What are the five functions of amnion?

Answer 27

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 fetal membranes

Question 28

What is the outer sac that forms the outer boundary of the entire conceptus (fetus with fetal membranes)?

Answer 28

Chorion

Question 29

a ventral diverticulum of the hindgut splanchnopleure

Answer 29

allantois

Question 30

What are the three functions of allantois?

Answer 30

respiratory, excretory, digestive

Question 31

a membranous structure formed by the apposition of the fetal chorioallantoic membrane ( CAM) and maternal endometrium (inner layer of the wall ) of the uterus

Answer 31

placenta

Question 32

food of embryo is uterine milk that diffuses through the chorion and amnion

Answer 32

histotrophe

Question 33

What are some functions of placenta?

Answer 33

1. mediates physiological exchange between fetus and mother 2. Secretes hormones like chorionic gonadotrophin 3. Acts as a barrier to prevent mixing of fetal & maternal blood

Question 34

placenta present in the species of horse, pig, cow and partially in goat and sheep

Answer 34

epitheliochorial placenta

Question 35

placenta present in carnivores such as dog and cat, other canine /feline species

Answer 35

endochorial placenta

Question 36

placenta resent in rodents, primates (monkey), human

Answer 36

hemochorial placenta

Question 37

What are the four types of placenta according to shapes and distribution?

Answer 37

1. Diffuse 2. Cotyledonary 3. Zonary -Complete or Incomplete 4. Discoid –Single or Double

Question 38

Villi are distributed throughout the chorionic vesicle except the undilated ends. Found in horses and pigs.

Answer 38

Diffuse placenta

Question 39

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

Answer 39

cotyledonary

Question 40

cotyledonary placenta are found in what animals?

Answer 40

ruminants

Question 41

villi are concentrated in a wide zone that forms a belt around the chronic vesicle which can be either complete or incomplete

Answer 41

zonary placenta

Question 42

Complete zonary placenta has a belt of villi surrounding the entire chronic vesicle which can be found in what animals?

Answer 42

dogs and cats

Question 43

Found in bear, skunk, mink, weasel, ferret & raccoon

Answer 43

incomplete zonary placenta

Question 44

Villi are concentrated in oval-shaped disks. Single or double. A single ______ placenta has one disk located at one end of the chorionic vesicle which are found in humans & rodents

Answer 44

discoid

Question 45

uterine endometrium is sloughed off during parturition

Answer 45

deciduate placenta

Question 46

uterine endometrium remains intact during parturition, found in horse & pig

Answer 46

adeciduate placenta

Question 47

It is a process in which a developing embryo, moving as a blastocyst through a uterus, makes contact with the uterine wall and remains attached to it until birth.

Answer 47

implantation

Question 48

In species w/ long umbilical cords such as swine, neck or limb strangulation in varying degree may occur.

Answer 48

strangulation by umbilical cord

Question 49

a condition characterized by parts of the amnion being attached to the embryonic structures particularly the CNS or limbs, or the distal parts of appendages showing evidence of chorionic constriction

Answer 49

amniotic bands

Question 50

accumulation of excessive amount of fluid in the amnion (hydramnios) or in the allantois (hydrallantois)

Answer 50

hydrops of allantois or amnion

Question 51

associated with some fetal malformation that interferes with its ability to swallow

Answer 51

hydramnios

Question 52

What are the two types of implantation?

Answer 52

non-invasive and interstitial

Question 53

trophoblasts invade & partially destroy the epithelium of the uterine endometrium.

Answer 53

interstitial implantation

Question 54

trophoblast do not grow into the epithelium of the uterine endometrium and can be physically separated from the latter

Answer 54

non-invasive implantation