Exam 1 - Note Set 2

Question 1

The third week of development is characterized by the formation of the ________ _______ _____

Answer 1

Trilaminar Embryonic Disc

Question 2

Process by which the bilaminar embryonic disc is converted into the trilaminar embryonic disc.

Answer 2

Gastrulation

Question 3

Development of body form

Answer 3

Morphogenesis

Question 4

Gastrulation results in the formation of the three germ layers which give rise to the various tissues and organs of the body.
(three germ layers)

Answer 4

Ectoderm
Mesoderm
Endoderm

Question 5

Gastrulation begins with the formation of the _________ ______ on the epiblast

Answer 5

Primitive Streak

Question 6

Source of the germ layers

Answer 6

Epiblast

Question 7

The primitive streak disappears by the end of the…

Answer 7

Fourth Week

Question 8

The ________ extends form the oropharyngeal membrane cranially to the primitive node caudal and provides rigidity to the embryo.

Answer 8

Notochord

Question 9

The ________ appears at day 16 as a small diverticulum from the umbilical vesicle into the connecting stalk

Answer 9

Allantois

Question 10

The proximal part of the allantois persists as the _______, which extends from the bladder to the umbilicus

Answer 10

Urachus

Question 11

The urachus forms the _______ _______ _______ in the adult

Answer 11

Median Umbilical Ligament

Question 12

An undifferentiated connective tissue derived from mesoderm

Answer 12

Mesenchyme

Question 13

Early in the 3rd week, the mesoderm is organized into three distinct columns… (3)
Which one is adjacent to the notochord?

Answer 13

Paraxial Mesoderm - adjacent to notochord
Intermediate Mesoderm
Lateral Mesoderm

Question 14

Near the end of week 3, the paraxial mesoderm differentiates and divides into paired block-like structures which are arranged in a craniocaudal sequence. These structures are called _______ and each pair lie to either side of the developing ______ _______

Answer 14

Somites

Neural Tube

Question 15

___ pairs of somites develop between day 20 and day 30.

By week 5, there are ___ to ___ pairs of somites

Answer 15

38 pairs (day 20 to 30)
42 to 44 pairs (week 5)

Question 16

Somite development begins at the _______ region

Answer 16

Occipital

Question 17

Somites give rise to… (3)

Answer 17

Axial Skeleton
Axial Musculature
Dermis of Skin

Question 18

The __________ _______ will form the three major body cavities of the trunk (pericardial, pleural & peritoneal cavity)

Answer 18

Intraembryonic Coelom

Question 19

During the third week of development, blood vessels appear first in the… (3)

Answer 19

Umbilical Vesicle
Connecting Stalk
Chorion

Question 20

The heart begins to beat by day ___ or ___

Answer 20

day 22 or 23

Question 21

The first system to become functional

Answer 21

Cardiovascular System

Question 22

By the end of week __, oxygen and nutrients are entering the embryo, while carbon dioxide and waste products are excreted into the maternal blood via the _______ ______

Answer 22

week 3 (oxygen and nutrients)
Chorionic Villi (CO2 & waste)

Question 23

In some cases, when the embryo dies, the chorionic villi degenerate and form cysts which resemble a bunch of grapes.

Answer 23

Hydatidiform Mole

Question 24

Hydatidiform Mole most commonly form with fertilization of an oocyte which lacks a…

Answer 24

Female Pronucleus

Question 25

A fertilized oocyte that lacks a female pronucleus is called __________

Answer 25

Monospermic

Question 26

The major event of week 4 of development.

Answer 26

Folding of the Embryo

Question 27

Ventral folding of the embryo occurs at the… (3)

Answer 27

Cranial End
Caudal End
Lateral Edges

Question 28

External features such as the eyes, ears, nose, limbs and digits become apparent in weeks __ through __

Answer 28

weeks 5 though 8

Question 29

during week __, spontaneous movements of the embryo occur, including twitching of the trunk and limbs

Answer 29

week 6

Question 30

Which germ layer gives rise to more volume than any other layer?

Answer 30

Mesoderm

Question 31

Embryonic development is controlled by the interaction of genetic and environmental factors. What are the 3 phases it occurs in?

Answer 31

Growth
Morphogenesis
Differentiation

Question 32

An interaction between tissues which leads to a change in the course of development.

Answer 32

Induction

Question 33

Three forms of tissue signaling

Answer 33

Diffusible Molecule
Nondiffusible Matrix
Direct Physical Contact

Question 34

Length of normal pregnancy:
____ days
____ weeks
____ weeks after fertilization

Answer 34

280 days
40 weeks
38 weeks after fertilization

Question 35

LNMP

Answer 35

Last Normal Menstrual Period