Embryology 4 (final)

Question 1

Spaces form in the lateral intraembryonic mesoderm and cardiogenic mesoderm. These spaces are called ________________ spaces. These are the start of the intraembryonic coelom (embryonic body cavity)

Answer 1

coelomic

Question 2

The coelomic vesicles subsequently fuse together (coalesce) to form a single, horse-shoe-shaped cavity that eventually gives rise to…

Answer 2

body cavities

Question 3

Embryonic nutrition is obtained from the maternal blood by diffusion through the….

Answer 3

extraembryonic coelom and umbilical vesicle

Question 4

In the 3rd week, blood vessel formation begins in the extraembryonic mesoderm of the….

Answer 4

umbilical vesicle, connecting stalk, and chorion (embryonic blood vessels begin to develop 2 days later)

Question 5

The early formation of the cardiovascular system is correlated with the urgent need for blood vessels to bring oxygen and nourishment to the embryo from the maternal circulation through the…

Answer 5

placenta

Question 6

The formation of the embryonic vascular system involves 2 processes. What are they?

Answer 6

vasculogenesis and angiogenesis

Question 7

________________ is the formation of new vascular channels by the assembly of individual cell precursors (angioblasts make vessels)

Answer 7

vasculogenesis

Question 8

_________________ is the formation of new vessels by budding and branching from pre-existing vessels

Answer 8

angiogenesis

Question 9

Blood vessel formation in the embryo and extraembryonic membranes during the 3rd weeks begins when mesenchymal cells (within the mesoderm) differentiate into endothelial cell precursors, aka…

Answer 9

angioblasts

Question 10

Blood vessels develop from specialized endothelial cells of vessels as they grow on the ___________________ and allantois at the end of the 3rd week

Answer 10

umbilical vesicle (source of RBCs/WBCs)

Question 11

The heart and great vessels form from mesenchymal cells in the….

Answer 11

cardiogenic mesoderm/area

Question 12

Paired endocardial heart tubes, develop during the 3rd week and fuse to form a…..

Answer 12

primordial heart tube

Question 13

The tubular heart joins with blood vessels in the embryo, connecting the stalk, chorion, and umbilical vesicle to form a….

Answer 13

primordial cardiovascular system

Question 14

The GI tract is the main organ system derived from the ______________ germ layer

Answer 14

endodermal

Question 15

Which germ layer covers the ventral surface of the embryo and forms the roof of the yolk sac?

Answer 15

endoderm

Question 16

Lengthening of the ________________, causes the embryo to curve into a fetal position as the head and tail regions (folds) moves laterally. As the head an tail and 2 lateral folds move ventrally, they pull the amnion down with them, such that the embryo lies within the amniotic cavity

Answer 16

neural tube

Question 17

A significant event in the establishment of body form is folding of the flat trilaminar embryonic disc into a somewhat cylindric embryo. The embryonic disc undergoes a process of folding that creates the basic vertebrate body form, called the tube-within-a-tube body plan. A major force responsible for embryonic folding in the differential growth of different portions of the embryo. Folding occurs in the _________ and ___________ planes and results from the rapid growth of the embryo. The growth rate at the sides of the embryonic disc fails to keep pace with the rate of the growth in the long axis as the embryo increases rapidly in length. Folding at the cranial and caudal ends and sides of the embryo occurs simultaneously

Answer 17

median, horizontal

Question 18

As the embryo grows rapidly, particularly in length, it undergoes a process of folding that generates the recognizable vertebrate body form. During the 4th week, the embryonic disc and the amnion grow vigorously, but the _____________ hardly grows at all. Bc the yolk sac is attached to the ventral rim of the embryonic disc, the differential expansion is thought to drive the ballooning of the embryonic disc in a 3D cylindrical shape.

Answer 18

yolk sac

Question 19

Where is most of the body folding concentrated in?

Answer 19

thin, flexible outer rim of the embryonic disc

Question 20

The cranial, caudal, and lateral margins of the disc fold completely under the dorsal axial structures and give rise to the….

Answer 20

ventral surface of the body

Question 21

The cranial, caudal, and lateral margins of the disc fold completely under the dorsal axial structures and give rise to the ventral surface of the body. Even though the 3 folds have different names, they become continuous with one another as a ring of tissue at the position of the future ______________

Answer 21

umbilicus (belly button)

Question 22

The _____________ of the original embryonic disc covers the entire surface of the 3D embryo except for the future umbilical region, where the yolk sac and the connecting stalk emerge

Answer 22

ectoderm

Question 23

An embryo body design is composed of 2 main tubes, an outer ectodermal tube forming the external layer of the _________________, an inner endodermal tube forming the inner layer of the _______. The space between the 2 tubes is filled mainly with mesoderm, the lateral plate mesodermal part of which splits to form the body cavity/coelom

Answer 23

skin (epidermis), gut

Question 24

After the neural tube forms, it becomes subdivided in the cranial-caudal axis into forebrain, midbrain, and hindbrain, and the ______________

Answer 24

spinal cord

Question 25

Neural crest cells are a unique population of cells that arise from the ________ part of the forming neural tube during neurulation. Neural crest cells migrate from the tube and become many structures including the _______________

Answer 25

dorsal, entire PNS

Question 26

At the end of the 3rd week, the neural tube is elevating and closing _____________, whereas the git tube is rolling and closing ___________ to create a “tube on top of a tube”

Answer 26

dorsally, ventrally

Question 27

Mesoderm holds the neural and gut tube together and the lateral plate mesoderm splits to form a visceral (____________) layer associated with the gut and parietal (___________) layer that, together with overlying ectoderm, forms the lateral body wall folds

Answer 27

splanchnic, somatic

Question 28

The space between the visceral and parietal layers of lateral plate mesoderm is the….

Answer 28

primitive body cavity

Question 29

The _______________ starts as continuous bilateral clumps of cells as the neural tube closes

Answer 29

neural crest

Question 30

What does the neural crest form into?

test q!

Answer 30

-entire PNS
-sensory and autonomic ganglia
-Schwann cells (glial cells)
-adrenal medulla
-melanocytes

they also move into the head and form the
-bones of the skull
-smooth m
-lens
-anterior pituitary
-ganglia of CN V, VII, IX, and X

Question 31

What are the 2 main embryo regions?

Answer 31

head (CNS level differentiates first, mesencephalic region of neural folds)

body (spinal cord level, lateral edges of fused neural tube)