Embryology Exam 2: Neuralation

Front 1

In which direction do cells of the primitive node migrate for form the notochord?

Back 1

they migrate cranially in the midline

Front 2

Describe the steps of mesoderm formation.

Back 2

1) cells of the primitive node migrate cranially in the midline to form the notochord
2) cells that ingress more caudally form the mesoderm lying on either side

Front 3

How does formation of the notochord begin?

Back 3

With extension from the primitive node of a hollow tube, called the notochordal canal

Front 4

What are the steps of notochord development?

Back 4

1) the notochordal process elongates by invagination of cells from the primitive pit
2) primitive pit extends into the notochordal canal
3) notochordal process is now a cellular tube that extends cranially from the primitive node to the prechordal plate
4) the floor of the notochordal process fuses with the underlying embryonic endoderm
5) Beginning at the cranial end of the embryo, the notochordal cells proliferate and the notochordal plate infolds to form the notochord
6) development of the notochord is complete followed by its detachment from the endoderm of the umbilical vesicle, which forms a continuous layer

Front 5

Formation of the neural plate and neural folds

Back 5

neuralation

Front 6

What is the embryo called during neurolation?

Back 6

the neurula

Front 7

In what process does closure of the folds to form the neural tube occur?

Back 7

neurulation

Front 8

In a scanning EM of a human embryo at day 20, what is visible?

Back 8

1) neural plate (clearly visible)
2) major subdivisions of the brain
3) only a small part of the primitive streak

Front 9

When does the primitive streak (for humans) disappear completely?

Back 9

Day 25

Front 10

What does the narrower caudal give rise to?

Back 10

the spinal cord

Front 11

What is the first step in developing the CNS?

Back 11

the formation of the neural plate in the ectoderm (cranial to the primitive node)

Front 12

Where does the neural plate first begin to form? What happens to it afterward?

Back 12

at the cranial end of the embryo; it differentiates in a head-tail direction

Front 13

What does the expanded cranial portion give rise to?

Back 13

the brain

Front 14

As the neural folds fuse, they form what structure?

Back 14

neural tube

Front 15

Describe neural crest formation.

Back 15

1) The neural folds fuse to form the neural tube.
2) Neural tube separates from surface ectoderm.
3) Neural crest cells form a flattened irregular mass, the neural crest.
4) neural folds approach each other
5) neural crest separates into right and left parts (which will give rise to sensory ganglia)
6) neural crest cells form pigment cells, the adrenal medulla, and many CT of the head.

Front 16

What do neural crest cells form?

Back 16

1) pigment cells
2) adrenal medulla
3) CT of head

Front 17

When the neural crest separates into right and left parts, what arises?

Back 17

they give rise to the sensory ganglia

Front 18

Why do the neural folds approach each other in neural crest formation?

Back 18

in preparation to bud off from the surface ectoderm

Front 19

What do neural crest cells form?

Back 19

a flattened irregular mass called the neural crest

Front 20

What is the embryonic layer from which nearly all the bodies of CT are derived?

Back 20

mesoderm

Front 21

Which embryonic layer means the "middle layer"?

Back 21

mesoderm

Front 22

What happens in early mesoderm development?

Back 22

a number of transient structures form and are lost as tissue structure is patterned and organized

Front 23

What is the first mesoderm structure that will form after the notochord in vertebrates (humans included)?

Back 23

somites

Front 24

When do somites form?

Back 24

at the end of the 3rd week

Front 25

Where are somites located?

Back 25

on each side of the neural tube (NOT NOTOCHORD)

Front 26

How many pairs of somites form during the somite period of human development? When does this occur?

Back 26

1) 38 pairs
2) day 20-30

Front 27

What happens during somite formation?

Back 27

the paraxial mesoderm differentiates, condenses, and begins to divide into paired cuboidal bodies

Front 28

In which direction do somites form?

Back 28

craniocaudally (from head to tail)

Front 29

Where do somites first appear? Where do the rest appear?

Back 29

where the eye will be; toward the caudal region

Front 30

Which is the oldest cranial or caudal somites?

Back 30

cranial?

Front 31

What do somites give rise to?

Back 31

1) axial skeleton
2) musculature
3) dermis of the skin

Front 32

What is a major, fluid-filled cavity that can be seen to form both within the embryo and outside the embryo?

Back 32

coelom

Front 33

What embryonic structure means "cavity"?

Back 33

coelom

Front 34

What is the single primitive cavity that lies within the mesoderm layer that will eventually form the 3 major anatomical body cavities?

Back 34

INTRAembryonic coelom

Front 35

What three major anatomical body cavities does the INTRAembryonic coelom form?

Back 35

1) pericardial
2) pleural
3) peritoneal

Front 36

What are the types of blood vessel formation?

Back 36

1) vasculogenesis
2) angiogenesis

Front 37

What system is essential for the increase demand of bring 02 and nutrients to the growing embryo from maternal circulation?

Back 37

cardiovascular system

Front 38

During pregnancy, the cardio system of the mother develops which type of circulation?

Back 38

a primordial uteroplacental circulation develops

Front 39

What are the stages of blood vessel formation?

Back 39

1. mesenchymal cells differentiate into endothelial cell precursors (angioblasts)
2. These cells aggregate to form isolate angiogenic cells (blood islands)
3. small cavities appear within the blood islands and endothelial cords by confluence of intercellular clefts
4. Angioblasts flatten to form endothelial cells that arrange themselves around the cavities in the blood island to form the endothelium
5, These endothelium-lined cavities soon fuse to form networks of endothelial channels
6. vessels sprout into adjacent areas by endothelial budding and fuse with other vessels

Front 40

What is an isolated angiogenic cell?

Back 40

blood islands

Front 41

T/F. Blood cell formation (hematogenesis) begins in the embryo before the 5th week.

Back 41

False; it begins after the 5th week.

Front 42

Where does hematogenesis occur?

Back 42

at the aorta and then in the embryonic mesenchyme (liver, spleen, and later bone marrow and lymph nodes)

Front 43

T/F. Fetal and adult erythrocytes are derived from the sane hematopoietic progenitor cells.

Back 43

False; they are derived from different hematopoietic progenitor cells

Front 44

What are the stages of blood vessel formation?

Back 44

1. mesenchymal cells differentiate into endothelial cell precursors (angioblasts)
2. These cells aggregate to form isolate angiogenic cells (blood islands)
3. small cavities appear within the blood islands and endothelial cords by confluence of intercellular clefts
4. Angioblasts flatten to form endothelial cells that arrange themselves around the cavities in the blood island to form the endothelium
5, These endothelium-lined cavities soon fuse to form networks of endothelial channels
6. vessels sprout into adjacent areas by endothelial budding and fuse with other vessels

Front 45

What are the stages of blood vessel formation?

Back 45

1. mesenchymal cells differentiate into endothelial cell precursors (angioblasts)
2. These cells aggregate to form isolate angiogenic cells (blood islands)
3. small cavities appear within the blood islands and endothelial cords by confluence of intercellular clefts
4. Angioblasts flatten to form endothelial cells that arrange themselves around the cavities in the blood island to form the endothelium
5, These endothelium-lined cavities soon fuse to form networks of endothelial channels
6. vessels sprout into adjacent areas by endothelial budding and fuse with other vessels

Front 46

What are the stages of blood vessel formation?

Back 46

1. mesenchymal cells differentiate into endothelial cell precursors (angioblasts)
2. These cells aggregate to form isolate angiogenic cells (blood islands)
3. small cavities appear within the blood islands and endothelial cords by confluence of intercellular clefts
4. Angioblasts flatten to form endothelial cells that arrange themselves around the cavities in the blood island to form the endothelium
5, These endothelium-lined cavities soon fuse to form networks of endothelial channels
6. vessels sprout into adjacent areas by endothelial budding and fuse with other vessels

Front 47

What is an isolated angiogenic cell?

Back 47

blood islands

Front 48

What is an isolated angiogenic cell?

Back 48

blood islands

Front 49

What is an isolated angiogenic cell?

Back 49

blood islands

Front 50

T/F. Blood cell formation (hematogenesis) begins in the embryo before the 5th week.

Back 50

False; it begins after the 5th week.

Front 51

T/F. Blood cell formation (hematogenesis) begins in the embryo before the 5th week.

Back 51

False; it begins after the 5th week.

Front 52

Where does hematogenesis occur?

Back 52

at the aorta and then in the embryonic mesenchyme (liver, spleen, and later bone marrow and lymph nodes)

Front 53

T/F. Blood cell formation (hematogenesis) begins in the embryo before the 5th week.

Back 53

False; it begins after the 5th week.

Front 54

T/F. Fetal and adult erythrocytes are derived from the sane hematopoietic progenitor cells.

Back 54

False; they are derived from different hematopoietic progenitor cells

Front 55

Where does hematogenesis occur?

Back 55

at the aorta and then in the embryonic mesenchyme (liver, spleen, and later bone marrow and lymph nodes)

Front 56

Where does hematogenesis occur?

Back 56

at the aorta and then in the embryonic mesenchyme (liver, spleen, and later bone marrow and lymph nodes)

Front 57

T/F. Fetal and adult erythrocytes are derived from the sane hematopoietic progenitor cells.

Back 57

False; they are derived from different hematopoietic progenitor cells

Front 58

T/F. Fetal and adult erythrocytes are derived from the sane hematopoietic progenitor cells.

Back 58

False; they are derived from different hematopoietic progenitor cells