Chapter 12- Reporting Flashcards
The dorsal layer is the _________________, which
underlies ectoderm and, forms
the _______________
somatic (parietal) mesoderm, somatopleure
The ventral layer is the
__________________________,
which overlies endoderm and,
forms the ______________________
splanchnic (visceral) mesoderm, splanchnopleure
the space between the two layers becomes the body cavity and called _________________
coelom
In mammals, the coelom is subdivided
into the ________, ________, and ________, enveloping the
thorax, heart, and abdomen, respectively
pleural, pericardial, and
peritoneal cavities
this is the first functional unit in embryo development,
with the heart as the first functioning
organ–heart, blood cells, and an intricate
system of blood vessels.
circulatory system
Contributes to forming
the early heart structure,
including the left
ventricle, parts of the
atria, and the outflow
tract.
primary (blue)
Supports heart growth by
adding cells to the initial
structure, forming the
right ventricle, remaining
atrial parts, and the
inflow tract.
secondary (red)
It become the base of the aorta and pulmonary arteries, and the right ventricle
conus arteriosus and truncus arteriosus
Cardiogenic mesoderm
specification and heart formation
rely on signals from adjacent
endoderm, especially the anterior
region, via ______ and ______
signaling pathways. This
interplay among cell layers is
crucial for proper heart
development in embryogenesis
BMP and FGF
This is essential for heart formation; its
removal halts heart development.
Posterior endoderm lacks the
ability to induce heart cell
formation. BMPs from the
endoderm stimulate heart and
blood development
anterior endoderm
activated by BMP
signaling, is vital for cardiac
protein expression.
Fgf8
During embryonic development,
migrating cardiac precursor cells
in the posterior region encounter
rising levels of ___________________ from neighboring tissues,
especially the posterior
mesoderm.
retinoic acid (RA)
What are the two heart-forming primordia?
endocardium and mycardium
It lines the heart and is
continuous with blood
vessels.
endocardium
It will give rise to the
heart muscles that will
pump for the lifetime of
the organism
myocardium
carry nutrients from the yolk
sac into the heart’s sinus
venosus, where they flow
into the atrial region
through a valve-like flap
vitelline veins
The initial formation of blood vessels
gives rise to the complex network of arteries,
veins, and capillaries in the body
vasculogenesis
what are the three types of constraints on the construction of blood vessels?
physiological, evolutionary and physical
The embryonic
cells must obtain nourishment.
physiological constraint
Extension of
blood vessels to the yolk sac
evolutionary constraint
- Transport of fluids
performed by large tubes.
physical constraint
During vasculogenesis, a network of
blood vessels is created _________ from
the lateral plate mesoderm.
de novo
Blood vessels and blood cells are
believed to share a common precursor,
the ______________.
hemangioblast
Common progenitor blood vessels and
blood cells:
hematopoietic and endothelial
The pathway whereby ventral mesoderm cells
differentiate into hemangioblasts appears to be induced by the _______________ and the notch signaling pathway
Cdx4 gene
Phases of vasculogenesis
- cell leaving the primitive streak
- angioblast multiply and differentiate into endothelial cells
- endothelial cells form and connect to form the primary capillary plexus
this is the network of capillaries
plexus
Blood vessel formation is first seen in the _________________, where undifferentiated
mesenchyme cells cluster to form blood islands.
wall of the yolk sac
sites of vasculogenesis
extraembryonic and intraembryonic vasculogenesis
Growth factors and vasculogenesis
- basic fibroblast growth factor
- vascular endothelial growth factors
required for the generation of
hemangioblasts from the
splanchnic mesoderm, is a protein that
plays a crucial role in the
regulation of cell growth,
proliferation, and differentiation
basic fibroblast growth factor
is a protein that
plays a crucial role in the
regulation of cell growth,
proliferation, and differentiation.
bFGF
enable the differentiation of the
angioblasts and their
multiplication to form
endothelial tubes, play a crucial
role in promoting the growth of
blood vessels, a process known as angiogenesis
vascular endothelial growth factors
- mediate the interaction between
the endothelial cells and the
pericytes. - are particularly important in
angiogenesis, the process by
which new blood vessels are
formed from pre-existing vessels.
angiopoietins
The critical factor for angiogenesis is
____________________
VEGF-A
can also induce the secretion of VEGFA and
induce blood vessel formation
hypoxia
During angiogenesis, some endothelial
cells in the existing blood vessel can
respond to the VEGF signal and begin
“sprouting” to form a new vessel.
These cells are known as the __________
and they differ from the other vessel
cells
tip cells
Tip cells produce _________ that
are densely packed with
VEGFR-2 (VEGF receptor-2) on
their cell surfaces.
filopodia
have an extensive coating of
smooth muscle and a rich and elastic
extracellular matrix
arteries
have less extensive musculature
and are characterized by valves that
direct the flow of blood.
veins
One of the main inducers of VEGF
proteins is ________ (low oxygen). The
HIF-loc transcription factor that
activates the VEGF-A gene (among
others) is functional only at lower
oxygen levels
hypoxia
is mainly derived from the sprouting of endothelial cells from the dorsal aorta during the initial steps of nephrogenesis
kidney vasculature
- a condition of pregnant woman
- is the leading cause of premature infants and a major cause of maternal and fetal deaths
preeclampsia
- Second circulatory system, the
_____________ ______________ - forms a separate system of vessels which is
essential for draining fluid and
transporting lymphocyte
lymphatic vasculature
this emits a signal that
instructs the lateral plate mesoderm. This
instruction guides the lateral plate
mesoderm to become precursors of
blood and blood vessels.
neural tube
Promotes differentiation.
○ Fgf8 (Fibroblast Growth Factor 8):
○ Further guides cardiogenic
mesoderm development.
○ Ensures proper heart tissue
formation
Bone Morphogenetic Protein (BMP)
Importance of BMP signals
- contribute to cardiogenic mesoderm formation
- differentiation of hemangiogenic mesoderm
-produced by the notochord,
plays a critical role.
● It blocks BMP signaling in the center of
the embryo
Noggin
● early stage
● Cardiogenic mesoderm emerges from
the splanchnic lateral plate mesoderm.
● Head mesenchyme, ectoderm,
somatopleure, splanchnopleure, and
endoderm are formed.
Stage A (25 hours)
● Progression occurs
● Gut forms, and endocardial primordia
begin to take shape around it.
● The endocardium, which will
eventually line the inner chambers of the
heart, starts its initial formation.
Stage B (26 hours)
● Notable features include
● Neural tube: Precursor to the central
nervous system.
● Foregut: Anterior part of the primitive
gut.
● Endocardial tube: The developing heart
tube.
● Ventral mesocardium: Surrounds the
emerging heart structures.
● Myocardium begins to form around the
pericardial cavity.
Stage C (28 hours)
● Endocardium: The innermost layer,
lining the heart chambers.
● Myocardium: The middle layer
composed of cardiac muscle cells.
● Epicardium, which will eventually cover
the heart, is also in progress.
Stage D (29 hours)
- which means it has
two hearts. This condition is induced by
surgically cutting the ventral midline,
preventing the two heart primordia from
fusing.
Cardia bifida
- exhibits a lack of migration of cardiac precursor cells.
● Cardiac precursor cells in the mutant fail
to migrate properly toward the midline,
leading to abnormal heart development.
Miles Apart Mutant
: This gene encodes
the enzyme retinaldehyde
dehydrogenase-2, which plays a crucial
role in synthesizing retinoic acid
RADII2
a marker specific to the early heart fields during development
tbx5
As development progresses, heart
precursor cells experience increasing
amounts of retinoic acid. This exposure
likely influences heart development and
differentiation.
Retinoic acid exposure
The chamber that
receives blood.
atrium
the chamber responsible for pumping blood
ventricle
Process of cardiac and looping and chamber formation
- schematic diagram of cardiac morphogenesis in humans
- xin expression in chick embryos
- atrial and ventricular specification
this is the generation of blood cells
hematopoiesis
can divide either to produce
more stem cells or to replenish
differentiated cells; they can also
regulate to form more cells when body
equilibrium is stressed by injury or
environmental factors
stem cells
capable of producing
all the blood cells and
lymphocytes of the body. It
generates series of intermediate
progenitor cells whose potency is
restricted to certain lineages
pluripotential hematopoietic stem cell
- blood islands in the ventral mesoderm surrounding the yolk sac
splanchnopleure
critical in the
formation of the blood
islands in the mammalian
extraembryonic
mesoderm
BMP4
prevents BMP2 signaling,
abolishes ventral mesoderm and
blood cell production
swirl mutation
Two distinct populations of hematopoietic
stem cells
yolk sac-derived stem cell and definitive hematopoietic stem cell
hematopoietic stem cell that produces
blood for the embryos
yolk sac- derived stem cell
This mesenchymal area is often called the________________
aorta-gonad-mesonephros region
remarkable cell,
common precursor of red blood cells
(erythrocytes), white blood cells
(granulocytes, neutrophils, and
platelets), and lymphocytes
bone marrow
dependent on
osteoblast in the bone marrow
pluripotent HSC
provide niche that attract HSCs, prevents
apoptosis, and keeps HSCs in a
state of plasticity
endosteal osteoblast
- produce blood cells and lymphocytes
lineage restricted stem cells
what are the two lymphocyte stem cells?
megakaryocyte/ erythroid precursor cell and granulocyte/ monocyte precursor cell
red blood cell lineage or platelet lineage
megakaryocyte/ erythroid precursor cell
basophils, eosinophils, neutrophils and monocytes precursor
granulocyte/ monocyte precursor cell
can only form red blood cells
erythroid progenitor cell
produce the first
recognizable differentiated
member of erythrocyte lineage
erythropoietin
red blood cell
precursor and it makes globin
proerythroblast
synthesizing enormous
amounts of hemoglobin
erythroblast
when mammalian
erythroblast expels its nucleus, it becomes ___________. It lacks nucleus,
no longer synthesize globin mRNA, and
can translate existing messages into
globins
reticulocyte
mature red blood cells and
there is no division, RNA synthesis, or
protein synthesis takes place
erythrocyte
Induce different sets of transcription
factors and these specify the fate of the
particular cells
hematopoietic inductive microenvironments
Paracrine involved in
blood cell and lymphocyte
formation. It is made by several
types, but collected and
concentrated by ECM of the
stromal (mesenchymal) cells
cytokines
colonies that
were predominantly
erythroid
spleen
colonies
that were predominantly
granulocytic
bone marrow
it is derived from its own stem
cell and not only differentiates
into osteoblast, it also produces a new population of bone marrow
stem cells
hematopoietic stem cell niche
a
paracrine factor known to
be involved in vascular
remodeling formation of
hematopoietic
microenvironment
angiopoietin-1
Two major functions of endoderm
- Induce the formation of several mesodermal organs
- Construct the linings of two tubes within the vertebrate body
- it extends to the length
of the body and the buds from the
digestive tube forms the liver,
gallbladder, and pancreas
digestive tube
forms as an outgrowth of the digestive tube and eventually bifurcates into the two lungs
respiratory tube
region of digestive system
tube anterior to the point where the
respiratory tube branches off
pharynx
In the foregut cells from the lateral portions of
the anterior endoderm move ventrally to
form the lateral portions
Anterior Intestinal Portal (AIP)
forms from the posterior endoderm
Caudal Intestinal Portal
region of ectoderm and it breaks and create the oral opening of the digestive tube
oral plate or stomodeum
meeting of endoderm and ectoderm at the anus
anorectal junction
is the view that the embryo
constructed itself “from scratch”, no
small, preformed individual resided
within the sperm or egg
epigenesis
a small central
diverticulum forms between the second
pouches, eventually becoming the _________________
thyroid gland
The respiratory tube sprouts from the
___________________ (between the fourth
pair of pouches) to form the lungs
pharyngeal floor
constricts to form the esophagus,
which is followed in sequence by the stomach,
small intestine, and large intestine.
digestive tube
generate only the
lining of the digestive tube and its
glands
endodermal cells
mesenchymal cells from the
splanchnic portion of the lateral plate
mesoderm will surround the tube to
provide the muscles for ________________
peristalsis
The endoderm also forms the lining of three
accessory organs that develop immediately
caudal to the stomach:
liver, pancreas and gallbladder
is a bud of endoderm
that extends out from the foregut into the
surrounding mesenchyme
hepatic diverticulum
develops from the fusion of
distinct dorsal and ventral diverticula. As they
grow, they come closer together and eventually fuse
pancreas
are a derivative of the digestive tube.
lungs
The laryngotracheal endoderm becomes
the lining of the trachea, the two ________, and
the _________________ of the lungs.
bronchi, air sacs (alveoli)
this is secreted very late in gestation, and it
usually reaches physiologically useful levels at
about week 34 of human gestation
sphingomyelin and lecithin
the cells of this membrane
secrete amniotic fluid; thus,
embryogenesis still occurs in water
amnion
the outermost extraembryonic
membrane and responsible for gas
exchange
chorion
an extra-embryonic
membrane of reptiles, birds, and
mammals arising as a pouch, or sac,
from the hindgut
allantois
a small membranous structure
outside the embryo with various
functions during embryonic
development
yolk sac
