Chapter 12- Reporting Flashcards by Ken Valdellana

The dorsal layer is the _________________, which
underlies ectoderm and, forms
the _______________

somatic (parietal) mesoderm, somatopleure

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The ventral layer is the
__________________________,
which overlies endoderm and,
forms the ______________________

splanchnic (visceral) mesoderm, splanchnopleure

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the space between the two layers becomes the body cavity and called _________________

coelom

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In mammals, the coelom is subdivided
into the ________, ________, and ________, enveloping the
thorax, heart, and abdomen, respectively

pleural, pericardial, and
peritoneal cavities

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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

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Contributes to forming
the early heart structure,
including the left
ventricle, parts of the
atria, and the outflow
tract.

primary (blue)

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Supports heart growth by
adding cells to the initial
structure, forming the
right ventricle, remaining
atrial parts, and the
inflow tract.

secondary (red)

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It become the base of the aorta and pulmonary arteries, and the right ventricle

conus arteriosus and truncus arteriosus

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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

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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

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activated by BMP
signaling, is vital for cardiac
protein expression.

Fgf8

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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)

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What are the two heart-forming primordia?

endocardium and mycardium

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It lines the heart and is
continuous with blood
vessels.

endocardium

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It will give rise to the
heart muscles that will
pump for the lifetime of
the organism

myocardium

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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

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The initial formation of blood vessels
gives rise to the complex network of arteries,
veins, and capillaries in the body

vasculogenesis

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what are the three types of constraints on the construction of blood vessels?

physiological, evolutionary and physical

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The embryonic
cells must obtain nourishment.

physiological constraint

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Extension of
blood vessels to the yolk sac

evolutionary constraint

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Transport of fluids
performed by large tubes.

physical constraint

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During vasculogenesis, a network of
blood vessels is created _________ from
the lateral plate mesoderm.

de novo

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Blood vessels and blood cells are
believed to share a common precursor,
the ______________.

hemangioblast

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Common progenitor blood vessels and
blood cells:

hematopoietic and endothelial

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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

1. schematic diagram of cardiac morphogenesis in humans 2. xin expression in chick embryos 3. 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

1. Induce the formation of several mesodermal organs 2. 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