19 Questions
During vasculogenesis, where do the blood vessels develop from?
Mesoderm
What is the main difference between vasculogenesis and angiogenesis?
Vasculogenesis involves the formation of brand new blood vessels, while angiogenesis involves the sprouting of blood vessels
What does angiogenesis primarily involve?
Sprouting of blood vessels
Where do the paired endocardial heart tubes form during vasculogenesis within the embryo?
Mesenchyme
What day does the embryonic heart begin beating?
Day 21
Which type of chorionic villi is characterized by the presence of blood vessels (capillaries) within the mesenchymal core?
Tertiary chorionic villi
Why is a circulation that exchanges between maternal and fetal tissues necessary in the context of embryonic growth?
To overcome inadequate nutrient diffusion between embryo and endometrium
What is the primary function of the cytotrophoblastic shell in chorionic villi?
Facilitates attachment to the endometrium
When does the presence of blood vessels and red blood cells in the fetus coincide with the beginning of gas, nutrient, and waste exchange between mother and embryo?
Day 21
Where do the red blood cells develop first in the early embryo?
Allantois and umbilical vesicle
Which vessel returns blood from tertiary villi back to the embryonic heart?
Umbilical vein
What happens by the 4th week regarding the paired heart tubes?
They fuse to form a single 'ventricle' and atrium
Which structure brings the atria superior as it bends in a counter-clockwise direction?
Sinus venosus
From which vessel does blood flow through the umbilical vesicle in the early 4th week of embryonic development?
Vitelline vein
What is the role of syncytiotrophoblast in the maternal-fetal circulation?
Secreting hCG to induce decidual cell apoptosis
Why does the syncytiotrophoblast prevent the endometrium from being lost during menstruation?
By secreting high levels of progesterone
What effect does hCG have on the ovary?
Maintains high levels of progesterone secretion
Which cellular component forms primary chorionic villi projecting into the lacuna?
Cytotrophoblast
How does the trophoblast contribute to the nourishment of the embryo?
By diffusing glycogen for energy supply
Study Notes
- Development of embryonic vessels starts early in the 3rd week, arising from the mesoderm.
- Vasculogenesis involves the formation of new blood vessels from the mesoderm, while angiogenesis involves the sprouting of blood vessels formed through vasculogenesis.
- Angioblasts derived from the mesoderm develop in specialized regions called blood islands, which later develop lumens and become blood vessels through vasculogenesis.
- Within the embryo, vasculogenesis leads to the formation of angioblastic cords in the mesenchyme during gastrulation/neurulation.
- The embryonic heart starts to beat at day 21, coinciding with the presence of blood vessels and red blood cells in the fetus.
- Chorionic villi undergo development stages from primary to tertiary, with tertiary villi allowing for substance exchange between maternal and fetal tissues.
- By the 4th week, the paired heart tubes fuse to form a single ventricle and atrium, with the maternal-fetal circulation depending on fetal cardiovascular structures and endometrial exchange mechanisms.
Learn about the early stages of embryonic vascular development, including vasculogenesis and angiogenesis. Understand how blood vessels form from mesoderm and connect to each other through specialized regions called blood islands.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
