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Questions tagged [embryology]

The study of the development of an embryo from fertilisation through to description as a foetus.

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105 views

At what stage is the nervous system developed enough to interpret neuronal signals as 'pain'?

According to this article in Live Science, one of the reasons the fetus can't feel pain until 19 weeks is because the nervous system isn't fully developed. But according to this article, the heart ...
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2k views

What is cytoplasmic localization?

I was studying development of chick but didn't understand what is cytoplasmic localization. My book says: After third cleavage , the rest of the cleavages are irregular and completely delimited ...
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2k views

What is this part of blastula called and how is endoderm formed?

Could you tell me what the yellow mass within the blastocoel is called ? I know that blastocoel is a fluid filled cavity, so are the yellow coloured cells the inner part of blastoderm or are they some ...
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1answer
159 views

Which process is needed to complete male reproductive development?

In order to properly complete male reproductive development: ...
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1answer
214 views

How many areas are there in Brodmann map?

I read Wikipedia claiming 52. I heard that this can be extended to 54. I see there is no limit of having more areas - just better understanding of the neuroblast migration and fibroblast too, probably....
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1answer
41 views

Does the yolk sac for Danio rerio form at the vegetal pole?

Does the yolk sac in general form always at the vegetal pole? If so, is this the case for Danio rerio (the zebrafish)?
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18 views

How to supply oxygen to a culture vessel?

I'm reading this paper: https://www.jstage.jst.go.jp/article/jpsa/51/3/51_0130043/_pdf From day 17 of the culture period until hatching, pure oxygen was supplied at a flow rate of approximately 500 ...
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1answer
164 views

Is the blastopore imaginary?

I've been told in my zoology class that the blastopore is an imaginary pore found in gastrula, from which mouth develops first in protostomes and anus develops first in deuterostomes. But we've also ...
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1answer
410 views

What is the mechanism of folic acid deficiency and neural tube defects?

I am having difficulty finding the mechanism by which folic acid reduces the risk of neural tube defects. I know that it does so, but what in particular actually occurs with folic acid deficiency to ...
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1answer
54 views

Roles of creatine and bilirubin in foetus circulation

I think they are not inputs from maternal placenta. I think they are the results of foetus metabolism. However, I do not understand it how and where exactly. What are the roles of creatine and ...
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3k views

How many consecutive cell divisions are required to form the adult human body from the single cell zygote?

The preferred question would have been what is the total number of cells in a full term human foetus and how many cell divisions are required to reach that number. However estimates of total cell ...
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1answer
28 views

Modern views on the correspondence of moles

In his Memoirs, Casanova wrote: In the midst of the dimple which added such a charm to her chin Esther had a little dark mole, garnished with three or four extremely fine hairs. These moles, which ...
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1k views

Is there a difference between an organizer and inducer substance?

There is a question in my Embryology textbook's exercise that asks about an organizer and inducer substance. I found their definitions and now I am wondering if they are the same things?
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why is the cleavage in frogs holoblastic and not meroblastic?

background information The cleavage of the frog embryo during the embryo development is holoblastic (complete cleavage). However when we look at yolk-rich eggs we see a cleavage pattern which is ...
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1answer
257 views

Why are Birds and Reptiles with abundant yolk sac polyspermic?

I was given an explanation that birds and reptiles are polyspermic because they have an abundant yolk sac. But how does it explain the thing? Chicken as an adult is not using in my opinion yolk as an ...
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38 views

Archenteron vs Gastrocoele

What is Difference between “Archenteron” and “Gastrocoele”. Are they same or different? Gastrula is characterized by Archenteron or Gastrocoele or Both?
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Why is cartilage replaced by bones in a vertebrate adult?

Why is cartilage present in a vertebrate embryo replaced by bones in an vertebrate adult even though cartilage can also provide me the structural framework like as in Chondrichthyes and they seem to ...
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20 views

How does axon guidance system precisely targets specific axons?

Axons find their way to the terminus by responding to axon guidance molecules (AGMs) that attract and repel growth cones or make them stir. This I understand. Through a very specific combination of ...
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40 views

What are limitations of giving birth to a baby from a frozen embryo?

Recently the story of a woman giving birth to baby girl from an embryo frozen 24 years ago hit the news. After an in vitro fertilization the embryo was frozen on 14 October 1992( Article in the ...
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72 views

What is the difference between endometrial lining and endometrial stroma?

This is in the context of embryology whereby the syncytiotrophoblast erodes the endometrial stroma during the penetration and implantation of the zygote. But I don't know the correct terminology of ...
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60 views

Myoblasts Formation

Myoblasts arise from mesenchymal stem cells (MSCs), and are precursors to myocytes. In muscles, in the basement membrane, there are also present satellite cells which can divide to generate muscle ...
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78 views

Front versus back in animal anatomy [closed]

Throughout various species, there seems to be a clear distinction between the front and the back. The musculature of the front, when engaged, closes or curls up the body, protecting it, while the ...
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1answer
1k views

Could bone marrow transplants be used to prevent tissue rejection of trans-species organs?

So the immune system doesn't calibrate (for want of a better euphemism) to recognize it's own cells until fairly well along in fetal development & the major components of the immune system (...
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1k views

Can a chicken really be hatched outside of the egg?

This YouTube video (screenshots attached) claims to show Japanese schoolchildren breaking an egg into a kind of clingfilm "hammock in a cup", and then growing and hatching a chick from it in an ...
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94 views

Which X-Y chromosomes have the developmental genes for mammals?

I know that for a given mammal, half the chromosomes come from father and half from mother. This is typically denoted as x-y. I've recently read about "toolkit" genes that control how a cell develops ...
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88 views

Has an ectopic pregnancy's blastocyst ever been made to implant?

Has an ectopic pregnancy's blastocyst ever been successfully extracted from the Fallopian tube and made to implant in the uterus?
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379 views

How far is stem cell research from being to generate a new organ?

How far are we from being able to use stem cell research to generate a sperm, a heart, a liver, and a kidney? In stem cell research, my understanding is that you must start off with some cell to ...
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253 views

Does a zygote express all genes?

If a zygote has all the cytoplasmic determinants and all the specific transcription factors, does that mean that all genes in the genome are expressed?
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1answer
4k views

What's the difference between an embryo and a fetus?

The most I've been able to come up with is that fetuses are embryos slightly farther along in their development. Is that correct?
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3k views

When can a virus modify DNA in every cell of a living organism?

I've recently heard about experiments with brain tissue, where a virus is introduced in a rats brain, causing a "glow when electric charge is present" protein to be created. This protein then helps to ...
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1answer
46 views

Why can early embryos survive freezing?

According to this Blastocyst & Embryo Freezing in IVF Embryos can be frozen at the pronuclear stage (one cell), or at any stage after that up to and including the blastocyst stage (5-7 days ...
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1answer
49 views

When do the first neurons appear in humans?

According to this Neural Plate The neural plate appears in day 18 in humans (very specific). and according to this Neural Plate (wiki) The progenitor cells that make up the precursors to neural ...
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1answer
40 views

If DNA methylation inactivates genes, does DNA demethylation activate them?

DNA demethylation can be passive or active. The passive process takes place in the absence of methylation of newly synthesized DNA strands by DNMT1 during several replication rounds – for example, ...
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1answer
48 views

How does gene affect organs development in eukaryotic cells? [closed]

I'm totally new to biology and apologies if you find this basic. The central dogma insists that genetic information flows in this direction: DNA -> RNA -> proteins So far so good, it is very clear ...
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1answer
33 views

How necessary is human zygote cytoplasm for generating a human?

I'm primarily questioning the roles of genetics and cytoplasmic factors of zygote in generating a human being with a natural embryological process. For instance, is there an experiment where we check ...
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2answers
3k views

What is the difference between the neural tube and the dorsal ventral cord?

I was wondering what the difference is between the neural tube and the dorsal ventral cord. I know that the neural tube forms during embryonic development from the ectoderm layer that folds inwards. ...
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2answers
4k views

Negative role of Placenta

How can a placenta turn hostile to the mother or fetus ? What are the abnormalities found during placental delivery ?
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1answer
2k views

Waste generation by embryo [closed]

How does an embryo produce waste products even when its organ systems are not developed fully ? How does the placenta identify or differentiate waste materials from embryo ? Which organelle or ...
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1answer
108 views

Manifestations of open foramen ovale in adults

I read that foramen ovale opens in 30% of adults. I do not know how much of these openings can then close again. Probably, none. It is not pathogenic if no symptoms. It allows blood to enter from ...
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1answer
113 views

Is there any bank of animations for Embryology?

I am trying to find animations which can anonymous or generalised for Embryology. However, I have not find any single good source. Is there any bank of animations for generalised embryos?
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1answer
58 views

How does the zygote divide much faster than other cells?

Normally a cell has a mechanism that controls its division. As far as I know, it checks surface area and stuff like that to decide to go for mitosis or not. However, this is not the case for a zygote....
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1answer
676 views

difference between blastula and blastocyst

What is the difference between these 2 terms. I believe that blastocyst is for animals, but structurally is there any difference? And how would you be able to identify each?
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1answer
320 views

Why does cell differentiation start with the morula?

I suppose that cell differentation has to start by some external symmetry breaking. The first time there are two different types of cells is the morula with roughly 16 cells: there are some 12-15 ...
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1answer
81 views

Where does craniocaudal closure of anterior neuropore start?

Closure of the cranial neuropore is bidirectional, and final closure occurs in the area of the future forebrain. Closure of the caudal neuropore is strictly craniocaudal and finishes at the level of ...
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1answer
395 views

Why is the threshold between human embryo and human fetus defined as 8 weeks after fertilization?

Why is the threshold between human embryo and human fetus defined as 8 weeks after fertilization? What's happening on the 8th week? Note: definition of embryo based on Wikipedia's current definition.
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1answer
94 views

Function and process of TCTE-1 receptor

I was wondering if anybody knew of the function and process of the TCTE-1 receptor during the binding of a sperm with an egg. The only think I know of TCTE-1 is that it is a species-specific receptor. ...
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1answer
180 views

Significance of prostaglandins in semen?

I am trying to figure out how prostaglandins in the semen relate to the female reproductive tract. More specifically, How does prostaglandins in semen help the female reproductive tract increase the ...
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2answers
50 views

Regulation of the replication of mtDNA at embryonic level

While reading an article on mitochondrial inheritance I came across this link. The results state that mitochondrial DNA replication is regulated in different cells of an embryo at different levels. ...
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1answer
340 views

What is a zygote?

During fertilization, the nuclear membrane of the pro-nucleus of the ovum and sperm degenerate. Is the cell is stage called a zygote? After the dissolution, mitosis occurs and two cells are formed.Or ...
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Is SCNT possible with only the nucleus of a somatic cell (rather than a whole somatic cell)?

The following figure from Life: The Science of Biology (11th edition) explains how SCNT (somatic cell nuclear transfer) was used in the cloning of Dolly: (The original paper about cloning Dolly - ...