The study of the development of an embryo from fertilisation through to description as a foetus.
1
vote
1answer
23 views
Dynamic of the number of cells over time as the embryo grows
I would like to investigate the dynamic of the number of cells over time as the embryo grows. I am interested in any multicellular animal species for which we can have some data. How does the number ...
-1
votes
0answers
24 views
0
votes
2answers
90 views
Can a viable embryo develop from the fusion of two egg cells?
For a zygote to form, two haploid gametes undergo meiosis and fuse during fertilisation. Since two egg cells (or even two sperm cells) are both haploid, is it theoretically possible for them to make ...
3
votes
0answers
36 views
How can there not be purpose movement in the fetus until week 18 when a fetus can open its mouth and suck its fingers at week 11?
According to Fetal Movement
According to an overview produced by the Royal College of Physicians
of Edinburgh, purposive movement begins at about 18 weeks, gradually
replacing reflex movements
...
1
vote
1answer
99 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?
1
vote
1answer
33 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 ...
0
votes
0answers
347 views
What is the difference between apomixis, agamospermy and apospory?
Some websites say agamospermy is just a synonym of apomixis but the definition of both terms is different. Others give almost same definition of apospory and agamospermy while also saying that ...
2
votes
0answers
30 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 ...
2
votes
1answer
86 views
Does the mesoderm evolve from the ectoderm or the endoderm?
I know the embryos of most animals develop into 3 germ layers. However primitive animals, such as Cnidarians, only have 2 germ layers - they lack a mesoderm. Therefore the 3rd germ layer must have ...
0
votes
2answers
38 views
Cell differentiation by non-identical copies
There are in principle two ways that two cells with the same mother cell can differentiate/specialize/diverge:
Because they are not perfect identical copies (= different internal influencing factors)....
1
vote
1answer
106 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 ...
1
vote
0answers
222 views
Shell-less Chick development - Incorporation of Calcium carbonate instead of Calcium lactate pentahydrate powder?
I'm a college undergrad biology student and currently studying developmental biology as part of my curriculum.
I've read a research journal titled, A Novel Shell-less culture system for chick embryo ...
0
votes
1answer
22 views
I need a site for online courses
I need a site which has online courses for anatomy of limb and head and neck and also embryology, so far I have used www.coursera.org and it was really organized and helpful but unfortunately it does ...
4
votes
0answers
63 views
Are there predefined implantation sites in mammalian uterus?
I do surgical embryo transfer of genetically modified (microinjected) mouse embryos (at 1 or 2 cell stage). As most of the constructs are new, we expect that it may affect birth rate. In case there ...
11
votes
1answer
674 views
Has the gestation (pregnancy) period for humans always been 9 months?
At this point in our evolutionary progress, the expected human gestation period is (roughly) nine months long. My question is, has this duration of time always been the same for homo sapiens? Or, are ...
1
vote
1answer
27 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 ...
5
votes
1answer
95 views
Can 12 mitotic divisions produce 6000 nuclei?
The following quote is from "Principles of Development" by Tickle & Wolpert:
"After fertilization and fusion of the sperm and egg nuclei, the zygote nucleus undergoes a series of rapid mitotic ...
2
votes
1answer
62 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 ...
1
vote
0answers
10 views
Are there any studies detailing the overall “-omics” effects of using bleach to synchronise a C. elegans population?
I wasn’t able to find papers detailing the changes in the transcriptome/proteome of C. elegans when synchronised by bleaching vs not-bleaching. Hopefully someone can point me in the right direction!
3
votes
2answers
60 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 ...
4
votes
1answer
136 views
Is a part of the spinal cord from the mesoderm?
The caudalmost part of the neural tube is formed by the caudal eminence. Isn't this mesodermal? So does it mean that, a part of the spinal cord is mesodermal in origin?
Does it have any significance ...
1
vote
1answer
45 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 ...
0
votes
0answers
46 views
Mental Symphysis
Why dow we consider mandibular symphysis(symphysis menti) as type of Amphiarthrosis that too of symphysis variety, eventhough it lacks movement and cartilage at joint?
Why don't we consider as ...
4
votes
0answers
214 views
Why are sutural bones more common in lambdoid suture? [closed]
Why are sutural bones (Wormian bones) are more commonly present at lambdoid suture? Is the tortuous nature of lambdoid suture a reason for that?
Evidences for my claim:
They(sutural bones) occur ...
2
votes
1answer
913 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 ...
1
vote
0answers
67 views
What is the difference between Totipotent cells and Pluripotent cells? [duplicate]
I read the Wikipedia article about Cell Potency
(Article on Cell Potency)
Totipotency is the ability of a single cell to divide and produce all of the differentiated cells in an organism.
while ...
1
vote
0answers
62 views
What are the chances that the contraceptive pill will cause death of human zygote? [closed]
The preventative pill, as I understand it, can cause zygotes to fail to attach to the uterine wall, or pry them off of it.
Ignoring any and all ethical implications, what are the chances that this ...
1
vote
0answers
210 views
Why does rotational cleavage take place in mammels like humans. What is its significance? [closed]
What is the actual reason behind the rotational cleavage that takes place in humans? Why does it happen? If it doesn't occur, what will happen
1
vote
0answers
169 views
How do genes code for differences in arms and legs?
So to me it seems like arms and legs are pretty similar that they almost have the same blueprint. And if you change part of it like the number of digits, you will have 12 fingers and 12 toes.
But at ...
3
votes
1answer
657 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?
9
votes
1answer
1k views
Can only fully matured sperm fertilize an egg?
Are only mature sperm able to fertilize an egg? If so, is there typically a reserve of mature sperm that are saved after an ejaculation or does a male need to wait for new sperm to mature before ...
2
votes
0answers
49 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 ...
1
vote
0answers
30 views
Are the human placenta chorionic villi and villous tree the synonyms?
Are the human placental chorionic villi and the villous tree the synonyms? Or, if not, can I say that these tissues would have practically the same gene expression profile in an RNA microarray ...
1
vote
1answer
306 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 ...
2
votes
2answers
1k 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 ...
2
votes
0answers
27 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 ...
1
vote
1answer
642 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 ...
3
votes
1answer
2k views
Mesoderm vs Mesenchyme- what's the difference?
My embryology textbook states that mesoderm can exist as Mesenchyme or Epithelium. I'm not sure what 'epithelium' means. Here is a quote for context:
Somatic, splanchnic, and somite mesoderm can be ...
1
vote
2answers
2k 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.
...
2
votes
1answer
872 views
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 ...
1
vote
0answers
49 views
How is bilateral asymmetry determined in embryonic development?
What are the mechanisms that ensure consistent left-right asymmetric placement of various internal organs (heart, liver, etc) or consistent left-right asymmetric development of paired organs (brain, ...
0
votes
1answer
103 views
Embryo development terms
I'm trying to couple the following terms:
cytoplasmic determinants, induction, positional information, hox genes, pattern information, morphogenisis, determination and differentiation.
I hope ...
0
votes
3answers
11k views
How scientists can be confident that human embryo tail is really a tail?
From Wikipedia:
Human embryos have a tail that measures about one-sixth of the size of the embryo itself. As the embryo develops into a fetus, the tail is absorbed by the growing body.
How are we ...
1
vote
1answer
204 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?
1
vote
0answers
157 views
Is the amount of blood same in the pulmonary and systemic foetal circulation?
We learn that the stroke volume is the same for the right and left side of the heart. So the amount of blood in either circulations should also be the same. (is it? I myself doubt this statement. As ...
6
votes
1answer
136 views
How only one follicle develops into graffian follicle?
I've studied that one out of many follicle develops into mature or graffian follicle. The fact which confuses me is that, since all follicles are in same ovary, close to each other with equal supply ...
3
votes
1answer
111 views
Is the thecal sac ectoderm?
The thecal sac, or dural sac, is the membranous sheath of dura mater that surrounds the spinal cord and the cauda equina. The thecal sac contains the cerebrospinal fluid in which the spinal cord '...
0
votes
1answer
91 views
Conjoined twins formation theory
is it theoretically possible to take two fertilized mammalian eggs and push them together to make conjoined twins? How about forming non-identical conjoined twins?
0
votes
0answers
651 views
What tools are used in animal cloning?
So I was reading up on articles to do a project about cloning but there were no places in the article where It states the tool used to take the gene out of the nucleus and insert it into plasmids ? ...
0
votes
2answers
590 views
Polar bodies fertilization
Suppose a sperm fertilized a 2nd polar body( haploid) is there a chance of somewhat normal development?
