developmental biology


29.11.17 | Busy, busy week 📚 

I’m studying really hard for the upcoming test in developmental biology. It’s a super interesting subject (in fact, one of my favourite this semester), yet extremely demanding. With all this information and a ton of details, I can definitely feel my brain working at top speed right now 🧠 

Anyway, I hope I’ll manage to understand and memorise everything by Saturday! 📖 

Stay motivated! 🌟 



Dermatomes of the Adult Male

A dermatome is an area of the body supplied by a single spinal nerve ganglion. Physical sensations (and as such, autonomic/spinal reactions) are controlled by these nerves.

Technically “dermatome” only refers to the skin supplied by that nerve (derma - “skin”, -tome “single section”), but as the lower graphics show, we’ve also determined what nerves control the sensations of our muscles.

As you can see in the graphic of the trigeminal nerve innervation at the top, there’s a moderate amount of variation between individuals, but the basic layout is generally the same.

Because the basic layout of our nerves is known, when someone damages a nerve, which nerve has been damaged can sometimes be determined by what area of the skin has abnormal sensations. A few years ago, I damaged my elbow at work, and it was determined that my ulnar nerve had been affected, due to the lower third of my arm and hand being numb. Thankfully it’s since recovered, but in some situations, nerve damage can cause permanent altering of sensation in the parts of the body affected.

Atlas of Applied (Topographical) Human Anatomy for Students and Practitioners. J. Howell Evans, 1906.


Evo-Devo (Despacito Biology Parody) | A Capella Science

Reconstructing life at its beginning, cell by cell

After 13 rapid divisions a fertilized fly egg consists of about 6,000 cells. They all look alike under the microscope. However, each cell of a Drosophila melanogaster embryo already knows by then whether it is destined to become a neuron or a muscle cell – or part of the gut, the head, or the tail. Now, Nikolaus Rajewsky’s and Robert Zinzen’s teams at the Berlin Institute of Medical Systems Biology (BIMSB) of the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC) have analyzed the unique gene expression profiles of thousands of single cells and reassembled the embryo from these data using a new spatial mapping algorithm. The result is a virtual fly embryo showing exactly which genes are active where at this point in time. “It is basically a transcriptomic blueprint of early development,” says Robert Zinzen, head of the Systems Biology of Neural Tissue Differentiation Lab. Their paper appears as a First Release in the online issue of Science.

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the best parts of my lectures so far this year:

  • “the chances of your kidney jumping out of your body and trying to invade me while we’re walking down church street are approximately zero”
  • “this is called the invariant chain. it has 4 variants”
  • “they are named very systemically; we have Th1, Th2, and Th17″
  • “why are we trying to be sponges”
  • “it’s the sponge equivalent of your body trying to destroy someone who gets too close to you on the tube”
  • “It sounds like I have a weird thing for sponges but it’s just very relevant to this subject matter”
  • “what happens if we don’t have neutrophils?” *nothing on the slide but a giant poster with “DEATH” in all caps*
  • basically anything that happens on socrative during immuno 
  • our development professor showing us a video about evo-devo to the tune of Despacito and everyone dying from secondhand embarrassment
  • The entire lecture on Sonic Hedgehog
  • our microbiology lecturer bringing plush microbes to lecture to give cute examples of bacterial morphologies (I now really want a giant microbe thanks gary)
  • the video of bacterial cell walls lysing to really sad violin music
  • “It is not birth, marriage, or death, but gastrulation, which is truly the most important time in your life.“ 

Gametogenesis, Spermatogenesis & Oogenesis notes for my Developmental Biology! We’ve tackled it way back our Biology 1, how lovely i forgot most of them. 😅
We will have a test ‘bout this topic so i really need to study. Have a wonderful day everyone! ❁*:・゚✧❁

So touched with those studyblrs who keep on messaging me, i love you all! ˚₊*(ˊॢo̶̶̷̤◡ुo̴̶̷̤ˋॢ)*₊˚⁎

anonymous asked:

Since you're the leading expert in gay science, can you tell us the definitive ranking of the STEM fields from most to least gay?

1. Marine Biology (have you seen a squid???? fucking gay as hell)

2. Biophysics (queering physics with bio? so gay)

3. Physical Chemistry (basically just the Olivia Newton John Physical music video played on a loop)

4. Astronomy (Sally Ride claimed space for the gays)

5. Geology (they lick rocks, need I say more?)

6. Synthetic Chemistry (name one thing the straights have ever made, i’ll wait)

7. Ecology (there’s literally a field called queer ecology so)

8. Structural Biology (x rays turn you gay)

9. Inorganic Chemistry (the rainbow flag of science with all the pretty colors)

10. Microbiology (love me some gay bacteria)

11. Math (you can’t derive heterosexuality in Boolean space)

12. Molecular and Cell Biology (MAP kinase kinase kinase kinase)

13. Analytical Chemistry (lol anal)

14. Theoretical Physics (not even straight in theory)

15. Particle Physics (particularly gay)

16. Evolutionary and Developmental Biology (the straights hate evolution, this is a fact)

17. Neuroscience (use your brain, it is gay)

Not Ranked: the social sciences because it wouldn’t be fair because they’re too gay for an accurate comparison 

Also Not Ranked: Engineering (for the straights)

The differences between spina bifida occulta, spina bifida with meningocele, and spina bifida with myelomeningocele.

In the development of the embryo, the neural tube closes around 28 days post-fertilization.

Oftentimes, the woman does not even know she’s pregnant at that point. So much happens in early development, so much can go wrong…many times the egg is fertilized, but has such faulty genes that it terminates itself even before the menstrual cycle is delayed. And many times there are multiple eggs fertilized, and two eggs trying to develop in the uterus, but one of them is terminated by the body long before the “twins” would be visible on an ultrasound.
Chinese scientists fix genetic disorder in cloned human embryos
A method for precisely editing genes in human embryos hints at a cure for a blood disease.

A team in China has taken a new approach to fixing disease genes in human embryos. The researchers created cloned embryos with a genetic mutation for a potentially fatal blood disorder, and then precisely corrected the DNA to show how the condition might be prevented at the earliest stages of development.

The report, published on 23 September in Protein & Cell1, is the latest in a series of experiments to edit genes in human embryos


In 1905, E. G. Conklin published a remarkable fate map of the ascidian embryo. He showed that “all the principle organs of the larva in their definitive positions and proportions are here marked out in the 2-cell stage by distinct kinds of protoplasm.” This study of cell lineage has been the basis for all subsequent research on the autonomous specification of tunicates. The color plates of this study are considered to be some of the best examples of embryological illustration and descriptive anatomy.


Scales, Feathers and Hair Have a Common Ancestor


Reptiles have scales. Birds have feathers. Mammals have hair.
How did we get them?

For a long time scientists thought the spikes, plumage and fur characteristic of these groups originated independently of each other. But a study published Friday suggests that they all evolved from a common ancestor some 320 million years ago.

This ancient reptilian creature — which gave rise to dinosaurs, birds and mammals — is thought to have been covered in scale-like structures. What that creature looked like is not exactly known, but the scales on its skin developed from structures called placodes — tiny bumps of thick tissue found on the surface of developing embryos.

Scientists had previously found placodes on the embryos of birds and mammals, where they develop into feathers and hairs, but had never found the spots on a reptilian embryo before. The apparent lack of placodes in present-day reptiles fueled controversy about how these features first formed…

(read more: NY Times)

photographs by Nicolas Di-Poï & Michel C. Milinkovitch


Watching Embryos Develop From Earliest Moments

Using new microscopy techniques, researchers are getting to watch life develop from the beginning. The gifs above were created from work being done at the Howard Hughes Medical Institute.

Scientists William Lemon, Fernando Amat and Philipp Keller recorded the developing embryo of a fly called Drosophila melanogaster three hours after it was laid as an egg until it started crawling.

To view the fitful movements that occur in the embryo as early nonspecific cells transform into specialized ones and systems develop, they attached fluorescent compounds that glow under certain light to proteins in the nucleus of the its cells. They then trained a device called a simultaneous multiview light-sheet microscope onto the developing organism to follow the action, and took a picture every 30 seconds over the course of a day.

Their work, published last year in the journal Nature Methods, investigated the tracking and development of nuclei to understand where cells start and where they wind up. Understanding this evolution is one of the main goals of developmental biology. 

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