August272013
heythereuniverse:

Human embryo after zona drilling | Wellcome ImagesColour-enhanced scanning electron micrograph of a human embryo at day 3. The egg has been fertilised in vitro and has developed to this stage in culture. The coat around the egg (zona pellucida) has been treated with acid Tyrodes solution to make a hole so an individual cell can be removed. This cell can then be used for genetic diagnosis before the embryo is transferred to the woman’s uterus. This allows the selective implantation of embryos that do not carry the genetic disease in question.

heythereuniverse:

Human embryo after zona drillingWellcome Images

Colour-enhanced scanning electron micrograph of a human embryo at day 3. The egg has been fertilised in vitro and has developed to this stage in culture. The coat around the egg (zona pellucida) has been treated with acid Tyrodes solution to make a hole so an individual cell can be removed. This cell can then be used for genetic diagnosis before the embryo is transferred to the woman’s uterus. This allows the selective implantation of embryos that do not carry the genetic disease in question.

(Source: Flickr / medicospace, via fyeahmedlab)

August222013
bpod-mrc:

12 August 2013
Helping Healthier Pregnancies
Pregnancy is stressful, and we don’t mean decisions about decorating the nursery. Growing a baby places a big stress on a woman’s body. This is especially felt in her blood system, which has to work hard supplying blood to the placenta – the interface between a developing foetus and its mother’s womb. Problems with maternal spiral arteries that supply blood to the placenta causes a life-threatening condition called pre-eclampsia, which kills thousands of women annually and leads to babies being born too small. By studying pregnant mice, scientists have discovered that a molecule called galectin-1 plays a vital role in growing maternal blood vessels during early pregnancy. The mother of the foetus on the right was treated with a chemical that blocks galectin-1 and shows the signs of pre-eclampsia, unlike the normal one on the left. This work could be crucial for helping prevent the condition in human mothers in future.
Written by Kat Arney
—

 Sandra M. Blois
Charité - Universitätsmedizin Berlin
Published in PNAS (110)28: 11451-11456 

bpod-mrc:

12 August 2013

Helping Healthier Pregnancies

Pregnancy is stressful, and we don’t mean decisions about decorating the nursery. Growing a baby places a big stress on a woman’s body. This is especially felt in her blood system, which has to work hard supplying blood to the placenta – the interface between a developing foetus and its mother’s womb. Problems with maternal spiral arteries that supply blood to the placenta causes a life-threatening condition called pre-eclampsia, which kills thousands of women annually and leads to babies being born too small. By studying pregnant mice, scientists have discovered that a molecule called galectin-1 plays a vital role in growing maternal blood vessels during early pregnancy. The mother of the foetus on the right was treated with a chemical that blocks galectin-1 and shows the signs of pre-eclampsia, unlike the normal one on the left. This work could be crucial for helping prevent the condition in human mothers in future.

Written by Kat Arney

(via fyeahmedlab)

July92013
medicalschool:

A human egg is never alone. When released from the ovary, the ooycte (orange) is surrounded by two structures: a matrix of glycoproteins, called the zona pellucida (brown rim), and a layer of follicler cells, called the corona radiata (yellow). Human fertilization begins when the sperm finds its way through the corona radiata and binds to a sugar group in the zona pellucida.
Image: Light micrograph showing sperm and an egg cell (or ovum) during a failed IVF attempt.

medicalschool:

A human egg is never alone. When released from the ovary, the ooycte (orange) is surrounded by two structures: a matrix of glycoproteins, called the zona pellucida (brown rim), and a layer of follicler cells, called the corona radiata (yellow). Human fertilization begins when the sperm finds its way through the corona radiata and binds to a sugar group in the zona pellucida.

Image: Light micrograph showing sperm and an egg cell (or ovum) during a failed IVF attempt.

June232013
June52013
frontal-cortex:

“An early event in Drosophila development is that the embryo lays down a pattern of seven two-part stripes that are perpendicular to the anterior-posterior (head to tail) axis.  Each stripe expresses a specific pattern of gene expression, and each eventually becomes a specific part of the body plan of the mature fly; eve is expressed in the anterior half of each stripe. The blue stripes (top and bottom panels) are eve expression, the red in the center (bottom panel) is Kruppel expression, and each green dot represents a single nucleus.” (ItTakes30 / Berkeley Drosophila Transcription Network Project)

frontal-cortex:

“An early event in Drosophila development is that the embryo lays down a pattern of seven two-part stripes that are perpendicular to the anterior-posterior (head to tail) axis.  Each stripe expresses a specific pattern of gene expression, and each eventually becomes a specific part of the body plan of the mature fly; eve is expressed in the anterior half of each stripe. The blue stripes (top and bottom panels) are eve expression, the red in the center (bottom panel) is Kruppel expression, and each green dot represents a single nucleus.” (ItTakes30Berkeley Drosophila Transcription Network Project)

May252013

medicalschool:

Scanning electron micrographs of an embryo at Carnegie stage 10 (approximately week 4) 

May182013
ohyeahdevelopmentalbiology:

raptinawe:

This confocal micrograph shows stage V–VI oocytes (800–1000 micron diameter) of an African clawed frog (Xenopus laevis), a model organism used in cell and developmental biology research. Each oocyte is surrounded by thousands of follicle cells, shown in the image by staining DNA blue. Blood vessels, which provide oxygen to the oocyte and follicle cells, are shown in red. The ovary of each adult female Xenopus laevis contains up to 20 000 oocytes. Mature Xenopus laevis oocytes are approximately 1.2 mm in diameter, much larger than the eggs of many other species. (Photo by Vincent Pasque, University of Cambridge/Wellcome Images)(via Up Close: 2012 Wellcome Image Awards)

ohyeahdevelopmentalbiology:

raptinawe:

This confocal micrograph shows stage V–VI oocytes (800–1000 micron diameter) of an African clawed frog (Xenopus laevis), a model organism used in cell and developmental biology research. Each oocyte is surrounded by thousands of follicle cells, shown in the image by staining DNA blue. Blood vessels, which provide oxygen to the oocyte and follicle cells, are shown in red. The ovary of each adult female Xenopus laevis contains up to 20 000 oocytes. Mature Xenopus laevis oocytes are approximately 1.2 mm in diameter, much larger than the eggs of many other species. (Photo by Vincent Pasque, University of Cambridge/Wellcome Images)

(via Up Close: 2012 Wellcome Image Awards)

May172013

biomedicalephemera:

Top: Uterine lining at 5 1/2 months, displaying thin maternal separation from fetus, and high level of placental implantation
Center: Relation of placenta to uterus at 5 weeks and 8.5 months
Bottom: Major arteries and veins of the placenta

Did you know that the placenta is a temporary organ that’s actually created by the fetus, and not the woman?

The human female is a curious creature; like our close great ape cousins, but unlike almost all other mammals, they build up a thick barrier in the uterine wall, to protect against any potential embryo that might implant itself. When there’s no embryo implantation, the thickened wall is shed, in the process known as menstruation.

The thing is, most mammals don’t menstruate. They go into heat, and occasionally shed uterine lining (if the uterus is scratched, or an egg tries to implant but fails, for example), but there’s no regular cycle of bloody discharge relating to breeding. This is because other mammals go through triggered decidualization (developing a uterine lining only when a fertilized egg begins to implant itself), while the great apes (and a couple other convergently evolved families, including bats) experience spontaneous decidualization, where they develop a thick uterine lining during every ovulation, before an egg can even attempt to implant itself.

Why the different linings? Well, it turns out that there are three types of mammal placentas (remember, placentas are developed by the embryo/fetus, not the mother):

  1. Epitheliochordal, which is completely superficial, and does not connect in any significant way to the mother’s body. The endometrial epithelium, connective tissue, and uterine epithelium are all preserved and undisturbed in the mother. The fetus is separated from the mother by three layers of tissue. Nutrients and waste are delivered and eliminated through diffusion, rather than direct connection. This group includes equids, swine, and ruminants.
  2. Endotheliochordal, which is slightly more invasive to the mother, only preserves the uterine epithelium. Nutrients and waste are not exchanged through direct connection to the mother, but the placenta only leaves one layer of tissue between it and the mother. This group includes cats and dogs.
  3. Hemochorial is the most invasive form of placenta in the animal kingdom. The embryo directly hooks itself up to the host (mother’s) blood flow, and leaves no tissue layers between the female and the placenta. This allows much more efficient nutrient transfer to the embryo or fetus, but is also potentially the most harmful to the female since the embryo attaches itself so securely to the uterine wall. The female must develop preemptive measures (a thickened uterine lining) to protect herself from a life-form that is literally driven to take all of the nutrients it needs to develop, and which has adapted to connect itself directly to the host. This group includes elephant shrews, most bats, and most primates.

Interested in more about the science behind reproduction and how amazingly efficient the human embryo is at sucking its host clean, just to obtain its needed resources for development?

PZ Meyers at Pharyngula has an understandable explanation of the article I referenced for this post.

There is also a great site by R. Bowen about the pathophysiology of the reproductive system.

An American Text-Book of Obstetrics for Practitioners and Students. Edited by Richard C. Norris, 1895.

(via fyeahmedlab)

May72013
medicalschool:

Embryology of the Diaphragm 

medicalschool:

Embryology of the Diaphragm 

(Source: cranialintelligence.files.wordpress.com)

April62013

the-science-llama:

Bat Embryos

The first image are embryos of the species Molossus rufus, the black mastiff bat. These images formed part of an embryonic staging system for this species. — By Dorit Hockman

The second image shows a bat embryo developing from 18 weeks to 24

(via many-splendored-rat)

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