Category Archives: Embryology

Page Summary: It is false to claim that no one knows when life begins and dishonest to argue that abortion does not kill a human being. Every new life begins at conception. This is an irrefutable fact of biology. It is true for animals and true for humans. When considered alongside the law of biogenesisthat every species reproduces after its own kindwe can draw only one conclusion in regard to abortion. No matter what the circumstances of conception, no matter how far along in the pregnancy, abortion always ends the life of an individual human being. Every honest abortion advocate concedes this simple fact. Faye Wattleton, the longest reigning president of the largest abortion provider in the United StatesPlanned Parenthoodargued as far back as 1997 that everyone already knows that abortion kills. She proclaims the following in an interview with Ms. Magazine: I think we have deluded ourselves into believing that people don't know that abortion is killing. So any pretense that abortion is not killing is a signal of our ambivalence, a signal that we cannot say yes, it kills a fetus.1 On the other side of the pond, Ann Furedi, the chief executive of the largest independent abortion … Continue reading →

Nuclear condensation The nucleus becomes smaller, denser and takes on a characteristic, flattened form. Seen from above, the nucleus is oval and, from the narrow side, is pear-shaped. The acrosome lies over the tip. Nucleus and acrosome form the sperm cell's head that is bound to the mid-piece by a short neck. Acrosome formation The Golgi complex engender the vesicles, which then merge into a larger formation that settles close to the cell nucleus and finally inverts itself like a cap over the largest part of the nucleus. The acrosome corresponds functionally to a lysosome and thus contains lysosomal enzymes (hyaluronidase among others). Development of the flagellum The future axonemal structure grows out of one centriole (distal). This consists of a bundle of nine peripheral double microtubules and two single ones in the center. During its development, through the rotation of the nucleus and acrosomal vesicle, the flagellum primordium comes to lie on the opposite side of the acrosome. Four parts of the finished flagellum can be distinguished: The mature sperm cell is approximately 60 mm long and completely enveloped by the plasma membrane. Read the original post: Spermatogenesis - Embryology … Continue reading →

Lecture notes Darwin's evidence for evolution: Embryology I. The "facts of embryology" A. There is usually a difference in form between embryo and adult. B. Serial structures (e.g., segments, limbs) are usually identical in the embryo, but specialized and diverged in the adult. C. Different species in the same Class (e.g., mammals) often have very similar embryos, even if the adult forms are quite different. D. Embryonic structure is unrelated to "conditions of existence", unless the embryo is active (e.g., feeding) E. Embryos are sometimes more highly "organized" than adults (e.g., some parasitic forms). II. The "principles" that explain these facts A. Adult variations supervene at a rather late stage B. Variations in adult features are inherited (expressed by progeny) at correspondingly late stages C. These "principles" are generally but not universally true (an exception was the tumbler pigeon) when one looks at empirical evidence from domesticated varieties III. How do these principles explain the facts? A. Breeders select on adult characters, regardless of the juvenile characters B. Given this, and the two principles, the young of a new variety and the parental stock will tend to be more similar than the adults C. Darwin extrapolates this to larger groups: … Continue reading →

development human developing generation Embryology is the study of the development of organisms. This is as true of plants as it is of animals. Seed formation proceeds following fertilization in higher plants. The seed consists of the embryo, the seed coat, and another part sometimes called the endosperm. While plants are extraordinarily important for survival of animal life, animal embryology is described here. The dictionary definition limits the meaning of the term "embryo" to developing animals that are unhatched or not yet born. Human embryos are defined as developing humans during the first eight weeks after conception. The reason that many embryologists have difficulty with this terminology is that it is purely arbitrary. It would be difficult indeed, if not impossible, to discriminate a human embryo nearing the end of the eighth week from a developing human during the ninth week after conception. Correspondingly, there are no morphological events that distinguish a pre-hatching frog tadpole from a post-hatching tadpole (hatching never occurs synchronously in an egg massthere are always those that hatch early and those larvae which are dilatory). Embryologists consider development from a zygote to a multicellular organism. In the particular case of humans, development does not even stop … Continue reading →

embryology,vertebrate embryosEncyclopdia Britannica, Inc.the study of the formation and development of an embryo and fetus. Before widespread use of the microscope and the advent of cellular biology in the 19th century, embryology was based on descriptive and comparative studies. From the time of the Greek philosopher Aristotle it was debated whether the embryo was a preformed, miniature individual (a homunculus) or an undifferentiated form that gradually became specialized. Supporters of the latter theory included Aristotle; the English physician William Harvey, who labeled the theory epigenesis; the German physician Caspar Friedrick Wolff; and the Prussian-Estonian scientist Karl Ernst, Ritter von Baer, who proved epigenesis with his discovery of the mammalian ovum (egg) in 1827. Other pioneers were the French scientists Pierre Belon and Marie-Franois-Xavier Bichat. Baer, who helped popularize Christian Heinrich Panders 1817 discovery of primary germ layers, laid the foundations of modern comparative embryology in his landmark two-volume work ber Entwickelungsgeschichte der Thiere (182837; On the Development of Animals). Another formative publication was A Treatise on Comparative Embryology (188091) by the British zoologist Frances Maitland Balfour. Further research on embryonic development was conducted by the German anatomists Martin H. Rathke and Wilhelm Roux and also by the American scientist Thomas … Continue reading →

Masashige Kuwayama demonstrates vitrification warming at the Embryology and PGD workshop in London This video was filmed during the first vitrification workshop organised by the Embryology and PGD Academy (www.embryologyandPGDacademy.com) held at University College London. Masashige ... By: Embryology and PGD Academy … Continue reading →

Krishna IVF Clinic - Embryology, Oocyte Vitrification Krishna IVF Clinic is a pioneer institute in the field of Assisted Reproductive Technologies. Krishna IVF Clinic is one of the most successful IVF clinics in India. By: Krishna IVF … Continue reading →

Embryology - lab.5 (Vascular system) 5th lab of 2nd course of embryology .. Development of the vascular system of the embryo .. presented by Dr. Haider Jawad .. 2nd Stage .. Al-Nahrain Medical College. By: Al-Nahrain Medical College … Continue reading →

Masashige Kuwayama demonstrates vitrification at the Embryology and PGD workshop in London This video was filmed during the first vitrification workshop organised by the Embryology and PGD Academy (www.embryologyandPGDacademy.com) held at University College London. By: Embryology and PGD Academy … Continue reading →

Download Molecular Embryology How Molecules Give Birth to Animals PDF Download PDF Here: http://bit.ly/1HZBuqH. By: Ka Fuqua … Continue reading →