Chick embryos have been used widely as model systems for studies in experimental embryology and teratology. Especially early chick embryos are very useful for studies of neural tube defects. Local anesthetics such as lidocaine, tetracaine and ketamine are known to inhibit the formation of microfilaments and cause neural tube defects. We made a try to figure out the effect of local anesthetics on neurulation in early chick embryo, which is stage 8 by Hamburger & Hamiliton classification. After 6~9 hours incubation in media treated with above local anesthetics, we observed the effects of these agents by LM and EM. Stage 8 chick embryos responded to local anesthetics in a dose related manner. Tetracaine showed most potent effects. Neural folds failed to make a contact, so the neural tube was left open. In high dosage, the case of no growth or little growth of embryo was also observed. On scanning electron microscopic examination, the surface of neuroepithelium was flattened in embryos treated with ketamines. On transmission electron microscopic examination. neuroepithelium of embryos cultured in ketamine showed the decrease of microfilaments and less conspicuous feature of mitochondria and rough ER(endoplasmic reticulum)'s.
Actin Cytoskeleton ; Anesthetics, Local* ; Animals ; Chick Embryo* ; Classification ; Embryology ; Embryonic Structures ; Ketamine ; Lidocaine ; Microscopy, Electron ; Mitochondria ; Neural Crest ; Neural Tube ; Neural Tube Defects ; Neurulation* ; Teratology ; Tetracaine

Chick embryos have been used widely as model systems for studies in experimental embryology and teratology. Especially early chick embryos are very useful for studies of neural tube defects. We made a try to figure out the effect of Ca++ on neurulation using Ca++ antagonist and Ca++ free media in early chick embryo, which is stage 8 by Hamburger & Hamilton classification. After 6~9 hours incubation in media treated with verapamil and media without Ca++, we observed the effects of these agents by LM and EM. All of 12 embryos incubated in Ca++ free media showed that neural tube was diffusely opened along the whole axis and other deformity was not found. The chick embryos cultured in medium treated with verapamil revealed various abnormalities in dose related manner. The case of arrest of the growth was also observed, which was not found Ca++ free media group. On scanning electron microscopic examination, the surface of neuroepithelium was flattened in embryos cultured in Ca++ free media.
Animals ; Axis, Cervical Vertebra ; Chick Embryo* ; Classification ; Congenital Abnormalities ; Embryology ; Embryonic Structures ; Microscopy, Electron, Scanning ; Neural Tube ; Neural Tube Defects ; Neurulation* ; Teratology ; Verapamil

Cloacal malformations are characterized by the confluence of the lower urinary tract, the female reproductive tract, and the rectum to create a common channel with a single opening on the perineum. The presence of a cloaca is a normal phase of early human embryological development. Between the 4^th and 7^th weeks of gestation, the cloaca undergoes subdivision to form the hindgut and urogenital sinus. Failure of this process results in the congenital anomaly termed persistent cloaca (PC). The term urorectal septum malformation sequence (URSMS) is also used to describe this anomaly. The classic description of this process which is still cited in many standard textbooks dates from the 19^th century. However, this has been increasingly called into question by the findings of studies using modern scientific methodology. Urogenital sinus anomalies are defined by the confluence of the urethra and vagina to form a common channel of varying length with a single perineal opening. In this condition, the anorectal canal opens separately on the perineum. The presence of a urogenital sinus represents a transient phase of the normal development of the lower genital tract in the female fetus. However, the form of urogenital sinus most commonly encountered in the developed world is a feature of disordered sexual differentiation and does not arise simply from the persistence of the anatomical structure which is a feature of normal fetal development.
Cloaca/embryology* ; Female ; Humans ; Urogenital Abnormalities/embryology* ; Vagina/embryology*

Animals ; Brain ; embryology ; Ear ; embryology ; Esophagus ; embryology ; Fallopian Tubes ; embryology ; Female ; Heart ; embryology ; Humans ; Kidney ; embryology ; Liver ; embryology ; Lung ; embryology ; Male ; Organogenesis ; physiology ; Penis ; embryology ; Rabbits ; Stomach ; embryology ; Vagina ; embryology

The microsurgical anatomy of the middle cerebral artery(MCA) was reviewed. Embryology, segments, major branches, perforating branches, anomalies of the MCA and the anatomy of the Sylvian fissure were summarized.
Embryology ; Middle Cerebral Artery*

In this study, the embryological characters of Pterocypsela formosana (Asteraceae) were investigated with the traditional paraffin section methods. The anther has 4 sporangiates, the anther wall development follows the dicotyledonous type and comprises of an epidermis, endothelium, a middle layer and a single-layered tapetum, the tapetum belongs to glandular type. Meiosis of the microspore mother cells is of the simultaneous type, for the formation of mostly tetrahedral tetrad, the mature pollen grains are 2 celled. The ovary is bicarpellate, unilocular, one ovule and basal placenta, the ovule is unitegmic, tenuinucellate, inverted campylotropous and with developed endothelium, archesporial cell of megaspore differentiates immediately below the nucellar epidermis and functions as megasporocyte after development and belongs to tenuinucellate ovule type. The megasporocyte undergoes meitotic to form a liner tetrad, only one chalazal megaspore becomes the functional megaspore which forms female gametophyte including 7-celled and 8-nucleated after three successive mitosis, the female gametophyte is of the Polygonum type. Two polar nuclei melt into a secondary nuclei before fertilization, the chalazal antipodal cells are ephemeral and degenerate shortly after forming. Fertilization is porogamous and belongs to premitotic type of syngamy. The division of the primary endosperm nucleus is earlier than the zygote, the endosperm is of the nuclear type with the presence of haustoria, and the embryogeny belongs to asterad type chicory variant. The developed suspensor on early stage has important significance to the embryo development.
Asteraceae ; embryology ; Meiosis ; Reproduction

A Case of Mullerian duct cyst as a large pelvic mass encountered in 25-year-old man is introduced. The treatment, pathological and radiological appearence are discussed, and also the embryology and history of this entity are reviewed.
Adult ; Embryology ; Humans

Transverse testicular ectopia is an uncommon anatomical abnormality in which both gonads migrate toward the same hemiscrotum. A case report, review of the embryology, differential diagnosis and suggested management are detailed witha brief review of literature.
Diagnosis, Differential ; Embryology ; Gonads

Undergraduate students struggle to comprehend embryology because of its dynamic nature. Studies have recommended using a combination of teaching methods to match the student's learning style. But there has been no study to describe the effect of such teaching strategy over the different types of learners. In the present study, an attempt has been made to teach embryology using the combination of analogies and simple 2D animations made with Microsoft powerpoint software. The objective of the study is to estimate the difference in academic improvement and perception scale between the different types of learners after introducing analogies and 2D animation in a lecture environment. Based on Visual, Aural, Read/Write, and Kinesthetic (VARK) scoring system the learners were grouped into unimodal and multimodal learners. There was significant improvement in post-test score among the unimodal (P < 0.001) and multimodal learners (P < 0.001). When the post-test score was compared between the two groups, the multimodal learners performed better the unimodal learners (P=0.018). But there was no difference in the perception of animations and analogies and long-term assessment between the groups. The multimodal learners performed better than unimodal learners in short term recollection, but in long term retention of knowledge the varied learning style didn't influence its outcome.
Embryology* ; Humans ; Learning* ; Teaching

Cleft lip and palate are the most common congenital malformations in humans. Using 43 staged human embryos and early fetuses ranging from the 4th to 12th week of development, we investigated the development of the lip and palate in order to provide the basic developmental concepts required for managing these anomalies. The lower lip appeared as bilateral mandibular arches at Carnegie stage 11, and these were completely merged at stage 15. The components of the upper lip, medial nasal prominence and maxillary process, appeared at stage 16, and completely merged at stage 20. The median palatine process appeared at stage 16, and the lateral palatine process, at stage 17. The palatine processes and the nasal septum started to fuse abruptly at stage 23, and from external observation seemed to be fused at the 9th week. However, complete fusion did not take place until the 12th week of development. The tongue was prominent at stage 16, showed differentiation of the muscular tissue at stage 21, and was located superior to the lateral palatine process before stage 23. These results may be used in understanding the different mechanisms present in the formation of various congenital anomalies in this region.
Female ; Gestational Age ; Human ; Lip/embryology* ; Palate/embryology* ; Pregnancy