Gastrulation The embryonic disc develops from bilaminar (2 layers) to trilaminar (3 layers). The bilaminar disc comprises epiblast + hypoblast. The trilaminar disc comprises ectoderm, mesoderm, endoderm. All of which derives from the epiblast (none from the hypoblast).Blastocyst formation The blastocyst is a circular cyst; it's divisions are: • Trophoblast: the outer cell mass. • Embryoblast: the inner cell mass. The blastocyst resides within the uterine cavity and eventually invades the uterus. The uterine walls, from inside to outside, are: • Endometrium • Myometrium • PerimetriumTrophoblast division Trophoblast divides into: • Cytotrophoblast, the inner cell line, which maintains a similar shape as the trophoblast. • Syncytiotrophoblast, the external cell line, which invades the uterine wall to lay the foundation of the placenta.Within the cytotrophoblast, the embryoblast transforms into: • The epiblast (which are columnar cells) – the original mass of inner cells • The hypoblast (which are small cuboidal cells) – a new layer of cells underneath the epiblast. The bilaminar germ disc exists where the epiblast and hypoblast meet.At this stage, the syncytiotrophoblast invades into the uterine wall. Epiblast divison The epiblast generates cells that become: (1) Ectoderm - Amniotic cavity fills the cavity internal to the ectoderm. (2) Endoderm - Yolk sac fills the cavity internal to the endoderm. (3) MesodermGastrulation Ectoderm forms the primitive streak: a dimpling at the germ disc - the site of gastrulation. • Gastrulation is a process of invagination, wherein ectodermal cells pass from the ectodermal surface to the primitive streak. Mesodermal cells spread out between the ectoderm and endoderm and also surround these cell lines.The germ disc is now trilaminar. In addition to the mesoderm mentioned previously, there also exists an additional mesoderm layer: the extraembryonic mesoderm just internal to the cytotrophoblast.Germ layer derivatives The key germ layer derivatives (note that these are numerous and we only list the highlights):Ectoderm • Skin + derivatives (hair, nails, etc...) • Adrenal medulla • Nervous tissue • Sense organs Mesoderm • Musculoskeletal (including heart muscle) • Adrenal cortex • Testes + ovaries • Kidneys + uretersEndoderm • Epithelial lining of: GI, Respiratory, Urinary, Reproductive systems

embryonic foldingoverview The trilaminar embryo at approximately day 21 Using standard embryological convention: • The ectoderm in blue (within the amniotic cavity) • The endoderm in yellow (within the yolk sac) • Intraembryonic mesoderm lies in between them. • Extraembryonic mesoderm surrounds the embryo.Day 23 • The extraembryonic mesoderm forms a mushroom shape (forming what appears to be a cap and the beginning of a stalk) • The ectoderm-lined floor of the amniotic cavity curls under at its edges the endoderm-lined roof of the yolk sac, also tucks under. • Accordingly, so does the intraembryonic mesoderm.Day 26 • The extraembryonic mesoderm further curls and the stalk (the vitelline duct) narrows. • The curling of the amniotic cavity accentuates and so does the yolk sac and the intraembryonic mesoderm.The trilaminar germ disc structures at Days 21, 23, and 26Day 21 from top to bottom • The trilaminar germ disc comprises ectoderm, mesoderm (which is intraembryonic), and endoderm. • Within the mesoderm, lies the the ectoderm-derived neural tube, notochord, bilateral somites, and neural crest. • There is folding of the neural tube. - the neural folds abut centrally, first, but remain open at their ends anteriorly and posteriorly. - the neural groove lies deep within the neural tube. - the neural crests form at the tips of the neural folds.Day 23 • The neural crest cells are now making their migrations. • Neural tube folding: - The neural tube is now folded a long distance along its center but remains open at the anterior and posterior neuropores. - We see the somites, centrally, where the neural folds abut; they generate bumps that appear on the surface of the overlying neural tube. Day 26 • The somites (the paraxial mesoderm) differentiate into the central musculoskeletal elements – (from medial to lateral): sclerotome (which forms bone), myotome (which forms muscle), and dermatome (which forms skin). embryonic folding with the development of the key structures of the trilaminar germ discThe trilaminar embryo at approximately day 21 Using standard embryological convention: • The ectoderm in blue (within the amniotic cavity) • The endoderm in yellow (within the yolk sac) • Intraembryonic mesoderm lies in between them. • Extraembryonic mesoderm surrounds the embryo. • The connecting stalk connects the embryo to the uterus. • The embryo lies within the chorionic cavity, which, itself, is lined with extraembryonic mesoderm. • The allantois is the tip of the posterior endoderm that extends into the connecting stalk – a hindgut diverticulum.Day 23 • The extraembryonic mesoderm forms a mushroom shape (forming what appears to be a cap and the beginning of a stalk) • The ectoderm-lined floor of the amniotic cavity curls under at its edges the endoderm-lined roof of the yolk sac, also tucks under, accordingly, so does the intraembryonic mesoderm. • The connecting stalk is tucked under the endo- and ectodermal folds. • The neural tube is now folded a long distance along its center but remains open at the anterior and posterior neuropores.Day 26 • The extraembryonic mesoderm further curls and the stalk (the vitelline duct) narrows. • The curling of the amniotic cavity accentuates and so does the yolk sac and the intraembryonic mesoderm. • There is further folding of the connecting stalk and outpouching of the endodermal allantois. • There's further the growth of the neural tube, which is fully closed (anterior and posterior neuropores have closed). • The gut structures endoderm forms are visible: from anterior to posterior – the foregut, midgut (which attaches to the yolk sac via the vitelline duct), and the hindgut.

Adventures in Medical School

Oocyte Transport to uterine cavity: • Takes ~3-4 daysFemale Reproductive Tract • Upper vagina, cervix, uterus, and uterine tubes - Endometrial lining of the uterine cavity - Key features of the uterine tube: the isthmus, ampulla (the widest part

Midgut malformations • Rotation defects • Omphalocele • Meckel's diverticulum Recall that, typically, the primary intestinal loop undergoes 270 degrees counterclockwise rotation as it elongates; in the final position, the large intestine "frames" the small intestine.Rotation Defects • Non-rotation - When rotation does not occur, the small intestine lies to the right of the large intestine (thus, it this defect is sometimes referred to as "left-sided colon"). • Reversed rotation - When rotation occurs clockwise; in this case, the duodenum will pass ventral to the transverse colon, instead of dorsal to it. • Mixed rotation - When rotation of the cranial and caudal intestinal segments is not coordinated: only the cranial end undergoes the first rotation, and only the caudal end undergoes the second. The cecum lies at the midline, just inferior to the pyloric region of the stomach. Because the mesentery is pulled with the intestine as it rotates, mixed rotation can resort in volvulus, aka, torsion, of the mesentery around the superior mesenteric artery. Bands of mesentery can constrict and obstruct the digestive tract; the duodenum is particularly susceptible to entrapment by the mesentery of the cecum. Omphalocele • Occurs when the abdominal viscera protrude through the umbilical ring - The viscera is covered in a vascular membrane, which is susceptible to rupture (not to be confused with gastroschisis, in which the viscera protrude from the anterior body wall but are not covered by a membrane). - Omphalocele is often present in conjunction with other abnormalities, and is thought to occur as result of failure to fully retract during midgut rotation, lateral body folding failures, or failure of connective tissues in the abdominal wall. Meckel's diverticulum • Present when the vitelline duct fails to fully regress. - Its location and length are variable, and, in many cases, is asymptomatic. However, if the diverticulum contains pancreatic or gastric tissues, bleeding ulcers can form. Hindgut Malformations • Fistulas • Imperforate anusFistulas • Rectourethral fistulas occur when the urinary and digestive tracts are connected. - Thus, both urine and feces are directed through the urethra, and surgery is required. • Rectovaginal fistulas are characterized by a connection between the vagina and rectum. - The connection between the rectum and vagina channels rectal contents to the vagina; surgery is required to form a separate outlet for feces. Imperforate anus Presents in various permutations; corrective surgeries are necessary to treat imperforate anus, which is often accompanied by fistula.Agenesis - Characterized by the formation of a blindly ending anorectal canal.Anal atresia - Occurs when the anal membrane is abnormally thick, and prevents the anus from opening to the external environment.

Adventures in Medical School

ANTIQUE PULL DOWN CHART, MAMMAL REPRODUCTION CHART, DENOYER GEPPERT, EMBRYOLOGY SCHOOL CHART, SCIENTIFIC ILLUSTRATION [ SHIPS FREE ] Amazing piece, displays brilliantly! Authentic, late 1930s, original print. Printed in Germany and distributed by Denoyer Geppert, Chicago. Title: Histolog.- embryologische Tafeln. (History - Embryology Tablets) "Fortpflanzungsorgane und Entwicklung der Jungen der Saugetiere" (Reproductive organs and development of the young of the mammals) Published by: "Zeichnung & Lithographie: W. Gummert, Berlin. Verlag: Gerhard Gambke, Berlin-Steflitz 1. Made In Germany" Wooden dowels top and bottom. These large charts were used as teaching aids by Universities all over the world. Quality craftsmanship and incredibly artistic. Display as is or frame behind glass. See pictures for condition details. 43.5” wide, chart | 47” wide, bottom dowel | 42.5” long unrolled CONDITION Light staining and finger print smudges here and there. Large strip of discoloration along the bottom from being stored/rolled up, commonly seen with these charts. Minor fraying to canvas along edges, etc. Light creasing throughout. Canvas backing is in very good condition overall. Some separation of chart and dowel bottom right corner, the rest is solid and secure. A small hole and some wear bottom center from the ring pull rubbing when the poster was rolled up. See last picture. Small brown stains/spots along the top from the staples that adhere the poster to the dowel. See pics for condition details. Questions? We’re happy to help. [ SHIPS FREE ] ___________________________________________________________________________________ SHOP SCOUT AND FORGE - scoutandforge.com FOLLOW US ON facebook AND instagram FOR A GLIMPSE BEHIND THE SCENES - @scoutandforge ___________________________________________________________________________________ Scout and Forge is a workshop and showroom specializing in Vintage Americana. Located in historic downtown Long Grove, IL. Offering uniquely curated vintage and reclaimed home furnishings. We ship anything, anywhere. Have questions? Drop us a line. ___________________________________________________________________________________ Heavy and oversized pieces ship freight, contact for exact quote to your location. For more information on freight shipping see our shop policies. We ship international, for accurate shipping quote please contact before purchase. ___________________________________________________________________________________

normal skull anatomy and development Neurocranium Divides into the… • Cranial vault, which provides a roof for the brain. • Skull base, which provides a floor for the brain. Viscerocranium • Comprises the facial bones. skull development • The cranial vault and viscerocranium develop via intramembranous ossification (again, which has no intermediate cartilaginous model). • The skull base develops via endochondral ossification, which develops via a cartilaginous matrix. The cranial vault comprises: • Frontal bone, Parietal bone, upper portion of the Occipital bone, and Squamous portion of the Temporal bone – all of these develop via intramembranous ossification. The key bones of the the skull base: • The lower portion of the Occipital bone, the Petrous portion of the Temporal bone, and the Sphenoid bone – all of these bones develop via endochondral ossification. • Key viscerocranial bones: The Zygomatic bone and Maxilla and Mandible – they develop via intramembranous ossification. • The bones of the face derive from embryonic cells from the pharyngeal arches (from neural crest cells (other than the laryngeal cartilages, which derive from mesoderm)). Skull Sutures • At birth, the skull has openings (sutures) to accommodate brain growth, because the cranial vault ossifies early via intramembranous ossification. These sutures allow the fetal skull to ossify quickly prior to delivery [via intramembranous ossification] (so the brain doesn't get squashed) and yet still accommodate skull distortion during birth (called, molding) and permit rapid brain growth during the first two years of life when the brain quadruples in size to 75 percent of its adult volume! • Metopic - forms between midline aspects of the left/right aspects of the frontal bone. • Coronal - lies between the frontal and parietal bones. • Sagittal - lies between the bilateral parietal bones. • Lambdoid - lies between the parietal bones and occipital bone. • There are three additional minor sutures: frontonasal, temporosquamosal, and frontosphenoidal. The fontanelles The large openings that exist in the newborn calvarium. • The frontal bone covers the majority of the anterior frontal lobes. • The parietal bones cover the remainder and the parietal lobes. • The occipital bone covers the occiput. Anterior fontanelle • Forms at the junction of the sagittal, coronal, and metopic sutures at the anterior of the skull – it's palpable in midline, just behind the forehead; it closes at 1.5 to 2 years of age. Posterior fontanelle • Forms from the intersection of the sagittal and lambdoid sutures; it closes at 3 - 6 months of age.

ANTIQUE PULL DOWN CHART, MAMMAL REPRODUCTION CHART, DENOYER GEPPERT, EMBRYOLOGY SCHOOL CHART, SCIENTIFIC ILLUSTRATION [ SHIPS FREE ] Amazing piece, displays brilliantly! Authentic, late 1930s, original print. Printed in Germany and distributed by Denoyer Geppert, Chicago. Title: Histolog.- embryologische Tafeln. (History - Embryology Tablets) "Fortpflanzungsorgane und Entwicklung der Jungen der Saugetiere" (Reproductive organs and development of the young of the mammals) Published by: "Zeichnung & Lithographie: W. Gummert, Berlin. Verlag: Gerhard Gambke, Berlin-Steflitz 1. Made In Germany" Wooden dowels top and bottom. These large charts were used as teaching aids by Universities all over the world. Quality craftsmanship and incredibly artistic. Display as is or frame behind glass. See pictures for condition details. 43.5” wide, chart | 47” wide, bottom dowel | 42.5” long unrolled CONDITION Light staining and finger print smudges here and there. Large strip of discoloration along the bottom from being stored/rolled up, commonly seen with these charts. Minor fraying to canvas along edges, etc. Light creasing throughout. Canvas backing is in very good condition overall. Some separation of chart and dowel bottom right corner, the rest is solid and secure. A small hole and some wear bottom center from the ring pull rubbing when the poster was rolled up. See last picture. Small brown stains/spots along the top from the staples that adhere the poster to the dowel. See pics for condition details. Questions? We’re happy to help. [ SHIPS FREE ] ___________________________________________________________________________________ SHOP SCOUT AND FORGE - scoutandforge.com FOLLOW US ON facebook AND instagram FOR A GLIMPSE BEHIND THE SCENES - @scoutandforge ___________________________________________________________________________________ Scout and Forge is a workshop and showroom specializing in Vintage Americana. Located in historic downtown Long Grove, IL. Offering uniquely curated vintage and reclaimed home furnishings. We ship anything, anywhere. Have questions? Drop us a line. ___________________________________________________________________________________ Heavy and oversized pieces ship freight, contact for exact quote to your location. For more information on freight shipping see our shop policies. We ship international, for accurate shipping quote please contact before purchase. ___________________________________________________________________________________

t54 C34 For sale here is an original vintage roll down school chart of EMBRYOLOGY - HISTOLOGY TABLE 10 The formation of the internal organs of the embryo invertebrates according to morphology. by Prof. Dr. K. Smalian & W. Gummert. Published by Gerhard Gambke in the 1950s This histology chart shows the internal organ formation in various vertebrates types of embryo. Size (approx) Width (including poles):125cm Length: 85cm (without poles 119cm x 81cm) CONDITION Printed on paper, it is backed with canvas and has black wooden poles top and bottom. This chart has spent most of its life rolled up in a school cupboard so the colours are still bright. Obviously these charts are not new so please check all photos before purchase. There may be wear that comes with age. The overall condition of this chart is very, very good, there is some slight yellowing of the paper due to its age. All of our charts are original vintage items from schools across Europe. We have many other charts and maps for sale in our shop. We are open to hearing offers.

Notes Key Points/Stages ~Days 18-22 • Progenitor heart cells arise near the primitive streak on approximately day 16, and migrate through splanchnic layer of lateral plate mesoderm. • Blood islands form in the cardiogenic region. • Blood islands unite to form right and left endocardial tubes. • A single endocardial primitive heart tube forms when lateral embryonic folding facilitates fusion of the paired tubes. • On approximately day 21, myocardial progenitor cells surround the heart tube. • The myocardium forms and secretes cardiac jelly. • Soon, the heart tube will comprise 3 layers: 3 layers: inner endocardium, muscular myocardium, and outer epicardium. • The epicardium arises from the proepicardial organ, which arises from a mass of mesodermal cells at the caudal end of the tube that cover the myocardium. ~Day 18 Key points: • Cardiac progenitor cells migrate/ingress through the streak and craniolaterally through the mesoderm to form blood islands in the cardiogenic region. • These blood islands unite to form the cardiac crescent in the 1st heart field; then second heart field forms. - 1st Heart Field gives rise to the left and right atria, left ventricle, and a portion of the right ventricle. - 2nd heart field gives rise to the rest of the right ventricle, and the outflow tracts (including the bulbus/conus cordis and the truncus arteriosus). • Blood islands of the heart fields give rise to right and left endocardial tubes.Anatomical Features: • Amniotic cavity lined by ectoderm. • Yolk sac lined by endoderm. • Mesoderm overlying the amniotic cavity comprises the parietal, aka, somatic mesoderm. • Mesoderm overlying the yolk sac comprises splanchnic, aka, visceral mesoderm; houses myocardial cells. • Intra-embryonic cavity will eventually be divided to form the pleural, pericardial, and peritoneal cavities. - Paired dorsal aortae are present, formed from blood islands that lie close to the midline. ~ Day 22 Key Points: • Days 18-22, lateral embryonic folding facilitates fusion of the endocardial tubes, while cephalic folding brings the heart and pericardial cavity into the thorax. Anatomical Features: • Amnion (aka, amniotic membrane), which comes to envelop the embryo. • Surface ectoderm is deep to the amnion. • The neural tube has formed between the neural crest, dorsally, and the notochord, ventrally. • Paired dorsal aortae and the foregut are present. • Parietal mesoderm has fused ventrally and contributes to the body wall, deep to the surface ectoderm. • The splanchnic mesoderm covers the ventral surface of the foregut. • Dorsal mesocardium secures the single endocardial tube to the parietal peritoneum; the dorsal mesocardium later gives rise to the transverse sinus. • The pericardial cavity, is the space surrounding the heart tube. • Heart tube features: - Endocardium - Myocardium - Cardiac jelly, an extracellular matrix produced by the myocardium, lies between the two layers of the heart. Review adult histologyRegions of the heart tube, from caudal to cranial: • Right and left horns of the sinus venosus • Atrium • Ventricle • Bulbus cordis • Truncus arteriosus (which is often referred to as a proximal subdivision of the bulbus cordis) • Aortic sac; the aortic sac gives rise to the aortic arches. Review: Features of the Adult Heart Fetal circulation Adult circulation

Midgut malformations • Rotation defects • Omphalocele • Meckel's diverticulum Recall that, typically, the primary intestinal loop undergoes 270 degrees counterclockwise rotation as it elongates; in the final position, the large intestine "frames" the small intestine.Rotation Defects • Non-rotation - When rotation does not occur, the small intestine lies to the right of the large intestine (thus, it this defect is sometimes referred to as "left-sided colon"). • Reversed rotation - When rotation occurs clockwise; in this case, the duodenum will pass ventral to the transverse colon, instead of dorsal to it. • Mixed rotation - When rotation of the cranial and caudal intestinal segments is not coordinated: only the cranial end undergoes the first rotation, and only the caudal end undergoes the second. The cecum lies at the midline, just inferior to the pyloric region of the stomach. Because the mesentery is pulled with the intestine as it rotates, mixed rotation can resort in volvulus, aka, torsion, of the mesentery around the superior mesenteric artery. Bands of mesentery can constrict and obstruct the digestive tract; the duodenum is particularly susceptible to entrapment by the mesentery of the cecum. Omphalocele • Occurs when the abdominal viscera protrude through the umbilical ring - The viscera is covered in a vascular membrane, which is susceptible to rupture (not to be confused with gastroschisis, in which the viscera protrude from the anterior body wall but are not covered by a membrane). - Omphalocele is often present in conjunction with other abnormalities, and is thought to occur as result of failure to fully retract during midgut rotation, lateral body folding failures, or failure of connective tissues in the abdominal wall. Meckel's diverticulum • Present when the vitelline duct fails to fully regress. - Its location and length are variable, and, in many cases, is asymptomatic. However, if the diverticulum contains pancreatic or gastric tissues, bleeding ulcers can form. Hindgut Malformations • Fistulas • Imperforate anusFistulas • Rectourethral fistulas occur when the urinary and digestive tracts are connected. - Thus, both urine and feces are directed through the urethra, and surgery is required. • Rectovaginal fistulas are characterized by a connection between the vagina and rectum. - The connection between the rectum and vagina channels rectal contents to the vagina; surgery is required to form a separate outlet for feces. Imperforate anus Presents in various permutations; corrective surgeries are necessary to treat imperforate anus, which is often accompanied by fistula.Agenesis - Characterized by the formation of a blindly ending anorectal canal.Anal atresia - Occurs when the anal membrane is abnormally thick, and prevents the anus from opening to the external environment.

Learning about phylogeny from ontogeny By studying ontogeny (the development of embryos), scientists can learn about the evolutionary history of organisms. Ancestral characters are often, but not always, preserved in an organism's development. For example, both chick and human embryos go through a stage where they have slits and arches in their necks that are