Embryology Curriculum Objectives
MED EMBRYOLOGY, UNIVERSITY OF ILLINOIS-URBANA/CHAMPAIGN
EMBRYOLOGY LECTURES 1,2,3
Subject Matter: Germ Cells and Their Formation; The Ovarian Cycle; Fertilization; Basic Structural Features of the Uterine Wall and Changes During the Menstrual Cycle References: Prerequisites: Objectives: 1. Describe the general steps involved in the development of spermatozoa (spermatogenesis and spermiogenesis) and mature ova (oogenesis). 2. Compare and contrast spermatogenesis and oogenesis with regard to a) cytoplasmic changes, b) chromosomal changes (meiotic events), c) the time course of the two processes, and d) the number of mature gametes produced by each primary spermatocyte and primary oocyte. 3. Describe the general steps involved in the development of the ovarian follicle and its transformation into a corpus luteum. 4. Describe the basic structure (histology) of the fully developed uterine wall of a nonpregnant woman and the general changes it undergoes during the menstrual, proliferative, and secretory phases of the menstrual cycle. 5. Summarize the roles of the hypothalamus, anterior pituitary gland, and ovaries in the control of the menstrual cycle. 6. List briefly the source, site of action, and the principal action of each of the following hormones in the control of the menstrual cycle: Gonadotropin-releasing hormone (GnRH), Follicle stimulating hormone (FSH), Luteinizing hormone (LH), Estrogen, Progesterone. 7. Identify the site of fertilization, and describe the general steps involved in this process. When does fertilization occur with respect to the events of the menstrual cycle? Moore and Persaud, 8th ed., Ch. 1, 2 None
Key Words: primordial germ cells (PGC’s), gametogenesis, gametes (germ or sex cells), sex chromosomes, autosomes, sex determination, haploid, diploid, mitosis, meiosis, chromatids, centromere, first meiotic (reduction) division, second meiotic (maturation) division, pairing (synapsis) of homologous chromosomes during meiosis, first and second polar bodies, spermatids, spermiogenesis, acrosome reaction, capacitation, oogenesis, oogonia, primary oocyte, diplotene phase of meiosis I, dictyotene, follicle (granulosa) cells, primary follicle, growing follicle, antral follicle, mature (Graafian) follicle, antrum, follicular fluid, zona pellucida, cumulus oophorus, theca folliculi (externa and interna), arrested metaphase, stigma, ovulation, Mittelschmerz, corona radiata, ostium of the oviduct, oviduct, ampulla of the oviduct, zygote, conceptus, dispermy, aneuploidy, trisomy, monosomy, nondisjunction, corpus luteum of menstruation, corpus luteum of pregnancy, corpus albicans, perimetrium, myometrium, endometrium, basal layer, compact layer (stratum compactum), spongy layer (stratum spongiosum), decidua (functional layer), uterine epithelium, uterine glands, uterine milk, uterine coiled (spiral) arteries, menstrual cycle, menstrual phase (menstruation, menses), proliferative (follicular) phase, secretory (progestational or luteal) phase, edema, premenstrual (ischemic) phase
EMBRYOLOGY LECTURE 4
Subject Matter: The First Two Weeks: Early Developmental Changes in the Conceptus and Uterine Wall Before and After Implantation Begins References: Prerequisites: Objectives: 1. Describe the changes that occur in the conceptus from zygote to blastocyst formation. 2. List the usual sites of implantation; list the more common ectopic implantation sites. 3. Describe the process of implantation including the differentiation of the trophoblast into cytotrophoblast and syncytiotrophoblast and the decidual reaction in the surrounding maternal tissue. 4. Summarize the changes that occur within the conceptus and surrounding maternal tissues during the week after implantation is initiated. Moore and Persaud, 8th ed., Ch. 3 Lectures 1-3
5. Describe the role of human chorionic gonadotrophin (hCG) in the maintenance of pregnancy. 6. List three pathological conditions associated with elevated levels of hCG.
Key Words: conceptus, cleavage, blastomeres, morula, compaction, blastocyst, blastocyst cavity (blastocele), trophoblast, inner cell mass (embryoblast), embryonic pole, implantation, implantation site, ectopic pregnancy, tubal pregnancy, abdominal pregnancy, ovarian pregnancy, syncytiotrophoblast (syntrophoblast), cytotrophoblast (Langhans’ cells), chorion, amniotic cavity, amnion, yolk sac, epiblast, hypoblast, bilaminar (embryonic or germ) disc, lacunae, lacunar networks, maternal (endometrial) sinusoids, decidual reaction, extraembryonic mesoderm, extraembryonic coelom, extraembryonic somatic mesoderm (of amnion and chorion), extraembryonic splanchnic mesoderm (of yolk sac), body (connecting) stalk, primary (stem) villi, placenta previa, human chorionic gonadotrophin (hCG), neoplastic trophoblastic diseases (includes the following three general categories): hydatidiform mole, invasive mole, choriocarcinoma
EMBRYOLOGY LECTURE 5-6
Subject Matter: Weeks 3-8 of development during the embryonic period and beyond: Formation of the Trilaminar Embryonic Disc and Early Developmental Changes Within the Embryonic Disc and Extraembryonic Structures: Folding of the Trilaminar Embryonic Disc and Establishment of a Cylindrical Embryo; Establishment of the Primordia of Organs and Organ Systems; Embryonic Induction. General Characteristics of the Embryonic and Fetal Period. References: Prerequisite: Objectives: 1. Describe the components of the bilaminar embryonic disc at the end of the second week of development. List the sources of these two layers. 2. Describe briefly the process of gastrulation and the origin of the three primary embryonic germ layers. 3. Describe the source and mechanism of origin of the notochord. 4. List the two areas in the embryonic disc that remain free of mesoderm. Moore and Persaud, 8th ed., Ch. 4-6 Lectures 1-4
5. Describe the regional differences that appear within the embryonic mesoderm during the third week of development. 6. Outline the main features of neurulation. 7. Describe the changes that occur within the extraembryonic structures during the third week, especially the development of the chorionic villi. (The rudiments of all four extraembryonic membranes are now present.) 8. List the major derivatives of the three primary embryonic germ layers. 9. Describe briefly the role of the head fold, tail fold, and lateral body folds a) in converting the flat trilaminar embryonic disc into a C-shaped cylindrical embryo, b) in establishing the gut, and c) in narrowing the umbilical ring. 10. Define embryonic induction and give several examples of the phenomenon. 11. Describe the sequence of events involved in the formation of the neural tube and neural crest. 12. Describe the source of the somites, and list the major derivatives of these structures. 13. Calculate the estimated date of delivery given the last menstrual period (LMP). 14. Distinguish between fertilization age and menstrual (gestational) age. 15. Characterize the main features of the embryonic and fetal periods of development. When are teratogens more likely to cause major structural abnormalities? Key Words: first missed menstrual period, epiblast, hypoblast, gastrulation, endoderm, mesoderm, primitive streak, primitive groove, primitive knot (node), invagination, trilaminar embryonic disc (blastodisc), notochord, prochordal plate, oropharyngeal (buccopharyngeal) membrane, cardiogenic area, cloacal membrane, teratoma, pluripotential cells, neural plate, neural induction, neural folds, neural crest, neural tube, allantois, paraxial mesoderm, somites, intermediate mesoderm, lateral (plate) mesoderm, embryonic (intraembryonic) coelom, somatic and splanchnic mesoderm, somatopleure, splanchnopleure, angiogenesis, angioblasts, blood islands, endothelium, primitive heart (endocardial) tubes, secondary villi, tertiary villi, intervillous spaces, embryonic period, organogenesis, foregut, midgut, hindgut, stomodeum, proctodeum, oropharyngeal membrane, cloacal membrane, umbilicus (umbilical ring), yolk stalk (vitelline duct), sclerotome, dermatome, myotome, embryonic induction, last menstrual period (LMP), gestational age (menstrual age), fertilization age, biparietal diameter, crown-rump length, lanugo, brown fat, quickening, premature infants, postmature infants, “small for gestational age,” teratogen
EMBRYOLOGY LECTURE 7
Subject Matter: Origin, Early Development and Components of the Primitive Bilaterally Symmetrical Arterial System; Normal Changes (Transformations) in the Aortic Arch Region and Departures from Normal Causing Congenital Abnormalities; Origin and Functional Significance of the Ductus Arteriosus During Fetal Life and Its Fate, Normal and Abnormal, After Birth; Origin of the Descending Aorta and Its Major Unpaired Branches by Fusion of Paired Arteries Present Earlier; Origin of the Circle of Willis, Its Major Branches and Pathways for Arterial Blood to Reach It. References: Prerequisites: Objectives: The student should know 1. that the entire arterial system consists initially of endothelial tubes formed from angioblasts and that this system is bilaterally symmetrical initially. 2. the normal and abnormal fates of the six pairs of aortic arches and related levels of the dorsal aortae, including origin of the ductus arteriosus from the left sixth aortic arch, its functional significance during fetal life, the normal mechanism of its closure functionally and structurally after birth, its adult derivative, and consequences of failure of this bypass to close normally. 3. the method of formation (sources) of the primitive pulmonary arteries and primitive subclavian arteries. 4. the role of fusion of paired arteries in formation of the single descending aorta and its three unpaired branches to abdominal viscera. 5. the function of the paired umbilical arteries prior to birth and the fates of their different levels after birth. 6. the method of formation of the vertebral arteries, why they receive their blood from the subclavian arteries in the adult, where the basilar artery forms and the functional relationships of vertebral arteries to the basilar and of the latter to the developing circle of Willis. 7. the method of formation of the arterial circle of Willis and the development of its major branches to the developing brain. Moore and Persaud, 8th ed., Ch. 13 Lectures 1-6
Key Words: angioblast, endothelium, endothelial tubes, paired aortic arches (aortic arch arteries), branchial (pharyngeal) arches, aortic sac, paired dorsal aortae, maxillary arteries, external carotid arteries, stapedial arteries, hyoid arteries, coronary arteries, common carotid arteries, internal carotid arteries, brachiocephalic (innominate) artery, carotid ducts, arch of the aorta, seventh intersegmental arteries, right and left subclavian arteries, right and left pulmonary arteries, pulmonary vascular resistance, ductus arteriosus (and its ductal muscle), patent ductus arteriosus, bradykinin, functional (versus structural) closure of the ductus arteriosus, ligamentum arteriosum, right and left recurrent laryngeal nerves (branches of right and left vagus nerves), descending aorta, right and left vitelline arteries, celiac artery (trunk), superior and inferior mesenteric arteries, right and left umbilical arteries, common iliac arteries, internal iliac (hypogastric) arteries, superior vesical arteries, lateral umbilical (or vesico-umbilical) ligaments, external iliac arteries, right and left vertebral arteries, basilar artery, posterior communicating arteries, anterior communicating artery, anterior, middle and posterior cerebral arteries, circle of Willis, postductal and preductal coarctations (of the arch of the aorta), collateral circulation, maternal rubella infection, teratogen, neonatal respiratory distress, double aortic arch (arch of the aorta) and its retroesophageal component, vascular ring
EMBRYOLOGY LECTURE 8
Subject Matter: Origin, Early Development and Components of the Primitive Bilaterally Symmetrical Sources of the Adult Venous System Other Than the Pulmonary Veins; Normal Changes (Transformations) and Departures from Normal Causing Congenital Abnormalities; Origin and Functional Significance of the Ductus Venosus (and Its Sphincter Valve) During Fetal Life and Its Fate After Birth; Origin, Normal and Abnormal Changes (Transformations) of the Primitive Pulmonary Vein and Its Branches; Origin and Development of the Lymphatic System References: Prerequisites: Objectives: The student should know 1. that the entire venous system consists initially of endothelial tubes formed from angioblasts and that this system is bilaterally symmetrical initially except for the pulmonary veins. Moore and Persaud, 8th ed., Ch. 13 Lectures 1-7
2. three general principles in venous system development: a) the essentially plexiform nature of the embryonic vascular system (making variations from normal relatively common); b) the natural tendency for blood to seek the most direct route of flow because of hemodynamic factors; and c) except for the pulmonary veins, all transformations return blood eventually to major unpaired veins located on the right side of the body and discharging into the right side of the heart. 3. the normal and abnormal fates of the paired common cardinal and anterior (precardinal) veins and the formation of related veins. 4. the normal and abnormal fates of the paired vitelline veins including formation of hepatic sinusoids and all major related veins. 5. the normal and any abnormal fates of the paired umbilical veins, including formation of the ductus venosus, its functional significance during fetal life, its method of closure after birth and its adult derivative, and also including the clinical usefulness of a patent ligamentum teres. 6. the normal and any abnormal fates of paired posterior cardinal (postcardinal), subcardinal and supercardinal veins and anastomoses among them, with special emphasis on those components that persist to become segments of the composite adult inferior vena cava and its major branches; formation of any additional components incorporated into the adult inferior vena cava or serving as some of its major branches; utilization of the proximal end of the original right vitelline vein as the proximal end (hepato-cardiac segment) of the adult inferior vena cava. 7. the pattern of branching of the primitive pulmonary vein relative to the development of paired lungs and the differences of opinion about the origin of this primary or original vein. 8 . the differences of opinion about the initial relationship of the developing lymphatic system to the developing venous system, establishment of the definitive relationship of the thoracic ducts to the venous system, and development of the lymph nodes and the “seeding” of these structures with lymphocytes originating from the thymus gland.
Key Words: angioblast, endothelium, systemic veins, original (primitive or common) pulmonary vein, anterior cardinal (precardinal) veins, right and left brachiocephalic veins, internal and external jugular veins, subclavian veins, left superior intercostal vein, common cardinal veins, superior vena cava, coronary sinus (usually considered as former left horn of sinus venosus but considered by some as part of former left common cardinal vein), oblique vein of the left atrium, septum transversum, vitelline veins and their anastomoses (cross connections), hepatic portal vein (persisting embryonic components: right vitelline vein
between cranial and middle anastomoses; middle anastomosis; possibly a short segment of the left vitelline vein caudal to the middle anastomosis), splenic and superior mesenteric veins, hepatic sinusoids, hepato-cardiac component of the adult inferior vena cava (proximal end of the right vitelline vein), umbilical veins, ligamentum teres, ductus venosus and its sphincter valve, venous shunts, ligamentum venosum, posterior cardinal (postcardinal) veins, subcardinal veins, supracardinal veins, anastomoses among them (postcardinal, postsubcardinal, post-supracardinal, subcardinal and sub-supracardinal), crista dividens, valve of the inferior vena cava, inferior vena cava, persisting embryonic components: right hepato-cardiac component = proximal end of original right vitelline vein; hepatic segment = enlarged intrahepatic channel formed from hepatic sinusoids; mesenteric segment = new channel formed in caval fold between liver and right subcardinal vein (together hepatic + mesenteric segments are sometimes called the hepatosubcardinal anastomosis or hepatic segment of the inferior vena cava); right subcardinal vein (cranial to the subcardinal anastomosis); right sub-supracardinal anastomosis (caudal to the subcardinal anastomosis); right supracardinal vein (all components caudal to the subcardinal anastomosis are sometimes lumped as the renal segment); the postcardinal (= iliac) anastomosis; cranial to the latter possibly a right postsupracardinal anastomosis and a short caudal portion of the right postcardinal, subcardinal anastomosis, renal veins, suprarenal veins, gonadal (ovarian or testicular) veins, azygos vein, hemizygous vein, double superior vena cava, left superior vena cava, double inferior vena cava at the lumbar level, absence (partial) of the inferior vena cava, total versus partially anomalous (abnormal) pulmonary venous connections (drainage), cardiovascular versus lymphatic systems, primary lymph sacs (two jugular, two iliac = ilio-inguinal, one retroperitoneal, one cisterna chyli), paired thoracic ducts (of embryo) versus major (left) and minor (right) thoracic ducts of adults, lymph nodes, lymph sinuses, lymphocytes, thymus gland (third pharyngeal pouch derivative), lymph nodules, germinal centers of lymphocyte production, cystic lymphangioma hygroma
EMBRYOLOGY LECTURES 9-10
Subject Matter: Origin and Early Development of the Heart; Its Changing Relations to the Pericardial Cavity and Openings of Major Veins; Normal and Abnormal Partitioning of the Heart (Including Development and Function of the Normal Right-to-Left Interatrial Shunt Via the Foramen Ovale and Closure of the Latter at Birth); Development of the Conducting System of the Heart Moore and Persaud, 8th ed., Ch. 8, 13 Lectures 1-8
References: Prerequisite: Objectives:
The student should know:
1. why the cardiovascular system is the first system to function in the embryo. 2. the origin of the heart-forming cells in relation to the future pericardial cavity; how these spatial relationships are changed by action of the head fold of the body; how and where paired endocardial tubes form; when and in what sequence they fuse. 3. the five primary subdivisions of the heart formed by relative growth changes of the endocardial tube (and related epimyocardium = myoepicardial mantle) and when circulation of the embryo’s blood begins. 4. the succession of bendings undergone by the originally straight heart tube to attain definitive relationships of the five primary subdivisions of the heart prior to absorption of the sinus venosus into the heart wall. 5. the meaning of myogenic versus neurogenic origin of heart contractions. 6. the method of subdividing the single atrioventricular canal (region) into right and left atrioventricular canals and the formation of atrioventricular valves. 7. the incomplete attempts to partition the atrium prior to birth, the formation of the foramen ovale and its valve, the functional significance of the foramen ovale mechanism during fetal life and the mechanism of its closure postnatally, both functionally and structurally. 8. the displacement of the opening of the sinus venosus into the atrium (sinoatrial orifice) to the right of the midline, the absorption of the walls of the sinus venosus into the right atrium, the adult veins that then open directly into the right atrium, and the role of the sinus venosus as pacemaker of the primitive heart. 9. the developmental fates of the right and left horns of the sinus venosus and of the sinoatrial valves. 10. the partitioning of the ventricle by means of the muscular and membranous parts of the interventricular septum, the multiple sources of the membranous part (septum membranaceum), the absorption of the bulbus cordis into the ventricles. 11. the partitioning of the bulbus cordis and truncus arteriosus into aorta (ascending) and pulmonary trunk, why these “vessels” entwine one another and how and where their semilunar valves are formed. 12. why it becomes necessary to develop a conducting system within the heart and the origin and location of the components of this conducting system. 13. the common defects (congenital abnormalities) of the heart, how their existence can be explained readily as failure or modification of specific normal developmental events and which of these defects produce acyanotic versus cyanotic neonates.
Key Words: cardiogenic area, pericardial cavity (coelom), septum transversum, paired endocardial heart tubes (versus single = fused endocardial heart tube), truncus arteriosus, bulbus cordis, ventricle, atrium, sinus venosus and its right and left horns, sinoatrial opening (orifice), sinoatrial valves, bulboventricular loop, dorsal mesocardium, myoepicardial mantle (epimyocardium), cardiac myoblasts, myocardium, epicardium (visceral pericardium), parietal pericardium, cardiac jelly, contractions of myogenic (versus neurogenic) origin, ebb-and-flow (versus unidirectional flow) of blood, single (unpartitioned) atrioventricular canal, dorsal and ventral endocardial cushions (versus single = fused endocardial cushion = septum intermedium), right and left atrioventricular canals, septum primum, foramen primum, foramen secundum, septum secundum, foramen ovale, valve of the foramen ovale (persisting part of septum primum), interatrial septum (postnatal), coronary sinus (persisting left horn of sinus venosus), orifice of coronary sinus, sinus venarum (versus primitive right atrium or auricle), crista terminalis (cranial part of right sinoatrial valve), sulcus terminalis, valves of inferior vena cava and coronary sinus (lower part of right sinoatrial valve), pulmonary vein contribution to wall of left atrium (versus primitive left atrium or auricle), interventricular septum (muscular part), interventricular groove, interventricular foramen, interventricular septum (membranous part, closing interventricular foramen), trabeculae carneae, papillary muscles, chordae tendinea, atrioventricular (tricuspid and mitral or bicuspid) valves, bulbar ridges, subendocardial tissue, aorticopulmonary (spiral) septum (of bulbus cordis and truncus arteriosus), aorta (ascending), pulmonary trunk, semilunar valves, conus arteriosus, pacemaker, Purkinje (atypical muscle) fibers, sinoatrial node, atrioventricular node, atrioventricular bundle, crista dividens, functional (versus structural) closure of foramen ovale, fossa ovalis, limbus fossae ovalis (annulus ovalis), isolated dextrocardia, dextrocardia with situs inversus, ectopia cordis (extra thoracic, thoracoabdominal or abdominal), probe patent foramen ovale, secundum type atrial septum defect, endocardial cushion defect with primary type atrial septum defect, atrioventricularis communis (persistent or common atrioventricular canal), sinus venosus type atrial septum defect, common atrium, membranous (versus muscular) interventricular septal defect, cor triloculare biatriatum, persistent truncus arteriosus, aorticopulmonary (spiral) septum defect (aortic window), complete transposition of the great arteries (aorta and pulmonary trunk), pulmonary trunk stenosis, pulmonary valve stenosis, infundibular pulmonary stenosis, tetralogy of Fallot, pulmonary atresia, aortic valve stenosis, subaortic stenosis, aortic atresia
EMBRYOLOGY LECTURE 11
Subject Matter: Origin, Normal and Abnormal Development of the Respiratory System; Relationship of the Two Developing Lungs to the Two Pericardioperitoneal Canals (Future Pleural Cavities) and the Changing Relationships of the Latter to the Pericardial Cavity; the Methods of
Partitioning the Coelom (Body Cavity) into One Pericardial Cavity, Two Pleural Cavities and One Peritoneal Cavity, Including Development of the Mediastinum and Normal and Abnormal Development of the Diaphragm References: Prerequisite: Objectives: The student should understand 1. formation of the endodermal laryngotracheal groove from the floor of the pharynx and its separation (as the endodermal laryngotracheal tube) from the gut tube except for retention of its cranial connection as the glottis, as well as any characteristic departures from normal development. 2 derivation of larynx and trachea from the laryngotracheal tube; the normal branching pattern of the caudal end of the latter to form two stem bronchi and their asymmetrical branching forming the five primary bronchi (the basis for the five lobes of the normal adult lungs), as well as any characteristic departures from normal development. Moore and Persaud, 8th ed., Ch. 10 Lectures 1-10
3. subsequent branching patterns resulting in establishment of all endodermal-lined passageways for air to and from terminal alveoli. 4. development of capillaries of the pulmonary circulation and of lymphatics in relation to development of air passageways and the source of the splanchnic mesoderm in which they develop. 5. provision for growth of developing lungs, first laterad into the medial walls of the future pleural cavities (pericardioperitoneal canals), which provide the visceral pleura covering the lungs, and later lateroventrad around the pericardial cavity as the pleural cavities invade the lateroventral body walls, thereby lengthening the pleuropericardial membranes. 6. method of partitioning the two pleural cavities from the pericardial cavity, role of the changing position of the common cardinal veins in this process, and contribution of the two pleuropericardial membranes to formation of the mediastinum. 7. method of partitioning the two pleural cavities from the peritoneal cavity involving formation of the diaphragm, its embryonic sources, the source of its nerves and characteristic congenital malformations of the diaphragm.
Key Words: pharynx, laryngotracheal groove, tracheoesophageal folds, tracheoesophageal septum, laryngotracheal diverticulum, laryngotracheal tube, glottis, larynx, recanalization of the larynx, laryngeal ventricles, vestibular folds (false vocal cords), vocal folds (true vocal cords), esophagus, trachea, right and left initial (primary) lung buds (stem bronchi) and their side branches (collectively forming the five primary bronchi = bronchopulmonary buds, three on the right, two on the left), lung lobe pattern, bronchotracheal glands, bronchioles, terminal bronchioles, respiratory bronchioles, alveolar ducts, alveoli (terminal air sacs), intraalveolar fluids, prenatal respiratory movements, growth of lungs into splanchnic mesoderm of medial walls of two pericardioperitoneal canals (future pleural cavities), development of capillaries of pulmonary circulation and lymphatics in this splanchnic mesoderm, visceral versus parietal pleura, surfactant, atelectasis, hyaline membrane disease (= respiratory distress syndrome), tracheoesophageal fistula, esophageal atresia, aspiration pneumonia, polyhydramnios, laryngeal web, tracheal stenosis or atresia, tracheal diverticulum, tracheal lobe, congenital bronchial cysts, azygos lobe (of lung), hypoplasia of lungs (associated with posterolateral diaphragmatic hernia), agenesis of lungs, inverted U-shaped coelom (before action of head fold of body), displacement of transverse portion of inverted U (= future pericardial cavity) ventrad and caudad by action of head fold of body, two common cardinal veins (their role in formation of two pleuropericardial membranes), role of pleuropericardial membranes in separation of two pleural cavities from one pericardial cavity and, with dorsal mesoesophagus, in formation of the mediastinum, septum transversum, two pleuroperitoneal membranes and the dorsal mesoesophagus (their roles in separating two pleural canals from one peritoneal cavity and in diaphragm formation), central tendon of diaphragm, source of muscle cells of diaphragm, source of nerve fibers of phrenic nerves of diaphragm, congenital diaphragmatic hernia, foramen of Bochdalek, congenital eventration of the diaphragm, esophageal and retrosternal (parasternal) hernias of the diaphragm
EMBRYOLOGY LECTURES 12-13
Subject Matter: Development of the Nervous System: Spinal Cord Level; Normal and Abnormal Development of the Vertebral Column References: Prerequisites: Objectives: 1. Describe the inductive relationships and morphogenetic processes involved in the formation of the neural tube and neural crest. Moore and Persaud, 8th ed., Ch. 14, 17 Lectures 1-12
2. Describe the formation of the low lumbar, sacral, and coccygeal levels of the spinal cord. 3. Describe the process of cell division within the neuroepithelium (ventricular zone), and the formation of the intermediate (mantle) zone, marginal zone, and ependymal layer. 4. Distinguish between alar and basal plates. What types of neurons form from the neuroblasts which develop within these two regions? 5. Describe the embryonic origins of the nervous and non-nervous cells in the central nervous system and peripheral nervous system including the autonomic nervous system. 6. List the derivatives of neural crest cells. 7. Describe the process of myelination of nerve fibers within the central nervous system and peripheral nervous system. When does myelination occur? 8. Describe the embryonic origin of the meninges. 9. Explain the relative positional changes that occur between the caudal end of the spinal cord (conus medullaris) and vertebral column, and the resultant formation of the lumbar cistern, cauda equina, and filum terminale. Explain how these changes allow for lumbar puncture (spinal tap). 10. Describe the normal and abnormal development of the vertebral column. Describe the general features of spina bifida occulta and the various types of spina bifida cystica.
Key Words: neural plate, neural folds, neural groove, neural tube, neural crest, central canal, rostral neuropore, caudal neuropore, neurulation, canalization, neuroepithelium (ventricular zone), intermediate (mantle) zone, marginal zone, gray and white matter, ependymal layer, neuroblasts, neurons, glioblasts (spongioblasts), astroblasts, fibrous astrocytes, protoplasmic astrocytes, oligodendrocytes, neuroglia, macroglia, microglia, alar plate, basal plate, sulcus limitans, roof plate, floor plate, posterior gray column (horn), anterior gray column, lateral gray column, anterior median fissure, funiculi (posterior, anterior, and lateral), spinal ganglia (dorsal root ganglia), pseudounipolar neurons, leptomeninges, pia mater, arachnoid layer, dura mater, subarachnoid space, cerebrospinal fluid (CSF), conus medullaris, cauda equina, filum terminale, coccygeal ligament, lumbar cistern, lumbar puncture (spinal tap), autonomic ganglia (paravertebral or sympathetic chain, prevertebral, and terminal), preganglionic and postganglionic fibers, Schwann cells, myelin sheath, sclerotome, intervertebral disc, centrum, nucleus pulposus, chordoma,
neural (vertebral) arch, spina bifida occulta, spinal dermal sinus, spina bifida cystica, rachischisis, meningocele, meningomyelocele, myeloschisis
EMBRYOLOGY LECTURES 14-15
Subject Matter: Establishment of Definitive Relationships of Extraembryonic (Fetal) Membranes to Each Other and to the Uterine Decidua in Single and Twin Pregnancies, With Emphasis on the Formation and Function of the Placenta and Umbilical Cord; Maternal-Fetal Relationships References: Prerequisites: Objectives: 1. Define the three subdivisions of the decidua (basalis, capsularis, and parietalis) that become distinguishable after implantation is completed. [Some obstetrics references use the term decidua vera instead of decidua parietalis.] 2. Describe the origin and structure of the placenta. 3. Describe the differentiation of the chorionic sac into the villous chorion and smooth chorion. 4. Describe the expansion of the chorionic sac, the elimination of the uterine cavity, and the fate of the various components of the decidua and chorion. 5. Describe the expansion of the amniotic cavity and subsequent a) fusion of amnion and chorion, b) elimination of the cavity of the chorionic sac, and c) formation of the umbilical cord. 6. List the components of the placental membrane (placental barrier) and umbilical cord. 7. Describe briefly the mechanisms of transplacental exchange. 8. List the functions of amniotic fluid. 9. List the sources of amniotic fluid and describe its circulation pattern during normal pregnancy. 10. Define oligohydramnios and polyhydramnios, and list fetal abnormalities that are associated with each condition. Moore and Persaud, 8th ed., Ch. 7 Lectures 1-13
11. Describe the origin of monozygotic and dizygotic twins. 12. Describe all possible relationships of amnion, chorion, and placenta for monozygotic and dizygotic twins.
Key Words: chorion, amnion, yolk sac, allantois, urachus, median umbilical ligament, fetal component of the placenta, maternal component of the placenta, chorion frondosum (villous chorion), chorion laeve (smooth chorion), decidua basalis, decidua capsularis, decidua parietalis (decidua vera), placental septa, cotyledons, intervillous spaces, chorionic plate, amniochorionic membrane, anchoring villi, fibrinoid material, Nitabuch’s layer, spiral arteries, placental membrane (placental barrier), syncytial knots (nuclear aggregations), umbilical cord, umbilical vessels, false and true knots, Wharton’s jelly, parturition, amniotic fluid, oligohydramnios, polyhydramnios, dizygotic and monozygotic twins, erythrocyte mosaicism, human placental lactogen (hPL), amniocentesis, Apt test, Rh hemolytic disease, bilirubin, RhoGAM
EMBRYOLOGY LECTURE 16
Subject Matter: Limb development References: Moore and Persaud, 8th ed. Chapter 6, 14, 16 Objectives: lectures 1-15 1. 2. Describe the origin and location of the two pairs of embryonic limb buds. Discuss the epithelial and mesenchymal portions of the limb buds and the role of these structures in patterning and growth during limb bud development. Describe the generation of skeletal elements, muscle masses, and innervation in the developing limbs. How do the developing limbs attain their final posture?
3.
4.
5. What is the role of apoptosis in separation of the digits during embryonic development? 6. How are the developing limbs used to estimate the defined Carnegie Embryonic Staging of Human Development? During very early limb bud stages how do cell signaling centers function to generate patterning along the cardinal axes of the prospective limb?
8.
9.
What are the 4 types of congenital abnormalities and examples within three of the categories that affect limb development? How can knowledge of developmental limb patterning mechanisms increase our understanding of congenital malformations? To what extent do children have the ability to regenerate fingers and toes?
10.
11.
Key Words: limb bud, lateral plate mesoderm, somites, myogenic cells, apical ectodermal ridge, mesenchyme, progress zone, chondrification, centers of ossification, dermatomes, apoptosis, developmentally-regulated genes, bone morphogenetic proteins, cellular retinoic acid binding proteins, muscle segmentation homeobox proteins, HOXA and D proteins, fibroblast growth factors, Wnt-7a, En-1, LIM, sonic hedgehog, retinoic acid, Carnegie Embryonic staging of Human Development, congenital abnormalities, malformation, disruption, deformation, dysplasia, club foot, oligohydramnios, thalidomide, dilantin, Trisomy 18, rocker bottom feet, achondroplasia, syndactyly, polydactyly, postaxial deletions, synpolydactyly, digit regeneration
EMBRYOLOGY LECTURE 17
Subject Matter: Normal and Abnormal Development of the Digestive System and Its Mesenteries Moore and Persaud, 8th ed., Ch. 11 Lectures 1-16
References: Prerequisite: Objectives:
The student should understand: 1. how the arterial supply of each specific organ indicates its derivation from one (or more) of the three subdivisions of the primitive gut. 2. how rotation of the stomach around its longitudinal axis is correlated with a) adult positions of its greater and lesser curvatures, b) changing relations of the vagus nerves to the stomach, c) transformation of the dorsal mesogastrium into the greater omentum, d) fusions of parts of the greater omentum necessary for attainment of adult relationships and e) formation of the lesser peritoneal sac (omental bursa) and epiploic foramen.
3. how rotation of the duodenum around its longitudinal axis is correlated with a) fusion of pancreatic rudiments, b) formation of adult pancreatic ducts, and c) ventral to dorsal shift of point of attachment of the common bile duct to the duodenum. 4. events occurring during temporary umbilical herniation of the midgut loop and during “reduction of the midgut hernia” including a) the adult digestive organs involved, b) their normal changes in position relative to each other and to the superior mesenteric artery, and c) the specific congenital abnormalities resulting from failures to complete normal events or from abnormal events during these periods. 5. how the free dorsal mesentery of certain derivatives of the digestive tube disappears during development, leaving these derivatives firmly fixed in position (retroperitoneal). 6. the source and role of the urorectal septum in partitioning the cloaca and cloacal membrane, derivation of the rectum and upper anal canal from the posterior (dorsal) subdivision of the cloaca, and the role of the proctodeum and rupture of the anal membrane in completing formation of the anal canal. 7. the role of persisting intraembryonic portions of the stalk of the yolk sac (vitelline duct) and sometimes of associated blood vessels in producing a variety of abnormalities of the ileum, all of them modifications of a basic Meckel’s diverticulum, and some of them of clinical importance. 8. how the swallowing (and absorption) of amniotic fluid is anmportant factor in regulating the volume of this fluid, and what specific congenital abnormalits of the digestive system impair this function.
Key Words: primitive gut, foregut, midgut, hindgut, endoderm, splanchnic mesoderm, celiac artery, superior and inferior mesenteric arteries, tracheoesophageal septum, superior retention band (of the duodenum), recanalization, greater curvature, lesser curvature, dorsal mesogastrium, septum transversum, ventral mesogastrium, lesser peritoneal sac (omental bursa) and its superior and inferior recesses, epiploic foramen (of Winslow), greater omentum, lienorenal ligament, gastrosplenic ligament, liver bud (hepatic diverticulum) and its primary subdivisions, hepatic cords, liver parenchyma, hepatocytes, hepatic ducts, hepatic sinusoids, space of Disse, hematocytoblasts, cystic duct, gall bladder, common bile duct, Kupffer cells, lesser omentum, falciform ligament, visceral peritoneum, dorsal and ventral pancreatic bud, main pancreatic duct (of Wirsung), accessory pancreatic duct (of Santorini), acinus, islets of Langerhans, alpha cells, beta cells (of islets), insulin, glucagon, cranial and caudal limbs of intestinal loop, inferior retention band (junction of midgut and hindgut), meconium, cecal diverticulum, appendix, antimesenteric border,
retrocecal, retrocolic, hepatic and splenic flexures, fixation (of parts of the intestine), retroperitoneal, cloaca, cloacal membrane, proctodeum (anal pit), urorectal septum, rectum, upper anal canal, anal membrane, lower anal canal, esophageal atresia or stenosis, polyhydramnios, pyloric stenosis, annular pancreas, duodenal atresia or stenosis, omphalocele (exomphalos), congenital umbilical hernia, yolk stalk (vitelline duct), Meckel’s diverticulum and its variations (cords, cysts, fistulas, sinuses), volvulus, Hirschsprung’s disease (congenital aganglionic megacolon), intestinal duplications, agenesis, various types of anorectal malformations
EMBRYOLOGY LECTURE 18
Subject Matter: Normal and Abnormal Development of the Urinary (Excretory) Portion of the Urogenital System and Normal Development of Adrenal (Suprarenal) Glands References: Prerequisite: Objectives: The student should understand 1. how some knowledge of the embryonic sources and development of the transitory pronephric and mesonephric kidneys is an essential prerequisite to understanding development of the adult metanephric kidneys and certain functional parts of the adult male reproductive system (as well as the existence in both sexes of certain nonfunctional vestiges sometimes of clinical significance). 2. the two specific sources (rudiments) of the persisting metanephric kidneys and the contributions each makes to the structure of these organs in the adult. 3. the sources of the urachus (median umbilical ligament), urinary bladder and urethra and how the latter two structures become connected to the metanephric kidneys and ejaculatory ducts, respectively. 4. how prenatal blood clearance by the metanephric kidneys is an important factor in regulation of the volume of the amniotic fluid and how this latter function is impaired by certain congenital abnormalities of the urinary system. 5. the positional changes undergone by the developing kidney. Moore and Persaud, 8th ed., Ch. 12 Lectures 1-17
Key Words:
intermediate mesoderm, nephrotome, nephrogenic cord, mesonephric ridge, genital ridge, urogenital ridge, urogenital mesentery, pronephros, pronephric duct, mesonephros, Wolffian body, mesonephric (Wolffian) duct, mesonephric tubule, glomerulus, Bowman’s (glomerular) capsule, renal corpuscle, afferent and efferent glomerular vessels, posterior cardinal vein, metanephros, ureteric bud (metanephric diverticulum), metanephrogenic mass (nephrogenic blastema), ureter, renal pelvis, major calyx, minor calyx, collecting tubules, renal pyramids, excretory or secretory tubules (nephrons) of metanephroi, proximal and distal convoluted tubules and ascending and descending limbs of Henle’s loop (of nephrons), hilum, cloaca, cloacal membrane, urorectal septum, vesicourethral canal, allantois, pelvic urogenital sinus, phallic urogenital sinus, urogenital membrane, trigone, ejaculatory duct, prostatic urethra, membranous urethra and penile urethra (of genetic males), renal artery, renal vein, kidney rotation, kidney migration, supernumerary kidney, renal agenesis, oligohydramnios, ectopic kidney, pelvic kidney, discoid (pancake) kidney, crossed renal ectopia, horseshoe kidney, inferior mesenteric artery, congenital polycystic kidney, urachus, urachal sinus, cyst or fistula, exstrophy of the bladder (ectopia vesicae), exstrophy of the cloaca
Instructions for Study: Separate study of development of the urinary (excretory) and reproductive (genital) systems is artificial since these two components of the urogenital system are so closely intertwined developmentally, especially in genetic males. Consequently, some overlap in the two units devoted to development of the urogenital system is unavoidable.
EMBRYOLOGY LECTURE 19
Subject Matter: Normal and Abnormal Development of the Reproductive (Genital) Portion of the Urogenital System Moore and Persaud, 7th ed., Ch. 13 Lectures 1-18
Reading: Prerequisite: Objectives:
The student should understand 1. the embryonic sources of all components of the gonads, the specific developmental changes undergone by the latter in the transformation of gonads into testes or ovaries, and the importance of presence or absence of the Y chromosome in controlling these transformations; that under abnormal circumstances, usually when abnormal sex chromosome compositions exist, gonads can form ovotestes or a testis on one side of the body and an ovary on the other.
2. the embryonic sources of and the specific developmental transformations undergone by all components of the composite passageway used by genetic males to transport spermatozoa from testes to the exterior, including the glands whose essential secretions are added to certain of these components, and the role of fetal masculinizing hormone(s) in these transformations. 3. the embryonic sources of and the specific developmental transformations undergone by all components of the composite passageway used by genetic females to transport the products of ovulation and copulation to the site of their interaction (activation, fertilization) and any sizable products of fertilization to the exterior eventually, and whether or not any of these transformations depend on the presence of fetal hormone(s). 4. the initial bisexuality of embryos of both sexes during the indifferent stage, as far as embryonic sources of internal reproductive passageways are concerned; that sex differentiation in either genetic sex therefore normally involves persistence and elaboration of one set of duct primordia and disappearance of the other; that this initial bisexuality accounts for the normal presence in either genetic sex of certain nonfunctional vestiges of the wrong duct system and, under abnormal hormonal circumstances during fetal development, persistence and elaboration of major portions of the wrong duct system, not concordant with the direction of gonad differentiation. 5. the nature of the single set of primordia for external genitalia initially formed by embryos of both sexes during the indifferent stage and their specific developmental transformations in the male direction in genetic males in the presence of fetal masculinizing hormone(s) or in the female direction in genetic females in the absence of said fetal hormone(s); that under abnormal hormonal circumstances, with or without abnormal sex chromosome compositions, decisive development in male or female directions fails to occur, resulting in a variety of intersexual configurations. 6. the normal prenatal descent of each testis (and its epididymis) through an inguinal canal into the primordium of a half scrotum (and essential related developmental events involving that inguinal canal), as well as specific kinds of abnormalities that result when specific developmental events in this region fail to occur or differ from normal.
Key Words: genetic sex, gonad, gonadal sex, bisexual, indifferent stage, sperm (spermatozoa), ovum, ovary, testis, coelomic epithelium, germinal epithelium, parietal or visceral peritoneum (mesothelium), mesenchyme, primordial germ cells, yolk sac, genital (gonadal) ridge, primary sex cord, testis (or testicular) cords, rete cords, rete testis, tunica albuginea, seminiferous cords, Sertoli (sustentacular) cells, tubuli recti, puberty, seminiferous tubules, spermatogonia, primary and secondary spermatocytes, spermatids, spermiogenesis, interstitial cells (of Leydig), masculinizing (androgenic) hormones, testosterone, mesorchium, genital ducts, vasa efferentia (efferent ductules or ductuli efferentes), epididymis (or duct of the epididymis), vas deferens, seminal vesicle, ejaculatory duct, rete ovarii, ovarian medulla, secondary sex
(cortical) cords, ovarian cortex, follicle cells, oogonia, primordial follicles, primary oocyte, primary follicles, first and second polar bodies, secondary oocyte, ovulation, activation, mature egg, ostium, paramesonephric (Müllerian) duct, uterine (Fallopian) tubes (or oviducts), uterovaginal primordium (or canal), Müller’s (sinus) tubercle, body and cervix of uterus, endodermal sinovaginal bulbs, endodermal vaginal plate, vagina, hymen, pelvic urogenital sinus, male urethra, prostatic urethra, prostate gland, prostatic utricle, membranous urethra, phallic urogenital sinus, bulbourethral (Cowper’s) glands, genital tubercle, penile urethra, endodermal urethral plate, ectodermal urethral plate, glans, female urethra, urethral glands and paraurethral glands (of Skene), greater (major) vestibular glands (of Bartholin), lesser (minor) vestibular glands, vestigial remnants (or vestiges), appendix epididymis, paradidymis, vesicular appendage (appendix vesiculosa), epoophoron, paroophoron, Gartner’s duct (canal or cyst), appendix testis, urethral (urogenital) groove, urogenital (urethral) membrane, urethral (urogenital) folds, perineum, labioscrotal swellings, primary urogenital opening, labia minora, clitoris, glans clitoris, penis (phallus), glans penis, prepuce (foreskin), external genitalia, hypospadias, epispadias, labia majora, scrotum, inguinal canal, gubernaculum testis, processus vaginalis, descent of the testis, tunica vaginalis, gonadotropic hormones, spermatic cord, congenital inguinal hernia, hydrocele, cryptorchidism, sterility, ectopic testes, male pseudohermaphrodites, female pseudohermaphrodites, ovotestes, congenital virilizing adrenal hyperplasia, adrenogenital syndrome, maternal masculinizing tumor, Klinefelter’s syndrome, Turner’s syndrome, sex chromatin (Barr body), agenesis, dysgenesis
Instructions for Study: Separate study of development of the urinary (excretory) and reproductive (genital) systems is artificial since these two components of the urogenital system are so closely intertwined developmentally, especially in genetic males. Consequently some overlap in the two units devoted to development of the urogenital system is unavoidable. Development of the reproductive system is very complex and is threedimensional. Consideration of its development as one unit is difficult but essential because many primordia, visibly identical in both sexes initially, undergo different developmental histories in the two sexes.
EMBRYOLOGY LECTURE 20
Subject Matter: Development of the Face, Palate, and Upper Respiratory System; Adult Derivatives of the Branchial Apparatus; Formation of the Tongue and Thyroid Gland References: Prerequisite: Objectives: Moore and Persaud, 8th ed., Ch. 8, 9 Lectures 1-19
1. Describe the action of the headfold in the establishment of the cranial end and ventral surface of the head and the formation of the blind endoderm-lined foregut. 2. Describe the formation of the stomodeum by invagination of ventral head ectoderm and the location and germ-layer composition of the buccopharyngeal (oropharyngeal) membrane between ectodermal stomodeum and endodermal foregut.
3. Describe the formation and germ-layer composition of paired branchial (pharyngeal) arches through the combined action on each side of the pharynx of four ectodermal branchial (pharyngeal) grooves and four endodermal pharyngeal pouches, and the location and germ-layer composition of the branchial membranes. 4. List the major adult derivatives of the branchial arches and pharyngeal pouches. 5. Identify the relationship between the branchial arches (and their derivatives) and the trigeminal, facial, glossopharyngeal, and vagus nerves. 6. Describe the formation of two nasal placodes (ectodermal thickenings within the frontonasal process) and their transformations into blind nasal sacs, secondarily opening into the stomodeum. 7. Describe the method of separation of the nasal sacs from the stomodeum externally by formation of the upper jaw and resulting formation of nostrils, as well as failure(s) of upper jaw formation resulting in unilateral or bilateral cleft lip. 8. List the sources of rudiments forming primary and secondary palates. 9. Describe all fusions involved in formation of the normal palate (or absence of fusions involved in formation of various types of cleft palate) and the role of the palate in separating nasal cavity and nasopharynx from the oral cavity. 10. Describe the origin and development of the nasal septum, fusion of the nasal septum with the future hard palate, and establishment of the definitive choanae connecting the nasal cavities with the nasopharynx.
11. Describe the method of formation and location of nasal conchae within the nasal cavities and the origin of paranasal air sinuses from the latter. 12. Describe the source and method of formation of the tongue and epiglottis. 13. Describe the derivation of the larynx from the cranial end of the laryngotracheal groove (and subsequent laryngotracheal tube) and of its cartilages and muscles from mesenchymal cores of the fourth, fifth, and sixth branchial arches.
Key Words: stomodeum, buccopharyngeal (oropharyngeal) membrane, foregut, mouth, pharynx, frontonasal process (elevation), branchial (pharyngeal) arches, branchial (pharyngeal) grooves, pharyngeal pouches, branchial (closing) membranes (plates), larynx, laryngeal cartilages and muscles, laryngotracheal groove, laryngotracheal tube, glottis (laryngeal orifice), hypobranchial eminence, epiglottis, arytenoid swellings, nasal placodes, nasal pits, nasal sacs, upper jaw (maxillary processes, median nasal processes = elevations, intermaxillary segment), nostrils, oronasal membrane, primitive choanae, cleft lip, Simonart’s band, primary palate (median palatine process), lateral palatine processes, incisive foramen, secondary palate, palatine raphe, hard palate, soft palate, uvula, cleft palate (various types), nasal cavity, nasopharynx, oral cavity, nasal septum, definitive choanae, olfactory region (of nasal cavities), receptors for odors (specialized dendrites), olfactory cells (specialized neurons), olfactory (I) cranial nerves, olfactory bulbs (of brain), nasal conchae, paranasal air sinuses, nasolacrimal ducts, atresia (of nasolacrimal ducts), pharyngeal tonsil (“adenoids”), Eustachian (pharyngotympanic) tubes, oropharynx EMBRYOLOGY LECTURES 21-22 Subject Matter: Development of the Nervous System: Brain, Cranial Nerves, and Sense Organs Moore and Persaud, 8th ed., Ch. 17,18 Lectures 1-20
References: Prerequisites: Objectives:
1. List the major adult derivatives of each of the five secondary brain vesicles. 2. Describe the location and orientation of the three brain flexures. 3. Describe the development of the choroid plexus and ventricular system of the brain. Describe the flow pattern of cerebrospinal fluid in the normal CNS. Define hydrocephalus. What conditions are associated with hydrocephalus? 4. Describe briefly the expansion of the telencephalon and the formation of the C-shaped lateral ventricles and caudate nucleus. 5. Describe the embryonic origin of the neurons that form the cranial nerves. 6. Characterize briefly the following brain abnormalities: anencephaly, acrania, microcephaly, hydranencephaly, encephalocele, hydrocephalus (communicating and noncommunicating), Arnold-Chiari malformation, cranial meningocele.
7. Briefly describe the formation of the optic cup, lens, and cornea. What are the inductive relationships between these three structures. 8. Identify the embryonic primordia of the membranous labyrinth of the ear, the middle ear ossicles, the tympanic membrane, and the auditory tube and tympanic cavity.
Key Words: primary brain vesicles, prosencephalon, mesencephalon, rhombencephalon, secondary brain vesicles, telencephalon, diencephalon, metencephalon, myelencephalon, midbrain (cephalic) flexure, cervical flexure, pontine flexure, sulcus limitans, medulla oblongata, pons, cerebellum, cerebellar cortex, Bergmann glial cells, ventricles, pyramids, choroid plexus, foramen of Magendie, foramina of Luschka, cerebral aqueduct, interventricular foramina, tectum, superior and inferior colliculi, tegmentum, substantia nigra, cerebral peduncles, thalamus, epithalamus, hypothalamus, infundibulum, pituitary gland, Rathke's pouch, adenohypophysis, neurohypophysis, falx cerebri, corpus striatum, caudate and lentiform nuclei, internal capsule, lamina terminalis, cerebral commissures, corpus callosum, cerebral cortex, subventricular zone, cranium bifida, arachnoid villi, optic vesicle, optic cup, sensory retina, pigmented retina, otic placode, otocyst.
EMBRYOLOGY LECTURE 23
Subject Matter: Congenital Abnormalities: Mechanisms of Development, Causes, Treatment, and Prevention References: Prerequisites: Objectives: 1. Understand how the development of congenital abnormalities is related to normal development. 2. Understand the major classes of causes of congenital abnormalities. 3. Know the sensitive periods for development of various organ systems. 4. Understand strategies of prevention and treatment of congenital abnormalities. Moore and Persaud, 8th ed., Ch. 20 Lecture 1-22
Key Words:
teratogen, teratology, syndrome, malformation, multifactorial, pleiotropic, critical or sensitive period