2 Flashcards
What is the embryonic origin of the mesoduodenum?
Dorsal mesentery
The intraembryonic coelom forms where?
Between somatic and splanchnic mesoderm
Which feature do the parietal pleura, parietal pericardium and parietal peritoneum share in common?
Derive from somatic mesoderm
Which structure does not contribute to diaphragm development?
Pleuropericardial folds
Delayed/failed closure by which structure typically accounts for diaphragmatic hernia formation?
Pleuroperitoneal membranes
An organ that develops in the peritoneal cavity and is then displaced outside of the parietal peritoneum is referred to as?
Secondary retroperitoneal
Which two chick embryo “extraembryonic” membranes derive from somatopleure?
Amnion and chorion
Which term best describes the human placenta?
Hemochorial
The maternal portion of the placenta develops from which area?
Decidua basalis
Which extraembryonic membrane actually covers the umbilical cord?
Amnion
The somatopleure is a membrane comprised of which two tissues?
Ectoderm and somatic mesoderm
The placental barrier “thins” during gestation to improve exchange. How does this occur?
Loss of mesenchyme and cytotrophoblast within the placental villi
What is the primary source of amniotic fluid after 12 weeks of gestation?
Fetal urine production
Where does the allantois originate?
Embryonic endoderm
Why is the allantois important?
Umbilical cord blood vessel formation
Which layer disappears during gestation?
Decidua capsularis
Based on amnion/chorion arrangement, which situation would most likely produce conjoined twins?
Monochorionic, monoamniotic twins
Splitting of the embryo at the inner cell mass stage would result in which membrane arrangement?
Mochorionic, diamniotic teins
Differentiation of mesoderm-derived angioblasts into endothelial cells is an example of which process?
Vasculogenesis
Where is the first site of intraembryonic blood cell formation?
AGM (aorta-genial-mesonephric region)
The “fetal” hemoglobin contains which two pairs of globin molecules?
2 alpha, 2 gamma
Which cell is the intermediate precursor to erythrocytes?
Reticulocyte
The Rh-incompatibility syndrome (hemolytic disease of the newborn) occurs when?
Rh- mother has a Rh+ fetus
What is the source of the mesothelium that makes up the parietal pericardium?
Lateral somatic mesoderm
What is the source of the mesothelium that makes up the visceral pericardium?
Proepicardial primordium
The mesenchyme of the pleuropericardial folds give rise to which layer?
Fibrous pericardium
The smooth part of the definitive left atrium derives from which structure?
Pulmonary veins
The sinus venarium derives from which structure?
Right sinus venosus
The coronaty sinus predominately derives from which structure?
Left sinus venosus
The crista terminalis marks the separation between which two structures?
Primitive and definitive right atrium
Where would you expect to find the “moderator band”
Right ventricle
Atrial septation and foramen ovale formation require closure of which passageway?
Osteum primum
Atrial septal and membranous interventricular septal defects could occur due to failed development where?
Endocardial cushion
The definitive right ventricle derives primarily from whichbarea of the embryonic heart tube?
Bulbus cordis
Which fetal shunt directs blood from the pulmonary trunk to the aorta?
Ductus arteriosus
A majority of the blood in the fetal left atrium enters from which source?
Right atrium
The definitive left ventricle derives primarily from which area of the embryonic heart tube?
Primitive ventricle
What is the source of the cardiac endothelium and myocardium?
Lateral splanchnic mesoderm
The ventricular papillary muscles derive from which source?
Myocardium
Which cells are essential to atrioventricular valve development?
Epicardial cells and endothelial derived endocardial cushion cells
What is the origin of the left subclavian artery?
Left 7th intersegmental artery
Which structure derives from or is contributed to by the 3rd aortic arch?
Common carotid arteries
Which structure derives from or is contributed to by the left 6th aortic arch?
Ductus arteriosus
Which structure derives from or is contributed to by the right 4th aortic arch?
Right subclavian
The brachiocephalic artery primarily derives from which structure?
Aortic sac
The yolk stalk is most closely associated with which artery?
Superior mesenteric
A lateral anastomosis of the first 6 cervical intersegmental arteries is the basis for which major adult artery?
Vertebral
Relative to the paired dorsal aortas, how are the syndromes of double aortic arch and right aortic arch similar?
The right dorsal aorta is retained in both
Which cardiac defect always accompanies failed conotruncal septation?
Interventricular septal defect
The cardiac malformation “transposition of the great vessels” primarily reflects failed development in the?
Conotruncus
The definitive adrenal and gonadal arteries derive from?
Lateral intersegmental arteries
List the four primary defects characterizing Tetralogy of Fallot
Pulmonary trunk stenosis
Rightward displacement of aorta
Ventricular septal defect
Right ventricular hypertrophy
List the four mechanisms that can explain atrial septal defects
Osteum secundum defects
Osteum primum defects
Sinus venosus related defects
Failed endocardial cushion defects
List three cell types that comprise the midgestation human “placental membrane”
Syncytiotrophoblast
Cytotrophoblast
Fetal endothelium
Name the three primary routes for blood circulation in the 4th week human embryo
Cardinal aorta
Vitelline-yolk sac
Umbilical
Trace the path a red blood cell would follow from the adult superior vena cava to the right internal carotid artery
Superior vena cava to the right atrium to tricuspid valve to right ventricle to pulmonary semilunar valve to pulmonary trunk to pulmonary arteries to lungs to pulmonary veins to left atrium to bicuspid mitral valve to left ventricle to aortic semilunar valve to aortic arch to brachiocephalic to right common carotid to right internal carotid
What are the fundamental differences between persistent truncus arteriosus and transposition of the great vessels
In persistent truncus arteriosus the conotruncal ridges fail to form in the truncus arteriosus so there is a large common overriding outflow tract for right and left ventricular output. Always includes a ventricular septal defect.
In transposition of the great vessels the conotruncal ridges form and partition the truncus but fail to spiral. The right ventricle pumps blood into the aorta and the left ventricle pumps blood into the pulmonary trunk. Accompanied by patent ductus arteriosus and atrial and/or ventricular defects.
A large dissecting needle has been passed through the outermost layer of the pericardium to the left ventricular chamber. Name the layers the pin passes through.
Fibrous pericardium Parietal pericardium Pericardial cavity Visceral pericardium Myocardium Endocardium
Outline the cardiac conduction system and describe its function.
SA node-atrial pathways-AV node-bundle of His-bundle branches, left and right-Purkinje fibers
The SA node serves as the pacemaker to initiate cardiac contraction and the conduction system serves to coordinate atrial and ventricular cobtraction
Name the three coelom derived closed body cavities and name the inner and outer layers lining each cavity
Ectoderm (outer covering and nervous system), endoderm (inner layer and lining of GI tract), mesoderm (middle layer and internal organs
A large dissecting needle passes through the outermost layer of the pericardium to the left ventricular chamber. Name the layers the pin passes through.
Epicardium, myocardium, endocardium
Which spinal nerve primarily innervates the diaphragm and where is the spinal cord origin of this nerve?
Phrenic nerve, in the neck
What is the embryonic origin of the mesogastrum, mesoduodenum, and mesocolon?
Splanchnic mesoderm
What is the origin of the pleuropericardial folds and how do they contribute to both the parietal pleura and parietal pericardium plus the fibrous pericardium?
Originate along the lateral body walls in the fifth week of embryonic development and project into the cranial ends of the pericardioperitoneal canals to divide the pleural cavities from the pericardial cavity
Name the four structures that contribute to diaphragm development
The septum transversum, pleuroperitoneal membranes, the dorsal esophageal mesentery, and the body wall
How do the pleuroperitoneal folds contribute to diaphragmatic hernia development and why do diaphragmatic hernias typically occur on the left side?
Fail to extend and branch appropriately, the right diaphragm is protected by the liver
What is the allantois and why is it important?
Hollow sac like structure filled with fluid that collects liquid waste and exchanges gases
Describe the basic structure of primary, secondary, and tertiary chorionic villi?
Primary-trophoblast only, secondary-trophoblast and mesoderm
Tertiary-trophoblast mesoderm and blood vessels
What are the primary functions of the placenta?
Provide oxygen and nutrients to the fetus while removing CO2 and waste
What is spindle nuclear transfer?
Three parent in vitro fertilization
Explain the difference between vasculogenesis and angiogenesis
Vasculogenesis is blood vessel formation from endothelial cells while angiogenesis is formation from preexisting vessels
What is a hemangioma?
Noncancerous growth of blood vessels
Where does vasculogenesis begin in the embryo and what is the first site of hematopoiesis in the embryo?
Yolk sac
What is a patent ductus arteriosus?
An ductus arteriosus that remains open causing abnormal blood flow
What is coarctation of the aorta?
Narrowing of the aortic arch
Retention of which vessel might explain a double IVC?
Left supracardinal vein
What is the origin of the ductus arteriosus and what happens if the ductus fails to close after birth?
Blood vessel connecting the main pulmonary artery to the proximal descending aorta - irregular transmission of blood between the aorta and the pulmonary artery
What is the most likely basis for the syndrome of anomalous right subclavian artery?
Dysphagia
What happens to the common, anterior, and posterior cardinal veins?
Join with the corresponding right and left cardinal veins to form the left common cardinal veins
What happens to the vitelline veins?
They drain blood from the yolk sac
Although there are initially two umbilical veins, the definitive human umbilical cord typically contains only a single umbilical vein. How does this occur and which umbilical vein is retained?
Shunted from the left portal vein - left
The human embryo/fetus develops three transient venous systems. What are they and what is the basic function of each?
The Germinal stage-conception
The Embryonic Stage-major organs form
The Fetal Stage-sex organs, bone, muscle, brain
The human inferior vena cava is a composite structure derived from multiple embryonic/fetal blood vessels. Describe the origin of the definitive human IVC.
Is formed by the union of the two common iliac veins at the level of the fifth lumbar vertebra, and returns blood to the right atrium of the heart from bodily parts below the diaphragm
How might you explain the occurrence of a double superior vena cava or left superior vena cava?
Caused by variations in the development of the embryonic thoracic venous system
Trace the path a red blood cell would follow from the adult hepatic portal vein to the right internal carotid artery.
Hepatic portal vein, liver, hepatic veins, inferior vena cava, right atrium
Where does heart development begin and what are the basic contributions of the primary vs. secondary heart fields to adult heart structure?
Mesodermal primary heart field will develop into left and right atria and the left ventricle, the secondary heart field will become the right ventricle and outflow tract
Outline the origin of each of the pericardial and heart layers: fibrous, parietal, and visceral pericardium, myocardium, and endocardium
Outside layer-, fibrous,parietal,visceral,myocardium and endocardium
Why is the proepicardial primordium important?
Essential element of cardiac development
What is heart looping and why is dorsal mesocardium degeneration important to this process?
Allows the straight heart tube to form a more complex structure reminiscent of the adult heart-it forms the transverse pericardial sinus
In which direction does the primordial ventricle bend and what does it become?
Straight and becomes C shape
Beginning with the primary venous inputs, outline the structure of the heart tube and the three primary routes for blood circulation in the 4th week human embryo
Forebrain-midbrain-hindbrain
What is the most likely basis for the syndrome of anomalous right subclavian artery?
Dysphagia
What happens to the common, anterior, and posterior cardinal veins?
Join with the corresponding right and left cardinal veins to form the left common cardinal veins
What happens to the vitelline veins?
They drain blood from the yolk sac
Although there are initially two umbilical veins, the definitive human umbilical cord typically contains only a single umbilical vein. How does this occur and which umbilical vein is retained?
Shunted from the left portal vein - left
The human embryo/fetus develops three transient venous systems. What are they and what is the basic function of each?
The Germinal stage-conception
The Embryonic Stage-major organs form
The Fetal Stage-sex organs, bone, muscle, brain
The human inferior vena cava is a composite structure derived from multiple embryonic/fetal blood vessels. Describe the origin of the definitive human IVC.
Is formed by the union of the two common iliac veins at the level of the fifth lumbar vertebra, and returns blood to the right atrium of the heart from bodily parts below the diaphragm
How might you explain the occurrence of a double superior vena cava or left superior vena cava?
Caused by variations in the development of the embryonic thoracic venous system
Trace the path a red blood cell would follow from the adult hepatic portal vein to the right internal carotid artery.
Hepatic portal vein, liver, hepatic veins, inferior vena cava, right atrium
Where does heart development begin and what are the basic contributions of the primary vs. secondary heart fields to adult heart structure?
Mesodermal primary heart field will develop into left and right atria and the left ventricle, the secondary heart field will become the right ventricle and outflow tract
Outline the origin of each of the pericardial and heart layers: fibrous, parietal, and visceral pericardium, myocardium, and endocardium
Outside layer-, fibrous,parietal,visceral,myocardium and endocardium
Why is the proepicardial primordium important?
Essential element of cardiac development
What is heart looping and why is dorsal mesocardium degeneration important to this process?
Allows the straight heart tube to form a more complex structure reminiscent of the adult heart-it forms the transverse pericardial sinus
In which direction does the primordial ventricle bend and what does it become?
Straight and becomes C shape
What happens to the right vs the left sinus venosus during atrial remodeling?
The sinus venosus is incorporated in the right atrium displacing the original right atrium which becomes an auricle
Where is the crista terminal is located?
Pectinate muscles
Why are the dorsal/ventral endocardial cushions important?
It separates the atria and ventricles from the inside
Explain how atrial septation occurs and why the foremen ovals is important?
The septum primum grows between the atria,next, the septum secundum grows to the right of the septum primum, blood travels from right atrium to left atrium through the foramen ovale
Which portions of the original heart tube represent the primary structure of the left and right adult ventricles?
Atrioventricular canal
Which cell populations account for atrioventricular valve and chordae tendinae development?
Endocardial endothelial
Outline the origin of the specific origins of the following: left and right ventricles and the interventricular septum
The interventricular septum separates the left ventricle from the right ventricle. The interventricular septum is slanted backwards and to the right, and it also curves to the right, which completes the oval of the thick ventricle and encroaches upon the chamber of the right ventricle
Compare the processes of atrioventricular vs semilunar valve formation
Their structure and function varies due to them closing off different parts of the heart.
What are the fundamental differences between adult and fetal cardiovascular function?
Fetus does not use its own pulmonary circuit until after it’s born
How does cardiovascular function change with the fetal to neonatal transition?
Increase in lung blood flow
What are the four major mechanisms that lead to atrial septal defects?
Atrial septum, atrioventricular canal, superior vena cava, coronary sinus
Why is failed membranous septum formation the primary cause of ventricular septal defects?
Excessive blood flow to the lungs
Describe the cause and impact of persistent turn is arteriosus and transposition of the great vessels
Defect occurs spontaneously; truancy’s arteriosus fails to properly divide into the pulmonary trunk and aorta
What is the fundamental difference between aortic stenosis and aortic atresia
Atresia is absense of body passage
Stenosis is narrowing of a passage
