THE CARDIOVASCULAR SYSTEM The picture shows the tranverse section of the embryo demonstrating the formation of the angioblastic cords
. In which region do these cords develop? The picture shows the lateral folding of the embryo and the fusion of the endocardial heart tubes
. What is the significance of this folding? This picture shows the formation of cardiac loop
. What are the five dilatations which form on the primordial heart tube? . What results in the bending of the heart tube? The picture shows the structure of a primordial heart
. Give the three pairs of veins which are received by the sinus nenosus. The picture shows blood circulation through a primordial heart
. Describe the circulation of blood through the primordial heart. The picture shows the formation of endocardial cushions
. What are endocardial cushions and what is their significance? The picture shows the septation of the atrium in the primordial heart
. Give the two septa which are responsible for the formation of the interatrial septa. . What results in the perforations denoted by the red arrows? . What results in the formation of foramen primum and foramen secundum? . What is its significance? . What result in the formation of foramen ovale? What is the significance of this foramen? . What structure does formen ovale forms in the adult? The diagram shows the division of the sinus venosus into the left and right horns
. Which structure is responsible for this division? . What are the derivatives/remnants of the left horn of the sinus venosus? . What is the fate of the right horn of the sinus venosus? The picture shows the absorption of the pulmonary vein into the left atrium
. What is the significance of this absorption? The diagram shows the septation of the ventricle
. What forms the pars muscularis of the interventricular septum? The diagram shows the septation of the ventricle
. What forms the pars membrenacea of the interventricular septum? The picture shows the development of the truncus arteriosus and the bulbus cordis
. What are bulbar and truncal ridges? The picture shows the formation of the aorticopulmonary septum
. What results in the formation of this septum? This diagram illustrates the spiral form of the aorticopulmonary septum
. What is the significance of this septum? The diagram shows the great arteries twisting around each other as they leave the heart
. How does the aortocopulmonary septum contribute towards this twisting? Short essay questions
. Describe the formation of the interatrial septum. (10 marks)
. Describe the formation of the interventricular septum. (8 marks)
. Describe the septation of the atrio-ventricular canal. (3 marks)
Multiple choice questions
. The umbilical arteries form the following structures in the adult
a) Medial umbilical ligament. b) Ligamentum arteriosum. c) Ligamentum venosum. d) Superior vesical arteries. e) Ligamentum teres.
. The interatrial septum is formed by
a) Pars muscularis. b) Septum primum and septum secundum. c) Septum secundum and foramen secundum. d) Septum primum and foramen primum. e) Pars membranacea.