Development of heart
- 1. DEVELOPMENT OF HEART AND GREAT VESSELS BY: RAJNISH KUMAR CIMS BILASPUR
- 3. Towards the end of 3rd week of gestation heart begin to develop. HOW DEVELOPMENT BEGIN?? A pair of endothelial tube fuses to become Primitive heart tube. This develop within pericardial cavity, suspended from it’s dorsal wall by a dorsal mesoderm.
- 5. Groves develop in primitive heart tube to divide into 5 regions.
- 7. The arterial and venous ends of the tube are surrounded by a layer of visceral pericardium. The primitive Heart tube then elongates within the pericardial cavity. As bulbus cordis and ventricle grow more rapidly then the attachment at either end,the heart first takes a U-shape and later S-shape
- 9. At the same time heart rotates slightly anticlockwise and twists so that right ventricle lies anteriorly and left atrium and ventricle posteriorly. Despite this,and increase In number of vessels entering and leaving,they still continue to enclosed together in this single tube of pericardium. As the tube develops Sinous venosus becomes incorporated into the atrium The Bulbus cordis becomes incorporated into the ventricle.
- 11. Endocardial chusions develop between the premitive atrium Ventricle. The inteventricular septum develops from the apex up towards the endocardial cushions.
- 12. Development of atrium is Slightly more complicated:- Septum primum grows down to fuse with the endocardial cushions,but leaves a hole in the Upper part know as foramen ovale. The septum secundum develops just right of septum primum and foramen ovale. There is valve like structure develops which allows blood fto go from right to left side of heart in the foetus.
- 13. At birth when there is an increased blood flow through the lungs and rise in left atrial pressure,the septum primum is pushed across to close the foramen ovale. Usually,the septum fuse oblitering ovale leaving a small residual dimple(fossa ovalis).
- 14. The sinus venous joins the atria,becoming the two venae cavae on the right and 4 pulmonary veins on the left.
- 16. The common arterial trunk(the truncus arteriosus), continues from the Bulbus cordis and give of 6 pair of aortic arches.
- 17. The aortic archs The aortic archs curve around the pharynx to join tO dorsal aortae which join together lower down as descending aorta. The 1st and 2nd arches disappear early. 3rd arch remain as carotid artery.
- 18. 4th Arch: On the right: Becomes the subclavian artery On the left Becomes the arch of aorta, giving of the left subclavian artery. 5thArch: disappear early.
- 19. Ventral part of 6th arch: Becomes the right and left pulmonary artery. The connection to the dorsal aortae disappear on the right but continue as ductus arteriosus on the left connecting with the aortic arch.
- 21. Congenital abnormality of heart Fallot’s tetralogy: Features of this abnormality are: Pulmonary stenosis, narrowing of the exit from the right ventricle ventricular septal defect, a hole between the two ventricles right ventricular hypertrophy, thickening of the right ventricular muscle overriding aorta, which allows blood from both ventricles to
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