Application of Medical Embryology 🗸 Flashcards
Lateral folding
converts the open coelom into a closed cavity
creates thoracic and abdominal cavity
closes fore and hindgut
Cranial folding
forms foregut and defines the thoracic cavity
developing heart tube displaced into thoracic cavity
Caudal folding
cloacal membrane and connecting stalk are displaced ventrally alongside neck of yolk sack
forms hind gut, anus and umbilical cord
heart development
begins at week 4
cardiac progenitor cells migrate through primitive streak into the visceral layer of lateral plate mesoderm
heart tube formed through craniocaudal and lateral folding
normal atrial septation
2 septa - primum (30 days) and secundum (33 days)
communication between right and left atria until birth - foramen ovale
how is the valve of the foramen ovale closed?
increased pressure in the right atrium caused by first breath and crying
and decreased pressure in the right atrium caused by constriction of umbilical cord
forms the interatrial septum
normal ventricular septation
muscular portion grows upwards from wall of expanding ventricle
membranous portion - growth of tissue from endocardial cushions
ventricular septation closely liked to septation of outflow tract
transposition of great vessels
aorta emerges from the right ventricle and pulmonary artery arises from left ventricle
abnormalities in heart development
embryo most at risk of defects weeks 3-8
Atrial septal defect (ASD)
Ventricular septal defect (VSD)
Tetralogy of Fallot
atrial septal defect (ASD)
incomplete closure of embryonic foramen ovale in the septum
ventricular septal defect (VSD)
incomplete closure of interventricular septum
tetralogy of Fallot
pulmonary stenosis, right ventricular hypertrophy, VSD, overriding aorta (can be associated with down’s syndrome)
