Development of CVS Flashcards
When does vascular system appear?
Middle of 3rd week
What mesoderm layers form circulatory system?
Lateral mesoderm plates- visceral (splanchnic) layer
Where are progenitor heart cells found?
Lie in the epiblast, cranial to primitive streak
When and what is instructed to form cardiogenic region
When- once primary heart field is formed
what- Endoderm instructs
Give a general summary of heart development
- Formation of the heart tube
- Heat tube elongates and bends to form cardiac loop
- Initially has single primitive atrium and single primitive ventricle. Blood enters through sinus venosus- entry of veins and exits the developing heart via the bulbus cordis, leading to paired dorsal aorta
- Septation- formation of septa to divide ventricles from the atria and the l and r atria and ventricles
How is the heart tube positioned?
With brain growth and cephalic folding, the buccopharyngeal membrane is pulled forward, and the heart and pericardial cavity move to thorax
What layers does the heart tube consist of?
Endocardium
Myocardium
Epicardium
What forms the cardiac loop?
Heart loop elongating and bending
What happens as the heart tube bends?
The atrial region moves cranially, taking a position dorsal to ventricular region
How is cardiac tube organized?
By regions along its craniocaudal axis (role for homeobox genes)
Where is the apex of the heart located?
5th intercostal space
What is the base of the heart attached to?
Pericardial wall
Name the 3 septa
Atrioventricular septum (AV spetum)
Interatrial septum
Interventricular septum
When does septation occur?
Days 28-37
What is the function of septum prinum and septum secundum?
Allow right to left shunting of blood throughout gestation
Why does the shunt close at birth?
Abrupt dilation of pulmonary vasculature combined wiht cessastion of umbilical flow reverses the pressure difference between the atria and pushes the flexible septum primum against the more rigid septum secundum
When does the heart start beating?
Day 21-22
Function of the umbilical vein and artery?
blood to/from placenta
Function of vitelline vein and artery?
Circulation around yolk sac, forms the blood vessels in the liver and from GI tract to liver
Function of cardical veins?
Drains blood from the whole body wall, head and neck
What is derived from secondary heart field?
Right ventricle and outflow tract
