PEDS mod 1 Flashcards
The cardiovascular system is mostly derived from which germ layer?
Mesoderm
When does the CV system begin to function?
When does the blood start to circulate?
When does the heart start to beat/contract?
- Begins by the end of the third week (18-20 days)
- Blood is circulating in the third week.
- Heart starts to beat at the beginning of the 4th week (22 days)
When is the critical period of development for the CV system?
The critical period of development is from day 20 to 50 after fertilization.
Forms with clusters of angiogenic cells located in the cardiogenic plate.
Heart tube
The angiogenic cell clusters coalesce to form right and left what?
•The angiogenic cell clusters coalesce to form right and left endocardial tubes.
When are the endocardial tubes within the pericardial cavity fused?
•At approximately day 21 they are completely fused
Cardiac looping is normally to which side?
When is the cardiac loop complete?
Looping is to the right.
By day 28 the cardiac loop is complete.
- ___________ heart loops to the left instead of to the right.
- May coincide with situs inversus (all organs are reversed)
Dextrocardia
During which month does the heart begin to septate?
•During the second month, the heart begins to septate. (Divide into partitions)
What begins the separation of the heart into its chambers?
The endocardial cushions begin the separation of the heart into right and left, Upper and lower chambers.
The ______ _______ reduces the flow of blood from the right atrium to the left.
The septum primum reduces the flow of blood from the right atrium to the left.
The atrial septum continues to grow until the _______ _______ is nearly closed and the flow of blood almost ceases.
•It continues to grow until the foramen primum is nearly closed and the flow of blood almost ceases.
Apoptosis occurs in the _____ _______ causing an opening: the foramen secundum.
Apoptosis occurs in the septum primum causing an opening: the foramen secundum.
•The foramen secundum allows for continued delivery of oxygenated blood to the left atrium.
•Septum secundum nearly overlaps the foramen secundum creating the ______ ______.
Foramen ovale
•The foramen ovale establishes a one-way passage for blood from the right atrium to the left.
Ventricular septation starts when?
42 days