Flashcards in Cardiovascular System Deck (27):
When does the prenatal heart start beating?
Early in the fourth week
Why is it so important for the embryo to get a functioning cardiovascular system quickly?
Because as it grows to a certain size it can no longer rely on simple diffusion for distribution of nutrients, oxygen, etc
List the four major types of blood vessels in the four week embryo
1) Dorsal aortae (paired), 2) Cardinal veins (A, P, and Common), 3) Umbilical veins and arteries (paired), Vietlline arteries and veins (unpaired)
What do the umbilical arteries and veins communicate with in the embryo?
What do the vitelline arteries and veins communicate with in the embryo, and where do the persist in the adult?
Communicate with yolk sac. Persist in GI tract as unpaired arteries of abdominal aorta
Which umbilical vein will persist, and which will degenerate?
The left will persist, the right will degenerate
What part of what germ layer holds cardiac progenitor cells?
The anteriomost portion of the splanchnic mesoderm
What gives rise to blood vessels in the embryo?
Where is the cardiogenic mesoderm relative to the oropharyngeal membrane in the neural plate stage embryo?
Anterior to the OP membrane
If the heart tube is anterior to the oropharyngeal membrane in the neural plate stage embryo, how do our hearts end up inferior to our mouths?
Head folding swings the heart tube, pericardial cavity, and septum transversum around the axis of the OP membrane
What brings the two endocardial heart tubes together to form one heart tube?
What is the embryonic heart outflow tract called and what does it develop into?
Truncus arteriosus, develops into aorta and pulmonary trunk
What is the entrance to the embryonic two-chambered heart called and what are its two parts?
Sinus venosus. It has right and left horns
What are the parts of the bulbus cordis and what does each part form?
Proximal third forms trabeculated part of the right ventricle, midportion (conus cordis) forms outflow tracts of both ventricles, distal third (trucus arteriosus) forms roots and proximal portion of aorta and pulmonary artery
What do the left and right horns respectively of the sinus venosus become in the heart
Left becomes coronary sinus, Right becomes sinus venarum (smooth walled portion of right atrium)
Anastomosis between left and right anterior cardinal veins leads to the creation of what veins?
Left and right brachiocephalic
Besides side of the body, how can the left brachiocephalic be told apart from the right?
Right is more vertical, left is more oblique
For prenatal and postnatal respectively, is the pressure higher in the left atrium or right atrium?
Prenatally it is higher in right atrium (allowing blood to flow through foramen ovale), postnatally pressure is higher in the LA than in RA
What is a probe patent foramen ovale and what is the significance?
A small opening (about the size of a dissecting probe) in the atrial septum. A clot can work its way through here into the LA, then LV, then up ascending aorta to carotids and head and neck.
How does the smooth wall of the LA form?
The primordial pulmonary vein gets incorporated into the wall of the LA, becoming the smooth walled portion (pectinate muscles are pushed to the left auricular)
What two vessels are created by partitioning of the truncus arteriosus, what shape is the septum between them, and what cells migrate to this area to assist in this process?
Aorta and pulmonary trunk. Spiral shaped. Neural crest cells
What four conditions might someone who had unequal partitioning of the truncus arteriosus have?
Stenotic pulmonary trunk, large aorta, right ventricular hypertrophy, patent (persistent) ductus arteriosus
What three parts does the membranous part of the IV septum come from?
Left bulbar ridge, right bulbar ridge, and fused endocardial cushions
In what part of the IV septum are congenital defects more common and why?
The membranous part, because it requires coordinated fusion of three separate embryonic parts
What is the tetralogy of fallot?
1) Pulmonary valve stenosis 2) Ventricular septal defect (VSD), 3) Overriding aorta (aorta overrides ventricular septum, received blood from both LV and RV), 4) Right ventricular hypertrophy (due to pulmonary valve stenosis. Some also have patent ductus arteriosus (PDA)
What are the three shunts of fetal circulation and from and to where do they shunt blood?
1) Foramen ovale (from RA to LA), 2) Ductus arteriosus (from pulmonary trunk to aorta), 3) Ductus venosus (shunt around liver)