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95 Cards in this Set

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What does vasculogenesis form?
the horseshoe-shaped endocardial tubes
Where do primitive blood cells and vessels form?
in the splanchnopleuric mesoderm
What is the cranial portion of vasculogenesis area and the surrounding splanchnopleuric mesoderm called?
cardiogenic area
What blood islands are in the cardiogenic area
R&L dorsal aortae (medial)
endocardial tubes (lateral)
What do the endocardial tubes become?
venous structures including:
posterior cardinal veins
anterior cardial veins
vitelline veins
single heart tube (formed by fusion of the R&L tubes
What does the cardiogenic area develop next to? What cavity will this form?
the intraembryonic coelom (future pericardial cavity)
What does cranial folding form?
aortic arch
What are the regions of the heart tube listed from caudal (blood intake) to cranial (outflow)?
R&L sinus venosus
single atrium
single ventricle
single bulbus cordis
single aortic sac
What does the aortic sac connect to?
1st aortic arches
What new layers does the splanchnopleuric mesoderm differentiate into?
myocardium (heart muscle) and cardiac jelly
mesothelial cells
What do mesothelial cells form?
serous epicardium or visceral pericardium
What are the 4 layers of the heart from inside to outside?
endocardium (primative enothelium)
cardiac jelly
myocardium-responsible for contraction
epicardium (visceral pericardium)
How does the transverse pericardial sinus form?
programmed cell death resulting in rupture of the dorsal mesentery of the heart
Describe what occurs when the heart tube begins to elongate, loop and fold on itself.
bulbus cordis-grows so that it is displaced inferiorly, ventrally and to the right side of the body
sinus venosus and atrium grow so they are superior and posterior
second aortic arch appears
What is dextrocardia?
when the base of the heart is directed to the right side of the body
What is it called when all organs are reversed?
situs inversus
At what day does blood start to circulate?
24
What do endocardial cushions form?
septum intermedium
What must properly form in order to avoid heart defects?
endocardial cushions
What can occur is endocardial cushions don't properly form?
atrial and ventricular septal defects, transposition of the great vessels
What contributes to the cells that form the endocardial cushion?
neural crest cells, this is why if a baby has craniofacial defects they are at an increased risk of having congenital heart defects
What happens to the sinus venosus as venous inflow shifts to the right?
it is incorporated into the wall of the atrium (results in smooth inner wall)
What does the anterior cardinal vein become?
superior vena cava
What does the right inferior vitelline vein become?
inferior vena cava
What does the left horn of the sinus venosus become?
coronary sinus
What does the right horn of the sinus venosus do?
it grows larger and is incorporated into the posterior wall of the primitive atrium (these areas will be smooth-walled)
What grows down from the superoposterior wall of the atrium and begins the process of forming a L&R atrium?
septum primum
What connects the R&L atrium?
ostium primum (it diminishes)
At week 6 what two things fuse, resulting in a right and left atria as well as dismissing the ostium primum?
septum primum and septum intermedium
During week 5 programmed cell death creates several new openings in the septum primum near the superior edge called what?
ostium secundum, this keeps the R&L atria connected
During the 5th week the septum secundum, which grows from the posteriosuperior wall of the primitive atrium, fuses with what?
septum intermedium
The arrangement of the foramen ovale in the septum secundum and ostium secundum in the septum primum allows what?
blood to flow from R atrium to L, but never L to R
During the 4th week a thick muscular interventricular septum starts to grow up from the inferior wall of the ventricle towards what?
septum intermedium
What stops growing during week 7, leaving the R&L ventricles connected?
muscular ventricular septum
What keeps the R&L ventricles connected?
interventricular foramen
What do ridges of the myocardium protruding toward the lumen of the R&L ventricle form?
trabeculae
When do the atrioventricular valves, chordae tendinae and papillary muscles start to differentiate?
weeks 5-8
Truncus swellings grow out as a spiral from the wall of what?
truncus arteiosus
What are the ridges that form from the walls of the truncus arteriosus called?
conotruncal
Conotruncal swelling divide the outflow of the heart into two spiraling channels. What are they?
aorta
pulmonary arteries
What type of cells contribute to both of the spiral ridges within the truncus arteriosus?
neural crest cells
At about the 8th week the proximal end of the growing conotruncal swellings grow inferiorly, contacting the septum intermedium and forming the thin membranous portion of what?(this completes separation of the ventriles)
interventricular septum
Failure to form the membranous portion of the interventricular septum, and thus filling in of the interventricular foramen leads to what?
interventricular defect, the most common congenital heart defect
What do the pulmonary and aortic semilunar valves form from?
Both form from the conotruncal swellings and
pulmonary-anterior swelling
aortic-posterior swelling
Ventricular septal defects cause increased or decreased pressure in the left ventricle?
increased, this forces blood to the right side and results in 1.2-1.7 times more blood passing into the pulmonary trunk than aorta
What is the congenital cardiac malformation in which the outflow of the heart is through a single vessel rather than a pulmonary trunk and aorta?
persistent truncus arteriosus
blood from both ventricles mix and go to both the body and lungs
What causes truncus arteriosus?
failure of the conotruncal ridges to fuse
Describe Transposition of the great vessels.
it is a congenital condition
the R ventricle pumps blood into the aorta and the left ventricle pumps blood into the pulmonary trunk
What causes transposition of the great vessels?
failure of the conotruncal ridges to spiral
What is the most common congenital heart defect to cause cyanosis?
Tetralogy of Fallot
What 4 things does tetralogy of fallot consist of?
ventricular septal defect
pulmonary stenosis
aorta that overrides both ventricles
hypertrophy of the R ventricle b/c it must equal pressure of the L ventricle
What is it called when pulmonary valves are abnormally small and the ductus arteriosus remains open?
pulmonary valvular stenosis
What could a systolic trill in the suprasternal notch and at the left upper sternal border signify?
pulmonary stenosis
What is it called when the aortic valve fuses together, leaving only a small opening for blood?
aortic valvular stenosis
Where is a systolic murmur located in aortic stenosis?
right sternal border
What can cause aortic stenosis in adults?
rheumatic disease
Enlargement of the aortic arch can occur b/c of what?
aortic stenosis, caused by jetting of blood
In coarctation of the aorta where is the constriction located 95% of the time?
just above or below the attachment of the ductus arteriosus
What is blockage above the ductus arteriosus which usually remains open?
Pre-ductal coarctation of the aorta
What is blockage below the ductus arteriosus?
Post-ductal coarctation of the aorta
When the patent ductus arteriosus contracts following birth what forms?
ligamentum arteriosum
What is the hallmark diagnosis of coarctation of the aorta?
hypertension in the upper extermites with hypotension in the lower limbs
Where would a murmur be heard in patients w/ coarctation of the aorta?
posteriorly in the interscapular region
Where do pacemaker cells initially reside?
at the caudal end of the heart at the sinus venosus
As the sinus venosus becaome incorporated into the atrium pacemaker cells reside near the junction of the superior vena cava w/ the atrium and form what?
SA node
What forms after development of the superior endocardial cushion?
AV node
What does aortic arch I form?
part of maxillary artery (in head)
What does aortic arch II form?
parts of very small hyoid and stapedial artery (in neck and head)
What does aortic arch III form?
common and part of internal carotid artery (in neck)
What does aortic arch IV form?
arch of the aorta
What does aortic arch V form?
it is not formed
What does aortic arch VI form?
pulmonary arteries
On the right side of the 6th aortic arch connection is lost with what?
the single dorsal aorta
Does connection remain for the dorsal aorta and 6th aortic arch on the left side?
yes, it is called the ductus arteriosus
What does the ductus arteriosus do?
produces a shunt for blood destined for the lungs to be shunted to the rest of the body during fetal development
What can be given to premature infants in order to speed closure of a patent ductus arteriosus?
Indomethican, a prostaglandin inhibitor
What can be used to keep a patent ductus arteriosus open longer?
Why would this be necessary?
Exogennous GPe1, this may be necessary for transpostion of the great vessels
What do the major branches off of the vagus nerve (CNX) develop?
recurrent laryngeal nerves
Because the 5th and 6th aortic arches partially disappear on the right side, the right recurrent laryngeal nerve runs under what?
right subclavian artery
The left side of the 6th arch remains attached so the left recurrent laryngeal nerve runs under what?
ligamentum arteriosum
What are the three pairs of veins returning blood to the embryonic heart at the sinus venosus in week 5 of development?
vitelline veins (serve yolk sac)
umbilical (allantoic) (serve placenta)
cardinal veins (serve embryo)
As the heart develops what happens to the sinus venosus?
it shifts to the posterior right side of the heart
What do the right and left vitelline veins go through as they approach the heart?
septum transversum
What do hepatic sinusoids develop from?
right and left vitelline veins
What forms the extensive vascular network called the hepatic sinusoids?
liver cords in the septum transversum
What does the GI use to drain blood back to the heart? (primitive)
hepatic sinusoids
What do the right vitelline veins give rise to?
portal veins, which will drain the developing GI tract
What channel in the liver brings blood from the left umbilical vein through the liver to the inferior vena cava?
ductus venosus
Which umbilical vein undergoes apoptosis at about the second month of development?
right
After birth the left umbilical vein will involute and form what?
ligamentum teres hepatis
What does the ductus venosus form?
ligamentum venosum
Discuss fetal circulation.
umbilical vein (oxygenated)bypasses liver-ductus venosus into inferior vena cava-R atrium-foramen ovale-ostium secundum-L atrium-L ventricle-aorta
What happens to blood that is pumped into the right ventricle during fetal circulation?
pulmonary artery or ductus arteriosus
What does the ductus arteriosus do?
Connects pulmonary trunk to the junction of the arch w/ the descending aorta
bypass lungs
What allows blood to flow from the right to left atrium?
foramen ovale and ostium secundum