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33 Cards in this Set
- Front
- Back
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What structure forms the pericardial cavity?
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Lateral plate mesoderm, which splits into a somatic and splanchnic layer.
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What is secreted in order to induce the the formation of a single endocardial tube? What secretes it?
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Vascular endothelial growth factor (VEGF), secreted by the hypertrophied foregut endoderm.
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What are the layers of the endocardial tube?
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Endocardium (Innermost)
Cardiac jelly Myocardium Epicardium (Outermost) |
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What are the five dilatations of the primitive heart tube?
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Truncus arteriosus
Bulbus cordis Primitive ventricle Primitive atrium Sinus venosus |
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What does the Truncus arteriosus form?
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Aorta and pulmonary trunk
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Which embryological structures form the ventricles?
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Bulbus cordis: Smooth parts of the right and left ventricle
Primitive ventricle: Trabeculated part of the right and left ventricle |
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What does the Sinus venosus form?
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The smooth part of the right atrium (sinus venarum), coronary sinus, and oblique vein of left atrium.
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What forms the aorticopulmonary septum?
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Neural crest cells migrate from the hindbrain region through pharyngeal arches 3, 4, and 6, and invade both the truncal and bulbar ridges.
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What results if there is only partial development of the AP septum?
What type of shunting is associated with this condition? |
Persistent truncus arteriosus
PTA results in a condition in which one large vessel leaves the heart and receives blood from both the right and left ventricles. PTA is usually accompanied by a membranous ventricular septal defect and is associated clinically with marked cyanosis (R->L shunting). |
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What happens in D-transposition of the great arteries? What must accompany this condition in order for life to be possible?
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D-Transposition of the great arteries (complete) is caused by abnormal neural cell migration such that there is nonspiral development of the AP septum. The aorta arises from the right ventricle, and the pulmonary trunk arises from the left ventricle. The systemic and pulmonary circulations are completely separated from one another.
This condition is incompatible with life unless an accompanying shunt exists (such as VSD, patent foramen ovale, or patent ductus arteriosus). This presents with marked cyanosis (R->L shunting of blood). |
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What causes Tetralogy of Fallot? What is the presentation of Tetralogy of Fallot? What are the four classic malformations?
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Abnormal neural crest cell migration such that there is skewed development of the AP septum.
TF results in a condition in which the pulmonary trunk obtains a small diameter while the aorta obtains a large diameter. Four classic malformations: PROVe Pulmonary stenosis Right ventricular hypertrophy Overriding aorta Ventricular septal defect Pulmonary |
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What is the shunt in Tetralogy of Fallot? How do you improve symptoms?
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Early cyanosis is caused by a right-to-left shunt across the VSD. This shunt exists because of the increased pressure caused by stenotic pulmonic valve.
Patients learn to squat to improve symptoms: compression of femoral arteries increases TPR thereby decreasing the right-to-left shunt and directing more blood from the RV to the lungs. |
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What causes the closure of the foramen ovale?
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Functional closure of the foramen ovale is facilitated both by a decrease in right atrial pressure from occlusion of the placental circulation and by an increase in left atrial pressure due to increased pulmonary venous return.
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What is heard on auscultation in an Atrial septal defect? What type of shunting is present?
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Loud S1 and a wide, fixed, split S2.
Left to right shunting. |
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What is the most common atrial septal defect?
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Foramen secundum defect
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What might result in premature closure of the foramen ovale?
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Closure of the foramen ovale during prenatal life results in hypertrophy of the right side of the heart and underdevelopment of the left side of the heart.
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What are the steps of the Atrioventricular septum formation?
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The dorsal AV cushion and ventral AV cushion approach each other and fuse to form the AV septum. The AV septum partitions the AV canal into the right AV canal and left AV canal.
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What is Ebstein's anomaly?
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Failure of the posterior and septal leaflets of the tricuspid valve to attach normally to the annulus fibrosis; they are instead displaced inferiorly into the right ventricle. As a result, the right ventricle is divided into a large upper "atrialized" portion and a small lower functional portion.
This condition is usually associated with an ASD. |
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What is tricuspid atresia?
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Tricuspid atresia (hypoplastic right heart) is caused when an insufficient amount of AV cushion is available to form the tricuspid valve. The result is complete agenesis of the tricuspid valve, so there is no communication between the right atrium and right ventricle.
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What is tricuspid atresia always accompanied by?
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Patent foramen ovale
IV septum defect Overdeveloped left ventricle Underdeveloped right ventricle |
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How does the interventricular septum develop?
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1. Muscular ventricular septum forms. Opening is called interventricular foramen
2. AP septum meets and fuses with muscular ventricular septum to form membranous interventricular septum, closing interventricular foramen. 3. Growth of endocardial cushions separates atria from ventricles and contributes to both atrial separation and membranous portion of the interventricular septum. |
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What causes membranous VSD?
What is the shunt? |
Membranous VSD is caused by faulty fusion of the right bulbar ridge, left bulbar ridge, and AV cushions. As a result, an opening between the right and left ventricles allows free flow of blood.
A large VSD is initially associated with L->R shunting of blood, increased pulmonary blood flow, and pulmonary hypertension. Patients with L->R shunting complain of excessive fatigue on exertion. |
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What is Eisenmenger syndrome?
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Uncorrected VSD, ASD, or PDA.
Initially, a VSD, ASD, or PDA is associated with L->R shunting of blood, increased pulmonary blood flow, and pulmonary hypertension. Later, the pulmonary hypertension causes marked proliferation of the tunica intima and tunica media of pulmonary muscular arteries and arterioles, resulting in a narrowing of their lumens. Ultimately, pulmonary resistance may become higher than systemic resistance and cause R->L shunting of blood and cyanosis. |
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What happens when the membranous and muscular IV septa fail to form?
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Common ventricle (cor triloculare biatriatum)
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What does the arterial system develop from in the head and neck?
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In the head and neck region, the arterial pattern develops mainly from six pairs of arteries (called aortic arches) that course through the pharyngeal arches.
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What does the arterial system develop from in the rest of the body?
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In the rest of the body, the arterial patterns develop mainly from the right and left dorsal aortae. The right and left dorsal aortae fuse to form the dorsal aorta, which then sprouts posterolateral arteries, lateral arteries, and ventral arteries (vitelline and umbilical).
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What is postductal coarctation? What does it present with clinically?
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Occurs when the aorta is abnormally constricted. A postductal coarctation is found distal to the origin of the left subclavian artery and inferior to the ductus arteriosus.
Clinically associated with increased blood pressure in the upper extremities, lack of pulse in femoral artery, a high risk of both cerebral hemorrhage and bacterial endocarditis, and rib notching (due to collateral circulation). |
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What congenital abnormality is associated with preductal coarctation?
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Turner syndrome (45, XO).
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What does the venous system develop from?
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The venous system develops from the vitelline, umbilical, and cardinal veins that empty into the sinus venosus.
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What supplies the SA and AV nodes?
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SA and AV nodes are supplied by the right coronary artery (RCA) in the majority of cases.
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What supplies the inferior portion of the left ventricle?
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80% of the time, the RCA supplies the inferior portion of the left ventricle via the posterior descending/intraventricular artery (PD), which is right dominant.
20% of the time, the PD arises from the circumflex artery (CFX), which is left dominant. |
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When do the coronary arteries fill?
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During diastole.
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What is the most posterior part of the heart? Why might dysphagia occur?
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Left atrium.
Enlargement can cause dysphage (due to compression of the esophageal nerve) or hoarseness (due to compression of the recurrent laryngeal nerve, a branch of the vagus). |
