Lecture 8 Flashcards
What are the 3 major veins that drain into the primodial/tubural heart?
1) Vitelline veins –> Associated w yolksac, low O2, becomes venous system IVC/portal system liver
2) Umbilical veins –> oxygenated blood from mom to Placenta, High O2,
3) Cardinal veins –> Body of fetus, low O2, right and left drain into common cardinal vein then sinus spenosum, right anterior and common cardinal veins becomes SVC
All eventually drain into sinus spenosum
Where does oxygenated blood come from in fetus?
The umbilical vein from the placenta, the lungs are nonfunctional
(eventually left umbilical vein regresses and you are left with only the right)
Describe pathway for fetal circulation
Umbilical vein –> Ductus venosus (BYPASSING liver) –> IVC –> Right atrium –> Oval foraman (BYPASSING lungs) –> Left atrium –> Left ventricle –> Aorta –> Body
Ductus arteriosus connects pulmonary trunk to aorta allowing to bypass pulmonary circulation (If blood gets into Right ventricle/pulmonary trunk this will help get rid of it)
What significant event happens as a baby takes its first breath?
(Neonatal circulation)
-Can now get oxygen into the lung, chord will be cut so blood will have to go through right side and lungs to get oxygenated
Describe events/pathway for neonatal circulation
-First breath causes decrease in pressure in pulmonary circulation = high pressure on left side heart than right = Closure of foramen ovale –> Becomes fossa ovalis
Ductus venosus closes –> Becomes ligamentum venosum (Liver function)
-Ductus arteriosus closes –> Becomes ligamentum arteriosum
Types of Ectopia Cordis
-Heart in an abnormal location
1) Thoracic Ectopia cordis
- Heart Partially/completely exposed on thoracic wall
Cause:
-Failure of fusion of lateral folds = faulty sternum/pericardium
2) Abdominal Ectopia cordis
- Heart protrudes through diaphragm into Abs
- lethal
Congenital Heart Defects (CHD) symptoms and effects
Symptoms:
1) Murmur/abnormal heart sound
2) Failure to thrive
3) Recurrent pulmonary infections
4) Cardiac Failure
5) Pulmonary hypertension
6) Infective endocarditis
Effects:
- Cardiac shunts –> abnormal communication between right and left side or heart
- Can be right to left or left to right
Congenital Heart Defects:
Down’s Syndrome
-Atrioventricular Septal Defect (ASD)
Cause:
-Endocardial cushion defect (Formed by neural crest cells–> Improper migration)
Types:
1) Primum ASD
2) Membranous VSD
-Always affects AV valves
Congenital heart defects:
Right to left shunting
Types of disease caused
-Allows deoxygenated systemic venous blood to bypass the lungs and return to the body
-Results in Cyanosis = blue babies
Types
1) Central –> Core/lips/tongue
2) Peripheral –> Extremities/fingers
Diseases:
1) Truncus arteriosus
2) Transposition of the great vessels
3) Tricuspid atresia
4) Total anomalous pulmonary venous return
Causes of Tetralogy of Fallot
- Right to left shunt
- Neural crest cells migrated improperly as forming aortical pulmonary septum (Anterior superior displacement)
1) Pulmonary Stenosis
- Anterior superior displacement of bulbar (infundibular) septum
2) Right ventricular hypertrophy
- Results from pulmonary stenosis
3) VSD (membranous)
- Misalignment of truncal/bulbar ridges, endocardial cushions
4) Overriding Aorta
- Aorta receives blood pumped from both ventricles
TET SPELLS
- Cyanosis that Results from tetralogy of fallot
- Can relieve by pushing knees of infant back to get more pulmonary pressure = circulation of oxygenated blood
Congenital heart defects:
Right to left shunts
Persistent truncus arteriosus
- Neural cells don’t come in at all = failure in formation of aortico-pulmonary septum
- De george
- Blood from right ventricle getting into aorta = Mild cyanosis
Congenital heart defects:
Right to left shunts
Transpositions of the great vessels
- Failure of migration of neural crest cells = absence of the spiral-twist in the aorticopulmonary septum
- Switching of aorta and pumonary trunk
- Not compatible w life unless combined w ASD, VSD, PDA
- Associated w maternal diabetes
Congenital heart defects:
Right to left shunts
Total anomalous Pulmonary Venous return
- Abnormal drainage of the pulmonary veins into the systemic neous circulation
- Severe cyanosis
- Not compatible w life unless w ASD, VSD, PDA
Congenital heart defects:
Left to right shunts
- Back leak of blood from the systemic to the pulmonary circulation
- ASD and VSD, PDA
-Acyanotic (not cyanosis)
-No flow of deoxygenated blood through the
systemic circulation
-Untreated can lead to hypertrophy
