Flashcards in Cardio - Embryology Deck (48):
To what structure(s) does the truncus arteriosus (TA) give rise?
Ascending aorta and pulmonary trunk
To what structure(s) does the bulbus cordis give rise?
Smooth parts (outflow tract) of left and right ventricles
To what structure(s) does the primitive ventricle give rise?
Trabeculated left and right ventricles
To what structure(s) does the primitive atrium give rise?
Trabeculated left and right atria
To what structure(s) does the left horn of sinus venosus (SV) give rise?
To what structure(s) does the right horn of sinus venosus (SV) give rise?
Smooth part of the right atrium
To what structure(s) do the right common cardinal vein and right anterior cardinal vein give rise?
Superior vena cava (SVC)
What embryonic structure(s) give(s) rise to the ascending aorta and pulmonary trunk?
Truncus arteriosus (TA)
What embryonic structure(s) give(s) rise to the smooth parts (outflow tract) of left and right ventricles?
What embryonic structure(s) give(s) rise to the trabeculated left and right ventricles?
What embryonic structure(s) give(s) rise to the trabeculated left and right atria?
What embryonic structure(s) give(s) rise to the coronary sinus?
Left horn of sinus venosus (SV)
What embryonic structure(s) give(s) rise to the smooth part of the right atrium?
Right horn of sinus venosus (SV)
What embryonic structure(s) give(s) rise to the superior vena cava?
Common cardinal vein and right anterior cardinal vein
Give the development stages of truncus arteriosus.
Truncus arteriosus rotates; Neural crest and endocardial cell migration --> truncal and bulbar ridges that spiral and fuse to form the aorticopulmonary (AP) septum --> Ascending aorta & pulmonary trunk
What are 3 conotruncal abnormalities associated with outflow tract formation (i.e., truncus arteriosus)?
(1) Transposition of great vessels (failure to spiral) (2) Tetralogy of Fallot (skewed AP septum development) (3) Persistent TA (partial AP septum development)
Describe the steps involved in interventricular septum development.
(1) MUSCULAR VENTRICULAR SEPTUM forms. Opening is called INTERVENTRICULAR FORAMEN.
(2) AP SEPTUM rotates and fuses with muscular ventricular septum, closing interventricular foramen.
(3) Growth of ENDOCARDIAL CUSHIONS separates atria from ventricles & contributes to both atrial separation and membranous portion of the INTERVENTRICULAR SEPTUM
Describe the steps involved in interarterial septum development.
(1) SEPTUM PRIMUM grows toward endocardial cushions, narrowing FORAMEN PRIMUM
(2) FORAMEN SECUNDUM forms in septum primum (foramen primum disappears)
(3) SEPTUM SECUNDUM develops as foramen secundum maintains right-to-left shunt (4) Septum secundum expands and covers most of the foramen secundum. The residual foramen is the FORAMEN OVALE (5) Remaining portion of septum primum forms VALVE OF FORAMEN OVALE (6) (Not shown) Septum secundum and septum primum fuse to form ATRIAL SEPTUM (7) (Not shown) Foramen ovale usually closes soon after birth because of high LA pressure
With what pathology is interatrial septum development associated?
Patent foramen ovale (caused by failure of septum primum & septum secundum to fuse after birth)
Where does fetal erythropoiesis occur and at what time intervals? What is a good mnemonic to remember this?
Yolk Sac (3-8 wk), Liver (6wk-birth), Spleen (10-28 wk), Bone marrow (18 wk - adult); Young Liver Synthesizes Blood
What globin chains comprise fetal hemoglobin? What about adult hemoglobin?
alpha2, gamma 2; alpha2, beta2
For blood in the umbilical vein, what is the PO2 and % O2 saturation? What kind of O2 saturation do umbilical arteries have?
PO2 = 30 mmHg & 80% saturated w/ O2; Low O2 saturation
What are the important shunts in fetal circulation?
(1) Blood entering fetus through umbilical vein is conducted via DUCTUS VENOSUS into IVC to bypass hepatic circulation
(2) Most oxygenated blood reaching the heart via IVC is diverted through the FORAMEN OVALE and pumped out of the aorta to the head and body
(3) Deoxygenated blood entering the RA from the SVC enters the RV, is expelled into the pulmonary artery, & then passes through the patent DUCTUS ARTERIOSUS into the descending aorta (and to the umbilical arteries); due to high fetal pulmonary artery resistance (due partly to low O2 tension)
What are the 2 major consequences of infant taking a breath at birth? Explain the factors/steps behind each of these consequences.
(1) Decreased resistance in pulmonary vasculature --> Decreased left atrial pressure vs. right atrial pressure = FORAMEN OVALE CLOSES (now called fossa ovalis) (2) Increase in O2 (from respiration) and Decrease in prostaglandins (from placental separation) => DUCTUS ARTERIOSUS CLOSES
What helps close a PDA (patent ductus arteriosus)? What keeps a PDA open?
Indomethacin --> DA remnant (i.e., ligamentum arteriosum); Prostaglandins E1 and E2
What is the structure derived from the umbilical vein? Within what other structure is this structure found?
Ligamentum teres hepatis (contained in the falciform ligament)
What is (are) the structure(s) derived from the umbilical arteries?
Medial umbilical ligaments
What is the structure derived from the ductus arteriosus?
What is the structure derived from the ductus venosus?
What is the structure derived from the foramen ovale?
What is the structure derived from the allantois?
Urachus-median umbilical ligament; (Note: The urachus is part of the allantoic duct between the bladder & the umbilis; Urachal cyst or sinus is a remnant)
What is the structure derived from the notochord?
Nucleus pulposus of intervertebral disc
Name the fetal structures from which the following postnatal structures are derived: (1) Ligamentum teres hepatis (2) Medial umbilical ligaments (3) Ligamentum arteriosum (4) Ligamentum venosum (5) Fossa ovalis (6) Urachus-median umbilical ligament (7) Nucleus pulposus of intervertebral disc
(1) Umbilican vein (2) Umbilical arteries (3) Ductus arteriosus (4) Ductus venosus (5) Foramen ovale (6) Allantois (7) Notochord
What is the first functional organ in vertebrate embryos?
Heart = First functional organ in vertebrate embryos
When does the heart begin beating spontaneously?
Beats spontaneously by week 4 of development
Briefly describe the process/purpose of cardiac looping. When in gestation does it occur?
Primary heart tube loops to establish left-right polarity; begins in week 4 of gestation
What is the defect in Kartagener syndrome, and how does it relate to cardiac looping?
Defect in left-right dynein (involved in L/R asymmetry) can lead to dextrocardia, as seen in Kartagener syndrome (primarily cilia dyskinesia)
What is the clinical approach to most patent foramen ovale?
Most are left untreated
What complication can result from patent foramen ovale? To what other congenital cardiology condition is this similar?
Can lead to paradoxical emboli (venous thromboemboli that enter systemic arterial circulation), similar to those resulting from an ASD
In what structure does ventricular septal defect (VSD) most commonly occur?
Ventricular septal defect (VSD) - most commonly occurs in the membranous septum
How do VSD patients appear at birth, and why?
Acyanotic at birth due to left-to-right shunt
From what structure(s) are the aortic/pulmonary valves derived?
Aortic/Pulmonary: derived from endocardial cushions of outflow tract
From what structure(s) are the mitral/tricuspid derived?
Mitral/Tricuspid: derived from fused endocardial cushions of the AV canal
What are 4 options for valvular anomalies?
Valvular anomalies may be stenotic, regurgitant, atretic (e.g., tricuspid atresia), or displaced (e.g., Ebstein anomaly).
Give an example an atretic valvular anomaly and a displaced valvular anomaly.
atretic (e.g., tricuspid atresia) or displaced (e.g., Ebstein anomaly)
Compared to adult Hb, what kind of affinity does HbF have for oxygen, and why? What does this HbF affinity allow?
HbF has higher affinity for oxygen due to less avid binding of 2,3-BPG. This allows HbF to extract oxygen from (HbA) maternal hemoglobin across the placenta.
Describe the shunt in fetal circulation that includes the patent ductus arteriosus. What causes this shunt?
Deoxygenated blood entering the RA from the SVC enters the RV, is expelled into the pulmonary artery, & then passes through the patent DUCTUS ARTERIOSUS into the descending aorta (and to the umbilical arteries); due to high fetal pulmonary artery resistance (due partly to low O2 tension)