Cardiovascular System Development Flashcards
Location of myoblasts and blood island cells in the trilaminar disc?
They are clustered around the cranial end of the neural plate
- What do blood island cells form?
2. What do myoblasts form?
- Endocardial tubes
2. Myocardial cells of the endocardial tubes
- Heart and heart linings arise from?
2. Heart structures arise from? Is this caudal or cranial?
- Splanchnic layer of the lateral plate mesoderm
2. Cardiogenic field; cranial
What is the cardiogenic field?
What are endocardial tubes?
What lies in between the cardiogenic field?
Site of endocardial tube formation
Paired regions in the embryo that consist of the precursor cells for development of the embryonic heart
Intraembryonic (pericardial) cavity
Where do blood island cells form?
Amniotic cavity expands and neurulation begins: endoderm becomes pinched inward and then blood island cells form what?
When endoderm is pinched off entirely (becomes circular), it becomes?
Between endoderm and splanchnic mesoderm
Blood island cells form left/right endocardial tubes and left/right dorsal aorta
Foregut tube
Blood island cells become?
Foregut gives rise to?
Endothelium
GI tract and part of respiratory tract
Endocardial tubes have fused to become?
Location?
What process allows the heart tube form?
Heart tube
Inside the pericardial cavity, suspended by the dorsal mesocardium (from splanchnic mesoderm) (ventral to neural tube and foregut)
Foregut closes, making the endocardial tubes closer to each other so they can fuse to form the heart tube
Name layers so far from ventral to dorsal
Heart tube, dorsal mesocardium, foregut, neural tube, neural crest
- Heart tube gives rise to ?
- This connects to __, which branches into?
- Where if the heart tube in relation to the neural tube?
- 1st aortic arch
- Aortic arch connects to dorsal aorta bilaterally, dorsal aorta branches into umbilical arteries
- Heart tube is ventral to neural tube
Heart tube detaches from mesoderm that suspends it to form?
~think: in adults, why is trachea and esophagus posterior to the heart?
Transverse pericardial sinus
Because the heart tube is ventral to the foregut tube, and foregut tube is what develops the GI and respiratory tracts
The mesoderm that composes the heart tube is differentiated into what 3 layers
What is the function of cardiac jelly and what layer is it secreted from?
Endocardium (endothelium), myocardium, and epicardium
Involved in septation of the heart and is secreted by myocardium
Heart pumps blood through outflow tract (aortic sac) to what 3 places?
Systemic circulation, via umbilical vessels to/from placenta, and via vitelline vessels to future gut
Neck region (aka ____) is supplied by?
Pharyngeal arches; aortic arches
Oxygenated blood flows from umbilical vein into right atrium via the
Ductus venosus (IVC) (blood from right atrium is then shunted to left atrium)
Some blood goes to the right ventricle still and then pulmonary circulation but without __
Oxygenation
What causes the atrial shunt to close at birth?
Lungs inflate once breathing begins, which increases pressure in left atrium leading to shunt closure
Brief 4 steps of heart tube compartmentalization
- Kink forms in heart tube (future ventricles and outflow tract)
- Primitive ventricles segment to form primitive atria (now 4 chambers)
- More segmentation into left and right ventricles
- Further ventricle differentiation by primary muscular fold; left and right atria begin segmenting (straddle the outflow tract)
What coincides with left/right atrial differentiation?
Right sided venous drainage (veins start disappearing)
Septation of atria and ventricles begins with
This leaves some space called?
What else starts growing at this time
Septum primum
Ostium primum - between the atria
Endocardial protrusions (cushions) into AV canal
What is ostium secondum?
What begins to grow from the dorsal wall of the atria
What do the endocardial cushions do
Perforations that form in septum primum when ostium primum closes
Septum secundum (sickle shaped)
Partition AV canal into 2 canals
Foramen ovale is located where?
Foramen secundum is located where?
Septum secundum
Septum primum
Cushion cells also form
Chordae tendinae
Valves are formed from?
Outflow tracts
- What happens in atrial septal defect
- When is it benign
- When is it problematic
- Malformation that allows significant left to right shunting after birth
- Patent ostium primum; benign since the holes do not line up so it won’t go all the way through
- If the holes don’t completely cover each other and blood can get through; eventual cardiac failure with enlarged right ventricle and pulmonary trunk
What is atrioventricular septal defect and what can it cause
Incomplete partitioning by endocardial cushions; allows R->L shunting and can lead to heart failure
What is ventricular septal defect
Failure to fully partition L and R ventricles allowing for L to R shunting
Tricuspid or mitral valve atresia?
Allows regurgitation into atria
Regurge in R atria can lead to R to L shunting
Can also impair flow through ventricular valves (impairing pulmonary/systemic circulation)
Double outlet left ventricle malformation
Failure to partition outflow tract with both the aortic and pulmonary outflows connected only to L ventricle and no outflow from the right ventricle
Combo of double outlet and ventricular septal defect leads to
Persistent truncus arteriosis
Life threatening in infancy
What is transposition of vessels?
When aorta comes from R ventricle and pulmonary trunk comes from L ventricle
Life threatening in infancy
Cardiomyopathy can occur when
Cardiac muscle proteins are defective/insufficient (myosin, troponin, etc.)
Gap junction connexin mutations (disrupting electrical conductance)
What is coarctation
Can lead to? Which is?
Abnormal atrophy and narrowing of the aorta
Patent ductus arteriosis: related to elevated pressure in pulmonary trunk/circulation and reduced pressure in systemic circulation
Main problem with double aortic arch?
Can potentially constrict esophagus and trachea
