3.1.3. Cardiovascular System Development Flashcards
Define Splanchnic mesoderm
mesoderm that overlies the endoderm and is a layer continuous with the mesoderm covering the yolk sac; gives rise to the mesothelial covering of viscera
Define Crista terminalis
the junction between the sinus venosus and the heart in the embryo; ridge of tissue in the right atrium
Define the Cardiogenic field (area)
a horseshoe shaped area in the splanchnic mesoderm on either side of the neural plate
Define Septum primum
the septum that separates the cavity of the primitive atrium into right and left chambers
Define Angiogenesis
physiological process through which new blood vessels form from pre-existing vessels
Define Septum secundum
semilunar in shape, grows downward from the upper wall of the atrium immediately to the right of the septum primum, with which it will fuse to close the foramen ovale
What are the Blood islands?
embryological structures which lead to the development of many different parts of the circulatory system; often seen on the umbilical vesicle, allantois, connecting stalk, or chorion
Define Ostium primum
an opening between the free edge of the septum primum and the AV cushions
What are the Vitelline veins?
veins which drain blood from the yolk sac
Define Ostium secundum
a foramen in the septum primum; precursor to the interatrial septum of the embryological heart
What are the Cardinal veins?
two short transverse veins which open on either side of the sinus venosus
Define Foramen ovale
hole in the fetal heart that allows blood to enter the left atrium from the right atrium; a cardiac shunt, which allows the blood to bypass pulmonary circulation
What are the Umbilical veins?
veins present in fetal development that carries oxygenated blood from the placenta to the fetus
The bulbus cordis gives rise to what structures?
together with the primitive ventricle will give rise to the developed ventricles
Define Ductus venosus
a fetal shunt that allows a portion of the umbilical blood flow to pass directly to the inferior vena cava, thereby allowing oxygenated blood from the placenta to bypass the liver
What is the Truncus arteriosus?
an embryologic trunk that originates from both ventricles and then differentiates into the aorta and pulmonary trunk
What is the Dorsal mesocardium?
part of the mesocardium of the fetal heart that breaks down to form the transverse sinus of the pericardium
What is the Aortic sac?
a dilated structure lined by endothelial cells located just above the truncus arteriosus, will give rise to the aortic arches
Define Transverse sinus
pericardial sinus from the mesoderm that will connect with the oblique sinus to form the pericardial sac
What is the Bulboventricular sulcus?
the junction between the ventricle and the bulbus cordis in the fetal heart
Define Epicardium
a serous membrane that forms the innermost layer of the pericardium and outermost surface of the heart
What are the Sinus horns?
right and left horns which supply the sinus venosus with venous blood from the vitelline, umbilical, and common cardinal veins
Define Mesocardium
embryonic mesentery supporting the embryonic heart in the pericardial cavity
What is the Oblique vein?
the remnants of the left sinus horn at 10 weeks gestation; supplies the left atrium
Define Endocardium
innermost layer of tissue that lines the chambers of the heart; similar to endothelium
What is the Coronary sinus?
a collection of veins joined together to form a large vessel that collects blood from the heart muscle; delivers deoxygenated blood to the right atrium
What is the Cardiac loop?
the term for the embryonic heart formed by the bending and twisting of the cardiac tube
What are the Endocardial cushions?
cells that play a vital role in proper heart septation; will give rise to the heart’s valves and septa
What is the Sinus venosus?
the large quadrangular cavity which proceeds the atrium on the venous side of the fetal heart; will be incorporated into the wall of the right atrium and give rise to the SA node
What are BMP 2, 4?
secretions from the endoderm and lateral plate mesoderm which induce the transcription factor NKX2.5 to produce heart-forming region
What are WNT inhibitors?
proteins that are secreted by the neural tube and block WNT proteins, which would inhibit normal heart development
What is NKX-2.5?
transcription factor for heart formation
When does the vascular system appear in embryonic development?
The vascular system appears in the middle of the third week, when the embryo is no longer able to satisfy its nutritional requirements by diffusion alone
What are the tree primary vascular systems
- Vitelline (will become blood vessels of digestive tract)
- Cardinal
- Umbilical
Throughout the development of the heart, blood must be able to flow through the heart _ ._
Throughout the development of the heart, blood must be able to flow through the heart continuously.
Four chambered heart functions as one chamber by using two shunts, _ _ and the _ _, because the lungs are not functioning.
Four chambered heart functions as one chamber by using two shunts, inter-atrial and the ductus arteriosus (from pulmonary trunk to aortic arch), because the lungs are not functioning.
In the embryo, pressure on the right side of heart is (higher/lower) than on the left.
In the embryo, pressure on the right side of heart is HIGHER than on the left.
Circulation resistance is high in pulmonary system because the lungs are not functioning; systemic circulation resistance low because it includes the placenta that is low pressure.
After _ _ (what event) the two shunts close, blood pumps into lungs and left side empties into systemic circulation so now the pressure on the right side is LOWER than on the left side.
After BIRTH the two shunts close, blood pumps into lungs and left side empties into systemic circulation so now the pressure on the right side is LOWER than on the left side.