Embryology Heart Development Quiz

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Questions and Answers

What is the first functional organ to develop in the embryo?

Heart (correct)

Kidneys

Lungs

Liver

At what day is the heart primordium first evident?

14 days

18 days (correct)

25 days

21 days

Which of the following structures is part of the primitive heart tube?

Right Atrium

Aortic Arch

Pulmonary Vein

Bulbus Cordis (correct)

What happens during lateral folding in the development of the heart?

Cardiogenic fields merge into the midline Signup and view all the answers

What is the fate of the truncus arteriosus in heart development?

Forms the pulmonary trunk and aorta Signup and view all the answers

Which end of the endocardial heart tube is the venous end?

Sinus Venosus Signup and view all the answers

What type of mesoderm is involved in the development of the heart?

Splanchnic mesoderm Signup and view all the answers

During cardiac looping, which structure moves dorsally and to the left?

Primitive Atrium Signup and view all the answers

What structure does the sinus venosus open into?

Primitive atrium Signup and view all the answers

What happens to the left horn of the sinus venosus during development?

It forms the coronary sinus Signup and view all the answers

Which vessel is directly connected to the right horn of the sinus venosus?

Common cardinal vein Signup and view all the answers

Which part forms the valve of the inferior vena cava?

Caudal part of the right valve Signup and view all the answers

What occurs to the body of the sinus venosus during heart development?

It becomes absorbed into the primitive atrium Signup and view all the answers

What structure is associated with the left common cardinal vein?

Vein of Marshall Signup and view all the answers

Which event is part of the development stages of the atria?

Absorption of the pulmonary veins into the left atrium Signup and view all the answers

Which structures contribute to the septum spurium during development?

Right venous valve and left venous valve Signup and view all the answers

What does the right atrium primarily develop from?

Most of the primitive atrium and a part of the sinus venosus Signup and view all the answers

What structure does the left sinus horn become during development?

The coronary sinus Signup and view all the answers

What is the function of the septum primum during the development of the heart?

To grow toward the septum intermedium and eventually create the foramen secundum Signup and view all the answers

What is formed when the upper part of septum primum shows gradual resorption?

The ostium secondum Signup and view all the answers

Which structure is responsible for dividing the primitive atrium into right and left chambers?

Inter-atrial septum Signup and view all the answers

What happens to the bulbus cordis during the development of the ventricles?

It moves slightly ventral to the ventricle Signup and view all the answers

During the formation of the cardiac septa, what results from the fusion of the endocardial cushions?

The septum intermedium Signup and view all the answers

How many pulmonary veins does the left atrium receive blood from upon completion of its growth?

Four Signup and view all the answers

What is one of the four heart malformations included in Tetralogy of Fallot?

Ventricular septal defect Signup and view all the answers

What happens to the aorta in pulmonary stenosis?

It becomes larger than the pulmonary artery Signup and view all the answers

Which structure is formed by the division of the truncus arteriosus?

Pulmonary trunk and aorta Signup and view all the answers

What characterizes Transposition of the Great Arteries (TGA)?

Both ventricles connect to the aorta Signup and view all the answers

Which fetal structure carries oxygenated blood from the placenta to the fetal circulation?

Umbilical vein Signup and view all the answers

Which aortic arch forms the common carotids and the first part of the internal carotids?

Third arch Signup and view all the answers

In fetal circulation, where does the oxygenated blood mix with deoxygenated blood?

In the inferior vena cava Signup and view all the answers

Which arch does not form in humans?

Fifth arch Signup and view all the answers

What primarily contributes to the formation of the left ventricle?

Mainly from the primitive ventricle with some contribution from bulbus cordis Signup and view all the answers

What is the primary interventricular foramen formed by?

The muscular portion grows from the floor of the ventricle Signup and view all the answers

Which structure aids in the partition of the truncus arteriosus?

Spiral Septum (aorticopulmonary septum) Signup and view all the answers

Which type of atrial septal defect results in a common atrium?

Absence of both septum primum and septum secundum Signup and view all the answers

What primarily constitutes the right ventricle?

Mainly from the bulbus cordis with some from the primitive ventricle Signup and view all the answers

What remains open in Roger’s disease?

The membranous part of the interventricular septum Signup and view all the answers

What is the role of the conus arteriosus?

Connects the right ventricle to the pulmonary trunk Signup and view all the answers

What occurs during the first step of ventricular septum formation?

Muscular tissue grows upwards from the ventricle floor Signup and view all the answers

What is the purpose of the ductus venosus in fetal circulation?

To bypass the developing liver Signup and view all the answers

How does blood flow from the right atrium to the left atrium in fetal circulation?

Through the foramen ovale Signup and view all the answers

What physiological change triggers the closure of the ductus arteriosus after birth?

Increase in pO2 levels Signup and view all the answers

What structure does the ductus arteriosus become after closure?

Ligamentum arteriosum Signup and view all the answers

What happens to blood flow to the left atrium after the ductus arteriosus closes?

It increases due to increased venous return Signup and view all the answers

What occurs to the foramen ovale after birth?

It becomes the walled-off fossa ovalis Signup and view all the answers

What structural change occurs to the ductus venosus after the umbilical cord is cut?

It transforms into the ligamentum teres Signup and view all the answers

Why is it important for the fetal heart to bypass pulmonary circulation?

Fetal blood cannot receive oxygen from the lungs Signup and view all the answers

Study Notes

Embryology of the Cardiovascular System

The cardiovascular system (CVS) develops as two regions near the cranial end of the embryo, derived from mesoderm.
The heart primordium is evident at 18 days, forming angioplastic cords which develop into heart tubes.
The heart is the first functional organ to develop.
It develops from splanchnic mesoderm in the wall of the yolk sac.
Angiogenic cells form right and left endocardial heart tubes.
Embryonic folding, involving lateral and cephalocaudal folding, brings the cardiogenic fields to the midline, allowing the primitive heart tube to form.

Primitive Heart Tube

Composed of five distinct segments:
- Sinus venosus
- Truncus arteriosus
- Bulbus cordis
- Common ventricle
- Common atrium
The endocardial heart tube has a venous end (sinus venosus) and an arterial end (truncus arteriosus).

Cardiac Looping

The heart tube grows and elongates, requiring looping to fit within the pericardial sac.
The primitive ventricle moves ventrally.
The primitive atrium moves dorsally and to the left.
This places the inflow portion (veins and atria) behind the outflow portion (ventricles and arteries).
Fetal hearts exhibit this same configuration.

Fate of the Sinus Venosus

The body of the sinus venosus is absorbed into the primitive atrium, forming part of the right atrium.
The septum spurium (a partition) and left venous valves combine with the inter-atrial septum.
The right horn of the sinus venosus contributes to the superior vena cava and valve of the coronary sinus.
The left horn contributes to the coronary sinus.
The common cardinal veins may develop into the oblique vein of the left atrium (vein of Marshall) or the inferior portion of the superior vena cava on the right side.
The umbilical and vitelline veins in the left horn typically lose connection in later development.

Development of the Atria

The atrioventricular canal divides into two halves due to the development of a ventral and dorsal endocardial cushion.
Subsequent division of the primitive common atrium results in right and left atria.
The right horn of the sinus venosus is absorbed by the right atrium.
Pulmonary veins are absorbed into the left atrium.

Development of the Ventricles

The bulbus cordis is on the right initially but shifts ventral to the ventricle.
The separate bulboventricular sulcus disappears, forming a common chamber.
The interventricular septum develops, dividing the common chamber into the right and left ventricles.
The right ventricle develops mainly from the bulbus cordis while the left ventricle develops partly from the bulbus cordis and partly from the primitive ventricle.

Partition of the Truncus Arteriosus

The bulbus cordis and truncus arteriosus initially form a single tube, but an aorticopulmonary septum divides it into the aorta and pulmonary trunk in the 5th week.
This septum develops from endocardial cushions.
The septum divides the truncus arteriosus into right and left portions (for pulmonary trunk and aorta).
Septum divides the truncus arteriosus into distinct regions: lower, middle, and upper.

Major Cardiac Anomalies

Atrial Septal Defects (ASD): Absence of the septum primum and/or septum secundum leading to a common atrium.
Ventricular Septal Defect (VSD): Absence of the membranous part of the interventricular septum.
Tetralogy of Fallot: A combination of four congenital heart defects: VSD, pulmonary stenosis, overriding aorta, and right ventricular hypertrophy.
Transposition of the Great Arteries (TGA): Abnormal rotation of aorticopulmonary septum causing the right ventricle to connect to the aorta and the left ventricle to the pulmonary artery.

Fetal Circulation

Oxygenated blood from the placenta enters the fetus via the umbilical vein.
This blood bypasses the liver via the ductus venosus.
Most blood enters the left atrium via the foramen ovale, bypassing the pulmonary circuit.
Blood flows to the systemic circulation from the left ventricle via the aorta.
Blood in the pulmonary trunk from the right ventricle is shunted into the systemic circulation via the ductus arteriosus.

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Description

Test your knowledge on the development of the heart during embryology. This quiz covers key stages, structures, and processes involved in heart formation from the embryo's earliest stages. Whether you're a student or an enthusiast, challenge yourself with these insightful questions!