The Development of the Heart and Anomalies of the Heart

Question 1

location of heart

Answer 1

in the midline, slightly to the left side of the body

Question 2

what is the first organ to start functioning in the fetus

Answer 2

the heart

Question 3

what sides of the heart deals with what

Answer 3

right half = venous blood
left half = arterial blood

Question 4

pulmonary circulation

Answer 4

push deoxygenated blood to the lungs for oxygentation

Question 5

systemic circulation

Answer 5

left half to push oxygenated blood to various tissues

Question 6

4 chambers of the heart

Answer 6

right and left atria: receiving chambers
right and left ventricles: distributing chambers

Question 7

4 valves of the heart

Answer 7

two atrio ventricular valves: tricuspid and mitral
two semilunar valves: pulmonary and aortic

Question 8

blood circulation

Answer 8

-right atrium receives venous blood from superior and inferior venacavae
-through tricuspid valve blood goes to right ventricle from the right right atrium
-right ventricle pumps blood into the pulmonary trunk which takes the blood to the lungs for oxygenation
-from the lungs oxygenated blood reaches the left atrium through the pulmonary veins
-through the mitral valve blood from the left atrium goes to the left ventricle
-the left ventricle pumps blood into the aorta which takes to all parts of the body

Question 9

embryonic heart

Answer 9

heartbeat can be detected at 4th week
heart not fully formed

Question 10

primordial cardiovascular system consists of

Answer 10

paired endocardial heart tubes

Question 11

development of the heart

Answer 11

-mainly from the mesoderm and some neural crest cells
-initially cranial to the oropharyngeal membrane
-cranial folding of the embryo brings it to its postnatal location
-lateral folding causes fusion of the right and left endocardial heart tubes to form a single heart tube

Question 12

heart tube with its chambers

Answer 12

-truncus arteriosis: forms ascending aorta and pulmonary trunk
-conus cordis: absorbed into ventricle to form right and left ventricles
-primitive ventricle
-primitive atria: partioned into right and left atria
-sinus venosus with right and left sinus horns: absorbed into right atrium

Question 13

differential growth and looping of the heart tube

Answer 13

some parts grow at a faster rate and some grow at a slower rate to allow the atrium to rotate upwards

Question 14

partitioning of AV canal

Answer 14

-connection between primitive atrium and primitive ventricle
-partioned into right and left sides
-formation of Dorsal and Ventral endocardial cushions which fuse with each other
-fused endocardial cushions divide the AV canal into right and left

Question 15

interatrial septum

Answer 15

-formation of septum primum: downward growth from roof of primitive atrium
-foramen primum continues right and left parts of primitive atrium
-after fusion of septum primum to endocardial cushions, roof connection is lost giving rise to foramen secundum
-formation of septum secundum: downward growth from primitive atrium
-formation of foramen ovale: gap between floppy septum primum and rigid septum secundum

Question 16

why do we need the right and left atrium interconnected in the fetus?

Answer 16

lungs are not active yet

Question 17

foramen ovale

Answer 17

-remains open and connects right atrium with left atrium until birth
-closes after birth
-patent foramen ovale

Question 18

development of the interventricular system

Answer 18

muscular part: develops as an upward growth from the floor of the primitive ventricular chamber
membranous part: from fusion of the truncal ridges

Question 19

spiral septum

Answer 19

septation of the outflow tract
-two cono-truncal ridges arise form walls of Truncus arteriosus and fuse to form spiral septum
-cardiac neural crest cells
-triple relationship between aorta and pulmonary trunk retained

Question 20

cardiac malfunctions

Answer 20

-ventricular septal defects
-atrial septal defects: shunting of blood from RA to LA
-persistence of embryonic structures: persistent foramen ovale, persistent ductus arteriosus
-inadequate oxygenation: cyanosis

Question 21

persistent truncus arteriosis

Answer 21

-defective division of the outflow tract
-associated with ventricular septal defect
-left to right shunting

Question 22

fallot’s teratology

Answer 22

-unequal division of the outflow tract, favouring the aorta
1. pulmonary trunk stenosis
2. VSD - ventricular septal defect
3. rightward displacement of aorta
4. right ventricular hypertrophy

Question 23

transposition of great vessels

Answer 23

-LV pumps blood into the pulmonary trunk and right ventricle into the (aorta) systemic circulation
-can be fatal

Question 24

dextrocardia

Answer 24

heart juts to the right side because of differential growth flipping