Lecture 5

Question 1

adult heart

Answer 1

workhorse of the body driving deoxygenated blood to lungs and back out to the rest of the body. four chambers are divided into left and right and top and bottom. 4 valves control unidirectional blood flow, 2 AV and 2 semilunar valves. Septum is a muscular wall dividing left from right. 2 outflow tracts deliver blood to systemic circulation (aorta) and lung circulation (pulmonary artery)

Question 2

Primitive heart tube formation

Answer 2

~Day 20, endocardial tubes form. As the embryo develops, folding process occurs, forcing the two tubes to fuse together. When the tube forms, it is mostly comprised of endothelial and myocardial cells. Hence, allowing it to beat.

Question 3

Heart tube looping

Answer 3

folding forms adult heart chambers. 5 different regions are precursors to major heart structures. In endocardial cushions, mostly mesenchymal cells which form internal structures in heart. Mostly gives blood flow direction.

Question 4

PV and AV cushion

Answer 4

inferior and superior cushions grow towards each other to form a bridge called the AV septum, dividing blood flow through two atrioventricular valves

Question 5

heart chamber separation

Answer 5

AV septum serves as a central point of chamber separation. Interventricular septum is formed with growth towards AV septum (separates left and right ventricles). Foreamen ovale is formed incomplete growth of septum primum towards AV septum (separates left from right atrium). AV valves form from AV canals

Question 6

outflow tract separation

Answer 6

separates blood leaving the heart (pulmonary and systemic circulation). Endocardial cushion between TA and BC form the aorticopulmonary septum through spiral septation. Conotruncal septation forms the aorta and pulmonary trunk.

Question 7

Pulmonary circulation

Answer 7

closed loop of vessels carrying blood to heart and lungs

Question 8

systemic circulation

Answer 8

carrying blood heats -> viscera

Question 9

vasculogenesis and angiogenesis

Answer 9

in mesoderm, the heart is formed in heart tube, new blood vessels are formed via angiogenesis

Question 10

fetal circulation anatomy

Answer 10

heart tube and dorsal aortae are formed by vasculogenesis. Angiogenesis from these two strucutres form the remainder of the developing vasculature.

Question 11

arteries

Answer 11

aortic arches, vitelline artery, umbillical artery

Question 12

veins

Answer 12

cardinal veins, vitellins veins, umbillical vein

Question 13

development of aortic arches

Answer 13

through another vasculargenesis process, dorsal aorta is made. When endocardial tubes fuse, so does the dorsal top portion of E.T forming left and right horns of aortic sac. Through angiogenesis, blood vessels sprout from aortic sac and connect to the horms of the dorsal aorta on either sides. Total 6 arches from aortic sac -> e.t

Question 14

Fate of aortic arches

Answer 14

1st: regresses, maxillary artery
2nd: regresses
3rd: common carotids
4th: left aortic arch, right subclavian
5th: regresses
6th: left pulmonary artery, right pulmonary vein.