Embryology 1 and 2

Question 1

Briefly define “cardiovascular field” and “vasculogenic”.

Answer 1

cardiovascular field is when blood vessels first appear in the yolk sac, allantois, connecting stalk and chorion

Question 2

Describe the formation of heart tube and name its constituent parts.

Question 2

Describe the formation of heart tube and name its constituent parts.

Question 3

Describe the formation of the bulboventricular loop

Answer 3

Primitive heart tube invaginate pericardium and as the growing tube becomes too large for the pericardium it needs to fold/ loop forming bulboventricular loo

bulbus cordis and ventricle enlarge and loop to the right and ventricles pushed left and inferiorly. atria pushed superior and posteriorly

Question 4

Describe the development of the cardiac valves and the special conducting system of
the heart.

Question 5

Ductus venous

Answer 5

ductus venous- shunts blood in left umbilical vein into inferior vena cava allows oxygenated blood from the placenta to bypass the liver

Question 6

when does the cardiovascular system start to form

Answer 6

4th week as the rapidly growing embryo can’t function by diffusion alone

Question 7

what do heart tubes do

Answer 7

fuse and join blood vessels in other areas of cariogenic field to form primitive cardiovascular system

Question 8

and explain “dextrocardia”.

Answer 8

Heart tube loops to the left (not right) and ventricles come to lie facing right (not left)

Question 9

formation of left and right atrioventricular canals

Answer 9

endocardial cushion growth. superior and inferior endocardial cushion push down and fuse to from canals

Question 10

partitioning left and right atria

Answer 10

Formation of septum primum. Ostium secundum forms by apoptosis to form septum primum. Ostium primum meets septum primum and formation of foramen ovale. one way shunt flowing blood between right and left atrium

Question 11

differences between foramen ovale before and after birth

Answer 11

Before it allows blood to pass from right to left atrium and after birth it closes
non-closure results in patent foramen ovale which is a hole in the heart

Question 12

describe partitioning of primitive ventricles

Answer 12

Muscular ventricular septum forms. Opening is called the intraventricular foramen. aorticopulmonary septum divides bulbs cordis and trucus arteriosus into aorta and pulmonary trunk

Question 13

what forms from trunks arteriosus

Answer 13

aortic arches, ascending aorta, pulmonary trunk

Question 14

what forms from bulbus cordis

Answer 14

outflow tracts (smooth) of L+R ventricle

Question 15

what forms from primitive ventricle

Answer 15

rough part of L+R ventricles

Question 16

what forms from primitive atrium

Answer 16

Rough part of L+R atria

Question 17

what forms from sinus venosus

Answer 17

right horn of smooth part of right atrium. left horn forms the coronary sinus

Question 18

describe formation of aortic sac

Answer 18

First arteries to appear in the embryo. Aortic sac is formed by the fusion of the 2 ventral aortae which then becomes an extension of the trances arteriosus
aortic arch branches from the aortic sac.

Question 19

Formation of aortic arches

Answer 19

6 pairs of aortic arches are formed from the aortic sac. Give rise to the great arteries of the neck and head.

Question 20

vasculogenesis

Answer 20

defined as the new formation of a primitive vascular network

Question 21

angiogenesis

Answer 21

defined as the growth of new vessels from the pre existing blood vessels

Question 22

development of lymphatic system

Answer 22

Develops at end of sixth week. thoracic duct develops from two vessels anterior to aorta and become the left and right thoracic ducts

Question 23

foraman ovale

Answer 23

shunts blood to right atrium to left atrium allows blood to bypass the lungs

Question 24

ductus arteriosus

Answer 24

shunts blood from right ventricle and pulmonary arteries to aorta.