Embryology

Question 1

where does the heart come from?

Answer 1

at 3 weeks
the primary heart field
visceral mesoderm
cranial to the developing neural tube

Question 2

how does the heart reach its final position?

Answer 2

lateral folding and crania-caudal folding

Question 3

name the 5 heart dilatations

Answer 3

truncus arteriosus 
bulbus cordis 
ventricle 
atrium 
sinus venosus

Question 4

which parts of the heart does the truncus arteriosus form?

Answer 4

aorta and pulmonary trunk

Question 5

describe the bulbus cordis

Answer 5

trabeculated part of right ventricle

outflow part of both ventricles

Question 6

describe the ventricle

Answer 6

trabeculated part of the left ventricle

Question 7

describe the atrium

Answer 7

trabeculated part of both atria

Question 8

describe the sinus venosus

Answer 8

right and left horns
smooth part of right atrium
coronary sinus

Question 9

what is the direction of blood flow in the primitive heart?

Answer 9

from caudal towards cranial

Question 10

what happens on day 23?

Answer 10

the heart begins to loop and fold

Question 11

describe looping and folding of the atrium

Answer 11

dorsal and cranial

Question 12

describe looping and folding of the ventricle

Answer 12

displaced left

Question 13

describe looping and folding of the bulbus cordis

Answer 13

inferiorly, ventrally to the right

Question 14

describe development of the aortic arches

Answer 14

6 pairs

associated with the pharyngeal arches

Question 15

what happens to pharyngeal arches 1 and 2?

Answer 15

mostly obliterated

Question 16

describes what happens to pharyngeal arch 3?

Answer 16

forms the common carotid aortic arch which is the first part of the internal carotid artery

Question 17

describe what happens to pharyngeal arch 4?

Answer 17

forms the right subclavian artery which is part of the aortic arch

Question 18

describe what happens to pharyngeal arch 6?

Answer 18

it sprouts branches that form the pulmonary aortic arch

ductus arteriosus on the left

Question 19

what is different about the pharyngeal arch 5?

Answer 19

rudimentary or absent

Question 20

describe the vitelline veins

Answer 20

drain the yolk sac
portal venous system draining the gut
hepatic sinusoids and veins
hepatic portion of inferior vena cava

Question 21

describe the umbilical veins

Answer 21

drain oxygenated blood from placenta
right degenerates
left remains as definitive umbilical vein

Question 22

describe the cardinal veins

Answer 22

give systemic venous system

Question 23

describe the anterior cranial veins

Answer 23

drain the head and neck
jugular system and left brachiocephalic vein
superior vena cava

Question 24

describe the posterior cardinal veins

Answer 24

drain the trunk
azygos and hemiazygos systems (body wall) 
gonadal and renal veins 
iliac veins 
inferior vena cava