heart development

Question 1

when does the cardiovascular system begin to develop

Answer 1

week 3

Question 2

progenitor heart cells migrate…

Answer 2

through the primitive streak into splanchnic lateral plate mesoderm

Question 3

after folding the heart has an inner… and outer…

Answer 3

inner endothelial layer

outer myocardial layer

Question 4

sinous venous

Answer 4

left/ right sinus horns that initially receive 3 paired veins

Question 5

primitive atrium

Answer 5

forms trabeculated part of right atrium and all of the left atrium

Question 6

primitive ventricle

Answer 6

forms trabeculated left ventricle

Question 7

bulbus cordis

Answer 7

• proximal: right ventricle

- distal: smooth part of the right and left ventricles

Question 8

truncus arteriosus

Answer 8

proximal ascending aorta, pulmonary trunk

Question 9

order in which the blood flows

Answer 9

right and left horns of the sinus venosus- atrium-ventricle- bolbus cords-trancus arteriosus

Question 10

cardiac looping occurs to the…

Answer 10

RIGHT

Question 11

proximal bulbous cordis is displaced…

Answer 11

caudally, ventrally, and to the right

Question 12

primitive ventricle is displaced to the

Answer 12

right

Question 13

primitive atrium is displaced

Answer 13

dorsally and cranially

Question 14

looping of the cephalic portions

Answer 14

• ventral
• caudal
• right

Question 15

looping of the caudal portion

Answer 15

• dorsal
• cranial
• left

Question 16

differential growth

Answer 16

one region is proliferating more rapidly than the other region- causes the hear to bend on itself
bulbus cordis and primitive ventricle

Question 17

septa will form in the …

Answer 17

• atrioventricular canal
• primitive atrium
• outflow tract
• primitive ventricle

Question 18

septum formation in the atrioventricular canal steps

Answer 18

• endocardial cushions form on the dorsal (inferior ) and ventral (superior) walls of the atrioventricular canal
• 2 cushions meet and fuse

Question 19

septum formation in the atrioventricular canal result

Answer 19

• complete division of the single atrioventricular canal into a right and left atrioventricular canal
• endocardial cushions also function as primitive valves

Question 20

septation of the atria

Answer 20

• the primary septum is the valve of the foramen ovale

- secondary septum forms foramen ovale

Question 21

atrial septal defects (ASDs)

Answer 21

-abnormal fixed opening in atrial septum caused by incomplete formation

Question 22

consequences of ASDs

Answer 22

• arrhythmia
• paradoxial embolism
• pulmonary hypertension
• right ventricular failure

Question 23

ASD- ostium secundum defect

Answer 23

• size of septum premium is insufficient to cover the entire oval fossa, or septum scandium fails to fully form
• near the center or middle of the atrial septum

Question 24

ASD- ostium primum

Answer 24

• involve region adjacent to the endocardial cushions
• ostium primum defects is less common but more severe
• surgical correlation is required to manage these defects

Question 25

normal closure of foramen ovale

Answer 25

after birth: fall in pressure in right atrium will result in valve of foramen ovale pressing against the secondary septum

Question 26

conotruncal ridges

Answer 26

ridges largely derived from neural crest mesenchyme that separate the aortic and pulmonary channels develop in a spiral configuration

Question 27

fusion of the conotruncal ridges

Answer 27

they fuse with one another in a cranial to caudal direction, forming the conotruncal septum which separates the aortic and pulmonary outflow tracts

Question 28

formation of the ventricular spetum

Answer 28

the caudal end of the conotruncal septum reaches the muscular portion of the ventricular septum and the atrioventricular septum -they fuse to complete the ventricular septum

Question 29

interventricular septum forms from a

Answer 29

- muscular portion - membraneous portion - right conus swelling - left conus swelling - endocardial cushion - neural crest cells

Question 30

muscular interventricular septum

Answer 30

- apical aspect of the right and left ventricles expand - expanding right and left walls grow closer to one another and form a protrusion into the lumen - continues to grow between the right and left ventricular chambers toward the endocardial cushions - the extension stops prior to reaching the fused endocardial cushions leaving the inter ventricular foramen

Question 31

membranous interventricular septum

Answer 31

- formation of the membranous part of the inter ventricular septum results in complete separation of the ventricles - muscular septum fuses with conotrucal septum and endocardial cushion

Question 32

ventricular defects

Answer 32

-90% are related to partial or incomplete formation of the membranous portion of the septum

Question 33

4 changes define the tetralogy fallot

Answer 33

- pulmonary stenosis - ventricular septal defects - overriding aorta - right ventricular hypertrophy