development of the heart

what is the crista terminalis

ridge to separate the pectinate muscle and smooth muscle of the heart

which germ layer does the heart develop from

cardiogenic mesoderm which is the lateral plate

what are primitive blood vessels called

haemangioblasts and myoblasts

what causes the fusion of the endocardial tubes

lateral folding of the heart tube

what are the 5 sections of the primitive heart tube from inferior to superior

sinus venosus, primitive atria, primitive ventricle, bulbus cordis and truncus arteriosus

what does the sinus venosus develop into

smooth R atrium and coronary sinus

what does the primitive atria develop into

L and R atria

what does the primitive ventricle develop into

L ventricle

what does the bulbus cordis develop into

ventricular outflow tracts and R ventricle

what does the truncus arteriosus develop into

prox. aorta and pulmonary artery

what limits the develop of the primitive heart tube

pericardium

when does the folding of the primitive heart tube take place

between days 23 and 28

where does the primitive ventricle fold

to the left

where does the primitive atria fold

posteriorly and superiorly

what connects the atria and ventricles

atrioventricular canal

what is the normal projection of the heart in an xray

projects to the left

what is dextrocardia

when the heart projects to the right

what is sinus invertus

when the abdominal organs and heart all project to the right

when do endocardial cushions form

at the end of the 4th week

what are endocardial cushions

divide the R and L canals

what is the septum primum

1st septation growing from the top of the atria to the endocardial cushion

what is the ostium primum

gap from the septation between the cushion and septum

what happens when the septum secundum begins to form

the ostium primum is obliterated and the ostium secundum shows

what is the septum secundum

second septum which grows superior to inferior

what shape does the septum secundum grow into

crescent

what is the gap formed by the septum secundum

foramen ovale

what is the foramen ovale in a fetus

a valve

what does the foramen ovale do

shunts the blood from the right to left side of the heart

why does the foramen ovale shut

after birth the changes in blood pressure where it is higher in the left atrium than the right

what is probe patent foramen ovale

small defect where a probe can be passed from one atrium to another

what causes atrial septal defects

septum primum / secundum defect where no valve is created in the fetus but a hole

what does ASD cause

right ventricular hypertrophy due to the mixed blood shunting from right to left

what is the ventricular septation

made of membranous and muscular components

how does the membranous component grow

from the endocardial cushions inferiorly down

how does the muscular component grow

from the floor of the primordial ventricle superiorly to the membranous component

when does ventricular septation occur

end of the 4th week

what usually causes ventricular septal defects

90% usually the membranous component

how do VSDs usually fix

small ones spontaneously

how does outflow tract septation usually occur

via spiral septation

when does outflow tract septation occur

5th week

what is the process of spiral septation

truncus arteriosus undergo truncoconal swelling towards each other in a spiral shape

where does oxygenated blood come from in fetal circulation

placenta then through the umbilicus and via umbilical vein towards the liver

what is the ductus venosus

shunts blood from the umbilical vein into the IVC and bypasses the liver

what does the ductus arteriosus do

shunts the blood from the pulmonary trunk to the asc. aorta to bypass the lungs

what does the ductus venosus form

ligamentum teres

what does foramen ovale form

fossa ovalis

what does ductus arteriosus form

ligamentum arteriosum which stops blood connecting from pulmonary trunk to the aorta

what is acyanotic congenital heart disease

left to right shunt or left side of heart abnormality

where does the ductus arteriosus connect to

desc. aorta to main pulmonary trunk

what is the normal post natal closure of ductus arteriosus

the formation of the ligamentum arteriosum

what is patent ductus arteriosus

when the ductus arteriosus doesnt fibrose and shut

what is treatment of PDA

usually a prostaglandin like ibuprofen or surgery using a clip in infants \>3mth

how does PDA treatment work

the ductus arteriosus contracts independantly to fibrose

what is coarctation of aorta

narrowed aorta which causes constriction

what is preductal coarctation

before the ductus arteriosus

what is post ductal coarctation

after the ductus arteriosus

what does coarctation cause for blood pressure

high BP in upper limb and low BP in lower limb

what are cyanotic heart lesions

when deoxygenated blood enters the systemic circulation as the blood bypasses the lungs

what is tetralogy of fallot comprised of

ventricular septal defect, overriding aorta, pulmonary stenosis and R ventricular hypertrophy

what is an overriding aorta

aorta which covers the ventricular septal defect

what is persistant truncus arteriosus

single vessel leaving the right side of the heart so no separation between pulmonary trunk and aorta

what can persistent truncus arteriosus cause

progressive heart failure

what is transposition of the great vessels

when the aorta connects to the R ventricle and the pulmonary artery connects to the L ventricle

what is blue baby

cyanosis when deoxygenated blood is delivered round the body