CVS Embryology Flashcards
When does the primordial heart begin to function?
Start of 4th week
Vasculogenesis =
blood vessel formation
Angiogensis =
vessels develop by sprouting/branching from pre-exsisting vessels
The 5 stages in blood vessel development in the embryo are:
- differentiation of mesenchymal cells
- angioblasts
- blood islands
- small cavities appear in blood islands
- endothelial lined cavities fuse to form endothelial channels
The nervous system is formed by
ectodermal cells (brain and spinal cord)
Blood vessels first appear where?
Wall of yolk sac
Heart tubes are formed by..
canalisation of angioblastic cords
Describe the arterial end of the tubular heart:
bulbus cordis
truncus arteriosus
aortic arches
Describe the middle of the tubular heart
ventricle (arterial end)
atrium (sinus venosus end)
Describe the venous end of the tubular heart
sinus venosus two horns (L + R)
one horn =
common cardinal vein
umbilibal vein
vitelline vein
The serous pericardium =
Derived from…
parietal and visceral layer
intra-embryonic coelom
Parital layer of serous pericardium and fibrous pericardium are derived from
somatopleuric mesoderm
The splanchnopleuric mesoderm forms the
visceral layer of serous pericardium
What forms the U - shape loop called the bulboventricular loop?
bulbis cordis and ventricle grow faster than other regions, so form a loop
What is dextrocardia?
Heart loop forms to left instead of right
Development of cardiac septa happens
27th and 37th days of embryonic phase
In atrial partioning, what things develop?
2 septum
2 foramen
These septum are the:
septum prinum
septum secundum
These foraminous are th:
foramen prinum
foramen secundum
The fossa ovals is formed by
septum secundum appears on right of septum prinum
grows and overlaps foramen secondum
Functions of oval foramen before birth
blood passage from left to right atria (non functioning lungs)
prevents passage of blood in opposite direction
Functions of oval foramen after birth
increases pulmonary blood flow
shifts pressure to left atrium
remnant of metal fossa ovalis
Non-closure of the fossa ovalis =
ASD - atrial septal defect
hole in the heart
Where can a hole appear in VSD (ventricular septal defect)?
Anywhere in the septum
The teratology of Fallot is made up by what 4 defects?
- Pulmonary Stenosis
- VSD
- Dextroposition of aorta
- Right ventricle hypertrophy
The SA node develops
during 5th week
Adult location of SA node is
high in right atrium
near entrance of SVC
AV node and Bundle of His develop from
cells of AV canal and sinus venosus
Crib death (or SIDS - sudden infant death syndrome) is caused by
abnormalities of conducting tissues
The first arteries to appear are the
right and left primitive aortae
Pharyngeal arches develop during weeks
4 and 5
The 1st arch of the aortia =
maxillary arteries
The hyoid and spatial arteries are from
the 2nd arch of the aorta
The common carotid and first part of internal carotid arteries are from the
3rd aortic arch
The 4th left aortic arch leads to
left common carotid
left subclavian artery
The 4th right aortic arch leads to
the right subclavian artery (proximal portion)
The 6th aortic arch on the left side makes the
left pulmonary artery
ductus arteriosus
The 6th aortic arch on the right side makes the
right pulmonary artery
The 5th aortic arch has the following fate:
terminae in dorsal aorta
not present
do not develop
The recurrent laryngeal nerve is a branch of the ______, which is from the _______
vagus
10th cranial nerve
The coronary arteries are from two sources
- migration of proepicardial (angioblast) cells
2. cells of epicardium
The cardinal veins act as the
main drainage system of embyro
List 4 venous system defects
- double IVC
- No IVC
- Left SVC
- Double SVC
Lymphatic system develops at
end of week 6
Thoracic duct develops from
caudal part of right thoracic duct
What is congenital lymphedema?
dilation of lymphatic vessels
Functions of the ductus venosus:
- bypass blood from umbilical vein to IVC
2. regulated by sphincter
Function of oval foramen
diverts blood from right atrium to left atrium
Function of ductus arteriosus
diverts blood from pulmonary trunk into descending aorta
What does Patent Ductus Arterioles (PDS) cause?
- failure of muscular wall to contract
- RSD (resp distress syndrome) - low O2
- lack of surfactant in lungs
What causes a correction of the aorta?
incorporation of muscle tissue in ductus arterioles into arch of aorta
Anti-clotting mechanisms in the endothelium include:
formation of platelet ring
formation of fibrin clot
Thrombomodulin =
binds thrombin and inactivates it
Heparin =
inactivates thrombin
Starling’s Forces (in exchange) include:
capillary hydrostatic pressure vs ISF hydrostatic pressure
AND
plamsa osmotic pressure vs ISF osmotic pressure
Oedema is the
accumulation of excess fluid
Ectopia cordis =
congenital malformation in which the heart is abnormally located either partially or totally outside of the thorax
