Embryology and Histology Flashcards
Which germ layer forms the heart?
Mesoderm
Name the 5 parts of the heart tube, from cranial to caudal end (the baby verily acquires stuff…)
Truncus arteriosus Bulbus cordis Ventricle Atrium Sinus venosus
What does the truncus arteriosus of the heart tube produce?
Aorta
Pulmonary trunk
What does the bulbus cordis of the heart tube produce?
Right ventricle
Outflow of both ventricles
What does the ventricle of the heart tube produce?
Left ventricle
What does the atrium of the heart tube produce?
Right and left atria
What does the sinus venosus of the heart tube produce?
Right atrium
Coronary sinus
Which 3 vessels enter the right + left horns of the sinus venosus?
Vitelline vein
Umbilical vein
Cardinal veins
What does the vitelline vein drain?
Yolk sac
What does the umbilical vein drain? Which of the veins is definitive?
Placenta
Left
What do the cardinal veins act as precursors for?
The systemic venous system
Remnants of the left horn of the sinus venosus give rise to the coronary sinus. True/False?
True
What is the function of the ductus venosus?
Directs O2-rich blood from placenta (umbilical vein) to IVC, bypassing the liver
What is the function of the foramen ovale?
Directs O2-rich blood from RA to LA so it goes to brain and not lungs
What is the function of the ductus arteriosus?
Directs deoxygenated blood from pulmonary artery to descending aorta so it goes to placenta to get O2
What is the remnant of the umbilical vein in adults?
Ligamentum teres
What is the remnant of the ductus arteriosus in adults?
Ligamentum arteriosum
What are the three layers of blood vessels from inner to outer?
Tunica intima
Tunica media
Tunica adventitia
Arterioles are mainly comprised of…
Tunica media (almost no adventitia)
Name the three types of capillaries in order from least to most holey?
Continuous
Fenasterated
Sinusoidal
Veins have a thick tunica media. True/ False?
False. It is thin.
Valves are inward extensions of…
Tunica intima
Give the three layers of the heart from inner to outer
Endocardium Myocardium Epicardium ---- visceral serous pericardium ---- parietal serous pericardium ---- fibrous pericardium
Layers of heart muscle are connected by… and electrical activity is conducted via …
Desmosomes
Gap junctions
In the foetal heart, what connects the umbilical vein (coming from placenta) to the IVC?
Ductus venosus
What is the importance of the ductus venosus?
Allows most of the blood from placenta to bypass the liver and go straight to heart
In the foetal heart, what connects the right atrium to the left atrium?
Foramen ovale
What is the importance of the foramen ovale?
Enables oxygenated blood entering RA (from IVC from umbilical vein from placenta) to enter LA, bypassing pulmonary circulation, i.e. oxygenated blood is not sent to the lungs
Once oxygenated blood has moved through the foramen ovale, where does it go?
Enters LV and pumped into the aorta to the body, importantly the brain
In the foetal heart, what connects the pulmonary artery to the descending aorta?
Ductus arteriosus
What is the importance of the ductus arteriosus?
Enables deoxygenated blood pumped through pulmonary artery to enter descending aorta to go to placenta to get oxygenated
Do the lungs take part in gas exchange in the foetus?
No, hence why the pulmonary circulation is cleverly bypassed in the foetal heart
What results in closure of the foramen ovale?
Baby’s first breath after delivery (usually)
What is the remnant of the umbilical vein in adults?
Ligamentum teres
What is the remnant of the ductus venosus in adults?
Ligamentum venosus
When a duct fails to close, what substance is given to maintain duct patency?
IV PGE2 until surgery
What are some signs of congenital heart disease?
Cyanosis Murmurs Abnormal pulses Reduced feeding Failure to thrive SOB Sweaty Hepatomegaly Crepitations
