Development Of Heart Part2 | Heart embryology | Cardiovascular system | First Aid Lectures | Lec2
Channel: Dr. Jamil Lectures
Date: 2023-05-02

Our official Website from where you can get lecture notes free:
https://whmenotes.blogspot.com
You can find the notes and illustrations for this lecture on our website at:
https://whmenotes.blogspot.com/2023/07/heart-embryology-cardiovascular-system.html


I this lecture we will discuss about Septation of the Heart chambers,patent foramen ovale,Ventricular Septal Defect (VSD),Development of Inflow Tracts,Development of outflow tract,Transposition of great vessels,tetralogy of Fallot,Persistent truncus arteriosusa and Development of Semilunar Valves.


Get complete cardiovascular and neurology & special senses medical lectures on subscription  with very low price. 
contact on social media
whatsapp = +923015721801
Instagram account    Dr_jamil56


https://youtu.be/gXGK6F_vDJQ
https://youtu.be/U3aD-wn2zMM
https://youtu.be/r9yQe_u8keQ

Septation of the Heart chambers
Atria
● Septum primum forms from top and grows down towards endocardial cushion,
narrowing foramen/ostium primum (foramen primum is an anterior opening between
septum primum and endocardial cushion)
● Septum primum doesn’t reach the endocardial cushion and a hole/gap develops in
septum primum towards top→This hole is called foramen/ostium secundum that
maintains right-to-left shunt of blood in fetus heart.
● Septum primum continues to grow until it reaches
endocardial cushion and foramen primum
regresses/closes.
● Septum secundum develops on the right side of septum
primum and expands to cover the most of foramen
secundum →It blocks the ostium/foramen secundum
→The remaining passage/ foramen is called the
foramen ovale.
Patent foramen ovale →failure of septum primum and septum secundum to fuse after
birth that results in opened foramen → venous thromboemboli (venous blood clots) can
enter the LA from RA via patent foramen ovale → LA → LV → enter systemic circulation as
“paradoxical embolism” → can cause stroke.
Ventricles
● A tissue called muscular interventricular
septum develops from apex and grows
upwards to endocardial
cushion→opening between muscular
ventricular septum and endocardial
cushion is called interventricular
foramen.
● A tissue called aorticopulmonary septum develops from endocardial cushion→
aorticopulmonary septum rotates and fuses with muscular ventricular septum to form
membranous interventricular septum →This rotation and fusion closes the
interventricular foramen and separates the RV from LV.
● Primitive ventricle forms left ventricle while part of Bulbus cordis forms right ventricle.
Ventricular Septal Defect (VSD)→ If tissues of interventricular septum don't form
properly,it leads to opened interventricular foramen known as VSD → It is the most common
congenital cardiac anomaly and usually occurs in membranous septum.
4
Development of Inflow Tracts
● Sinus venosus has 2 horns: right and left horn →each
horn has 3 veins
1. Common cardinal vein
2. Umbilical vein
3. Vitelline vein
● All the veins that drain into the left horn will break down
and no veins left → the remaining left horn develops into
the coronary sinus.
● The umbilical vein of the right horn also degenerates while
common cardinal & vitelline veins remain→ common cardinal vein develops into
superior vena cava (S.V.C) →Vitelline vein develops into inferior vena cava (I.V.C).
● Sinus venosus will be absorbed into Primitive atria → inflow tracts to RA has been
formed❗
Development of Outflow Tracts
● Neural Crest cells migrate into truncus arteriosus and form
truncal ridges on the right + left wall of T.A.
● Neural Crest cells also migrate into bulbus cordis and form
bulbar ridges on the right + left wall of B.C.
● Neural crest cells enter into the top part of B.C. towards T.A
called as conus cordis and form conus ridges on anterior +
posterior wall of conus cordis.
● Paired ridges approach and fuse with each other
➢ Truncal ridges fuses with each other and form truncal
septum
➢ Bulbar ridges fuses with each other and form bulbar
septum
➢ Conus ridges fuses with each other and form conus
septum
● Truncal and bulbar septa connect and form a spiral shape
around the central axis of conus septum (corkscrew) →It forms
aorticopulmonary septum that separates aortic arch from
pulmonary trunk.
● Blood flow
➢ To aortic arch → Blood flow from LV moves posteriorly of
bulbar septum, spiral upwards and leaves the trunk
anteriorly of truncal septum.
➢ To the pulmonary trunk → Blood from RV moves
anteriorly of the bulbar septum, spiral upwards and
leaves the trunk posteriorly of truncal septum.


#Drjamillectures
#firstaidlectures
#firstaidstep1lectures
#firstaidstep2lectures
#usmlelectures
#plablectures
#Nlelectures
#Nbelectures
#Amclectures
#Firstaidlecturesinurdu
#Drjameellectures
#MBBSlectures
#firstaidlecturesinurduhindi
#firstaidlecturesinhindi
#cardiovascularsystemlecturesinhindi 
#cardiology 
#ninjanerd 
#cardiovascularsystem
#USMLElecturesinurdu
#Usmlelecturesinhindi
#cardiologyfirstaidlectures
#cardiovascularsystemfirstaidlectures