2 - CV Development Flashcards
Adult circulatory system (terminology + basic purposes)
can be separated into 2 ‘sides’:
pulmonary:
- right side of heart
- oxygenation of blood
- removal of CO2
systemic:
- left side of the heart
- delivery system
- transport waste
key differences between fetal circulation and post-natal/adult circulation
fetal
gas exchange: in placenta
circulation: 2 open circuits, sides mix, in parallel
pressure: higher on right side
adult
gas exchange: in lungs
circulation: 2 closed circuits, sides seperated, in series
pressure: higher on left side
shunts and bypasses only open in fetal circulation
what causes the pressure gradient in fetal circulation?
right side high pressure: pulmonary vessels mostly constricted
left side low pressure: connected to placenta
- lungs are mostly dysfunctional, blood supply not needed
quiz on:
fetal circulation (anatomy + bloodflow)
see goodnotes
Key changes to circulation at birth
- gas exchange switches from placenta to lungs
-
pressure change:
- umbilical cord cut (lose placenta, pressure up in left)
- baby first cry (opens lung vasculature, pressure down in right)
- fetal circulatory structures close
Fetal structures (names and postnatal remnants)
foramen ovale –> fossa ovalis
ductus arteriosus –> ligamentum arteriosum
ductus venosus –> ligamentum venosum
umbilical arteries –> medial umbilical ligaments
umbilical vein –> ligamentum teres what in the actual fuck
transition occurs over months
steps in heart development
fetus
- two tubes (2 weeks)
- tubes fuse (4 weeks)
- tube elongates + develops segments see diagram 1
- tube folds see diagram 2
sections of the heart during development (names + future structure)
Truncus arteriosus –> aorta, pulmonary trunk
Bulbus Cordis –> right ventricle
Ventricle –> left ventricle
Atrium –> right and left atria + auricles
Sinus Venosus –> right atrium, SA node, coronary sinus
development of truncus arteriosus (TA)
- bulbar ridges form along the TA in a spiral shape
- ridges form the aorticopulmonary/spiral septum (AS)
- AS separates TA into aorta and pulmonary trunk
- separation also forms both semilunar valves (4 cusp vessel divides into 2, 3 cusp vessels)
spiral causes final orientation of A and PT
diagram 3
persistent truncus arteriosus
(cause, consequence, treatment)
cause: aorticopulmonary septum fails to develop
consequence: aorta and pulmonary trunk remain fused
- !does not affect fetus
- infant becomes cyanotic
!aorta and PT already connected
valve stenosis
(cause, consequence, treatment)
cause: unequal partitioning of truncus arteriosus (A and PT are unequal sizes)
consequence: valve stenosis occurs in smaller one
- infant cyanotic/acyanotic depending on the extent of stenosis
treatment: give !PGE1 to dilate ductal smooth muscle, balloon vavuloplasty (stretch valve to ‘permanently’ fix)
prostaglandin E1
patent ductus arteriosus
(cause, consequence)
cause: ductus arteriosus remains open
consequence: bloodflow between aorta and PT
- infant is acyanotic
- can become cyanotic if volume causes !pulmonary edema
!blood can’t get sufficient oxygenation in the lungs
formation of interarterial septum
- septum primum forms, foramen primum
- SP connects to endocardial cushion, foramen secundum forms in SP
- septum secundum forms, foramen ovale between SS and EC
- part of SP forms valve of FO
Atrial Septal Defect (ASD)
(alternate name + cause + consequences)
patent foramen ovale
cause: foramen ovale fails to close
consequence: bloodflow between atria
- infant is acyanotic
- can become cyanotic if volume causes !pulmonary edema
!blood can’t get sufficient oxygenation in the lungs
Interventricular septum formation
- IVS begins to form
- forms membranous portion connecting IVS to endocardial cushion
