Heart Flashcards
— is the 1st major system to develop
CVS
The early formation is correlated with the urgent need for —- and —
oxygen and nourishment
during the — week, a primordial —- develops
3rd week, a primordial uteroplacental circulation develops
3rd week, — cords appear
•Canalization of cords form—
3rd week –angioblastic cords appear
•Canalization of cords form endocardiac heart tubes
The two endocardiac heart tubes fuse to form —-– during — week
•Heart beat begins at day—
endocardiac heart tubes
•2 tubes fuse to form tubular heart –late 3rd week
•Heart beat begins –day 22-23
The endothelial heart tubes fuse to form a single — with a — end and a — end.
The endothelial heart tubes fuse to form a single primitive heart tube with a cranial (arterial) end and a caudal (venous) end.
As heart tube fuses
Surrounding mesenchyme thickens to form
•——-
•——-
As heart tube fuses
Surrounding mesenchyme thickens to form
•Myocardium
•Epicardium
Endothelial tube becomes——-
Endothelial tube becomes endocardium
Myocardium and endocardium is separated by
Cardiac jelly
The primitive heart tube elongates and develops alternate dilatations and constrictions giving rise to a/an —-shaped heart and — chambered heart
The primitive heart tube elongates and develops alternate dilatations and constrictions giving rise to an S-shaped heart- the 5-chambered heart
the 5-chambered heart:
Truncus arteriosus
Bulbus chordis
Primitive ventricle
Primitive atrium
Sinus venosus
The TA is continuous —- with the — , from which the——-arteries arise
The TA is continuous cranially with the aortic sac , from which the pharyngeal arch arteries arise
The sinus venosus is continuous — and receives the
•—- vein from the chorion (fetal part of placenta)
•—— vein from the umbilical vesicle
•——-vein from the body of the embryo
The sinus venosus is continuous caudally and receives the
•Umbilical vein from the chorion (fetal part of placenta)
•Vitelline vein from the umbilical vesicle
•Common cardinal vein from the body of the embryo
bulbus cordis and ventricle grow faster than other regions. T or F
T
Because the bulbus cordis and ventricle grow faster than other regions, the heart bends upon itself, forming a — -shaped — loop
Because the bulbus cordis and ventricle grow faster than other regions, the heart bends upon itself, forming a U-shaped bulboventricular loop
As the primordial heart bends, the atrium and sinus venosus come to lie dorsal to the — , — , and —
As the primordial heart bends, the atrium and sinus venosus come to lie dorsal to the TA, bulbus cordis, and ventricle
What is dextrocardia
the heart is positioned on the right side of the chest instead of its normal position on the left side
The junction btw the primitive atrium and ventricle forms the —-
The junction btw the primitive atrium and ventricle forms the AV canal
Towards the end of — week, masses of tissue (called— ) form on the dorsal and ventral walls of the AV canal
Towards the end of 4th week, masses of tissue (endocardial cushions) form on the dorsal and ventral walls of the AV canal
During the — week, the cushions approach each other and fuse
•Partitioning the canal into rt and lf —
During the 5th week, the cushions approach each other and fuse
•Partitioning the canal into rt and lf AV canals
By the end of the — week, the primordial atrium is divided into rt and lf atria by 2 septa (—- and —)
By the end of the 4th week, the primordial atrium is divided into rt and lf atria by 2 septa (Primum and Secundum)
Septum— - thin, crescentic-shaped membrane
Septum primum
Septum primum:
Septum primum- thin, crescentic-shaped membrane
•Grows from — of primordial atrium towards fusing endocardiac heart cushion
•Leaves gap at its lower end called—
•Atrium partially divided into Rt. & Lt. —& gap acts as a —-
Septum primum- thin, crescentic-shaped membrane
•Grows from roof of primordial atrium towards fusing endocardiac heart cushion
•Leaves gap at its lower end- ostium primum
•Atrium partially divided into Rt. & Lt. chambers & gap acts as a shunt.
As ostium primum becomes smaller, perforations appear central part of the septum called—
•Concurrently free edge of septum primum fuses with — side of fused endocardial Cushion.
As ostium primum becomes smaller, perforations appear central part of the septum – ostium secundum
•Concurrently free edge of septum primum fuses with left side of fused endocardial Cushion.
——- A cresentic, muscular membrane grow downwards from ventrocranial roof of rt atrium
Septum secundum- A cresentic, muscular membrane grow downwards from ventrocranial roof of rt atrium
Septum secundum- A cresentic, muscular membrane grow downwards from ventrocranial roof of rt atrium
•To the — side of septum primum
•—- week – overlaps foramen secundum
•Forms incomplete partitioning- ——
•Cranial portion of septum primum disappears Tor F
•Caudal part becomes a flap like valve of —-
Septum secundum- A cresentic, muscular membrane grow downwards from ventrocranial roof of rt atrium
•To the right side of septum primum
•5-6th week – overlaps foramen secundum
•Forms incomplete partitioning- foramen ovale
•Cranial portion of septum primum disappears
•Caudal part becomes a flap like valve of foramen ovale
Foramen ovale
•Before birth allow — to — shunt of blood
•Due to increase in —- atria pressures at birth there is closure of the foramen ovale
•Complete partitioning of the atria Tor F
Foramen ovale
•Before birth allow right to left shunt of blood
•Due to increase in left atria pressures at birth there is closure of the foramen ovale
•Complete partitioning of the atria
Changes in the Sinus venosus
•—- left horn of sinus venosus
•—-right horn of sinus venosus
•Left horn becomes —-
•Right horn becomes incorporated into the wall of — atrium (smooth part-—-)
•Rough part derived from primitive —both region separated by the—— (externally) &—- (internally)
Changes in the Sinus venosus
•↓ left horn of sinus venosus
•↑ right horn of sinus venosus
•Left horn becomes coronary sinus
•Right horn becomes incorporated into the wall of right atrium (smooth part- sinus venarum)
•Rough part derived from primitive atrium both region separated by the sulcus terminalis (externally) & crista terminalis (internally)
Left atrium
•Mostly smooth – derived from incorporation of the —- vein.
•how many pulmonary veins then open into — atrium
•left auricle is derived from ——-
Left atrium
•Mostly smooth – derived from incorporation of the primordial pulmonary vein.
•4 pulmonary veins then open into left atrium
•Left auricle is derived from primordial atrium
Atrial septal defects- 4 types. List them
Atrial septal defects- 4 types
•ostium secondum type
•Endocrdiac cushion with ostium primum defect
•Sinus venosus type
•Common atrium type
Partitioning of Primordial Ventricle
•First seen as a muscular median ridge growing from the—-of the ventricle near its —- and —— septum is formed
•The IV septum grows by dilation of the ventricles and by active proliferation of—- in the septum
•Till the — week, there is a crescent-shaped IV foramen btw the free edge of the septum and the fused endo. cushions
Partitioning of Primordial Ventricle
•First seen as a muscular median ridge growing from the floor of the ventricle near its apex- Interventricular septum (IV)
•The IV septum grows by dilation of the ventricles and by active proliferation of myoblasts in the septum
•Till the 7th week, there is a crescent-shaped IV foramen btw the free edge of the septum and the fused endo. cushions
The IV foramen permits communication btw the 2 ——
•The IV foramen usually closes by the end of the — week when the — ridges fuse with the—.
•Closure of IV foramen from 3 sources: —-& —- , ——
The IV foramen permits communication btw the 2 ventricles
•The IV foramen usually closes by the end of the 7th week when the bulbar ridges fuse with the endo.cushion.
•Closure of IV foramen from 3 sources: Right & left bulbar ridges, endocardiac cushion
Membranous interventricular septum-
•Extension of tissue from —Side of endocardiac cushion to — part of interventricular septum
Membranous interventricular septum-
•Extension of tissue from Rt. Side of endocardiac cushion to muscular part of interventricular septum
After closure of IV foramen-
•Pulmonary trunk now communicates with —- ventricle, while aorta communicates with ——ventricle
•Cavitation of ventricles gives rise to ——, —-, ——
After closure of IV foramen-
•Pulmonary trunk now communicates with right ventricle, while aorta communicates with left ventricle
•Cavitation of ventricles gives rise to trabeculae carnae, papillary muscles, chordae tendinae
Partitioning of bulbus cordis & truncus arteriosus
•—-week –active proliferation of mesenchyme into — in bulbus cordis & —- in Truncus arteriosus
•Undergoes — degrees spiraling forming a spiral——
•This septum divides the BC and TA into 2 ——, which are —— and —-
•Becos of the spiralling of the AP septum, the ascending aorta twists around the pulmonary trunk T of F
Partitioning of bulbus cordis & truncus arteriosus
•5th week –active proliferation of mesenchyme- bulbar ridges in bulbus cordis & truncal ridges in Truncus arteriosus
•Undergoes 180o spiraling forming a spiral aorticopulmonary septum (AP)
•This septum divides the BC and TA into 2 arterial channels- ascending aorta and pulmonary trunk
•Becos of the spiralling of the AP septum, the pulmonary trunk twists around the ascending aorta.T
Bulbus chordis:
Bulbus cordis incorporated into wall of ——-
•Right side becomes—— or ——(origin of pulmonary trunk)
•Left side – —-of the aorta
Bulbus cordis incorporated into wall of definitive ventricles
•Right side becomes-conus arteriosus or infundibulum (origin of pulmonary trunk)
•Left side –vestibule of the aorta
Ventricular septal defects
•VSDs – most common type of —-
•Occur more frequently in ——
•small VSDs may close spontaneously while large ones allow shunting of blood from — to —
Ventricular septal defects
•VSDs – most common type of CHD
•Occur more frequently in males
•small VSDs may close spontaneously while large ones allow shunting of blood from lf-rt
Examples of ventricular septal defect
Membranous VSD
Muscular VSDs- May appear anywhere in the muscular part
•Sometimes there are multiple small defects- called Swiss cheese VSD
Absence of the IV septum c
And auses single ventricle
Muscular VSDs occur becos of excessive
Tetralogy of Fallot
Tetralogy of Fallot
•Abnormality resulting from unequal division within the conutruncal region
•Displacement of the septum produces 4 CV alterations;
•Narrow rt ventricular outflow- Pulmonary stenosis
•Large VSD
•An overriding aorta arising directly above the septal defect
•Rt ventricular hypertrophy (becos of higher pressure on rt side)
PERSISTENT TRUNCUS ARTERIOSUS
•Results when—— ridges fail to form
•Hence no division of outflow tract
•—- artery arises some distance above the origin of the undivided truncus
•type of defect?
•Undivided truncus overrides both —-
PERSISTENT TRUNCUS ARTERIOSUS
•Results when conutruncal ridges fail to form
•Hence no division of outflow tract
•Pulmonary artery arises some distance above the origin of the undivided truncus
•VSD
•Undivided truncus overrides both ventricles
Transposition of great vessels
•Occurs when—- septum fails to follow its normal spiral course
•Hence, Aorta originates from — ventricle and pulmonary artery from —-
Transposition of great vessels
•Occurs when conutruncal septum fails to follow its normal spiral course
•Hence, Aorta originates from rt ventricle and pulmonary artery from left
