Cardiovascular System Flashcards
Which germ layer is the cardiovascualr system derived from?
Mesoderm
The cardiovascualr system is the _____major system in the embryo to become functional
First
What is the job of the cardiovascualr system in an embryo?
Reuqired to supply embryo with nutrients and dispose of wastes
The cardiovascualr system is derived mainly from which 3 things?
- Splanchnic mesoderm forms the primordium of the heart
- praxial and lateral mesoderm (near the otic placodes from which the internal ears develop)
- neural crest cells (from the regions between the otic vesicles and the caudal limits of the third pair of somites
Development of intraembryonic coelom
Spaces appear in the lateral mesoderm and coalesce to form the intraembryonic coelom
-this divided the intraembryonic meaoderm into a somatic layer and a splanchnic layer
What forms tbe body wall and what forms the gut wall?
Intraembryonic somatic mesoderm and ectoderm=somatopleure (body wall)
Intraembryonic splanchnic mesoderm and endoderm=splanchnipleure (gut wall)
Intrembryonic coleom will give rise to….
Pericardial, pleural and peritoneal cavities
The cardiogenetic field is established ______ to the ____
Cranial
Neural pate (brain)
Why does the cardiovascualr sysfem develop in the embryo when it does?
By day 16-18 embryo grows rapidly and needs more nutrients than diffusion can offer
How does the cardiogenic field form and when?
Epiblast cells by day 16-18 migrate to form cardiogenic field
Primary Heart Field (PHF) forms what
Development of Atria, left ventricle and most of the right ventrical
Secondary Heart Field (SHF) forms what
Rest of the right ventricle and outflow ducts
When do the primary and secondary heart fields develop?
Day 16-18
Day 18-20
What induces the formation of myoblasts and blood islands?
Underlying pharyngeal endoderm induces overlying mesoderm and cardiogenic region to form these
Formation of blood and vessels using signalling?
- FGF2 binds to FGFR to form mesoderm cells
- VEGF binds to VEGF-R2 to form hemangioblasts
- VEGF binds to VEGF-R1 to create tube formation (hemangioblasts on outside become angioblasts)
- VEGF binds to VEGFR1,2 to form arteries and veins
Vasculogenesis
Angiogenesis
The formation of new vascular channels by assembly of individual precursor cells called hemangioblasts
Formation of new vessels by budding and branching from preexisting vessels
The umbilical vein carries what to where
The umbilical arteries carries what to where
Well-oxygenated blood and nutrients from the chorion sac to the embryo
Poorly oxygenated blood and waste products from the embryo to the chorion
How mang veins drain into the tubular heart of a 4-week embryo?
3
3 paired veins that darin into the tubular hesrt of a 4-week emrbyo are:
- Vitelline veins: return poorly oxygenated blood from the umbilical vesicle to heart
- umbilical veins: carry well oxygenated blood from the chorion to heart
- common cardinal veins return poorly oxygenated blood from the body of the embryo to heart
The vitelline veins follow the ______ (yolk stalk) into the embryo
Omphaloenteric duct
-narrow tube connecting the umbilical vesicle (yolk sac) with the midgut
Where do the vitelline veins enter
Enter the venous end of the heart-sinus venosus
The _____ Vitelline vein regresses while the ______ vitelline vein…..
Left
Right forma most of the hepatic portal system
Umbilical veins run on each side of the ______ and go from where to where?
Liver
Carry well oxygenated blood from the placenta to the sinus venosus
What parts of the umbilical vein degenerate?
Right umbilical vein abd the cranial part of the left umbilical vein between the liver and the sinus venosus
The persistent caudal part of the __________ becomes the _______, which careies all the blood from the placenta to the embryo.
Left umbilical cord
Umbilical vein
Ductus venosus (DV)
A large venous shunt that develops within the liver and connects the umbilical vein with the inferior vena cava (IVC)
Which veins constitute the main venous drainage system of the embryo?
Cardinal veins
The anterior cardinal veins drain_____ part of the embryo
The posterior cardinal veins drain_____ parts of the embryo
Cranial
Caudal
Both the Cardinal Veins join the _________, which enter the_____
Common cardinal veins
Sinus venosus
During the 8th week, what happens to the cardinal veins?
The anterior cardinal veins become connected by an anastomosis which shunts blood from the left to the right anterior cardinal vein and become left brachiocephalic vein when the caudal part of the left anterior cardinal vein degenerates
Why does the liver grow rapidly?
Gots lots of nutrients and oxygen from umbilical vein so bypasses are needed
Umbilical vein looses connection with the hesrt and empty into the liver
When does the Inferior Vena Cava develop (not a date)
During a series of changes in the primordial veins of the trunk that occur as blood, returning from the caudal part of the emrbyo, is shifted from the left to the right side of the body.
The IVC is composed of what 4 segments?
- Hepatic segment (derived from the hepatic vein (proximal part of the right vitelline vein) and hepatic sinusoids)
- prerenal segment (derived from the right subcardinal vein)
- renal segment derived from the subcardinal-supracardinal anastomosis
- postrenal segment (dereived from the right supracaedinal vein)
What stops the liver from taking all the nutrients?
Venous shunt-ductus venosus develops in the liver and connects umbilical vein with the IVC. This created a bypass through the liver enabling more palcental blood to go to the heart
Phayngeal arches form during the _____
Fourth and fifth weeks
Pharyngeal arch arteries supply _____ to _____
Blood
Pharyngeal arches
Pharyngeal aech arteries arise from
The aortic sac and terminate in the dorsal aortae
Dorsal aortae
- initally, the paired dorsal aortas run through the entire length of the embryo
- later, the caudal portions of the dorsal aortae fuse to form a single lower thoracic/ abdominal aorta
- of the remianing paired dorsal aortae the right aorta regresses and the left becomes the primordial aorta