Cardiovascular System Flashcards

1
Q

Which germ layer is the cardiovascualr system derived from?

A

Mesoderm

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2
Q

The cardiovascualr system is the _____major system in the embryo to become functional

A

First

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3
Q

What is the job of the cardiovascualr system in an embryo?

A

Reuqired to supply embryo with nutrients and dispose of wastes

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4
Q

The cardiovascualr system is derived mainly from which 3 things?

A
  • 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
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5
Q

Development of intraembryonic coelom

A

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

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6
Q

What forms tbe body wall and what forms the gut wall?

A

Intraembryonic somatic mesoderm and ectoderm=somatopleure (body wall)

Intraembryonic splanchnic mesoderm and endoderm=splanchnipleure (gut wall)

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7
Q

Intrembryonic coleom will give rise to….

A

Pericardial, pleural and peritoneal cavities

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8
Q

The cardiogenetic field is established ______ to the ____

A

Cranial

Neural pate (brain)

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9
Q

Why does the cardiovascualr sysfem develop in the embryo when it does?

A

By day 16-18 embryo grows rapidly and needs more nutrients than diffusion can offer

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10
Q

How does the cardiogenic field form and when?

A

Epiblast cells by day 16-18 migrate to form cardiogenic field

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11
Q

Primary Heart Field (PHF) forms what

A

Development of Atria, left ventricle and most of the right ventrical

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12
Q

Secondary Heart Field (SHF) forms what

A

Rest of the right ventricle and outflow ducts

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13
Q

When do the primary and secondary heart fields develop?

A

Day 16-18

Day 18-20

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14
Q

What induces the formation of myoblasts and blood islands?

A

Underlying pharyngeal endoderm induces overlying mesoderm and cardiogenic region to form these

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15
Q

Formation of blood and vessels using signalling?

A
  • 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
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16
Q

Vasculogenesis

Angiogenesis

A

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

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17
Q

The umbilical vein carries what to where

The umbilical arteries carries what to where

A

Well-oxygenated blood and nutrients from the chorion sac to the embryo

Poorly oxygenated blood and waste products from the embryo to the chorion

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18
Q

How mang veins drain into the tubular heart of a 4-week embryo?

A

3

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19
Q

3 paired veins that darin into the tubular hesrt of a 4-week emrbyo are:

A
  • 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
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20
Q

The vitelline veins follow the ______ (yolk stalk) into the embryo

A

Omphaloenteric duct

-narrow tube connecting the umbilical vesicle (yolk sac) with the midgut

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21
Q

Where do the vitelline veins enter

A

Enter the venous end of the heart-sinus venosus

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22
Q

The _____ Vitelline vein regresses while the ______ vitelline vein…..

A

Left

Right forma most of the hepatic portal system

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23
Q

Umbilical veins run on each side of the ______ and go from where to where?

A

Liver

Carry well oxygenated blood from the placenta to the sinus venosus

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24
Q

What parts of the umbilical vein degenerate?

A

Right umbilical vein abd the cranial part of the left umbilical vein between the liver and the sinus venosus

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25
Q

The persistent caudal part of the __________ becomes the _______, which careies all the blood from the placenta to the embryo.

A

Left umbilical cord

Umbilical vein

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26
Q

Ductus venosus (DV)

A

A large venous shunt that develops within the liver and connects the umbilical vein with the inferior vena cava (IVC)

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27
Q

Which veins constitute the main venous drainage system of the embryo?

A

Cardinal veins

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28
Q

The anterior cardinal veins drain_____ part of the embryo

The posterior cardinal veins drain_____ parts of the embryo

A

Cranial

Caudal

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29
Q

Both the Cardinal Veins join the _________, which enter the_____

A

Common cardinal veins

Sinus venosus

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30
Q

During the 8th week, what happens to the cardinal veins?

A

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

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31
Q

Why does the liver grow rapidly?

A

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

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32
Q

When does the Inferior Vena Cava develop (not a date)

A

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.

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33
Q

The IVC is composed of what 4 segments?

A
  • 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)
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34
Q

What stops the liver from taking all the nutrients?

A

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

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35
Q

Phayngeal arches form during the _____

A

Fourth and fifth weeks

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36
Q

Pharyngeal arch arteries supply _____ to _____

A

Blood

Pharyngeal arches

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37
Q

Pharyngeal aech arteries arise from

A

The aortic sac and terminate in the dorsal aortae

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38
Q

Dorsal aortae

A
  • 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
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39
Q

Intersegmental arteries

A
  • are branches of the dorsal aorta
  • 30 or so intersegmental arteies, pass between and carey blood to the somites and their derivaties
  • intersegmental arteries in the neck join to form vertebral artery
  • in the thorax, it persists as intercostal arteries
40
Q

Most of the intersegmental arteries in the abdomen become ________ but the 5th pair _______. In sacral region form ______

A

Lumbar arteries, but the 5th pair of lumbar intersegmental arteries remain as the common iliac arteries

Lateral sacral arteries

41
Q

Fate of the Vitelline arteries

Which 3 remain?

A

Vitwlline arteries Pass to the vesicle and later the primoridal gut, which forms from the incorporated part of tbe umbilical vesicle.

Only 3 remain:

  • celiac arterial trunk to foregut
  • superior mesenteric artery to midgut
  • inferior mesenteric artery to hindgut
42
Q

Fate of the umbilical arteries

A

Proximal part of the umbilical arteries become the internal iliac arteries and superior vesicle arteries whereas distal part become medial umbilical ligament

43
Q

Development of the heart

A
  • heart formation begins toward the end of the 3rd week with a condensation of mesoderm ventral to the intraembryonic coelom-called the cardiogenic area
  • forms 2 angioblastic cords that canalize to become heart tubes
  • as lateral body folding occurs, heart tubes fuse to become single heart tube
44
Q

Genetic induction of the cardiogenic field

A

Endoderm expresses BMP 2,4 to increase expression of NKX-2.5 in mesoderm which is a master regulator transcription factor for development of cardiovascualr system.

Ectoderm (neural tube) increases WNT inhibitors like crescent and cerebus to inhibit wnt 3a,8 to inhibit cardiogenic field

45
Q

The fusion of the heart tubes begins at the ____ end and extends ______ until it is a singular tube

A

Cranial

Caudally

46
Q

The epitheliem of the heart tube develops from the

A

Endocardium of the heart

47
Q

Wall of ghe heart tube (and heart) consists of:

A
  • endothelium (becomes endocardium)
  • cardiac jelly (becomes subendocardial CT)
  • myocardium (thick layer of carduac muscle)
  • epicardium (or visceral later of oericardium forms from mesothelial cells on surface)
48
Q

Heart tube elingates and 5 dialations appear

A
  • Truncuc arteriosus
  • bulbus cordis
  • ventricle
  • atrium
  • sinus venosus
49
Q

The heart is initally suspended from the ___________ by _______, called the _________, but the central part of this mesentery soon degenerates, forming a communication ________

A

Dorsal wall

Mesentery

Mesocardium

The transcere pericardial sinus between the right and left sides of the pericardial

50
Q

Arterial and venous ends of the heart tube are _____

A

Fixed in position

51
Q

As bulbud cordis and ventricle grow, the heart tube bends upon itself becomes a

This causes the atrium and sinus venosus to move

This causes the bulbus cordis, ventrical and truncus arteriosis to move

A

U shaped bulboventricular loop

Dorsally and cranially and to the left

Ventrally and caudally and to the right (slightly)

52
Q

Contraction of the heart begins at ____

Blood circulation begins in _____

A

Day 22-myogenic origin

4th week

53
Q

Blood returns to the sinus venosus via…

A
  • cardinal veins from embryo
  • umbilical bein from placenta
  • vitelline veins from yolk sac
54
Q

Primitive citculation pathway in heart

A

Blood flows through the sinus venosus, atrium, ventricle, bulbus cordis, truncus arteriosis, aortic sac, aortic arches and into the dorsal aorta

55
Q

From the dorsal aorta blood flow to

A

The embryo via intersegmental arteries

The placenta via the umbilical arteries

The yolk sac via the vitelline arteries

56
Q

Partitioning of the heart begins when and is complete when

A

4th week

End of 8th week

Partitioning processes occur simultaneoulsy

57
Q

Division of the Atrioventricular (AV) Canal

A
  • seperates the atria from the ventricles and the left from the right side of the heart
  • endocardial cushions form on the ventral and dorsal walls. Grow ans fuse which divides the AV canal into left and right AV canals
  • after inductive signals from the myocaardium of the AV canal, a segment of the in er endocardial cells undergoes epithelial mesenchymal transformation (EMT), which then invaded the extracellular matrix
58
Q

Factors for EMT

A
  • TGF-Beta1 and beta2
  • BMP-2A and -4
  • Sinc finger protein slug
  • activin-receptor-like kinase (chALK2)

Reproted to be involved in the epithelial-mesenchymal transformation and formation of the endocardial cushions

59
Q

Division of the Primitive Artrium

A
  • need to divide the primitive atrium into the RA and LA
  • occurs via the formation of 2 septa-septum primum and septum secundum
  • septun primum grows down from the roof of the primitice atrium
  • opening between the bottom of the septum primum and the endocardinal cushions is the foramen primum
  • foramen primum disappears as the septum lrimin fuses with the endocardial cushions
  • perforations appear in the upper part of the septhm primun and join to form the foramen secundum
  • septum secundum grows downward from thr roof to the right of the septum primum
  • septum secundum does not fuse with the endocardial cushions but leaves an oval opening called the foramen ovale
60
Q

Before birth, well oxygenated blood is shunted from the right atrium through the ______ when the pressure increases

When the pressure decreases in the right atrium, the flaplike valve of the oval foramen is _____

A

Oval foramen into the left atrium

Pressed against the relatively rigid septum secundum which closes the oval foramen

61
Q

After birth, the pressure in the _______ increases as the blood returnes from the lungs.

Eventually the septum primum is ____

A

Left atrium

Pressed against the septum secundum and adheres to it permenantly closing the oval foramen and forming the oval fossa

62
Q

Rapid growth of heart tube is by

A

SHF proliferating rapidly and adding cells to the top (tube elongation)

63
Q

Cardiac jelly becomes

A

Connective tissue and then epithelail lining

64
Q

The primitive heart (tubular structure) is hanging where?

A

Pericardial cavity

65
Q

Division of the primitive ventricle

A
  • need to divide the primitive ventricle into a LV and RV
  • muscular ridge grows upward from the floor of the ventricle to form the interventricular septum
  • stops short of the endocardial cushions leaving the interventricular (IV) foramen
  • by end of 7th week, membrane grows downward to compelte the IV septum
66
Q

Closure of the IV foramen and formation of the membranous part of the IV septum result from the fusion of tissues from which sources:

A
  • right bulbar ridge
  • left bulbar ridge
  • Endocardial cushion
67
Q

After the closure of the IV foramen and formation of the membranous part of the IV seltum, the ________ is in communication with the ______ and the _____ commhnicates with the ______

A

Pulmonary trunk

Right ventricle

Aorta

Left ventricle

68
Q

Changes to the sinus venosus

A
  • initially, the sonus venosus has L and R horns that open into the atrium
  • R horn increases and L horn decreases
  • orifice moves to the R and opens into the RA
  • R horn of sinus venosus is incorporated into the wall of the RA
  • L horn of sinus venosus becomes the coronary sinus
69
Q

Most of the wall of the left atrium is ______ because it is formed by incorporation of the ______

A

Smooth

Primoridal pulmonary vein

70
Q

As the atrium expands, the primordial pulmonary vein and its main branches are incorporated into the wall of the _______as a result _____ are formed

A

Left atrium

4 pulmonary

71
Q

Partitioning of the bulbus cordis and trunchs arteriosus

A

Is a spiral partition, not a straight wall as they undergo a 180° spiraling.

  • divides the BC and TA into 2 channels
  • pulmonary trunk from the RV
  • Aorta from the LV
72
Q

Muscular bulbar and truncal ridges form and fuse to form the

A

Aorticopulmonary septum

73
Q

Bulbar and truncal ridges are derived largely from _________

A

Neural crest mesenchyme

Neural crest cells migrate through the primordial pharynx and pharyngeal arches to reach the ridges

74
Q

Fate of bulbus cordis

A

Bulbus cordis is incorporates into the walls of the definitive ventricle

  • in right ventircle, BC is represented by the conus arteriosus (infundibulum), which gives origin to the pulmonary trunk
  • in left ventricle, the bulbus cordis forms the walls of the aprtic vestibjle, the part of the ventriclar cavity just inferior to the aortic valve
75
Q

Structural anomalies of the cardiovascualr system occurance

A

Common

0.7% of live births and 2.7% of still births

76
Q

One of the Most common congential heart defects

A

Atrial septal defects (ASD) m

  • result from excessive resorption of the septum primim and or defective development of the septum secundum
  • can result in patent foramen ovale or patent foramen primum
77
Q

Ventricular septal defects (VSD)

A

Most common congenital heart defects

  • usually involve the membranous part of the septum
  • results in a patent interventricular foramen
78
Q

TGA

A

Transposition of the great arteries

Results when the aorticopulmonary septum doesn’t spiral and origin of great arteries is reversed

79
Q

Prental circulation differs from postnstal because

A
  • The lungs are nonfunctional

- the placenta serves in gas exchange, obtaining nutrients and elminating wastes

80
Q

Blokd returns to the fetus from the placenta via the ______

A

Umbilical vein (90% O2 saturated)

81
Q

Half of the blood retunring from placenta goes through the __________ to the________ and half goes trhough the ________ to the ______

A

Liver

IVC

Ductus venosus

IVC (67% 02 saturated)

82
Q

From IVC, blood goes to the ______ then either

A

Right atrium

Through the foramen ovale into the Left atrjym (90%) or
To the Right ventricle and pulmonary circuit (10%)

83
Q

Blood that leaves the Right ventricle into the ________ can go directly into the _____ via the ______

A

Pulmonary trunk

Aorta

Ductus arteriosus

84
Q

From the left ventricle, blood leaves the heart via the _______

A

Aorta (58% O2 saturated in descending aorta)

85
Q

Umbilical arteries arise as branches of the ______and carry blood to the ______

A

Internal iliac arteries

Placenta

86
Q

At the time of birth, must close fetal shints and replace palcental circulation with

A

Pulmonary circulation

87
Q

At birth, there is a decrease in pressure in the ______ and ______ of the heart because of

A

IVC
Rifht side

Loss of blood flow from the placenta

Inflation of the lungs which decrease pulmonary vascular resistance

88
Q

Pressure on the left sude of the heart increases because of the increase in ___

A

Pulmonary flow

89
Q

There is a breif period when blood flows from the aorta backward through ghe ductus venosus into the ___

A

Pulmonary trunk

-wall of ductus arteriosus constructs and closes

90
Q

Because pressure in the Left atrium is now greater then the Right atrium, fhe septum primum is______

A

Pressed against thr septum secundum and the foramen ovale closes

91
Q

Adult derivitates of fetal structures

  • umbilical vein
  • ductus venosus
  • umbilical arteries
  • foramen ovale
  • ductus arteriosus
A

Ligamentum teres

Ligamentun venosun

Medial umbilical ligaments and vesicular arteries

Fossa ovalis

Ligamentum arteriosum

92
Q

Patent Ductus Arteriosus (PDA)

A

Occurs commonly in premature babies

93
Q

Patent foramen ovale results from

A

Blood flowing from LA into RA and deceeae cardiac output

94
Q

3 bypasses

A
  1. Ductus venosus
  2. Foramen ovale
  3. Ductus arteriosus
95
Q

Ductus arteriosus

A

Sends medium oxygenated blood to descending aorta instead of pulmonary trunk (non functional lungs)

96
Q

What creates the muscular ridge

A

Myoblast proliferation