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Embryology: Summer Semester > Unit 2.L3-Development of Heart & Cardiovascular System > Flashcards

Unit 2.L3-Development of Heart & Cardiovascular System Flashcards

1
Q

Formation of the Earliest Cardiac field

By Day 15, what mesoderm splits and what is formed and how?

A
  • Day 15: Caudally, Lateral plate mesoderm splits to forms the pericardial coelom cranially.
  • How??: Cardiogenic cells in the Splanchnic lateral plate mesoderm move cranio-medially while the mesoderm is splitting.
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2
Q

Formation of the Earliest Cardiac field

Blood islands develop by Day 18, what is formed and how?

A

Day 18: Blood islands develop & merge at the cranial end to form a horseshoe-shaped endothelial cell “Cardiac Tube”

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3
Q

What forms the Cardic Tube (horseshoe-shaped endothelial cell)?

Day 18

A

Blood islands that develop and merge at the cranial end

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4
Q

By Day 15, cardiac specification between what occurs? And which cells move?

A
  • Cardiac specification between → endoderm/neural folds or epidermis, when mesodermal cells move to cranial ends
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5
Q

What does the Primative Streak Mesoderm cells invaginate between? What direction does it go? And what does it form?

Day 15

A

The Primitive Streak Mesoderm cells invaginate between neural fold & endoderm and go latero-cranially to form cardiogenic sub-fields
1. Atria (outer)
2. LV, RV (Ventricles)
3. C/T (Conotruncus or Outflow tract) (inner)

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6
Q

What is found in the Cardiogenic sub-fields?

A
  1. Atria (outer)
  2. LV, RV (Ventricles)
  3. Conotruncus; CT (Outflow tract;OFT) (inner)
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7
Q

By day 18, what does the cardiogenic sub-fields become?

3 Somite Stage

A

Two cardiac crescents that form the Primary & Secondary Heart Fields

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8
Q

What can be used to identify each type of cell in the primary and secondary heart field?

A

Lineage tracing identifies each type of cell using tissue-specific gene-promoters or specific RNA/protein markers (MLC; myosin light chain, C)

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8
Q

What is the position of the Primary Heart Field and what is present there?

A

Primary Heart Field (Cranially):
Atria & Ventricle progenitor cells

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8
Q

What is the position of the Secondary Heart Field and what is present there?

A

Secondary Heart Field (Caudally):
Outflow tract + Great Vessels

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9
Q

At Day 18, what does the endothelial cell tube forms? And how does it move? And what occurs to the embryo?

A

The endothelial cell tube→“Angioblastic” cord→moves rostrally as the embryo head folds

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10
Q

By Day 20, lateral folding forms what two structures that eventually move closer and fuse into what?

A

[2-pericardial coeloms + 2-heart tubes] come nearer & fuse → [2- heart-tube + 1-pericardial cavity]

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10
Q

Where does the septum transversum develop?

A

The septum transversum develops most cranially

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11
Q

How is the Dorsal Aorta formed?

A

Dorsal Aortae are formed bilaterally, independent of the heart

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12
Q

What is the origin of the Primary/first heart field (FHF) and what does it form?

A
  • Origin: Primitive streak
  • Forms: Left & Right Atria & Left Ventricle: (LA + RA + LV)
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13
Q

What is the origin of the Secondary heart field (SHF) and what does it form?

A
  • Medial origin: Splanchnic Pharyngeal Mesoderm
  • Forms: Right ventricle (RV), Outflow tract (CT or OFT)
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14
Q

What does lateral folding cause?

A

MIdline fusion of 2 heart tubes

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15
Q

When do we have a single heart tube?

A

Day 20

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16
Q

By Day 20, lateral folding merges two heart fields. What else is merged and formed? (2)

A
  1. Merging/fusing endocardial (endothelial) cell lining) & formation of [2-heart tubes + 2-Aortae]
  2. Formation of the Cardiac Jelly (extracellular matrix/ECM/connective tissue) & Myocardium
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17
Q

What suspends the tubular heart by day 22?

A

Dorsal mesocardium “suspends” the tubular heart

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18
Q

By Day 22:
1. What starts to fuses into a single heart tube?
2. What differentiates and what does it form?
3. What type of -cardium forms?

A
  1. 2-heart tubes start to fuse into Single heart tube
  2. Cardiomyocyte differentiate→Muscular heart walls
  3. Epicardium (visceral pericardium) forms
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19
Q

What is the origin of the Epicardium (visceral pericardium) formed by Day 22?

A

Origin: Mesothelial cells of the developing Sinus Venosus (PEO or Pre-Epicardial Organ)

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20
Q

How is the heart tube and central tendon of the diaphragm formed? (What folds and what moves ventral to the foregut? What structures position switch? Where does the septum transversum lies and what does it form?)

A
  1. The head folds & the tubular heart/pericardial cavity move ventral to the foregut
  2. Positions of the pericardial cavity and septum transversum reverses
  3. Septum transversum lies posterior to the pericardial cavity & forms the “Central tendon of the diaphragm”
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21
Q

What forms the central tendon of the diaphragm?

A

The Septum transversum that lies posterior to the pericardial cavity

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22
Q

What does the secondary heart field divide into?

A
  1. Anterior heart field (AHF; at outflow-OFT)
  2. Posterior heart field(PHF;at inflow-IFT)
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23
Q

What is the PEO? How does it develop? What does it give rise to?

A
  • Pre-Epicardial Organ: Cauliflower-like protrusion of the sinus venosus
  • Develops as a part of the posterior heart field, thus is intracardiac
  • Giving rise to epicardium
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24
Q

What are the neural crest cells role in heart development?

A

True extracardiac contributors to heart development as they migrate from the neural crest

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25
Q

What is right looping of the cardiac tube?

A
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26
Q

What is the role of the Sinus venosus (SV)?

A

This is the collecting compartment of the heart. Oxygenated blood from the placenta and deoxygenated blood from embryonic tissue are mixed in the sinus

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27
Q

What is the Primative atrium (PA)?

A

This is the compartment destined for further partition to the definitive atria

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28
Q

What is the Primitive ventricle (PV)?

A

This is the compartment destined for further partition to the definitive ventricles

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29
Q

What is the role of the Bulbus cordis (BC)?

A

This will contribute to the pulmonary trunk and aorta along with the truncus arteriosus

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30
Q

What is the role of the Truncus arteriosus (TA)?

A

This will contribute to the aortic arches

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31
Q

What is the Fibrous skeleton (FS)?

A

This is the area of connective tissue proliferation, site of future valves

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32
Q

How is the heart loop primed to folding into the D-loop?

A

Apoptosis in the dorsal mesocardium will allow movement of the early heart tube within the pericardial cavity to rotate & bend

Still attached to myocardial wall

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33
Q

By Day 22-28:
1. What happens to the dorsal mesocardium?
2. What sinus is formed?
3. What starts to fuse?

A
  1. The central part of the dorsal mesocardium degenerates
  2. Transverse pericardial sinus is formed
  3. Dorsal Aortae starts to fuse
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34
Q

By the end of week 3 (D22) what happens to the heart tube?

A
  • Heart tube starts “beating”
  • First: Spontaneous,asynchronous
  • Later, cells build a directional rhythm without any electrical circuitry or stimulation.
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35
Q

What happens to the heart at the end of Week 4?

A

Blood begins to flow (3D / 4D Doppler detects it)

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36
Q

When do we see all three layers of the heart?

A

end of week 4

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37
Q

What are the three distinct cell populations/layers that the cardiogenic mesoderm differentiates into?

A
  1. Endocardium (inside)
  2. Myocardium (muscle wall)
  3. Epicardium (outer wall)
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38
Q

What is present in the Endocardium layer? (4)

A

Endocardium (inside):

  • Endothelial lining
  • Endothelial tube
  • Valves
  • Cardiac Connective tissue (fibrous scaffold)
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39
Q

What is present in the Myocardium layer? (3)

A

Myocardium (muscle wall):

  • Myocytes/Myocardium
  • Conduction system (Purkinje fibers)
  • Myoendocrine cells (ANP-Atrial Natriuretic Factor)
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40
Q

What cells are present in the Epicardium layer? What do they form?

A

Epicardium (outer wall): Mesothelial cells of Sinus Venosus (from viseral) spread over the myocardium, forming outer layer of the heart(epicardium).

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41
Q

Epicardium gives rise to what? (2)

A
  • coronary vessels
  • Visceral pericardial lining
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42
Q

The fibrous pericardium is from where? What is a characteristic about it?

A
  • From the body wall
  • Muscular
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43
Q

Rapid growth elongates the heart tube, thus what happens?

A

Rapid growth elongates the tube, thus bend/kinks with dilations & constrictions

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44
Q

Heart detaches from what and is attached to what? This allows what?

A

Heart detaches from the dorsal mesocardium but is attached to pericardial wall on either side; thus, freely ROTATE on its AXIS

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45
Q

By Day 23-28, what occurs with heart looping?

A

Day23-28: Dextral looping (occurs on the right hand side)→U-shaped D-loop (ventral, rightward looping)→Bulboventricular loop

S-shaped heart

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46
Q

D-looping forms S-Shaped heart with Bulbus Cordis & Primitive Chambers, what other structures are formed? (7)

A
  • Bulbus cordis, Conus cordis, Conus arteriosus & Truncus arteriosus
  • Primordial ventricles: (PRV & PLV)
  • Primordial atrium (PA)
  • Sinus Venosus
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47
Q

Anything coming through the heart, is coming through what? What about out of the heart?

A
  • In: Sinus Venosus
  • Out: Truncus arteriosus
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48
Q
  • Where does the folding or D- looping take place?
  • Where do structures move?
  • What gives rise to the formation of the RV?
A
  • At primordial ventricles
  • Bulbus cordis and truncus arteriosus moves to the right then the primordial ventricles and atrium move to the left
  • Bulbus cordis
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49
Q

What does right-sided/ventral looping cause (D-looping)?

A

causes common atrium to lift up dorsally

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50
Q

What dictates blood flow? (4)

A
  • Cardiac cushions
  • Atrioventricular (AV) Canal
  • AV Valve
  • Septa formation
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51
Q

By Day 35, AV endocardial cushions form on what? from where?

A

AV endocardial cushions form on the dorsal & ventral walls of the AV canals from Cardiac Jelly (ECM) + Neural crest cells (NCCs)

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52
Q

The AV endocardial cushions partially close what? Thus splitting into what? And functions as?

Day 35

A

The cushions partially close the AV canal at the midline (Dorso-Ventrally), thus splitting it into right & left AV canals & functions as primitive valves: the “AV valves”

53
Q

What are the AV cushions (inner and outer) made up of?

A
  • Inner: endocardial cells
  • Outer: myocardial cells
54
Q

Heart Valves & Septal Membranes are sculpted via what?

A

Endothelial–Mesenchymal Transformation (EMT) (give rise to meschymal cells)

55
Q

What does the primitive heart valves undergo?

A

Extensive remodeling to form thin, delicate heart valve leaflets in the adult heart

56
Q

Myocardial Cells induce what? What does this result in?

A

Myocardial Cells induce EMT in Endocardial Cells (ECs), resulting in migratory mesenchymal cells that invade the extracellular matrix (of cushions) forming valves & membranous septa of the heart.

57
Q

What happens to the atrium by Day 27-28? And where does the septum premium grow towards?

A

Day 27-28: Division of Atrium →LA+RA occurs as the Septum primum grows towards AV-endocardial cushion

58
Q

What forms the foramen primum?

Day 27-28

A

Gap between Septum primum & AV-endocardial cushion forms Foramen Primum (hole in the atrial septum)

59
Q
  • Holes in the atrial septum allow what?
  • How is blood shunted? what does this allow?
A
  • Holes in the atrial septum allow blood oxygenated by the mother, coming from the Vena Cavas (SVC/IVC), to circumvent the pulmonary circulation (lungs not formed).
  • Thus, Blood is shunted between RA→ LA→TA→body
  • This allows ventricular walls to mature & thicken

TA: Truncus arteriosus

60
Q

what does the primordial inter-ventricular septum divide?

A

LV + RV

61
Q

What eventually happens to the septum primum and foramen primum?

A
  • Septum primum grows
  • Foramen primum almost disappears as it fuses with AV endocardial cushions, forming primordial AV septum
  • But before it closes new holes form!! Blood Shunting continues!
62
Q

How is the primordial AV septum formed?

A

Septum primum grows & Foramen primum almost disappears as it fuses with AV endocardial cushions

63
Q

Septum primum have perforations via what?
They fuse to form what?

A

Septum primum have perforations via apoptosis, which fuse to form Foramen Secundum

64
Q

What does the Foramen Secundum ensure?

A

Ensures continued shunting of blood from right to left atrium, bypassing the primitive lungs

65
Q

At week 5&6, what overlaps the Foramen Secundum and where does it grow from?

A

A thick crescentic muscular fold, “Septum Secundum” (very muscular) grows from the ventrocranial wall of Right Atrium & overlaps the Foramen Secundum

66
Q

Flutter Valve of Foramen Ovale controls what?

A

Controls unidirectional blood-flow

67
Q

How is the Flutter Valve of Foramen Ovale formed?

A
  • Muscular Septum Secundum forms an incomplete partition, leaving a hole between the atria→foramen ovale
  • Before birth, the foramen ovale allows oxygenated blood entering the right atrium to pass into the left atrium as the septum premium is weak/pliable
  • Septum Secundum is muscular & rigid; does not allow opposite flow!
68
Q

What happens in week 6-7 to myocytes from LV and RV?

A

Week 6-7: Myocytes from LV + RV→median ridge at the Ventricular apex, where muscular interventricular septum grows upwards towards the endocardial cushions.

69
Q

What does not touch the endocardial cushions? What does this form?

Wk 6-7

A

Interventricular septum does not touch the cushions, forming a intraventricular foramen to shunt blood

70
Q

What happens to the Ventricles at Week 6-7?

A

Ventricles rapidly expand and thicken

71
Q

How does the interventricular formen close?

A

Interventricular foramen closes: Two bulbar ridge fuse with endocardial cushion forming a membrane that touches the lower muscular septum.

72
Q

Ventricular cavities form what?

A

Ventricular Cavities→ Spongy muscular bundles→trabeculae carneae formed

73
Q

Spony muscular Bundles form?

A

Bundles→ Papillary muscles & tendinous cords (chordae tendineae)

74
Q

Tendinous cords run from the papillary muscles to what? What does this help form?

A

Tendinous cords run from the papillary muscles to the AV valves helps form the cusps of the AV valves and “sculpts” them as mature valves

75
Q

What sculpts the Aortic and pulmonary “trunk valves”? And controls apoptosis to thin and form Vale Cusps?

A

Swellings of the Subendocardial tissue and Migration of Cardiac Precursor Neural Crest Cells

76
Q

When does the conduction system of the heart occur?

A

Week 7-20

77
Q

Where is the origin of the Sinoatrial Node (SAN)

A

Natural Pacemaker:

  • SAN Origin→right wall of the Sinus Venosus (SV) or IFT & fuses with right atrium
  • Mature SAN→high in the right atrium, at the SV opening.
78
Q

What does the AV (Atrioventricular) Node (AVN) & Bundle of His do?

A

It conducts electrical impulse from Atria→ Ventricles via the “Bundle of His”, which has right bundle branch & left bundle branch

79
Q

What is the origin of the AV Node?

A

AVN origin→lower inter-atrial septum, superior to the endocardial cushions near the Coronary Sinus (CS) opening

80
Q

Where does electrical impulses from atria to venticles end up?

A

“Bundle of His”, which has right bundle branch & left bundle branch

81
Q

What makes up the outflow tract?

A

Bulbus Cordis + Truncus Arteriosus

82
Q

The outflow tract divides into what?

A

Two great vessels:
1. Ascending Aorta (Systemic circulation)
2. Pulmonary Trunk (to Lungs)

83
Q

What is the mechanism of Outflow division?

A

Truncal Ridges (TR)+ Bulbar ridges (BR) expand and form septa & divides OFT (OT)

84
Q

What divides Outflow Tract (OFT) into Aorta & Pulmonary Trunk (PT)?

A

Spiral Septa

85
Q

Truncal (TR) + bulbar ridges (BR) partitions the Outflow Tract (OFT) by a spiral septa such that what forms (2)? And what do they supply?

A

Aorta forms & supplies:

  • Oxygenated Blood Outflow of Left Ventricle (LV) to the Systemic Circulation

Pulmonary Trunk (PT) forms & supplies:

  • Deoxygenated Blood-flow of Right Ventricle (RV) to the Pulmonary Artery (PA)
86
Q

What happens during the closing of the interventricular foramen?

A

Incorporation of the inferior edges of Left & Right Bulbus cordis ridges into the left & right edges of the Intraventricular septum during the closing of the interventricular foramen begins the partitioning of the OFT

87
Q

Partition of the OFT: Forms what?

A

Forms the Aorta (connecting Left Ventricle) and Pulmonary Trunk (connecting Right ventricle)

88
Q

Teratogens (rubella virus) & multifactorial inheritance that cause congenital heart defects are how common?

A

8:1000 live births

89
Q

What are the two types of dextrocardia? How common?

A
  1. Dextrocardia w/ Situs Inversus (transposition of the abdominal viscera)
  • Normal Heart function; no heart defects (all organs reversed)
  1. Isolated Dextrocardia: The abnormal position of the heart & no displacement of viscera
  • Severe cardiac defects (D-loop becomes L-loop)
  • 1:10,000 live births
90
Q

Atrial septal defects:

  • More seen in who?
  • 20% in ?
  • 25% in?
A
  • More seen in females
  • 20% Down Syndrome
  • 25% Patent Foramen Ovale (PFO)→ Incomplete adhesion of (Septum Primum + Septum Secundum)
91
Q

Clinical Significance of the other heart defects:

  1. Ostium Secundum defects:
  2. Endocardial cushion defect:
  3. Sinus Venosus defect:
  4. Common Atrium: Abnormal
  5. Ventricular Septal defect:
A
  1. Ostium Secundum defects: Endovascular catheter-based closures repairs it. > females →3:1 ratio
  2. Endocardial cushion defect: Cleft in the anterior cusp of the mitral valve
  3. Sinus Venosus defect: Abnormal absorption of the Sinus Venosus into the right atrium
  4. Common Atrium: Abnormal [Ostium secundum + Ostium primum + sinus venosus]
  5. Ventricular Septal defect: Direct mixing of LV + RV blood
92
Q

Ventricular septal defects (VSDs):

  • Percentage of all CHDs?
  • More common in?
  • What clinical manifestations are common?
  • What happens to the VSDs?
A
  • Most common CHDs: 25% of all heart defects
  • More common in males (opposite of ASD)
  • Membranous VSDs are common; Incomplete closure of interventricular foramen
  • About 50% of VSDs close by end of 1st year, and babies are fine.
93
Q

What is the mechanism of ventricular septal defects?

A

Right side of the endocardial cushion does not fuse with the aorticopulmonary septum and the muscular part of the interventricular septum→A persistent TA is seen!

Persistent TA: mixing of blood d/t hole in the ventricle

94
Q

Large Ventricular Septal defects (VSDs) have excessive what?

A

Pulmonary blood flow and pulmonary hypertension, dyspnea and cardiac failure early in infancy

95
Q

By day 26, The heart tube joins with blood vessels in the embryo, connecting what? to form what?

A

The heart tube joins with blood vessels in the embryo, connecting the stalk, chorion, and umbilical vesicle to form a functional cardiovascular system having 3 branches by day 26

96
Q

What are the three branches that are formed by day 26? And what are their functions?

A
  1. The Arterial System (Dorsal Aorta) sends impure blood back into the Umbilical Artery (bilaterally)
  2. The Umbilical Veins: Supply Nutrients & O2
  3. Vascular plexus of Vitelline veins in the umbilical vesicle & Cardinal Veins connect to the heart tube
97
Q

Early Embryonic Venous System to ________ venous return

A

Right-sided

98
Q

The three paired veins drains what type of blood from what part of the body into the primordial heart (Atrium)?

A
  • 2-Vitelline veins drain deoxygenated blood from the umbilical vesicle into the Atrium.
  • 2-Umbilical veins drain oxygenated blood from the chorion into the Atrium.
  • 2-Common cardinal veins drain deoxygenated blood from the body to the Atrium.
99
Q

Initial Bilateral Venous Return System becomes what? And blood comes into the what?

A
  • Initial Bilateral Venous Return System becomes a Right-sided venous return
  • Blood comes into the Right Sinus Venosus & Right Atrium
100
Q

For right-sided venous return (Right Atrium), remodeling of the Bilateral System forms what?

A

For right-sided venous return (Right Atrium), remodeling of the Bilateral System forms “Right sided blood shunt”

101
Q

What forms the left brachiocephalic vein?

A

Anastomosis of the Anterior Left & Right Cardinal Vein forms Left Brachiocephalic Vein

102
Q

What occurs to the rest of the left Cardinal vein?

A

Rest of the left Cardinal vein is Lost→END of left side blood flow

103
Q

What are the Three Drainages to the Heart (RA)?

A

SVC + CS + IVC

  • SVC: Superior Vena Cava
  • CS: Coronary Sinus
  • IVC: Inferior Vena Cava
104
Q

Superior Vena Cava (SVC) forms from?

A

Right Anterior Cardinal Vein + Right Common Cardinal Vein

105
Q

Posterior Cardinal Veins drains into?

A

Mesonephroi & degenerates with it

106
Q

Coronary Sinus transports blood from where?

A

Blood from heart muscles into RA.

107
Q

Inferior vena Cava is the fusion of what?

A

Fusion of the 2 Vitelline Veins

108
Q

What is the roof of azygos vein?

A

Blood (thorax + Abdomen)→SVC

109
Q

During Venous System development what do the structures below become:

  • Cardinal Vein Anastomosis→
  • Umbilical Vein Anastomosis→
  • Fusion to the “Right Vitelline Vein”→
A
  • Cardinal Vein Anastomosis→Superior Vena Cava (SVC)
  • Umbilical Vein Anastomosis→“Ductus Venosus” Bypass (Left-UV) (liver bypass)
  • Fusion to the “Right Vitelline Vein”→Portal Vein (Inferior Vena Cava) (IVC)

Result: End of the Left Blood Return

110
Q

What is the fetal circulatory system?

A

Blood supply to and from the placenta and 3 Shunts

111
Q

Fetal circulatory system has 3 shunts to do what?
What are the 3 shunts?

A

Fetal circulatory system has 3 shunts to divert blood from undeveloped organs (lung & liver)

  • 3 Shunts are:
    1. Ductus arteriosus (do not want pressure from pul trunk to lung, connects aorta to pulmonary artery)
    2.Foramen Ovale (limits the pressure on pul circulation, allows blood in the RA to reach LA)
    3. Ductus Venosus (protects the liver by bypassing it)
112
Q

Initially, three systems of veins are present for the IVC (Day 26). What are they?

A
  1. Umbilical veins from the chorion
  2. Vitelline veins from the umbilical vesicle
  3. Cardinal veins from the embryo→Subcardinal veins →Supracardinal veins→ Subsupracardinal veins
113
Q

How do we get the final form of the Inferior Vena Cava?

A
  • The venous System in the Caudal portion of the Embryo passes through various stages of development.
  • Several veins form and degenerate, giving rise to newer sets of venous system.
  • However, some remnants of each of these system contributes to the final form of the Inferior Vena Cava, collecting deoxygenated blood rom the caudal-half of the body.
114
Q

What is the Superior Vena Cava?

A

A valve-less system collects blood from the neck, head, upper extremities, and chest

115
Q

Two dorsal aortae develop early and connect to what? via what?

A

Two dorsal aortae develop early and connect to the heart tube via first aortic arch arteries

Formation of dorsal aorta and aortic arches

116
Q

By day 26 the Truncus arteriosus is present which froms what?

A

Day 26: Truncus arteriosus→ Aortic Sac

  • 3 Pharyngeal arch arteries→2 Dorsal aortae
  • Vitelline & Umbilical arteries

Formation of dorsal aorta and aortic arches

117
Q

What happens to the aortic arch arteries on 35 day (which arch arteries degenerate? What structure is formed)? later on? (what aortic arch degenerates, which on remains)

A
  • 35 days: 1st & 2nd arch arteries mostly degenerate & a single dorsal aorta forms
  • Later: 5th aortic arch degenerates; III, IV & VI remain

Aortic arch arteris in the head, neck and thorax

118
Q

Where is the location of:

  • Aortic Arch I
  • Aortic Arch II
  • Aortic Arch III
  • Aortic Arch IV
  • Aortic Arch VI
A

Aortic Arch I: Maxillary Artery

  • Aortic Arch II: Stapedial artery (rare)
  • Aortic Arch III: Common cartoid artery and internal cartoid artery (external carotid artery us a angiogenic branch of AA III)
  • Aortic Arch IV: Right side-right subclavian artery (proximal portion); Left side-aortic arch (portion btw the left common carotid and subclavian arteries)
  • Aortic Arch VI: Right side-pulmonary artery; Left side-left pulmonary artery and ductus arterious
119
Q

How is the ductus arteriosus formed? What does this allow?

A
  • Left Aortic arch VI links truncus arteriosus to the Left dorsal aorta, forming ductus arteriosus (DA), allowing blood to bypass the lungs
  • This happens by connecting pulmonary trunk to left aorta
120
Q
  • Fetal pulmonary vascular resistance is what?
  • 90% of the blood is shunted through what?
  • What does the shunt allow?
A
  • Fetal pulmonary vascular resistance is high
  • 90% of blood shunted through the ductus arteriosus→aorta
  • Shunt also allows the wall of the left ventricle to thicken
121
Q

Failure of the Ductus Arteriosus to close after birth is called what? And causes and leads to what?

A
  • Patent Ductus Arteriosus (PDA) and the generation of a left-to-right shunting
  • Leads to pulmonary hypertension, heart failure & cardiac arrhythmias
122
Q

By Day 21 the Cardiovascular system begins to develop; _________ and ____________

A

By Day 21 the Cardiovascular system begins to develop; the 2-heart tubes and 2 dorsal aortae

123
Q

__________ develops from blood islands at the _______most end of the U-shaped ___________. Heart tubes fuse and begin to beat by _______.

A

Two primordial heart tubes develops from blood islands at the cranial most end of the U-shaped perocardio-peritoneal canal. Heart tubes fuse and begin to beat by week 4.

124
Q

___________ surrounding the heart tube forms the ____________

A

Splanchnic mesoderm surrounding the heart tube forms the primordial myocardium.

125
Q

The heart primordium has 4 __________: the ________,__________,_______ and ________

A

The heart primordium has 4 chambers: the Bulbus cordis, Ventricle, Atrium, and Sinus Venosus

126
Q

The _____________ (primordium of the ascending aorta and pulmonary trunk) is continuous caudally with the ___________, which becomes part of the ventricles.

A

The truncus arteriosus (primordium of the ascending aorta and pulmonary trunk) is continuous caudally with the bulbus cordis, which becomes part of the ventricles.

127
Q

As the heart grows, __________ gives the tube an S-shape, juxtaposing inflow (________) and outflow tract (____________) cranially.

A

As the heart grows, D-looping gives the tube an S-shape, juxtaposing inflow (Sinus Venosus) and outflow tract (Truncus arteriosus) cranially.

128
Q

The heart becomes partitioned into ______ between the _____________.

A

The heart becomes partitioned into four chambers between the fourth and seventh weeks

129
Q

Three systems of paired veins drain into the primordial heart: the ___________, the ___________ & _________

A

Three systems of paired veins drain into the primordial heart: the vitelline system (portal system); the cardinal veins & the umbilical veins

130
Q

The pharyngeal arches receive blood from ________ that arise from the _____________.

A

The pharyngeal arches receive blood from pharyngeal arteries that arise from the aortic sac

131
Q

By 6-8 week, most of ______,_____, & __________ are lost. Rest form adult arterial arrangement of the _______________, __________ and __________ arteries.

A

By 6-8 week, most of 1st, 2nd & 5th arch arteries are lost. Rest form adult arterial arrangement of the carotid, subclavian, and pulmonary arteries.

132
Q

__________originates from the pulmonary trunk and connects to the __________suppling deoxygenated blood.

A

Ductus arteriosus originates from the pulmonary trunk and connects to the L. dorsal aorta suppling deoxygenated blood.

Embryology: Summer Semester (10 decks)

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