Cardiovascular Development B Flashcards
What are the two heart fields in the developing heart?
- Primary Heart Field
- Splanchnic mesoderm → gives rise to the primitive heart tube
- Secondary Heart Field
- Adjacent splanchnic mesoderm that is subsequently added to the developing heart tube through both cranial and caudal ends
- Primary Heart Field
- _________ → gives rise to the _________
- Secondary Heart Field
- ________ that is subsequently added to the developing heart tube through both _____ and ______ ends
- Primary Heart Field
- Splanchnic mesoderm → gives rise to the primitive heart tube
- Secondary Heart Field
- Adjacent splanchnic mesoderm that is subsequently added to the developing heart tube through both cranial and caudal ends
Cardiac neural crest cells arise from ________ and also migrate into the primary heart tube through the ______ where they mostly contribute to the ________
Cardiac neural crest cells arise from beside the hindbrain and also migrate into the primary heart tube through the arterial pole of the OT where they mostly contribute to the outflow tract
Label the image
Label the image
The __________ is the only part of the heart that forms exclusively from the primary heart tube (1st heart field)
The left ventricle is the only part of the heart that forms exclusively from the primary heart tube
The right ventricle is derived from the _______ (heart field)
The right ventricle is derived from the secondary heart field
The ______ are a mix of primary and secondary heart field
The atria are a mix of primary and secondary heart field
The aorta and pulmonary trunk are a mix of _____ and _______
The aorta and pulmonary trunk are a mix of secondary heart field and neural crest (OT)
The epicardium is derived from:
Proepicardial organ
Label the heart
*** Know Left and Right Coronary arteries ( first branches off of the aorta) ***
The first two branches off of the aorta are the:
Left and Right Coronary arter
The left coronary artery divides into two branches:
Circumflex artery
Left Anterior Descending Artery (LAD)
_________ are branches off the base of the ascending aorta”
Coronary arteries are branches off the base of the ascending aorta”
Coronary veins collect in ______ which empties into _______
Coronary veins collect in coronary sinus which empties into right atrium
Label
What is the major contributor to the coronary vessels?
Sinus Venosus → vascular sprouts from sinus venosus (venous tissue) → makes arteries, capillaries and veins → migrate over the heart as a vascular plexus
→ Endocardium believed to also be a source
Coronary plexus undergoes remodeling via ________ derived from _______ to give rise to ______
Coronary plexus undergoes remodeling via addition of smooth muscle cells derived from the epicardium (some cells fo the epicardial layer delaminate and differentiate as smooth muscle and wrap vessels) to give rise to larger vessels
Coronary plexus undergoes remodeling via ________ derived from _______ to give rise to ______
Coronary plexus undergoes remodeling via addition of smooth muscle cells derived from the epicardium (some cells fo the epicardial layer delaminate and differentiate as smooth muscle and wrap vessels) to give rise to larger vessels
The _______ is similar to the sinus venosus but is found superiorly
The aortic sac is similar to the sinus venosus but is found superiorly
_________ fuse to form a single descending aorta
Dorsal aortae fuse to form a single descending aorta
______ and _______ contribute to dorsal aortae
Splanchnic and somitic mesoderm contribute to dorsal aortae
Development of arteries:
Label the image:
Blood vessels run through the _______ connecting the outflow tract to the dorsal aorta
Blood vessels run through the pharyngeal arches connecting the outflow tract to the dorsal aorta
There are _____ aortic arches
There are 5 aortic arches
1, 2, 3, 4, 6 (#5 lost in evolution)
Which aortic arches degenerate?
1 and 2 → leaves aortic arches 3, 4, 6
Label the image
Label the image
What is the fate of the aortic arches?
1, 2 → degenerate
3 → Common carotid arteries
Right 4 → Right subclavian
Left 4 (and aortic sac) → Arch of the aorta
Left 6 → Ductus arteriosus
Aortic arch remodeling:
1, 2 → ________
3 → ________
Right 4 → ________
Left 4 (and ________) → ________
Left 6 → ________
1, 2 → degenerate
3 → Common carotid arteries
Right 4 → Right subclavian
Left 4 (and aortic sac) → Arch of the aorta
Left 6 → Ductus arteriosus
Label the image
Label both the vessels and the aortic arch from which they develop
Right subclavian from the Right 4th aortic arch
Common carotids from the R & L 3rd
Ductus arteriosus from the L 6th
1 and 2 degenerate
The ______ feeds blood into the R common carotid and R subclavian
The Brachiocephalic artery feeds blood into the R common carotid and R subclavian
Label the Final arrangement of arteries
The _____________ branch off the vagus nerve (cranial nerve X) and has an indirect course through the neck.
It gets caught under the ______ on right and under ______ on the Left
The Recurrent Laryngeal Nerves branch off the vagus nerve (cranial nerve X) and has an indirect course through the neck.
It gets caught under the 4th arch (Right subclavian Artery in shoulder) on right and under 4th and 6th arch (Arch of the aorta) on the Left
Why do the recurrent laryngeal nerves extend into the superior mediastinum and then back into the neck?
Because they are caught under the Aortic Arches during development (4th and 6th)
Venous return initially converges onto the _______
Venous return initially converges onto the left and right horns of the sinus venosus
The ______ return deoxygenated blood from the body of the embryo
- label the image
The cardinal veins return deoxygenated blood from the body of the embryo
Which vessels carry oxygenated blood from the placenta to the embryo?
Umbilical veins
Which vessels return blood from the yolk sac before it is lost in body folding? Why is this blood important?
Vitelline veins carry blood from the yolk sac and is important for bringing blood cells
How do the inferior veins change from 28-32 days to 53-54 days?
Goes from three pairs of inferior veins connected to the heart to one inferior vein connected to the heart (terminal inferior vena cava)
Which vessel(s) do(es) the liver engulf?
The liver engulfs the umbilical and vitelline veins
True or false, the liver engulfs the umbilical, vitellin and inferior cardinal veins
F
The liver engulfs the umbilical and vitelline veins but DOES NOT engulf the cardinal veins
What happens to the umbilical and vitelline veins?
- Left vitelline vein and right umbilical vein degenerate or are repurposed
- Terminal portion of right vitelline vein persists as connection to heart
- Left umbilical vein persists but loses connection to heart and now connects to remnant of right vitelline vein
Label the image:
_______ and ________ will contribute to veins of the liver
Vitelline and umbilical veins will contribute to veins of the liver
Terminal portion of left umbilical vein travels through liver as ________ before fusing with ________
Terminal portion of left umbilical vein travels through liver as ductus venosus before fusing with terminal portion of right vitelline vein
Distal part of L umbilical vein stuck inside as shunt (ductus venosus) → not being processed by the liver
Distal part of L umbilical vein stuck inside the liver as shunt (_________) → not being processed by the liver
Distal part of L umbilical vein stuck inside as shunt (ductus venosus) → not being processed by the liver
The terminal portion of the inferior vena cava formed by _______
The terminal portion of the inferior vena cava formed by Right vitelline vein
Days 53-54: All blood from placenta and lower body enters heart through ________
Days 53-54: All blood from placenta and lower body enters heart through inferior vena cava
Which veins remain as contributers to the inferior vena cava?
Right vitelline vein → terminal portion of IVC
Inferior cardinal veins → lower portion of inferior vena cava
What happens tot he superior cardinal veins?
- Left superior cardinal vein (SCV) established anastomosis with right SCV
- Left SCV loses contact with heart and now drains into right CCV (Common cardinal veins)
- This Anastomosis forms the left brachiocephalic vein
- The right CCV becomes the superior vena cava
Label the image:
- 35-38 days
- Common cardinal veins → Superior cardinal veins
- 53-54 days
- Superior cardinal veins form anastomosis (Right and Left SCV connect) → forms left brachiocephalic vein
- 56-60 days
- Connection to heart on the left is lost and the Right CCV (common cardinal vein) becomes the superior vena cava (SVC)
Fate of sinus venosus:
- Left horn of sinus venosus forms the ________ (collects blood from _______)
- Right horn of sinus venosus is ______ and forms ________
Fate of sinus venosus:
- Left horn of sinus venosus forms the coronary sinus (collects blood from coronary veins → dumps blood into Rt atrium)
- Right horn of sinus venosus is absorbed into right atrium and forms posterior wall of right atrium
Label the image:
→ posterior wall of _______ connects to superior and inferior vena cava → feed directly into heart rather than ________
→ posterior wall of right atrium connects to superior and inferior vena cava → feed directly into heart rather than sinus venosus
Right horn of sinus venosus forms smooth (posterior wall) part of right atrium called the ________
Openings to _____, _____ and _______ are all brought into right atrium
Right horn of sinus venosus forms smooth part of right atrium called the Sinus Venarum
Openings to superior vena cava, inferior vena cava and coronary sinus are all brought into right atrium
How do the pulmonary veins form?
- Instead of forming from remodelled structures, form _____ from ______
- Pulmonary veins form within the ______ and then connect to ______
How do the pulmonary veins form?
- Instead of forming from remodelled structures, form de novo from dorsal mesocardium → degrades but first cells undergo vasculogenesis and give rise to pulmonary vein
- Pulmonary veins form within the dorsal mesocardium and then connect to heart and lungs
Proximal portions of the pulmonary veins become incorporated into _______ creating _______
_______ pulmonary veins each bring blood into _____ atrium
Proximal portions of the pulmonary veins become incorporated into wall of left atrium creating smooth part of left atrium
four pulmonary veins each bring blood into l_eft atrium_
Label the image
What does the asterisk represent?
Asterisk shows start of where proximal portions of pulmonary veins become incorporated into the wall of the left atrium
Describe the pathway of Fetal circulation
Inferiorly:
Placenta → Umbilical vein → Ductus venosus (liver shunt) → Inferior vena cava (oxygenated blood from ductus venosus & deoxygenated blood returning from lower body) → Right atrum → interatrial septum (bypass right ventricle) → Left atrium → Left ventricle → Aorta
Describe the pathway of Fetal circulation
- Inferior:
- Superior:
- Inferior:
- Placenta → Umbilical vein → Ductus venosus (liver shunt) → Inferior vena cava (oxygenated blood from ductus venosus & deoxygenated blood returning from lower body) → Right atrum → interatrial septum (bypass right ventricle) → Left atrium → Left ventricle → Aorta
- Superior:
- Superior vena cava (deoxygenated) → Right atrium → Right ventricle → Pulmonary trunk → Ductus arteriosus (connects pulmonary artery and aorta) → Descending aorta
How does circulation change postnatally?
- Lungs fill with air and pulmonary vascular pressure decreases (blood can flow into pulmonary arteries and through pulmonary circulation)
- Blood flow from placenta ceases
- Higher pressure in left atrium than right → atrial shunt closes (flat valve)
- Ductus arteriosus closes in response to increased oxygen (inhibits prostaglandins leaving a ligamentum arteriosium)
- Ductus venosus closes
- Ligamentum venosum
- Umbilical vein closes
- Ligamentum teres hepatis
Postnatal circulation:
- Lungs fill with air and pulmonary vascular pressure _______ (blood can flow into pulmonary arteries and through pulmonary circulation)
- placental blood flow?
- Higher pressure in left atrium than right → _______ closes (flat valve)
- Ductus arteriosus closes in response to _______ (inhibits ______ leaving a _________)
- Ductus venosus closes leaving behind:
- ________
- Umbilical vein closes leaving:
- __________
- Lungs fill with air and pulmonary vascular pressure decreases (blood can flow into pulmonary arteries and through pulmonary circulation)
- Blood flow from placenta ceases
- Higher pressure in left atrium than right → atrial shunt closes (flat valve)
- Ductus arteriosus closes in response to increased oxygen (inhibits prostaglandins leaving a ligamentum arteriosium)
- Ductus venosus closes
- Ligamentum venosum
- Umbilical vein closes
- Ligamentum teres hepatis
What is the problem with the image and how might it have occurred? Associated defects?
- Aorta and pulmonary trunk have switched positions = Transposition of the Great Arteries
- aorta is connected to right ventricle and pulmonary trunk to left atrium.
- In theory, this was a failure of the outflow tract to form in a spiral, but we don’t really know the cause.
- Often, there will be associated defects such as a patent ductus arteriosus and septal defects, which in this case are life-saving. Without some way to exchange blood between the two circuits, there would be no means to oxygenate the blood going out to the body.
What is the problem with the image?
Tetralogy of Fallow
- Tetralogy (meaning 4)
- Four aspects of the disease are:
- pulmonary stenosis,
- overriding aorta,
- ventricular septal defect and
- enlarged right ventricle (here is shown a patent ductus arteriosus too).
The image shows Tetralogy of Fallow. This includes 4 defects:
- pulmonary stenosis
- Overriding aorta
- Ventricular septal defect
- Enlarged right ventricle
What are these defects?
- Pulmonary stenosis =
- when the pulmonary valve (the valve between the right ventricle and the pulmonary artery) is too small, narrow, or stiff.
- An overriding aorta
- is a congenital heart defect where the aorta is positioned directly over a ventricular septal defect, instead of over the left ventricle. → aorta receives some blood from right ventricle as well as left ventricle → ↓oxygen in blood
- Ventricular septal defect:
- a birth defect of the heart in which there is a hole in the wall (septum) that separates the two ventricles of the heart.
- Right ventricular hypertrophy (also called right ventricular enlargement) happens when the muscle on the right side of your heart becomes thickened and enlarged
How might tetralogy of fallow occur?
The outflow tract septum is malformed → it separated the aorta and pulmonary trunk unevenly. Because the septum was malaligned, it also failed to fuse with the muscular ventricular septum, leading to a ventricular septal defect. As a result of the stenotic pulmonary trunk, the right ventricle has backup/retention of blood (and pumps harder to move blood to lungs), leading to enlargement.
What is wrong with the image?
What is truncus arteriosus?
Outflow tract didn’t form correctly:
- didn’t form completely (or at all), leaving a common outflow tract and ventricular septal defect.
- Truncus arteriosus is a term for a portion of the embryonic outflow tract
What is wrong with the image?
Double aortic arch
Aorta is hugging the trachea and esophagus → potential for harm through compression of esophagus and trachea
- With the significant remodeling that happens to the aortic arches, there is always the chance of variation. Most variations are harmless. This one is more dramatic and has potential for harm, through compression of esophagus and trachea.
What does the image show?
The aorta sometimes develops with a region of constriction, a condition called coarctation of the aorta. The narrowing is typically adjacent to the ductus arteriosus, suggesting a connection. Coarctations are defined as pre or post-ductal.
What congenital heart defect is shown in the image?
In this ectopia cordis, the heart protrudes out of the body. This is thought to be a failure in formation of the anterior thoracic wall, although the heart is typically not normal, suggesting a larger developmental problem.
What are the two most common congenital heart malformations?
Note that atrial and ventricular septal defects are the two most common congenital heart malformations.
