Heart I, III & III Flashcards
Where is the Angle of Louie? [level of the spine and level of ribs]
Spinal level T4-T5
At the 2nd rib
Coelomic Canal - what does it eventually form? What shape is it? Where does it develop?
Its the primordium of body cavities
Upsidedown “U” shaped
Develops in the lateral plate mesoderm and cardiogenic mesodern
What are the two layers of the mesoderm involved in heart development? What do each of them envolve into?
somatopleure mesoderm and splanchnopleure mesoderm
somatopleure - parietal layer of serous pericardium
splanchnopleure - visceral layer of serious pericardium
What is congestive cardiac failure (CHF)?
inability to maintain blood circulation
What is a cardiac tamponade?
What are the symptoms of a cardiac tamponade?
How do cardiac tamponade occur?
How are they treated?
Blood accumulation in the pericardial cavity.
Beck’s Triad - low arterior BP, JVD, muffled heart sounds
Stab wound or MI
pericardiocentesis
What is Ectopia Cordis?
What causes it?
rare- the pericardium and the heart are eposed through a defect in the chest wall
because of a failure of lateral walls to fuse in week 4
What is patent foramen ovale?
Most common ASD - failure of fusion between septum primum and septum secundum
long term = pulmonary hypertension
What is probe patent foramen ovale?
incomplete fusion between septum primum and septum secundum
What is Common atrium (cor triloculare biventriculare)?
the absence of interartial septum
you have only 1 atrium and 2 ventricles
occurs in people who have all 3 defects = ostium secundum fefect, endocardial cushion defect, sinus venosus defect
What is primum type ASD ?
Found in down syndrome - foramen primum not closed
What is secundum type ASD?
abnormally large foramen secundum or foramen ovale
What is sinus venosus type ASD?
defective absorption of sinus venosis into right atrium
What is membranous type VSD?
most common of ALL congential heart diseases! = 25%
caused by the failure of tissue from endocardial cushions to fuse with the primordial interventricular septum and the bulbar septum
Failure of contribution from fused endocardial cushions. Defects in muscular part of IV septum are rare. total absence is RARE.
Total absense results in a common ventricle (cor triloculare biatrium) = 1 ventricle and 2 atrium
can have associated mitral valve abnormality
L to R shunting
Ascultation of Heart Valves
What is the tetralogy of Fallot?
Pulmonary stenosis - primary defect due to asymmetrical partitioning of truncus artieriosis
right ventricular hypertrophy
Ventricular septal defect (VSD)
overriding Aorta
What are the treatment options for CHD?
PTCA-Coronary angioplasty
Coronary bypass graft
What PTCA in coronary angioplasty?
Percutaneous (through skin)
Transluminal (within lumen)
Coronary (a. which suppliies the heart)
Angioplasty (remodeling the a.)
Where does blood form?
from blood islands in the Yolk sac
What induces etraembryonic splanchnic mesoderm?
extraembryonic endoderm
What are angioblasts?
vessel-forming cells - endotheliual cell precursors differentiated mesenchymal cells
aggregate to form blood islands
What are hemangioblasts?
specialized endothelial cells
blood-forming cells
What is cardiogenic mesoderm?
upsidedown “U” shape extending back on both sides of the foregut
What induces early heart tissue?
endoderm
What does the splancnic mesoderm have?
cardiogenic plate - whcih is anterior to the oropharyngeal membrane
Where is the developing pericardial cavitiy located?
between somatic and splanchnic mesoderm
What do the vesicles in the pre-cardiac splanchnic mesoderm fuse to form?
paired endocardial primordia on both sides of the foregut
Explain lateral folding (heart formation)
endocardial primordia fuse along the midline = primitive tubular heart
inner endocardial lining becomes the endocardium - surrounded by a matrix called cardiac jelly
myocardium surrounds the cardiac jelly
What are the two folding events that take place in the formation of the heart?
lateral folding and head folding
What happens duing head folding?
the heart tube and pericardial cavity rotatate 180 degrees
lie ventral to foregut and caudal to oropharyngeal membrane
What direction do the heart tubes fuse and what to they form eventually?
begins cranially and ends caudally
forms a single heart tube
What happens during heart elongation?
bending of the heart tube to the right
bulbus cordis go down and the ventricles and atrium turn up
What is the direction of the primordial blood flow?
sinus venosus - atrium - ventricle - bulbus cordis - truncus arteriosis - aortic sac - pharyngeal arch arteries
What are the endocardial cushions and what is there significance?
they form on the dorsal and ventral walls of the AV canal
the dorsal and ventral cushions fuse = divide AV canal into R and L AV canal
role in the formation of interartial and interventricular septum
What happens during partitioning the primordial atrium?
septum primum and septum secundum are formed
foramen primum and foramen secundum are formed
2 foramen + 2 septum
What gives rise to the foramen ovale?
the septum secundum
the septum primum forms the valve of the oval foramen = after birth, fuses with septum secundum and forms fossa ovale
What do the parts of the sinus venosus form? [right horn, left horn, opening, sinus verarum, crista terminalis]
right horn = SVC and IVC
left horn = coronary sinus
the opening shifts to the right = right atrium
sinus venarum = smooth wall of right atrium
crista terminalis = separates the sinus verarum from primordial atrium
Where are bulbar and truncal ridges derived from?
neural crest mesenchyme
How are aorta and pumonary trunk formed?
the formation of the aorticopulmonary septum divides bulbis cordis and truncus artiosus into aorta and pulmonary trunk
What are the right to left shunts in fetal circulation?
foramen ovale and ductus arteriosus
What changes occur from fetal circulation to neonatal circulation?
foramen ovale closes = fossa ovale
ductus arteriosus closes = ligamentum arteriosum
Remember - ductus venosus bypasses the liver!
What is Patent Ductus Arteriosus (PDA)?
L to R shunt
pulmonary hypertension
assocated with materal rubella infection in early pregnancy
What is coarctation of the Aorta?
constriction of the aorta
upper limb hypertension
associated with Turner’s syndrome
What is transposition of great arteries?
most common cause of cyanotic heart disease in new borns
switching of aorta and pumonary trunk
immediately lethal unless combines with another defect - PDA, ASD, VSD
