Block 3 Anatomy: Embryology of the Heart I

Primordial heart and vascular system appear during the ____ week of development

3rd

The intraembryonic cavity over the cardiogenic field develops into the ______ ______

pericardial cavity

DEVELOPMENT OF THE SINUS VENOSUS Where does each sinus horn receive blood from?

1. Vitelline, omphalomesenteric, vein (VIT) 2. The umbilical vein (UV 3. Common cardinal vein (CCV)

SEPTUM FORMATION IN THE ATRIOVENTRICULAR CANAL: ____ valves form in the left atrioventricular canal and ____ valves form in the right atrioventricular canal

2 3

Heart starts beating on the ____ day

22-23

CARDIAC LOOP. The heart begins to bend in a specific manner on day ____.

23

FORMATION OF SEMILUNAR VALVES Number of tubercles that contribute to the pulmonary channel and how many to the aortic channel

3 3

Patent foramen ovale.

ASSOCIATION WITH OTHER DEFECTS Atrial septal aneurysm. Eustachian valve and Chiari network. Atrial septal defect. Ebstein's anomaly.

Due to abnormal endocardial cushion formation

Atrial and ventricular septal defects

The heart consists of four parts. List in order from cranial to caudal

Bulbus cordis Ventricle Atrium Sinus venosus

splanchnic layer

Cells are in splanchnic layer of LATERAL PLATE MESODERM**

COmplete absence of atrial septum

Cor trioculare beventriculare

The heart is on the right because the heart tube loops to the left instead of the right

Dextrocardia

DEVELOPMENT OF THE SINUS VENOSUS. In the middle of the fourth week,___?

In the middle of the fourth week, the sinus venosus receives blood from the right and left sinus horns

cardinal

N: bird, songbird of the bunting family. a leading dignitary of the Roman Catholic Church. of the greatest importance; fundamental.

SEPTUM FORMATION IN THE TRUNCUS ARTERIOSUS AND CONUS CORDIS: Contribute to the formation of both truncus and cordis cushions; hence the abnormalities of neural crest origin will contribute to congenital malformations of the great vessels as well as facial abnormalities.

Neural crest cells

Leaves a large opening between the atria; due to excessive resorption of septum primum or inadequate development of septum secundum.

Ostium secundum defect

Failure of fusion of the conotruncal ridges which is always accompanied by a defective interventricular septum. The undivided truncus receives blood from both sides of the heart

Persistent truncus arteriosus

Due to unequal divisiion of the conus because of the displacement of the conotruncal septum. This produces 4 alterations: 1. Pulmonary infundibular stenosis 2. Large interventricular septal defect 3. Overriding aorta that arises directly above the septal defect 4. Hypertrophy of the right ventricular wall

Tetraology of Fallot

The cephalic portion of the tube bends ____ ?

The cephalic portion of the tube bends ventrally, caudally, and to the right while the caudal portion moves dorsally, cranially, and to the left.

This bending forms the _____ _____, WHICH IS COMPLETE BY DAY 28

This bending forms the cardiac loop, WHICH IS COMPLETE BY DAY 28

Occurs when the conotruncal septum fails to follow the spiral course, and instead runs straight down. Because of this aorta originates from the right ventricle and the pulmonary artery originates from the left ventricle. This is usually accompanied by an open ductus arterioles.

Transposition of the great vessels

Characterized by either the absence of the fusion of the tricuspid valves, resulting in obliteration of the right atrioventricular orifice

Tricuspid atresia

FORMATION OF THE CARDIAC SEPTA T/F. The major septa of the heart form between the 27th and the 37th day of development.

True

The semilunar valves are fused for a variable distance, reducing the opening of the vessel

Valvular stenosis

MOST COMMON CONGENITAL CARDIAC MALFORMATION

Ventricular septal defect involving the membranous portion of the septum

cardinal

a leading dignitary of the Roman Catholic Church. Cardinals are nominated by the pope and form the Sacred College, which elects succeeding popes (now invariably from among their own number).

DEVELOPMENT OF THE SINUS VENOSUS. During the next few weeks (weeks 4-10) blood becomes shunted from left to right, causing obliteration of some structures. What structures are obliterated?

a. Right umbilical vein b. Left vitelline vein c. Left common cardinal vein

FORMATION OF HEART TUBE. Initially, the Cardiogenic area is ______ to the oropharyngeal membrane.

anterior

SEPTUM FORMATION IN THE TRUNCUS ARTERIOSUS AND CONUS CORDIS: In the process of growth, the swellings twist around each other, fuse, and form the ______ _______ that divides the truncus into an ____ channel and a _____ channel

aorticopulmonary septum aortic pulmonary

The atrioventricular junction forms the _____ _____ connecting the atrium and the embryonic ventricle.

atrioventricular canal.

FORMATION OF CONDUCTING SYSTEM OF HEART Cells derived form the left wall of the sinus venosus and from the atrioventricular canal, become the _____ _____ and _____ of ______, lying at the base of the interatrial septum

atrioventricular node bundle of His

The initially paired atria fuse and form a common ______

atrium.

_____ ____ also appear in the mesoderm, they unite to form a horse shoe shaped endothelial tube surrounded by myoblasts-forming the _______ ______

blood islands. cardiogenic field.

Now the heart is suspended in the pericardial cavity by ____ _____ at its cranial and caudal poles

blood vessels

brain vesicles grow:

brain vesicles grow cephalic rapidly and extend over the cardiogenic area and future pericardial cavity.

CARDIAC LOOP Composed of a proximal part, middle part, CONUS ARTERIOSUS AND CONUS CORDUS, and distal part. truncus arteriosus embryology. truncus arteriosus types. truncus arteriosus repair. truncus arteriosus prognosis

bulbus cordis

The embryo folds ______ and ______, which results in the merging of the paired, lateral, cardiac primordial.

cephalocaudally laterally

The oropharyngeal membrane is pulled forward by the growing brain while the developing heart and pericardial cavity move first to the ______ region then to ______

cervical thorax

SEPTUM FORMATION IN THE ATRIOVENTRICULAR CANAL: The valves are connected to the ventricular wall papillary muscles by means of ____ _____

chordae tendinae

SEPTUM FORMATION IN THE TRUNCUS ARTERIOSUS AND CONUS CORDIS: Similar to the truncus swellings and simultaneously with them, swellings also occur along the right dorsal and left ventral walls of the _____ ______

conus cordis

_____ segment cells migrate first form outflow tracts, then other parts sequentially right ventricle, left ventricle-sinus venous.

cranial

DEVELOPMENT OF THE SINUS VENOSUS The dividing line between teh original trabeculated part of the right atrium and its smooth walled part is formed by the ____ _____

crista terminalis

SEPTUM FORMATION IN THE ATRIOVENTRICULAR CANAL: The muscular tissue in the cords degenerates and become replaced by ____ ____ ___, covered by ______

dense connective tissue endocardium

SEPTUM FORMATION IN THE TRUNCUS ARTERIOSUS AND CONUS CORDIS: The right superior truncus swelling grows ____ and to the ____ while the left inferior truncus swelling grows _____ and to the _____

distally left distally right

Initially, the heart tube is attached to the dorsal side of the pericardial cavity by the _____ ______

dorsal mesocardium

The heart lies on the surface of the chest due to failure of the closure of the ventral body wall.

ectopia cordis

In the fourth and fifth weeks, two sets of atrioventricular ______ ______ appear. *First, a superior and inferior, later a left and right lateral atrioventricular cushions line the atrioventricular canal

endocardial cushions

The heart becomes a tube with an inner _______ and outer _____ layer.

endothelial myocardial

Cardiac progenitor cells lie in _______, from there they migrate through the PRIMITIVE STREAK

epiblast. The cardiac progenitor cells lie in the epiblast, immediately lateral to the primitive streak and from there, they migrate Myoblasts and blood islands Neural plate Primitive node Primitive streak field ... through the streak.

The myocardium thickens and secretes a thick layer of _____ _____ that separates it from the endothelium.

extracellular matrix

FORMATION OF THE CARDIAC SEPTA With growth, the free edge of the septum secundum begins to overlap the OSTIUM SECUNDUM, but opening remains. This is ____ _____. The upper part of the septum primum disappears; the remaining part becomes the ____ of the ____ _____

foramen ovale valve of the foramen ovale. Cryptogenic stroke. Migraine and vascular headache. Decompression sickness and air embolism. Platypnea-orthodeoxia syndrome.

SEPTUM FORMATION IN THE VENTRICLES An _____ ______ remains initially above the muscular interventricular septum, but becomes closed off with growth of tissue from the inferior endocardial cushion and its fusion with the CONUS SEPTUM.

interventricular foramen

Parts of the heart tube form _____ _____ that result in change of appearance and composition

local expansions

Cells migrate cranially and become rostral to _____ ______ and _____ _____.

oropharyngeal membrane neural folds

SEPTUM FORMATION IN THE VENTRICLES The site of closure of the former interventricular foramen becomes the ______________

membranous part of the interventricular septum

Each atrioventricular orifice is surrounded by local proliferations of _____ _____

mesenchymal tissue

SEPTUM FORMATION IN THE VENTRICLES The septum that develops to separate the left and right ventricles will have a ______ and a _______ part

muscular membranous

SEPTUM FORMATION IN THE ATRIOVENTRICULAR CANAL: Valves remain attached to the ventricular wall by _____ _____

muscular cords

SEPTUM FORMATION IN THE VENTRICLES The _____ ______ ____ is formed by the merging of the MEDIAL WALLS of the expanding ventricles

muscular interventricular septum

DEVELOPMENT OF THE SINUS VENOSUS. Because of all of the obliterations, all that remains of the left sinus horn is the _____ ____ of the left atrium and the ______ _____

oblique vein. coronary sinus. Because of all of the obliterations, all that remains of the left sinus horn is the oblique vein of the left atrium and the coronary sinus.

FORMATION OF THE CARDIAC SEPTA The opening between the lower rim of the septum primum and the endocardial cushion in the atrioventricular canal forms the ______ ______

ostium primum

FORMATION OF THE CARDIAC SEPTA Growth of the endocardial cushions obliterates the ostium primum, however, PERFORATIONS form in the upper part of the septum primum which then fuse to form the _____ ______. This allows the blood to flow from RIGHT atrium to LEFT ATRIUM

ostium secundum

The crescent part of the horseshoe shaped area expands to form the future ____ _____ and _____ regions

outflow tract ventricular

SEPTUM FORMATION IN THE TRUNCUS ARTERIOSUS AND CONUS CORDIS: These fusions divide the conus into the __________ and the ___________

outflow tract of the right ventricle (anterolateral) outflow tract of the left ventricle

BULBUS CORDIS. The conus cordis forms the ____ _____ of both ______

outflow tracts ventricles

Cells are induced by ____ _____ to form _____ ____

pharyngeal endoderm cardiac myoblasts

BULBUS CORDIS, The junction between the ventricle and bulbs cordis forms the ______ ______ ______ , visible externally as the bulboventricular sulcus.

primary interventricular foramen

FORMATION OF THE CARDIAC LOOP: BULBUS CORDIS The trabeculated primitive ventricle is now the ____ _____ _____, while the trabeculated part of the bulbus cordis is the ______ _____ ___

primitive left ventricle primitive right ventricle

FORMATION OF THE CARDIAC SEPTA At birth, the valve of the foramen ovale becomes pressed against the septum secundum, obliterating the oval foramen. In 20% of cases the fusion is incomplete resulting in a condition called ____ _____

probe patency

FORMATION OF THE CARDIAC SEPTA Additional development of the atria include: 1. Incorporation of the ____ _____ into the left atrium forming its smooth walled component. 2. The original trabeculated left atrium becomes the ____ ____ _____. 3. The original right atrium becomes the trabeculated _____ _____ _____.

pulmonary veins. left atrial appendage. right atrial appendage.

The middle parts of the superior and inferior cushions project into the lumen and fuse, dividing the , right atrioventricular, canal into a _____ and a ____ ____ ______

right and left atrioventricular orifice

DEVELOPMENT OF THE SINUS VENOSUS Because of the left to right shunt of blood, the ____ _____ _____ is incorporated into the right atrium forming its smooth walled portion. The sinuatrial orifice is guarded by the right and left and venous valves, which fuse dorsally, forming the ______ _____.

right sinus horn septum spurium

BULBUS CORDIS, The CONUS ARTERIOSUS (infundibulum) becomes incorporated into the _____ _____

right ventricle

FORMATION OF SEMILUNAR VALVES Gradually, the tubercles hollow out their upper surface and provide teh shape forming ______ _______

semilunar valves

FORMATION OF THE CARDIAC SEPTA At the end of the fourth week a sickle shaped crest grows from the roof of the atrium into the lumen. This is the first part of the _____ ______

septum primum

FORMATION OF THE CARDIAC SEPTA With the incorporation of the sinus horn into the right atrium a new fold develops, which is the ____ ____, never forms a complete partition.

septum secundum

FORMATION OF CONDUCTING SYSTEM OF HEART As the sinus venous becomes incorporated into the right atrium, the _______ _______, lying near the opening of the superior vena cava, becomes the pacemaker

sinoatrial node

FORMATION OF THE CARDIAC SEPTA The smooth walled portion of the right atrium, the ____ _____ is derived from the right horn of the sinus venous.

sinus venarum

FORMATION OF CONDUCTING SYSTEM OF HEART The pacemaker site of the heart is initially in the caudal part of the left cardiac tube, but then becomes a funciton of the ______ _______

sinus venosus

FORMATION OF THE CARDIAC LOOP: BULBUS CORDIS At the end of loop formation, the heart tube forms _____ just proximal and distal to the primary interventricular foramen

trabeculae

BULBUS CORDIS. The proximal part of the bulbus cordis forms the _______ _____ of the ______ _______.

trabeculated part of the right ventricle

THe dorsal mesocardium disappears creating a spaces, the ______ ______ ____

transverse pericardial sinus

BULBUS CORDIS, The _____ _____ will form the ROOTS OF THE AORTA AND PULMONARY TRUNK

truncus arteriosus

SEPTUM FORMATION IN THE TRUNCUS ARTERIOSUS AND CONUS CORDIS: The conus swellings also grow towards each other fuse and also fuse with the ____ _____

truncus septum

SEPTUM FORMATION IN THE TRUNCUS ARTERIOSUS AND CONUS CORDIS: In the fifth week, a pair of opposing ridges called _____ _____ (cushions) appear on the right superior wall (right superior truncus swelling) and on the left inferior wall (LEFT INFERIOR TRUNCUS SWELLING)

truncus swellings

FORMATION OF SEMILUNAR VALVES Semilunar valves are formed from _____ on the ____ _____ with contributions from neural crest cells

tubercles truncus swellings

The ventricular surfaces of the mesenchyme are hollowed out by blood flow, become thin and ____ form

valve

DEVELOPMENT OF THE SINUS VENOSUS The superior pat of the right venous valve disappears while the inferior part forms the....

valve of inferior vena cava valve of the coronary sinus