Anatomy Exam 4: Heart Development

Front 1

Blood islands develop, beginning in the 3rd week, from mesenchymal cells in what?

Back 1

splanchnic mesoderm

Front 2

The blood islands develop in a horseshoe-shaped plexus around the cephalic end of the neural plate, what does this plexus form?

Back 2

endocardial tubes

Front 3

Describe the cardiogenic area

Back 3

the cephalic central portion of the horseshoe-shaped plexus, in front of the buccopharyngeal membrane

Front 4

The portion of intraembryonic coelom located over the cardiogenic area will develop into what?

Back 4

the pericardial cavity

Front 5

The ________ develop bilaterally parallel & close to the midline, they vessels later connect w/ the arterial end of the heart tube

Back 5

dorsal aortae

Front 6

Lateral folding of the trilaminar germ disc brings together the 2 lateral endothelial tubes, where they fuse, forming what?

Back 6

a single endocardial HEART TUBE

Front 7

Mesoderm adjacent to heart tube thickens and forms what?

Back 7

the epimyocardial mantle

Front 8

The epimyocardial mantle is initially seperated from the endothelial tube by what?

Back 8

cardiac jelly

Front 9

The endothelial tube is invaded by cells from the __________, after being seperated from the epimyocardial mantle

Back 9

endothelium

Front 10

The wall of the heart tube develops into what 3 layers?
describe each

Back 10

endocardium- lines inner chambers

myocardium- muscular middle layer, forms most of wall thickness

epicardium-(visceral pericardium) covers outside

Front 11

The intrapericardial part of the heart tube will become the future ______________

Back 11

bulboventricular region

Front 12

Local swellings, that will develop into projecting structures, appear on the heart tube. What pre-structure swelling are present starting from the venous end to the arterial end?

Back 12

Venous End--->
> Sinus venosus (paired)
> Atrium
> Ventricle
> Bulbus cordis
---> Aterial End

Front 13

The proximal 1/3 of the bulbus cordis will contribute to the ___________
The middle portion, conus cordis, will form outflow tracts for the __________
The distal 1/3 (truncus arteriosus, will form the proximal portions of the _____ & _______

Back 13

proximal 1/3- right ventricle
middle (conus cordis)- outflow tracts of ventricles
distal 1/3 (truncus arteriosus)- aorta & pulmonary trunk

Front 14

As the initially straight heart tube continues to bend, the cephalic portion bends ____________________
while the caudal portion shifts __________________

what does this create by day 28?

Back 14

cephalic bends ventrally caudally & to right
caudal shifts dorsocranially & to left

creates cardiac loop

Front 15

If the heart tube loops to the left instead of right, the heart will be located on the (right/left) side of thorax.

What is this called?

Back 15

right side of thorax = dextrocardia

Front 16

Dextrocardia may coincide w/ a complete reversal of asymmetry in all organs, what is this called?

Back 16

situs inversus

Front 17

What is the truncoconal portion of the heart tube?

How does its position change during development?

Back 17

truncus arteriosis + conus cordis = truncoconal portion

Shifts from R side of pericardial cavity to more medially, ends up btwn dilatations of the atrium

Front 18

During the 4th week of development, the _____________ consists of a transverse portion & R & L sinus horns

Back 18

sinus venosus

Front 19

Each sinus horn is receiving what 3 veins?

Back 19

vitelline, umbillical, & common cardinal veins

Front 20

As the communication btwn sinus venosus & atrium shifts right, what happens to the sinus horns and their veins?

Back 20

-left vitelline & common cardinal veins dissappear
-left sinus horn shrinks & becomes oblique vein of left atrium & coronary sinus

Front 21

The coronary sinus drains blood from where?

Back 21

from cardiac veins

Front 22

In contrast, the right sinus horn enlarges & is incorporated into what?
What does it become?

Back 22

the right atrium

sinus venarum, smooth walled part of atrium

Front 23

The original R atrium form the rough walled part of the adult R atrium containing what?

Back 23

pectinate muscles

Front 24

The smooth (sinus venarum) & rough part of the atrium wall are seperated by what?

Back 24

crista terminalis

Front 25

Septum formation w/i common atrium begins with the formation of ____________, which grows from the roof toward endocardial cushions in the atrioventricular canal.

Back 25

septum primum
(sickle-shaped)

Front 26

The ________ is the temporary opening btwn the septum primum & endocardial cushions

Back 26

ostium primum

(btwn future R & L atrium)

Front 27

What appear in the septum primum before the ostium primum is closed?

What do they do?

Back 27

ostium secundum (perforations)

maintain blood flow from the R to L primitive atrium

Front 28

What is the septum secundum?

Back 28

2nd crescent-shaped fold that appears to the R of the septum primium

Front 29

The septum secundum never completely partitions the atrium, leaving what opening?

Back 29

foramen ovale

Front 30

The upper part of the septum primum degenerates and the lower part forms what?

Back 30

valve of the foramen ovale

Front 31

Until the fusion of the valve of the foramen ovale with the septum secundum at birth, blood flows from the ___________ to the _________ through the foramen ovale

Back 31

from the R atrium to the L atrium

Front 32

A probe patency of the foramen ovale persists in 25% of people, what is this?

Back 32

failure of the foramen ovale to close

Front 33

The R & L atria enlarge by incorporating other structures. What do each side incorporate?

Back 33

R atrium- left sinus horn (sinus venarum)

L atrium- pulmonary vein & its (4?) tributaries

Front 34

Heat defects may be due to 3 different factors, what are they?

Back 34

genetic: chromosomal abnormalities (Turners) of gene mutations
environmental: rubella virus
multifactorial: combination

Front 35

Atrial septal defects are common and include ostium secundum defects. What are the causes and effects of ostium secundum defects?

Back 35

caused by: excessive resorption of septum primum or inadequate development of septum secundum

effects: significant Left-to-right shunting of blood may occur due to higher pressure on left side

Front 36

Another atrial septal defect, a patent foramen ovale, causes what?

Back 36

if large enough, may permit left to right shunting of blood

Front 37

Another atrial septal defect, closure of the foramen ovale during fetal life, results in what?

Back 37

hypertrophy of the R side of hear (atrium & ventricle)
underdeveloped L side = left cardiac hypoplasia
=death shortly after birth

Front 38

Complete absence of the atrial septum results in what?

Back 38

common atrium (cor trilocular biventriculare)

= only 1 atrium, causes many problems

Front 39

What is the atrioventricular canal?

What are the two mesenchymal outgrowth from the canal?

Back 39

the junction btwn the original common atrium & L ventricle

endocardial cushions, develop at superior and inferior canal borders

Front 40

The superior & inferior cushion fuse, dividing the atrioventricular (AV) canal into 2 canals, providing what?

Back 40

separate openings between each atria and its corresponding ventricle (atrioventricular orifice)

Front 41

The right (____________) & left (_______/________) AV valves form when blood flow hollows & thins mesenchymal tissue on their ventricular surface,

Back 41

right- tricuspid valve
left- bicuspid/mitral

Front 42

The valve cusps are connected by _______ to papillary muscles

Back 42

chordae tendinae

Front 43

Septum formation in the conus cordis & truncus arteriosus occurs when.................

Back 43

conotruncal (endocardial) cushions spiral 180 degrees as they grow toward each other and fuse

Front 44

The conotruncual cushions develop from what?

They fuse to form what?

Back 44

migrating neural crest cells

aorticopulmonary septum

Front 45

what does the aorticopulmonary septum separate?

Back 45

aortic & pulmonary channels

Front 46

The inferior part of the aorticopulmonary septum fuses w/ an outgrowth from the inferior endocardial cushion to form what?

Back 46

forms membranous portion of the interventricular septum

Front 47

The muscular interventricular septum closes what?

Back 47

the interventricular foramen

Front 48

Ventricular septal defects, the most frequent isolated cardiac malformations, often involve what?

Back 48

the membranous portion of the interventricular septum

***small VSDs may close spontaneously

Front 49

*Unequal division of the truncus arteriosus may result in tetralogy of Fallot, what does this consist of?

Back 49

-pulmonary stenosis
-right ventricular hypertrophy
-ventricular septal defect
-overriding aorta

Front 50

Tetralogy of Fallot results in what?

Back 50

a right-to-left shunting of blood w/ cyanosis near time of birth due to poorly oxygenated blood in arterial circulation

Front 51

How can tetralogy of fallow be distinguished on an X-ray

Back 51

characteristic boot shaped heart

Front 52

Failur of the aorticopulmonary septum to spiral as it descends may result in what?

This condition is incompatible w/ postnatal survival unless what?

Back 52

transposition of the great arteries =
-aorta rising from R ventricle & pulmonary trunk from L ventricle -->CYANOSIS

unless accompanied by shunt, to allow oxygenated blood into aorta

Front 53

The developing heart tube bulges into the pericardial cavity & is suspended by _______________,
which subsequently disappears at future site of the _______________________

Back 53

dorsal mesocardium

transverse pericardial sinus

Front 54

The dorsal mesocardium disappear & the heart tube is suspended by it's arterial & venous ends. These ends become seperated by what when the heart tube folds?

Back 54

seperated by transverse pericardial sinus

Front 55

The ______________________ is formed by pericardial reflections at the venous end of the heart

Back 55

oblique pericardial sinus

Front 56

What heart defects are associated with the following disorders?
Down's syndrome
Turner's syndrome
22q11 syndrome
Congenital Rubella
Newborns of Diabetic mothers

Back 56

Down's syndrome- ASD
Turner's syndrome- coarctation of aorta
22q11 syndrome- truncus arteriosus
Congenital Rubella- PDA
Newborns of Diabetic mothers- transposition of great vessels