Embryology: Cardiovascular System

Front 1

Blood islands

Back 1

-aggregates of splanchnic mesoderm
-link with others to form blood vessels
-surrounding mesenchyme differentiates into CT and muscular layer of vessels

Front 2

reticulocyte

Back 2

immature RBC

Front 3

band cells

Back 3

immature neutrophils

Front 4

megakaryocytes

Back 4

platelets

Front 5

vascular endothelium

Back 5

develops from peripheral cells of blood islands

Front 6

hemocytoblasts

Back 6

-develops from central cells of blood islands
-differentiate into various types of blood cells in early embryo

Front 7

cardiogenic plates

Back 7

-left and right develop from the splanchnic mesoderm adjacent to the pericardial cavity
-cardiac tube: several vesicles develop inside cardiogenic plates and later unite to form this hollow tube

Front 8

head and lateral folding

Back 8

- left and right cardiac tube fuse together and become ventral to the foregut

Front 9

septum transversus

Back 9

-mesoderm caudal to the cardiac tube forms this future diaphragm

Front 10

dorsal mesocardium

Back 10

fold of mesodermal tissues that attaches the developing/bulging heart tube to the dorsal side of the pericardial cavity

Front 11

transverse pericardial sinus

Back 11

connects both sides of the pericardial cavity, with the further development of the dorsal mesocardium disappearing

Front 12

bulbus, ventricle and atrium

Back 12

local expansions of the cardiac tube

Front 13

truncus arteriosus and sinus horn

Back 13

1. truncus arteriosus: develops at cranial end
2. sinus horn: develops at caudal end

Front 14

layers of cardiac tube

Back 14

1. endocardium
2. myocardium
3. epicardium

Front 15

U shaped bulboventricular loop

Back 15

-entire cardiac tube becomes spiraled
-bulbus and ventricle become a U shaped loop
-loop grows and drops caudal/ventral becoming the bulboventricular loop

Front 16

shift of septum and atria

Back 16

-atrium and sinus shift cranially until they lie dorsal and cranial to the rest
-atrium grows rapidly lateral and forms a sacculation on each side which foreshadows the future atria

Front 17

sinus venosus

Back 17

-eventually becomes incorporated into the right side of the common atrium

Front 18

further development of bulboventricular loop

Back 18

-increases in size, merging the two into a single chamber
- at about the same time, median longitudinal groove in the ventricle indicates the partitioning

Front 19

folding of heart

Back 19

develops because pericardial cavity grows slower than the heart

Front 20

atrioventricular cushions

Back 20

-right and left develop at the common atrioventricular canal
- two cushions fuse together, forming the septum intermedium which creates left and right atrioventricular orificies

Front 21

septum primum

Back 21

-a sickle shaped membrane that grows down from the middorsal wall of the atrium
-expands ventrally towards septum intermedium

Front 22

foramen primum

Back 22

diminishing gap between the septum primum and septum intermedium

Front 23

foramen secundum

Back 23

single orifice created by the joining of many tiny perforations in septum primum

Front 24

septum secundum

Back 24

-membranous sheet develops from the right side of the septum primum
-thicker, more rigid that septum primum

Front 25

foramen ovale

Back 25

window created from incomplete growth of septum secundum
-blood passes from right atrium through the fa, the between the 2 interatrial septum and into the left atrium via the foramen secundum

Front 26

right atrium

Back 26

from primitive atrium and sinus horns

Front 27

sinus venerum

Back 27

-region in mature animal
- right horn of sinus venosus becomes completely incorporated and open into the right atrium where cranial and caudal vena cava opens

Front 28

coronary sinus

Back 28

formed by the left horn of the sinus venosus

Front 29

right auricle

Back 29

- original embryonic right atrium characterized by the the development of pectinate muscles=

Front 30

left atrium

Back 30

mainly developed from primitive atrium

Front 31

primitive pulmonary vein

Back 31

=single venous vessel which develops as an outgrowth of the left atrial wall
-later gains connection with veins of the developing lung buds

Front 32

smooth-walled part of left atrium

Back 32

-pulmonary vein and its branches become incorporated into the left atrium, forming the large smooth-walled part of the adult left atrium

Front 33

left auricle

Back 33

=pectinate muscle developed on original left atrium

Front 34

aorticopulmonary or spiral septum

Back 34

-two prominent longitudinal thickenings develop in endocardial linings of ta and bc
-they fuse, creating a septum that divides ta and bc into:
1. aortic off LV -and-
2. pulmonary trunk off RV
-

Front 35

conus arteriosus

Back 35

-distal most part of the bulbus incorporated in the RV
-area around the origin of pulmonary artery in the RV

Front 36

muscular interventricular septum

Back 36

- median partition that grows as a cresentric plate with the enlargement of the future halves of the ventricle

Front 37

interventricular foramen

Back 37

communication between the two ventricles due to incomplete partition of muscular interventricular septum

Front 38

ventral endocardial cushioon

Back 38

=septum intermedium
- outgrowth of tissue towards the muscular interventricular septum that closes the interventricular foramen

Front 39

membranous interventricular septum

Back 39

-formed by the closing of the interventricular foramen
-fuses with the muscular interventricular septum and spiral septum to complete the partition

Front 40

right and left AV valves

Back 40

-local mesenchymal thickening which develops around the margins of the AV orifices
-as they become hollowed out they form endocardial cusps

Front 41

endocardial cusps

Back 41

-formed by AV valves hollowing
-RV: tricuspid
-LV: bicuspid
-connected to papillary muscles by chordae tendinae

Front 42

semilunar valves

Back 42

-develop as small tubercles at the pulmonary and aortic channel
-tubercles become hollowed out at their surface and form semilunar valves

Front 43

conducting system

Back 43

develops by a differentiation of the myocardial tissue

Front 44

truncus arteriosus

Back 44

aorta, pulmonary artery

Front 45

bulbus cordis

Back 45

aorta, pulmonary artery and conus arteriosus

Front 46

primitive ventricle

Back 46

left and right ventricle

Front 47

primitive atrium

Back 47

right and left atria

Front 48

right horn of sinus venosus

Back 48

sinus venerum of right atrium

Front 49

left horn of sinus venosus

Back 49

coronary sinus of right atrium

Front 50

aorta

Back 50

truncus arteriosus and bulbis cordis

Front 51

pulmonary artery

Back 51

truncus arteriosus and bulbis cordis

Front 52

consus arteriosus

Back 52

bulbus cordis

Front 53

right ventricle

Back 53

primitive ventricle and bulbus cordis

Front 54

right atrium

Back 54

primitive atrium and sinus venosus

Front 55

left atrium

Back 55

primitive atrium

Front 56

left ventricle

Back 56

primitive ventricle

Front 57

coronary sinus

Back 57

left horn of sinus venosus

Front 58

sinus venerum of right atrium

Back 58

right horn of sinus venosus

Front 59

pulmonary stenosis

Back 59

-acyanotic cardiac defect
-constrictions at both valvular and infundibular levels
1. postenotic dilation of pulmonary trunk
2. right ventricular dilation and hypertrophy

Front 60

aortic stenosis

Back 60

-acyanotic cardiac malformation
-due to formation of fibrous subaortic ring
1. postenotic dilation of ascending aorta
2. LV dilation and hypertrophy
3. LA dilation

Front 61

interventricular septal defects

Back 61

-acyanotic cardiac malformation
1. primary hypertrophy of LV
2. secondary RV dilation and hypertrophy

Front 62

interatrial septal defects

Back 62

-acyanotic cardiac defect
1. enlarged foramen secundum and ovale
2. subsequent RV, RA and LA dilation and hypertrophy of ventricle
3. RA
4. LA

Front 63

Tetralogy of Fallot

Back 63

-cyanotic cardiac malformation
-dextroaorta:
1. pulmonary stenosis
2. I-V septal defect
3. dilation and hypertrophy of RV

Front 64

Eisenmenger complex

Back 64

-cyanotic cardiac malformation
- with dextroaorta:
1. I-V septal defect
2. RV dilation and hypertrophy

Front 65

Transposition of great vessels

Back 65

-cyanotic cardiac malformation
- transposition of great vessels w/ aorta emanating from the:
1. RV and pulmonary trunk
2. LV
- in order for animal to survive postnatally, one or more shunts allowing mixing of R and L circulations

Front 66

interatrial septal defects

Back 66

-shunts can occur as a result of interatrial septal defects:
1. patent ductus arteriosus
and/or
2. I-V septal defect

Front 67

persistent truncus arteriosus

Back 67

-cyanotic cardiac malformation
-both ventricles are equal in size

Front 68

components of early embryonic circulation

Back 68

1. single, tubular heart
2.1 pair of vitelline arteries
3.1 pair of umbilical arteries
4. 3 pairs of venous channels

Front 69

3 pairs of venous channels

Back 69

-components of early embryonic circulation
-drain into the sinus venosus: the vitelline (omphalomesenteric), umbilical and cardinal veins

Front 70

1 pair of umbilical arteries

Back 70

-component of early embryonic circulation
-from dorsal aortae to the allantois, derived from the extraembryonic mesoderm

Front 71

1 pair of vitelline arteries

Back 71

-component of early embryonic circulation
-from dorsal aortae to the yolk sac (derived from the extra-embryonic mesoderm)

Front 72

single, tubular heart

Back 72

-components of early embryonic circulation
-continuous with aortic arches that empty into paired dorsal aortae

Front 73

aortic arches gen

Back 73

-during development of pharyngeal arches, each receives its on CrN and artery, known as aortic arches
- arise from the aortic sac which is the most cranial part of the truncus arteriosus
- join R and L dorsal aortae
- in domestic animals, 6 pairs develop but all are not present at any one time

Front 74

derivatives of 1st and 2nd aortic arches

Back 74

none

Front 75

derivative of 3rd aortic arch

Back 75

common/ internal carotid artery

Front 76

derivatives of 4th aortic arch

Back 76

R: R subclavian a
L: continues as descending aorta

Front 77

derivative of 5th aortic arch

Back 77

none

Front 78

derivatives of 6th aortic arch

Back 78

R and L pulmonary artery
- L 6th retains its connection to the aorta as the ductus arteriosus

Front 79

aortic arch abnormalities

Back 79

1. patent ductus arteriosus (typical metallic murmur)
2. persistent R aortic arch results in vascular ring anomalies

Front 80

dorsal intersegmental arteries

Back 80

- branch of dorsal aorta
-arise bilaterally between the somites
-form intercostal and lumbar arteries

Front 81

branches of dorsal aorta

Back 81

1. dorsal intersegmental aa
2. lateral aortic branches
3. ventral aortic branches

Front 82

lateral aortic branches

Back 82

-branch of dorsal aorta
- supplies the derivatives of the intermediate mesoderm
- forms renal, testicular or ovarian arteries

Front 83

ventral aortic branches

Back 83

-branch of dorsal aorta
- supplies the splanchnic mesodermal and endodermal tissues of the thoracic and abdominal cavities
-develop into broncho-esophageal, celiac, and caudal mesenteric arteries

Front 84

fate of vitelline artery

Back 84

L: regresses
R: persists and forms cranial mesenteric artery

Front 85

fate of umbilical artery

Back 85

-proximal: contributes to the external and internal iliac arteries
-distal: form the round ligament of the urinary bladder

Front 86

cardinal vein

Back 86

-cr. and ca. join the common which enters the sinus venosus

Front 87

brachiocephalic trunk

Back 87

-cr. and ca. cardinal vv. become connected by a channel which develops into brachiocephalic trunk

Front 88

cranial vena cava

Back 88

-caudal part of L cr. cardinal degenerates
-R cr. and R common cardinal develops into cr. vena cava

Front 89

caudal cardinal vein

Back 89

-subcardinal and supracardinal vein graduallly develops to replace the ca. cardinal vein

Front 90

caudal vena cava

Back 90

-mainsegment develops from subcardinal veins of either side joining to form the subcardinal sinus
-ca. venacava joints R vitelline vein which develops into the hepatic segment of ca. vena cava and opens into the sinus venosus

Front 91

azygous veins

Back 91

-supracardinal vein develops on both sides into L and R azygous vv
-horse and dogs: only R persists
-pigs: only L persists
-ruminants: both L and R persists

Front 92

proximal vitelline vein

Back 92

-L: atrophies
-R: hepatic segment of caudal vena cava

Front 93

middle vitelline vein

Back 93

hepatic sinusoids and hepatic segment of caudal vena cava

Front 94

distal segment of vitelline vein

Back 94

portal venous system

Front 95

umbilical vein

Back 95

round ligament of the liver

Front 96

branching of azygous vein

Back 96

-most domestic animals: branching from R caudal cardinal
- pig and horse: branches from L side, found branching from coronary sinus in adults

Front 97

umbilical vein

Back 97

-oxygenated blood
-

Front 98

ductus venosus

Back 98

-upon reaching the liver, most of the blood flows through dv directly to ca. vena cava
-small amount of blood enters the liver sinusoids and mixes with blood from the portal circulation

Front 99

blood after leaving liver

Back 99

-oxygenated blood mixes with deoxygenated blood returning from the hind part of the body
-enters RA

Front 100

foramen ovale

Back 100

-allows passage of blood from RA to LA
-small amount remains in the RA

Front 101

blood in LA

Back 101

blood enters the LV and aorta, which supplies the cranial part of the body with oxygenated blood

Front 102

ductus arteriosus

Back 102

- deoxygenated blood returning from the cr. vena cava flows through RV and into pulmonary trunk
- majority of the blood passes through the da and mixes with the oxygenated blood of the aorta, supplying the abdomen and lower body
-becomes ligamentum arteriosum

Front 103

umbilical arteries fx

Back 103

blood flows through aorta then towards the placenta via 2 umbilical arteries

Front 104

fate of umbilical veins

Back 104

become the round ligament of the liver

Front 105

fate of the umbilical arteries

Back 105

-proximal part: contributes to the external and internal iliac arteries
- distal part: forms the round ligament of the urinary bladder