Cardiovascular Embryo

Question 1

What derives from neuroextoderm (neural crest) with respect to the heart

Answer 1

aorticopulmonary septum

Question 2

What derives from Mesoderm (lateral) with respect to the heart

Answer 2

blood cells
cardiovascular system
Muscles and connective tissue of heart
serous membranes of percardial cavity

Question 3

Where do blood vessels initially form

Answer 3

extraembryonic mesoderm of umbilical vesicle, connecting stalk, and chorion

Question 4

Why does blood vessel and heart formation occur

Answer 4

simple diffusion of oxygen and nutrive materials cant supply rapid growth of embryo

Question 5

Where do the primordial heart and great vessels begin to differentiate

Answer 5

cardiogenic area (horshoe shaped area cranially lateral to neural plate)

Question 6

What is the first appearance of the heart and what do they cannalize to form

Answer 6

Angioblastic cords

cannalize to form endocardial heart tubes

Question 7

What forms the primitive heart tube

Answer 7

Fusion of the endocardial heart tubes

Question 8

What does the primitive heart tube develop into

Answer 8

endocardium

Question 9

What are the dilations and constrictions of the heart tube from superior to inferior

Answer 9

Truncus arteriosus
Bulbus cordis
ventricle
atrium
sinus venosus

Question 10

What gives rise to the arteries suplying the pharyngeal arches

Answer 10

truncus arteriosus

Question 11

What section of the elongating heart tube recieves the veins of the embryo umbilical vesicle and placenta

Answer 11

Sinus venosus

Question 12

Which 2 sections of the elongating heart tube grow faster and why

Answer 12

Bulbus cordis and ventricle

truncus aretiousus and sinus venosus are fixed in the pharyngeal arches and septum transversum respectively

Question 13

What develops into the Myocardium and Epicardium

Answer 13

splanchic mesoderm surrounding the primitve heart tube and pericardial cavity

Question 14

Where do contractions begin when the heart first starts to beat

Answer 14

sunus venosus (initially uncoordinated)

Question 15

what first forms the partiioning of the atrioventricular canal and what does it develop from

Answer 15

Endocardial cushions on the dorsal and ventral walls

develops from induction of cardiac jelly (secreted by developing myocardium)

Question 16

When does the heart first begin to beat

Answer 16

begining of 4th week

Question 17

What is the first tissue that seperates the atrium called and where does it originate

Answer 17

septum primum

superoposterior wall

Question 18

What is the foramen of the septum primum that is a part of the valve action

Answer 18

Foramen secundum

Question 19

Where is the first opening of the septum primum located and what is it called

Answer 19

caudal ventral before closing

foramen primum

Question 20

what is the second layer of tissue dividing the atrium and where does it originate

Answer 20

Roof of atrium just right of foramen secundum

septum secundum

Question 21

Which of the artial dividers is thicker

Answer 21

septum secundum

Question 22

what is the opening of the septum secundum and where is it located

Answer 22

foramen ovale

near floor of right atrium

Question 23

describe the conditions necessary and path of blood trough the valve of the foramen ovale

Answer 23

pressure in right greater than left atrium
enters through floor of right atrium through froramen ovale
exits through foramen secundum in ceiling of left atrium

Question 24

What 3 veins does the sinus venosus recieve and where are they from

Answer 24

cardinal: embryo
vitelline: umbilical vesicle
umbilical: placenta

Question 25

What are the lateral expansions of the siuns venosus and when do they develop

Answer 25

Left and right horns | during bulboventricular loop folding

Question 26

Which horn of the sinus venosus becomes enlarged and why, and what happens to the other horn

Answer 26

Righ horn becomes enlarged divertion of blood flow to the right side (oblique anastomosis from anterior cardinal veins to right horn and degeneration of umbilical and vitelline veins on left side) Left becomes coronary sinsus

Question 27

What eventually becomes the coronary sinus

Answer 27

Left horn of the sinus venosus

Question 28

What forms the Sinus venarum of the right atrium

Answer 28

The joining of the right horn of the sinus venosus with the right atrium

Question 29

What portions of the right atrium are derived from primitive right atrium

Answer 29

the trabeculated surface of the right atrium and the right aruicle (also trabeculated)

Question 30

What forms the smooth wall of the left atrium

Answer 30

incorporation of the 4 branches of the primary pulmonary vein

Question 31

Once the left atrium merges with the branches of the primordial pulmonary vein what happens to the primitive left atrium

Answer 31

It is displaced anteriorly and to the left | becomes left auricle

Question 32

What begins the partitioning of the ventricles

Answer 32

growth of the muscular interventricular septum

Question 33

What is the halt in interventricular septum growth called and where does it appear

Answer 33

interventricualr foramen just before the fused endocardial cushions

Question 34

What closes the interventricular foramen

Answer 34

proliferation of tissue from the right side of the endocardial cushions and merging of that memranous interventricular septum with the aorticopulmonary septum

Question 35

What forms the atrioventricular valves

Answer 35

proliferation of tissue around the left and right atrioventicular canals and thining of the tissue on the ventriular sides (muscle replaced later with connective tissue forming valve cusps)

Question 36

what is the precursor of the papillary muscles and chordae tendinae

Answer 36

trabeculae carneae

Question 37

What causes the formation of trabeculae carneae

Answer 37

additional vavitation of ventricular walls

Question 38

what does the aorticopulmonary septum seperate

Answer 38

left and right ventricular outflow pathways (aorta and pulmonary trunk)

Question 39

What fuses to form the arorticopulmonary septum

Answer 39

bulbar and truncal ridges

Question 40

What produces the bulbar and truncal ridges

Answer 40

migration of neural crest cells into the bulbus cordis and truncus areriosus

Question 41

What does the bulbus cordis become in the right ventricle

Answer 41

Conus arteriosus (infundibulum)

Question 42

What does the bulbus cordis become in the left ventricle

Answer 42

aortic vestibule

Question 43

What does the truncus arteriosus become

Answer 43

Pulmonary trunk and proximal aorta

Question 44

What causes the twisted arrangement of the pulmonary trunk and proximal aorta

Answer 44

spiraling of the bulbar and truncal ridges

Question 45

What are the eventual derivatives of the sinus venosus

Answer 45

sinus venarum and the coronary sinus

Question 46

What are the eventual derivatives of the atrium of the heart tube

Answer 46

trabeculated parts of right and left atria

Question 47

What are the eventual derivatives of the vintricle of the heart tube

Answer 47

trabeculate parts of the right and left ventricles

Question 48

What are the eventual derivatives of the bulbus cordis

Answer 48

Conus arteriosus and aortic vestibule

Question 49

What are the eventual derivatives of the truncus arteriosus

Answer 49

Proximal aorta and pulmonary trunk

Question 50

Where do the pharyngeal arch arteries arise from

Answer 50

aortic sac

Question 51

What is the aortic sac

Answer 51

expanded cranial portion of the truncus arteriosus

Question 52

How many Pharyngeal arch arteries are there and which give rise to important arteries and which give rise to smaller ones or dissapear

Answer 52

6 3, 4, 6 are important 1 2 5 are smaller or dissapear

Question 53

What is the derivative of the 1st pharyngeal arch artery

Answer 53

part of maxillary artery

Question 54

What is the derivative of the 2nd pharyngeal arch artery

Answer 54

stapedial artery (stem)

Question 55

What is the derivative of the 3rd pharyngeal arch artery

Answer 55

Common carotid and proximal part of internal carotid

Question 56

What is the derivative of the 4th pharyngeal arch artery

Answer 56

Left: Part of arch of aorta (between left common carotid and subclavian) Right: Proximal part of right subclavian

Question 57

What is the derivative of the 5th pharyngeal arch artery

Answer 57

NOTHING

Question 58

What is the derivative of the 6th pharyngeal arch artery

Answer 58

Left: Proximal portion of left pulmonary artery and ductus arteriosus Right: Proximal portion of right pulmonary artery

Question 59

What is responsible for the asymmetry of the left and right recurrent laryngeal nerves of vagus

Answer 59

assymetrical development of left and right sixth paryngeal arch arteries

Question 60

What is the ductus arteriosus and what does it eventually become

Answer 60

shunt betweeen aorta and pulmonary trunk | eventually becomes ligamentum arteriosum

Question 61

why does the right reccurent laryngeal nerve loop around the 4 pharyngeal arch artery

Answer 61

because the disatl part of the 6th arch artery degenerates and the 5th fails to form 4th becomes right subclavian

Question 62

what does the left recurrent laryngeal artery loop around

Answer 62

ligamentum artteriosum

Question 63

where is the dorsal aorta located

Answer 63

inferior to the pharyngeal arches

Question 64

What are the three types of branches off of the dorsal aorta

Answer 64

Ventral (vitelline and umbilical) Lateral (kidneys, suprarenal glands, gonads) Dorsal intersegmental (body wall, head and neck, limbs, vertebral colum)

Question 65

What are the derivatives of the ventral vitelline branches of the dorsal aorta

Answer 65

esophageal celiac superior mesenteric inferior mesenteric

Question 66

What are the derivatives of the ventral umbilical proximal branches of the dorsal aorta

Answer 66

Superior vesical umbilical (adult) Internal iliac (proximal)

Question 67

What are the derivatives of the ventral umbilical distal branches of the dorsal aorta

Answer 67

Medial umbilical ligaments

Question 68

What are the derivatives of the lateral branches of the dorsal aorta

Answer 68

Renal Middle suprarenal gonadal arteries

Question 69

What are the derivatives of the Dorsal (intersegmental) branches of the dorsal aorta

Answer 69

All other branches of aorta

Question 70

What is the adult remnant of the left umbilical vein

Answer 70

Ligamentum teres hepatis

Question 71

What is the adult remnant of the ductus venosus

Answer 71

Ligamentum venosum

Question 72

What is the adult remnant of foramen ovale

Answer 72

Fossa ovalis

Question 73

What is the adult remnant of Ductus arteriosus

Answer 73

Ligamentum arteriosum

Question 74

What is the adult remnant of the distal umbilical arteries

Answer 74

Medial umbilical ligaments

Question 75

Where does the oxygen rich blood from the placenta go

Answer 75

To the Umbilical veins bypassing the liver capillary bed through the ductus venosus to enter the inferior vena cava

Question 76

Once oxygenated blood from the placenta has entered the inferior vena cava where does it go

Answer 76

gets divered through the foramen ovale into the left atrium some goes into right ventricle and mixes with deox blood from superior vena cava

Question 77

What type of blood is in the right ventricle in the womb and what happens to it

Answer 77

mixed blood | goes up through pulmonary trunk and most enters the ductus arteriosus to enter the descending aorta

Question 78

Which section of the body recieves the most oxygenated blood in the womb

Answer 78

head heart upper limbs and neck (blood straight from left atrium) Trunk and lower body get mixed from ductus arteriosus

Question 79

What maintains the patency of ductus arteriosus

Answer 79

prostaglandins and low o2 content in blood

Question 80

how does blood in the descending aorta return to the placenta

Answer 80

through umbilical arteries

Question 81

What mediates the closing of ductus arteriosus immediately after birth

Answer 81

high blood oxygen content | Bradykinin

Question 82

What releases the bradykinin that mediates the closing of ductus arteriosus

Answer 82

lungs after intial infalation

Question 83

Oxygenated or deoxygenated what type of blood do the umbilical arteries and veins carry

Answer 83

veins; oxygenated | arteries: deoxygenated

Question 84

What happens to the umbilical veins and arteries at birth

Answer 84

Umbilical arteries constrict | umbilical veins remain patent for some time

Question 85

Why is constriction of the umbilical vein and ductous venosus not essential after birth

Answer 85

because blood is nolonger flowing through the umbilical vein