anatomy cardiac embryology II

Question 1

What are the two major mechanisms by which blood vessels are formed

Answer 1

1.) Vasculogenesis (large vessels) 2.) Angiogenesis (small vessels)

Question 2

Vasculogenesis

Answer 2

Formation of new blood vessels through the differentiation of angioblasts which join together to form vascular structures. Larger blood vessels are formed this way

Question 3

Angiogenesis

Answer 3

formation of new blood vessels through budding and sprouting from existing vessels. This is usually how smaller blood vessels are formed.

Question 4

What forms the first aortic arch

Answer 4

Dorsal aortae (formed from primary outflow vessels- develop in dorsal mesenchyme on the dorsal side of the notal cord) that get pulled ventrally

Question 5

Describe the development of arches 2,3,4,and 6

Answer 5

Develop between days 26 and 29. Ventrally the aortic arches arise from the aortic sac (anterior expansion of the conus arteriosus) As these areches are fromed the first and second arches begin to regress.

Question 6

First aortic arch gives rise to

Answer 6

External carotid and maxillary arteries

Question 7

Second aortic arch gives rise to

Answer 7

Stapedial artery

Question 8

Thrid aortic arch gives rise to

Answer 8

left and right common carotid arteries and part of the internal carotid arteries

Question 9

Fourth aortic arch gives rise to

Answer 9

Right fourth arch: Right subclavian artery (proximal part) Left fourth arch: ascending part of the aorta (aortic arch)

Question 10

Six aortic arch gives rise to

Answer 10

Right sixth arch: pulmonary arteries Left sixth arch: ductus arteriosus

Question 11

Ductus arteriosus

Answer 11

Arises from the left sixth arch. Connects to the aorta and allows shunting blood to the pulmonary trunk to the decending aorta

Question 12

What forms the ligamentum arteriosum after birth

Answer 12

Ductus arteriosus

Question 13

Vitelline arteries arise from…

Answer 13

plexuses in the yolk sac

Question 14

Vitelline arteries give rise to what

Answer 14

1.) Celiac Trunk 2.) Superior Mesenteric Artery 3.) Inferior Mesenteric Artery

Question 15

Lateral Branches of the descending aorta give rise to

Answer 15

1.) Suprarenal arteries 2.) Gonadal arteries 3.) Renal arteries

Question 16

Gonadal arteries

Answer 16

Gonads descend and the vasculature follows - becomes fixed at the 3rd or 4th lumbar level

Question 17

Renal arteries

Answer 17

Kidneys ascend- vasculature is degenerated and reformed at each level until the final pair forms in the upper lumbar region

Question 18

Intersegmental branches of the aorta

Answer 18

arise from the posterolateral surface of the aorta and supply somite derivatives ( MUSCLES)

Question 19

What do dorsal branches of intersegmental arteries supply

Answer 19

1.) Developing neural tube 2.) Developing deep muscles of the back and neck (epimeri muscles) 3.) Cutaneous braches supply the dorsal skin

Question 20

What do ventral branches of intersegmental arteries supply

Answer 20

developing hypomeric muscles and associated skin

Question 21

intercostal arteries arise frm what

Answer 21

ventral branches of intersegmental arteries in the throacic region

Question 22

lumbar and lateral sacral arteries arise from what

Answer 22

ventral branches of intersegmental arteries in the lumbar and sacral region

Question 23

Name the vessels that arise due to anastamosis of intersegmental branches

Answer 23

1.) Vertebral artery 2.) Deep Cranial 3.) Ascending cervical 4.) internal throacic 5.) Superior epigastric 6.) Inferior Epigastric

Question 24

How are arteries of the limbs fromed

Answer 24

remodeling of intersegmental arteries

Question 25

Umbilical arteries

Answer 25

return DEOXYGENATED blood to the placenta. Initailly brances of the dorsal aorta but during the 4th week they shift their origin to internal iliac arteries (th pair of lumbar intersegmental arteries)

Question 26

Fate of umbilical arteries after birth

Answer 26

Proximal parts persist as internal iliac and superior vesicular arteries, distal parts become obliterated

Question 27

Vitelline veins

Answer 27

arise from the capillary plexuses in theyolk sac and carry blood from the yolk sac to the sinus venosus

Question 28

Hepatic sinusoids arise from

Answer 28

right and left vitelline plexuses

Question 29

Hepatocardiac portion of the inferior vena cava arises from? How?

Answer 29

Right vitelline vein. As the left sinus horn is reduced, blood from the left side of the liver is redirected to the right causing enlargement of the right vitelline vein

Question 30

Portal vein arises from

Answer 30

venous anstomosis around the liver develops into a single portal vein

Question 31

Superior Mesenteric vein arises from

Answer 31

right vitelline vein caudal to the liver

Question 32

In general, the portal system arises from?

Answer 32

Vitelline Plexuses

Question 33

Where do umbilical veins originate

Answer 33

chorionic villa - carry OXYGENATED blood to the embyro

Question 34

Fate of umbilical veins

Answer 34

initially two umbilical veins pass on either side of the liver. During the second moth the RIGHT becomes obliterated and the LEFT forms a connection with the right vitelline vein = ductus venosus

Question 35

how is the ductus venosus formed? What is its function?

Answer 35

Formed by the connection between the left umbilical vein and the right vitelline vein. Crutial during fetal life as it shunts oxygenated blood from the umbilical system to the IVC and right atrium allowing it to BYPASS THE PORTAL SYSTEM (prevents hepatic capillaries from sucking out all the oxygen)

Question 36

What forms the ligamentum teres hepatis after birth

Answer 36

left umbilical vein

Question 37

what forms the left brachiocephalic vein

Answer 37

anastamosis of the anterior cardinal veins

Question 38

The Superior Vena Cava arises from

Answer 38

the right anterior cardinal vein and the right common cardial vein

Question 39

What veins supplement the posterior cardinal veins

Answer 39

1.) Subcardinal veins 2.) Supracardinal veins

Question 40

Subcardinal veins

Answer 40

drain the kidneys and develop into the posterior cardinals

Question 41

Supracardinal veins

Answer 41

replace posterior cardinals in draining the posterior part of the body wall through series of intercostal veins

Question 42

what forms the azygous vein

Answer 42

right supracardinal vein

Question 43

what froms the hemiazygous vein

Answer 43

left supracardinal vein - loses its connection to the left sinus horn and drains into the right supracardinal system

Question 44

Hepatic segment of the IVC is derived from

Answer 44

right vitelline vein

Question 45

Renal segment of the IVC is derived from

Answer 45

right subcardial vein

Question 46

Postrenal segment of IVC is derived from

Answer 46

right supracardinal vein

Question 47

Sacral segement of IVC is dervied from

Answer 47

right and left posterior cardinal veins

Question 48

Describe fetal circulation

Answer 48

Oxygenated blood is carried by the umbilical vein- most of it goes through the ductus venosus (some goes through the hepatic sinusoids) to the right atrium where it is joined by deoxygenated blood from the superior vena cava. Due to high pressure on the right side of the heart (due to pulmonary resistance) a majority of the blood passes through the foramen ovale to the left atrium (some goes to the right ventricle and is pumped to the pulmonary trunk where it meets pulmonary resistance- some goes to the lungs, most is shunted through the ductus arteriosus to the descending aorta) from the left atrium it goes into the left ventricle and is pumped into the aorta where it goes through systemic circulation. Deoxygenated blood flows through the iliac arteries to the umbilical artery. FLows to the placenta due to low resistance where it gets reoxygenated.

Question 49

Describe circulatory changes at brth

Answer 49

1.) Closure of umbilical arteries 2.) Closure of umbilical vein and ductus venousus 3.) Closure of ductus arteriosus 4.) closure of foramen ovale

Question 50

what causes closure of the ductus arteriosus

Answer 50

initial inflation of the lung releases bradykinin causes closure. Complete obliteration takes 1-3 months

Question 51

What causes closure of the foramen ovale

Answer 51

occurs by increased presure in the left atrium (carrying blood from the lungs) and a decreased pressure in the right atrium (no more pulmonary vascular resistance). These pressures press the septum primum against the septum secundum closing the foramen ovale

Question 52

Patent ductus arteriosus(PDA)

Answer 52

failure of the ductus arteriosus to cloase completely. Generates a machine like murmur in the heart. Major risk factor is maternal rubella infection during pregnancy.

Question 53

Coarctation of the Aorta

Answer 53

lumen distal to the left subclavian is narrowed. May be proximal (preductal) or distal (postductal) to the ductus arteriosus

Question 54

Infnats with Turner sydrome are at a higher risk of what type of coarctation of the aorta

Answer 54

preductal coarctation

Question 55

What type of coarctation of the aorta is most common in adults

Answer 55

postductal coarctation

Question 56

Abnormal right subclavian artery

Answer 56

aries from the aorta distal to the left subclavian artery then crosses behind the esophagus to reach the right art

Question 57

Double aortic arch

Answer 57

right dorsal aorta persists and the two arches form a vascular ring around the trachea and esophagus

Question 58

Double inferior vena cava

Answer 58

due to failure of the left supracardinal vein to lose its connection with the left subcardinal vein

Question 59

Absence of inferior vena cava

Answer 59

blood from the lower body reaches the heart via the azygous vein (and superior vena cava) Due to failure of the right subcardinal vein to connect to the liver

Question 60

Left superior vena cava

Answer 60

blood from the irght is channeled to the left via the right brachiocephalic vein. The left superior vena cava drains into the coronary sinus (then right atrium) Due to the presistance of left anterior cardinal vein and obliteration of right common cardinal vein

Question 61

Double Superior Vena cava

Answer 61

due to persistance of the left anterior cardinal vein and failure of the formation of the left brachiocephalic vein