Cardiovascular (embyrology)

Question 1

Where does the entire blood vascular system develop from?

Answer 1

Splanchnic mesoderm

Question 2

Prenatal Hematopoiesis

Answer 2

Yolk sac and allantois splanchnic mesoderm: 4-5 wks
Liver: 6 wks to mid gestation
Spleen and thymus: 8-16 weeks
Bone marrow: 16 weeks to beyond

Question 3

Which organs takes over the function of bone marrow when it’s damaged?

Answer 3

Liver and spleen

Question 4

How many BVs are in the umbilical cord?

Answer 4

3: 2 umbilical arteries and 1 umbilical vein
arteries becoming lateral ligaments of the bladder

Question 5

What do the vitelline veins and arteries connect?

Answer 5

Early heart with the yolk sac

Question 6

What does the umbilical veins and arteries connect?

Answer 6

Early heart with the allantois and placenta

Question 7

What do the cardinal veins (cranial, caudal and common) connect?

Answer 7

Heart with the body parts

Question 8

Early blood flow

Answer 8

Vitelline or umbilical vein –> sinus venosus –> atrium –> ventricle –> truncus arteriosis –> aortic arches –> dorsal aorta –> vitelline artery (yolk sac) or umbilical artery (allantois)

Question 9

Where does the heart develop?

Answer 9

Cranial to the developing embryo

Question 10

How does the heart migrate?

Answer 10

Embryo folding migrates heart from cranial to the embryo to the pharyngeal area

Question 11

Where does the yolk sac and allantois orginate?

Answer 11

YS: mid gut
A: outpocketing from the hind gut

Question 12

Stages in Heart Development

Answer 12

D18: blood islands and myoblasts cr. to the neural plate
D 20-35: Fusion, division and folding of endocardial tubes and an anticlockwise turn brings atria dorsal to ventricles
Pericardial cavity (intraemryonic coelom) cr. to embryo

Question 13

___________ gives rise to the pulmonary artery and aorta

Answer 13

Truncus arteriosus

Question 14

What does the right sinus venosus form?

Answer 14

Overdevelops and forms smooth part of the right atrium

Question 15

What does the left sinus venosus form?

Answer 15

Atrophies and forms coronary sinus and oblique vein of left atrium (left to right shift in circulation)

Question 16

Endocardial cushion

Answer 16

Divides Av canal into right and left AV canals

Question 17

Interartrial septa 1 & 2

Answer 17

Divides atria into right and left atrium
1: valve for the foramen ovale
2: foramen ovale opens in 2 and allows blood to move from right to left atrium

Question 18

Interventricular septa

Answer 18

Divides ventricles into right and left
Foramen filled by membranous tissue from endocardial cushion and base of truncus arteriosus

Question 19

What does partitioning of the truncus arteriosus involve?

Answer 19

Formation of spiral septum that divides the TA into:
1. Aorta that connects with l. ventricle
2. Pulmonary artery that connects with the r. ventricle

Question 20

What does the failure of spiral formation (TA) do?

Answer 20

Reverses arrangement so the aorta is connected to the r. side and pulmonary a. is connected to the l.

Question 21

Ectopic Cords

Answer 21

Heart located in the neck region (cattle)

Question 22

Spiral Septal Defect

Answer 22

Small opening between the pulmonary trunk and aorta
Venous blood has direct access to aorta before going to lungs
Like patent ductus arteriosus

Question 23

Interventricular Septal Defect

Answer 23

An opening in the membranous part of the interventricular septum (most frequent)
Caused by abnormal closure of the interventricular foramen

Question 24

Dextrocardia

Answer 24

Mirror image heart that occurs as an isolated defect or with a complete inversus

Question 25

Tetralogy of Fallot

Answer 25

Causes cyanosis in domestic animals and human From failure of migration of neural crest cells in distal part of TA Craniofacial abnormalities

Question 26

What are the 4 lesions of Tetralogy of Fallot

Answer 26

1. Interventricular septal defect 2. Pulmonary stenosis 3. Dextro-aorta 4. Hypertrophy of r. ventricle (consequence of first 3 defects) *first 3 from abnormal partitioning of TA by spiral septum*

Question 27

Aortic arches

Answer 27

1-6 pairs Connecting ventral aortrae with dorsal aortrae that fuse caudally

Question 28

Which arches degenerate?

Answer 28

1, 2, 5

Question 29

Arch 3

Answer 29

Becomes internal carotid Dorsal aorta between 3 & 4 degenerate freeing intl carotid

Question 30

Arch 4

Answer 30

On l. side becomes arch of aorta R. side becomes root of subclavian

Question 31

Arch 6

Answer 31

Left: proximal part is pulmonary artery and distal part is ductus arteriosus Right: proximal part is pulmonary artery and distal part degenerates

Question 32

What makes up the right subclavian?

Answer 32

Right 4th arch Right dorsal aorta up to 7th intersegmental 7th intersegmental

Question 33

What makes up the left subclavian?

Answer 33

7 intersegmental exclusively

Question 34

Vertebral both sides

Answer 34

1-6 cervical intersegmental fuse proximally and degenerate distally Remains connected to 7th intersegmental (becomes subcalvian)

Question 35

Where does the right subclavian move?

Answer 35

Upward joining the root of common carotid (area will become the brachiocephalic trunk)

Question 36

How is the subclavian in the dog and pig?

Answer 36

Right subclavian originates from brachiocephalic trunk Left subclavian from arch of aorta

Question 37

How is the subclavian in the horse and ox?

Answer 37

Both subclavians originate from the brachiocephalic trunk

Question 38

Recurrent laryngeal nerves

Answer 38

Left: hooks around ducuts arteriosus, atrophies and become ligamentum arteriosus Right: hooks around right subclavian

Question 39

Vascular ring anomaly

Answer 39

Abnormal origin of the right subclavian artery (originating from arch of aorta) Proximal part of dorsal aorta degenerates

Question 40

Symptoms of vascular ring anomaly

Answer 40

Esophagus dilation proximal to the site of crossing Difficulty swallowing solid food leading to regurgitation

Question 41

Foramen ovale

Answer 41

Changes to fossa ovalis Increased pressure in l. atrium @ birth causes fusions of septum 1 & 2

Question 42

Ductus arteriosus

Answer 42

Atrophies and becomes ligamentum arteriosus due to increased blood oxygen, bradykinin secretion and decreased prostagladin secretion

Question 43

Anomalies dealing with fetal adaptations

Answer 43

Interatrial septal defect Persistent ductus arteriosus Persistent ductus venosus leading to portosystemic shunt

Question 44

Patent Ductus Arteriosus

Answer 44

DA fails to close @ birth Blood shunts from aorta to pulmonary artery Signs: continuous murmur

Question 45

Portosystemic Shunt

Answer 45

Portal vein blood bypasses liver Blood not detoxified leading to nervous signs and brain injury