CV System

Question 1

What is the Cardiogenic Plate?

Answer 1

splanchnic mesoderm anterior to embryo, first sign of heart development. This is where bilateral vessels are formed. Becomes cardiac muscle cells surrounding endocardial tube.

Question 2

What are the five primitive heart regions?

Answer 2

Truncus Arteriosis
Bulbus Cordis
Ventricle
Atrium
Sinus Venosus

Question 3

Truncus arteriosis becomes

Answer 3

Pulmonary Trunk and Ascending Aorta

Question 4

Bulbus Cordis becomes

Answer 4

Right Ventricle

Question 5

Ventricle becomes

Answer 5

Left Ventricle

Question 6

Atrium becomes

Answer 6

Left and Right auricles

Question 7

Sinus Venosus becomes

Answer 7

(L) Right coronary sinus and (R) Right wall of atrium.

Question 8

What is the Foramen Ovale

Answer 8

the septum between L and R atrium because fetus requires blood flow between R–>L

Question 9

How does the foramen ovale become a valve at birth?

Answer 9

instead of blood pressure being higher in Right atrium (so blood flows into LA), pressure equalizes so foramen closes and acts as a valve

Question 10

How are aorta and pulmonary trunk formed?

Answer 10

The truncus arteriosus spirals, ridges along the wall grow inward and create a spiral septum?

Question 11

How are AV and semilunar valves formed?

Answer 11

by excavation/erosion of vessel wall.

Question 12

How many aortic arches are there and what do they become?

Answer 12

3 –> internal carotid and common carotid (proximal)

up to 6 arches.

Question 13

Ductus Arteriosus

Answer 13

shunts blood from pulmonary trunk to aorta, so right ventricle gets exercised even if low blood flow from lungs. becomes constricted at birth so pulmonary trunk shifts blood flow to lungs. becomes ligamentum arteriosum.

Question 14

The embryonic sinus venosus receives three veins. what are they and what do they do?

Answer 14

vitelline veins drain the yolk sac (becomes portal vein)
umbilical veins drain the allantois
cardinal veins drain the embryo

Question 15

vitelline veins

Answer 15

form the liver sinusoids and portal vein, as they are engulfed by the liver. portal vein forms from anastomoses between right and left vitelline veins and enlargement/atrophy of selective anastomoses

Question 16

umbilical veins

Answer 16

form liver sinusoids as they are engulfed by the liver. right umbilical vein atrophies and left sends placental blood to the liver.

Question 17

ductus venosus

Answer 17

a shunt that forms between left umbilical vein and right hepatic vein that shunts drains blood into caudal vena cava, avoiding liver sinusoids because placenta can detoxify blood. If it persists after birth, its called a Portosystemic Shunt. Can also be caused by anastomosis between portal vein and caudal vena cava/azygos vein.

Question 18

lymph vessel formation

Answer 18

start as lymph sacs in three regions, then outgrowth forms lymphatic vessels/ducts.

Question 19

lymph node formation

Answer 19

formed by local invaginations of mesoderm that partition the vessel lumen into sinusoids?