HT, GV, AS/GV, FC, ChaB

Question 1

In which layer are blood islands developed in?

Answer 1

Mesoderm

Question 2

What 3 locations do blood islands develop in?

Answer 2

1. Region of future heart
2. Both sides of notochord
3. Wall of yolk sac and connecting stalk

Question 3

What 3 things do blood islands form?

Answer 3

1. Heart
2. Blood vessels
3. Blood cells

Question 4

What is the embryonic coelom?

Answer 4

Angle between amniotic cavity and yolk sac

Question 5

What 3 parts does the embryonic coelom differentiate into, and what do these parts become?

Answer 5

• Rostral/cranial part becomes pericardial coelom, which will later become the thorax.
• Caudal/tail end becomes peritoneal coelom, which is the abdominal region.
• Connecting the 2 coelom is the Pericardioperitoneal Canal, in the thoracic region.

Question 6

What will the oropharyngeal membrane eventually close then rupture to become?

Answer 6

It will close the foregut to become the mouth

Question 7

What will the cloacal membrane eventually close then rupture to become?

Answer 7

It will close the hindgut to become urogenital and anal openings

Question 8

What are the folds of the embryo?

Answer 8

4 folds (2 lateral, 1 cranial, and 1 caudal)

Question 9

What does the lateral folding cause?

Answer 9

The heart tube bends in the middle

Question 10

What does the cranial folding cause?

Answer 10

Brings the heart into the developing thoracic region

Question 11

While the heart is still developing, how does blood enter and leave?

Answer 11

Blood enters caudally from sinus venosus and is pumped out by truncus arteriosus

Question 12

What are the 3 types of circulation in the embryo?

Answer 12

1. Umbilical
2. Vitelline
3. Embryonic

Question 13

Purpose of umbilical circulation?

Answer 13

Acquire oxygen and nutrients through placenta and disposes of waste

Question 14

Purpose of vitelline circulation?

Answer 14

Picks up fresh blood cells from site of production (wall of yolk sac)

Question 15

Purpose of embryonic circulation?

Answer 15

Nourishment of embryo as delivered to tissues of embryo

Question 16

What structures seen in the adult heart prove the twisting of the primitive heart?

Answer 16

Ascending aorta and pulmonary trunk spiral slightly as they ascend

Question 17

What is the endocardial cushion?

Answer 17

Cells growing between the atria and ventricle that will give rise to the septum and heart valves.

Question 18

What is the septum primum?

Answer 18

Starts to divide atria medially

Question 19

What is the foramen primum?

Answer 19

Diminshing space between endocardial cushion and septum primum

Question 20

What is the septum intermedium?

Answer 20

Divides atrium and ventricle and fuses with the septum primum

Question 21

What is the foramen secundum?

Answer 21

Space that arises from the middle of the septum primum breaking down after fusing with septum intermedium

Question 22

What is the septum secundum?

Answer 22

Grows next to septum primum within right atrium region

Question 23

What is the foramen ovale?

Answer 23

Space between septum primum and septum secundum

Question 24

Describe how the definitive interventricular septum arises?

Answer 24

First, ventricular septum arises from bottom, which is muscular.
Then, septum intermedium grows downwards to form fibrous sheet that will fuse with muscular part.
Together = interventricular septum

Question 25

Where do aortic arches carry blood from?

Answer 25

Heart to dorsal aortae