UNSW Embryology

Cardiovascular System Development- Stage 13/14

© Dr Mark Hill (2011)

Acknowledgements

G7 An overview of blood flow through the embryo of oxygenated blood. Note the umbilical artery and veins anastomose within the chorion of the placenta, there is no direct connection of maternal and foetal blood. Maternal Blood umbilical vein liver anastomosis ductus venosus sinus venosus atria ventricles truncus arteriosus aortic sac aortic arches dorsal aorta pair of umbilical arteries Maternal Blood

The umbilical and vitelline (yolk sac) venous inflow to the heart.
	F6: Oblique section through both umbilical veins in body wall. Follow them to E6.
E6-E4: Both umbilical veins with a large vitelline vein in the central, mesenteric region.
E1,D7: Umbilical veins enter liver, along with vitelline. Most venous blood drains through the liver region into the sinus venosus, which nestles in the cranial surface of the growing liver. This is the site of the caudal attachment of the free heart to the body mesenchyme.
D3,D2: Entry of venous blood into sinus venosus. Note smaller left horn of sinus venosus, and larger right horn of sinous venosus. Sinus venosus is also located caudal of to atria. Both right ventricle and left ventricle with ventricular septum at this level.
D1-C7: Drainage of right horn of sinus venosus into right atrium.

Stage 13/14 Pages

In addition to the pathway text listings below, are individual pages with cross-section excerpts covering the following blood pathways:

• venous inflow to the heart
• ventricles into the aortic system
• caudal path of the arterial blood
• embryo's venous blood

Venous Inflow to the Heart

Follow the umbilical and vitelline (yolk sac) venous inflow to the heart. Start with F6. (More? venous inflow to the heart)

• F6: Oblique section through both umbilical veins in body wall. Follow them to E6.
• E6-E4: Both umbilical veins with a large vitelline vein in the central, mesenteric region.
• E1,D7: Umbilical veins enter liver, along with vitelline. Most venous blood drains through the liver region into the sinus venosus, which nestles in the cranial surface of the growing liver. This is the site of the caudal attachment of the free heart to the body mesenchyme.
• D3,D2: Entry of venous blood into sinus venosus. Note smaller left horn of sinus
• venosus, and location of sinus venosus caudal to atria.
• D1-C7: Drainage of right horn of sinus venosus into right atrium.
• We now trace the low pressure pathway of the embryo's venous blood.
• B1: Identify the large veins lateral to dorsal aortae - these are the superior or anterior cardinal veins which drain the head region. Now go directly to D6.
• D6: Identify the large veins lateral to dorsal aortae - these are the inferior or posterior cardinal veins which drain the lower part of the embryo.

Serial Section table (Stage 13/14)

Stage 13/14 Embryo (Pig)
A1	A2	A3	A4	A5	A6	A7
B1	B2	B3	B4	B5	B6	B7
C1	C2	C3	C4	C5	C6	C7
D1	D2	D3	D4	D5	D6	D7
E1	E2	E3	E4	E5	E6	E7
F1	F2	F3	F4	F5	F6	F7
G1	G2	G3	G4	G5	G6	G7

Quick Links

Page 2 | Abnormalities | OMIM | Questions | Medline
Page 3 | Pig Stage 13/14
Page 4 | Human (Stage22) | Selected Human highpower
Molecular | Blood | Text only page | WWW Links
Heart Movies
Postnatal

Development Notes ----------------- Menstrual Cycle Week 1 Week 2 Week 3 Week 4 Placenta Serial Images Molecular Dev Abnormal Dev Postnatal Dev Notes Index

System Notes ----------------- All Systems Heart/Cardiovascular Respiratory Coelomic cavity Gastrointestinal Tract Head and Neck Neural Neural Crest Eye Ear Nose Endocrine Renal Genital Musculoskeletal Integumentary

Movies ----------------- Movies Quicktime Flash Audio Week 1 Week 2 Week 3 Stage 13 Stage 22 Neural Heart Gastrointestinal Renal Genital Other Embryos

Other Embryos ----------------- All Animals Chicken Fly Frog Mouse Rabbit Rat Worm Zebrafish Guinea Pig

UNSW Embryology ISBN: 978 0 7334 2609 4

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