2014 Group Project 5

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The Group assessment for 2014 will be an online project on Fetal Development of a specific System. This page is an undergraduate science embryology student and may contain inaccuracies in either description or acknowledgements.

Cardiovascular

--Mark Hill (talk) 15:16, 26 August 2014 (EST) OK you have some headings, how about some content, references, sources for each section. See Lab 3 Assessment.

Introduction

• The cardiovascular system is one of the first systems to function within the embryo
• The heart begins to function during the 4th week

[Textbook- Larsen's Human Embryology, 4th ed.]

Timeline

--Z3418340 (talk) 00:21, 27 August 2014 (EST)

(From Textbook- Larsen's Human Embryology, 4th ed. - http://www.mdconsult.com.wwwproxy0.library.unsw.edu.au/books/page.do?eid=4-u1.0-B978-0-443-06811-9..10012-0&isbn=978-0-443-06811-9&uniqId=462162262-2#4-u1.0-B978-0-443-06811-9..10012-0--fig42)

Primordial heart tube

• Arises predominantly from splanchnic mesoderm in the cardiogenic region
• Initially bilateral, the cardiogenic region cranially merges to form a horseshoe
• During the third week (Approximately day 18), angioblastic chords develop in the cardiogenic mesoderm. It forms the bilateral endocardial heart tubes
• Lateral folding of the embryo brings the heart tubes into the ventral midline.
• Fusion of the heart begins cranially and extends caudally.
• Certain dilations appear in the heart tube including:
  • Truncus arteriosus
  • Bulbus cordis
  • Primordial ventricle
  • Primordial atrium
  • Sinus venosus (further divided into right horn and left horn)

Heart tube looping

• Most looping occurs in the fourth week of development and is completed by the fifth.
• The straight heart tube begins to elongate, most notably with growth in the bulbus cordis and primitive ventricle.
• This causes the heart to bend ventrally and rotate to the right- this forms a C-shaped loop.
• The ventricular bend moves caudally. The distance between outflow and inflow tracts diminishes
• The inflow (atrial) and outflow tracts converge. Myocardial cells are added forming the truncus arteriosus.

Historic Findings

Recent research, enabled by powerful molecular techniques, has revolutionized our concepts of cardiac development. It was firmly established that the early heart tube gives rise to the left ventricle only, and that the remainder of the myocardium is recruited from surrounding mesoderm during subsequent development. Also, the cardiac chambers were shown not to be derived from the entire looping heart tube, but only from the myocardium at its outer curvatures. Intriguingly, many years ago, classic experimental embryological studies reached very similar conclusions. However, with the current scientific emphasis on molecular mechanisms, old morphological insights became underexposed. Since cardiac development occurs in an architecturally complex and dynamic fashion, molecular insights can only fully be exploited when placed in a proper morphological context. In this communication we present excerpts of important embryological studies of the pioneers of experimental cardiac embryology of the previous century, to relate insights from the past to current observations.

https://www.youtube.com/watch?v=WXLPxjJszio

--Z3418340 (talk) 00:21, 27 August 2014 (EST)