Tubular heart

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Tubular heart
Tubular Heart 2.png
Diagram to illustrate the simple tubular condition of the heart.
Details
Days22
Precursor Splanchnic mesoderm
Gives rise to Heart
Identifiers
Latin cor tubulare
TE heart_by_E5.11.1.1.1.0.5 E5.11.1.1.1.0.5
Anatomical terminology

The tubular heart or primitive heart tube is the earliest stage of heart development. [1] The heart is the first organ to develop during human embryonic development. [2]

Contents

From the inflow to the outflow, the tubular heart consists of sinus venosus, primitive atrium, the primitive ventricle, the bulbus cordis, and truncus arteriosus. [3] The sinus venosus will become part of the right atrium and contain the primary cardiac pacemaker. [4] The primitive atrium and primitive ventricle will develop into the upper and lower chambers of the heart. [5] The bulbus cordis will form part of the right ventricle, while the truncus arteriosis split into pulmonary and aortic vessels that carry blood away from the heart. [5] Blood flow is driven by contractions and is different compared to that of an adult heart. [6]

The tubular heart forms primarily from splanchnic mesoderm, an embryonic tissue that develops into several key structures in the body. [7] It consists of three layers essential for proper heart function, corresponding to those in the adult human heart: the endothelial lining, the muscular bulk, and the external surface. [6] The endothelial lining acts as a barrier between the blood and surrounding tissues, the muscular bulk contains cardiac muscle that contracts to pump blood, and the external surface provides a protective covering for the heart. [8]

Development

The development of the human heart begins during the third week of embryonic life, in the cardiogenic area of the chest. At around day 18, this area develops into the splanchnic mesoderm, where stem cells form two endocardial tubes, one on each side of the embryo's midline. [6] As the embryo folds, these tubes are brought together in the future chest cavity. By day 21-22, the endocardial tubes fuse to form a single primitive heart tube structure known as tubular heart. [6]

After this stage is the formation of the main chambers of the tubular heart, which are the truncus arteriosus, bulbus cordis, primitive ventricle, primitive atrium, and sinus venosus. [6] The heart tube is suspended within the heart cavity by the dorsal mesocardium, which is a temporary layer of tissue that connects to the developing heart tube, and later degenerates to allow further growth. Finally on day 23, the heart tube begins to elongate and bend, initiating the process of cardiac looping. [2] [9]

Cardiac looping

The process of cardiac looping rearranges the regions of the primitive heart tube so that all regions are in the correct positions for features of the mature heart to develop. [10] This looping process is mediated by a few key laterality genes including inversin and lefty genes. [11] There are three stages to cardiac looping: the C-shaped, S-shaped and terminal stage. [10] During the C-shaped phase, the primitive tube bends into a loop that points towards the right, initiating the looping process. [12] In the subsequent S-shaped phase, the dorsal mesocardium, a structure that initially supported the primitive tube, begins to break down. This allows for the primitive atrium to loop upwards, towards the right and the back of the heart. Finally, during the terminal looping stage, the primitive atrium is moved closer to the head with respect to the primitive ventricle and this last movement helps rearrange the segments of the tube into their final positions. [10]

At the end of cardiac looping, all primitive segments of the heart are formed and in the correct positions they will occupy in the mature heart’s structure. [12] These segments then continue to remodel in order to develop into the final structures that are needed for the mature heart to function. [11]

Related Research Articles

<span class="mw-page-title-main">Mesoderm</span> Middle germ layer of embryonic development

The mesoderm is the middle layer of the three germ layers that develops during gastrulation in the very early development of the embryo of most animals. The outer layer is the ectoderm, and the inner layer is the endoderm.

<span class="mw-page-title-main">Pulmonary artery</span> Artery in pulmonary circulation carrying deoxygenated blood from heart to lungs

A pulmonary artery is an artery in the pulmonary circulation that carries deoxygenated blood from the right side of the heart to the lungs. The largest pulmonary artery is the main pulmonary artery or pulmonary trunk from the heart, and the smallest ones are the arterioles, which lead to the capillaries that surround the pulmonary alveoli.

<span class="mw-page-title-main">Congenital heart defect</span> Defect in the structure of the heart that is present at birth

A congenital heart defect (CHD), also known as a congenital heart anomaly, congenital cardiovascular malformation, and congenital heart disease, is a defect in the structure of the heart or great vessels that is present at birth. A congenital heart defect is classed as a cardiovascular disease. Signs and symptoms depend on the specific type of defect. Symptoms can vary from none to life-threatening. When present, symptoms are variable and may include rapid breathing, bluish skin (cyanosis), poor weight gain, and feeling tired. CHD does not cause chest pain. Most congenital heart defects are not associated with other diseases. A complication of CHD is heart failure.

A germ layer is a primary layer of cells that forms during embryonic development. The three germ layers in vertebrates are particularly pronounced; however, all eumetazoans produce two or three primary germ layers. Some animals, like cnidarians, produce two germ layers making them diploblastic. Other animals such as bilaterians produce a third layer between these two layers, making them triploblastic. Germ layers eventually give rise to all of an animal's tissues and organs through the process of organogenesis.

<span class="mw-page-title-main">Atrium (heart)</span> Part of the human heart

The atrium is one of the two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular mitral and tricuspid heart valves.

<span class="mw-page-title-main">Persistent truncus arteriosus</span> Medical condition

Persistent truncus arteriosus (PTA), often referred to simply as truncus arteriosus, is a rare form of congenital heart disease that presents at birth. In this condition, the embryological structure known as the truncus arteriosus fails to properly divide into the pulmonary trunk and aorta. This results in one arterial trunk arising from the heart and providing mixed blood to the coronary arteries, pulmonary arteries, and systemic circulation. For the International Classification of Diseases (ICD-11), the International Paediatric and Congenital Cardiac Code (IPCCC) was developed to standardize the nomenclature of congenital heart disease. Under this system, English is now the official language, and persistent truncus arteriosus should properly be termed common arterial trunk.

<span class="mw-page-title-main">Bulbus cordis</span> Part of the developing heart

The bulbus cordis is a part of the developing heart that lies ventral to the primitive ventricle after the heart assumes its S-shaped form. The superior end of the bulbus cordis is also called the conotruncus.

<span class="mw-page-title-main">Sinus venosus</span> Cavity in the hearts of chordates

The sinus venosus is a large quadrangular cavity which precedes the atrium on the venous side of the chordate heart.

In embryology, Carnegie stages are a standardized system of 23 stages used to provide a unified developmental chronology of the vertebrate embryo.

<span class="mw-page-title-main">Endocardial cushions</span>

Endocardial cushions, or atrioventricular cushions, refer to a subset of cells in the development of the heart that play a vital role in the proper formation of the heart septa.

<span class="mw-page-title-main">Septum secundum</span>

The septum secundum is a muscular flap that is important in heart development. It is semilunar in shape, and grows downward from the upper wall of the atrium immediately to the right of the septum primum and ostium secundum. It is important in the closure of the foramen ovale after birth.

<span class="mw-page-title-main">Crista terminalis</span> Anatomical feature of the heart

The crista terminalis is a vertical ridge on the posterolateral inner surface of the adult right atrium extending between the superior vena cava, and the inferior vena cava. The crista terminalis denotes where the junction of the embryologic sinus venosus and the right atrium occurred during embryonic development. It forms a boundary between the rough trabecular portion and the smooth, sinus venosus-derived portion of the internal surface of the right atrium. The sinoatrial node is located within the crista terminalis.

<span class="mw-page-title-main">Aorticopulmonary septum</span> Anatomical entity

The aorticopulmonary septum is developmentally formed from neural crest, specifically the cardiac neural crest, and actively separates the aorta and pulmonary arteries and fuses with the interventricular septum within the heart during heart development.

<span class="mw-page-title-main">Truncus arteriosus</span> Structure during embryonic development

The truncus arteriosus is a structure that is present during embryonic development. It is an arterial trunk that originates from both ventricles of the heart that later divides into the aorta and the pulmonary trunk.

The heart is the first functional organ in a vertebrate embryo. There are 5 stages to heart development.

<span class="mw-page-title-main">Human embryonic development</span> Development and formation of the human embryo

Human embryonic development or human embryogenesis is the development and formation of the human embryo. It is characterised by the processes of cell division and cellular differentiation of the embryo that occurs during the early stages of development. In biological terms, the development of the human body entails growth from a one-celled zygote to an adult human being. Fertilization occurs when the sperm cell successfully enters and fuses with an egg cell (ovum). The genetic material of the sperm and egg then combine to form the single cell zygote and the germinal stage of development commences. Human embryonic development covers the first eight weeks of development, which have 23 stages, called Carnegie stages. At the beginning of the ninth week, the embryo is termed a fetus. In comparison to the embryo, the fetus has more recognizable external features and a more complete set of developing organs.

<span class="mw-page-title-main">Smallest cardiac veins</span> Small veins in the walls of all four heart chambers

The smallest cardiac veins are small, valveless veins in the walls of all four heart chambers that drain venous blood from the myocardium directly into any of the heart chambers.

The endocardial tubes are paired regions in the embryo that appear in its ventral pole by the middle of the third week of gestation and consist of precursor cells for the development of the embryonic heart. The endocardial heart tubes derive from the visceral mesoderm and initially are formed by a confluence of angioblastic blood vessels on either side of the embryonic midline. The endocardial tubes have an intimate proximity to the foregut or pharyngeal endoderm.

Neural crest cells are multipotent cells required for the development of cells, tissues and organ systems. A subpopulation of neural crest cells are the cardiac neural crest complex. This complex refers to the cells found amongst the midotic placode and somite 3 destined to undergo epithelial-mesenchymal transformation and migration to the heart via pharyngeal arches 3, 4 and 6.

<span class="mw-page-title-main">Heart development</span> Prenatal development of the heart

Heart development, also known as cardiogenesis, refers to the prenatal development of the heart. This begins with the formation of two endocardial tubes which merge to form the tubular heart, also called the primitive heart tube. The heart is the first functional organ in vertebrate embryos.

References

  1. ↑ Schleich, J-Mark (May 2002). "Development of the human heart: days 15–21". Heart (British Cardiac Society). 87 (5): 487 – via BMJ Journals.
  2. 1 2 Farraj, Kristen L.; Zeltser, Roman (2024), "Embryology, Heart Tube", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID   29763109 , retrieved 2024-11-02
  3. ↑ Sadler, Thomas W. (2006). Langman's medical embryology (10th ed.). Lippincott Williams & Wilkins.{{cite book}}: CS1 maint: date and year (link)
  4. ↑ Faber, Jaeike W (2019). "Sinus venosus incorporation: contentious issues and operational criteria for developmental and evolutionary studies". Journal of Anatomy. 234 (5): 583–591 – via PubMed Central.
  5. 1 2 "Development of the Heart | Anatomy and Physiology II". courses.lumenlearning.com. Retrieved 2024-11-24.
  6. 1 2 3 4 5 Betts, J. Gordon; Young, Kelly A.; Wise, James A.; Johnson, Eddie; Poe, Brandon; Kruse, Dean H.; Korol, Oksana; Johnson, Jody E.; Womble, Mark (2022-04-20). "19.5 Development of the Heart - Anatomy and Physiology 2e | OpenStax". openstax.org. Retrieved 2024-11-02.
  7. ↑ Yonei‐Tamura, Sayuri; Ide, Hiroyuki; Tamura, Koji (2005). "Splanchnic (visceral) mesoderm has limb‐forming ability according to the position along the rostrocaudal axis in chick embryos". Developmental Dynamics. 233 (2): 256–265. doi:10.1002/dvdy.20391. ISSN   1058-8388.
  8. ↑ Félétou, Michel (2011), "Multiple Functions of the Endothelial Cells", The Endothelium: Part 1: Multiple Functions of the Endothelial Cells—Focus on Endothelium-Derived Vasoactive Mediators, Morgan & Claypool Life Sciences, retrieved 2024-11-24
  9. ↑ Mathew, Philip; Bordoni, Bruno (2024), "Embryology, Heart", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID   30725998 , retrieved 2024-11-02
  10. 1 2 3 Moreno-Rodriguez, R. A.; Krug, E. L. (2010-01-01), McQueen, Charlene A. (ed.), "Cardiovascular Development*", Comprehensive Toxicology (Second Edition), Oxford: Elsevier, pp. 3–33, ISBN   978-0-08-046884-6 , retrieved 2024-11-02
  11. 1 2 Mjaatvedt, Corey H.; Yamamura, Hideshi; Wessels, Andy; Ramsdell, Anne; Turner, Debi; Markwald, Roger R. (1999-01-01), Harvey, Richard P.; Rosenthal, Nadia (eds.), "10 - Mechanisms of Segmentation, Septation, and Remodeling of the Tubular Heart: Endocardial Cushion Fate and Cardiac Looping", Heart Development, San Diego: Academic Press, pp. 159–177, doi:10.1016/b978-012329860-7/50012-x, ISBN   978-0-12-329860-7 , retrieved 2024-11-02
  12. 1 2 Linask, Kersti K.; Lash, James W. (1998), de la Cruz, María Victoria; Markwald, Roger R. (eds.), "Morphoregulatory Mechanisms Underlying Early Heart Development: Precardiac Stages to the Looping, Tubular Heart", Living Morphogenesis of the Heart, Boston, MA: Birkhäuser, pp. 1–41, doi:10.1007/978-1-4612-1788-6_1, ISBN   978-1-4612-1788-6 , retrieved 2024-11-02


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