bulb of the aorta

Examples of bulb of the aorta in the following topics:

• Ascending Aorta

  • The ascending aorta is the first portion of the aorta; it includes the aortic sinuses, the bulb of the aorta, and the sinotubular junction.
  • The ascending aorta is a portion of the aorta beginning at the upper part of the base of the left ventricle, on a level with the lower border of the third costal cartilage behind the left half of the sternum; it passes diagonally upward, forward, and to the right, in the direction of the heart's axis, as high as the upper border of the second right costal cartilage.
  • The aortic root is the portion of the ascending aorta beginning at the aortic annulus, the fibrous attachment between the heart and the aorta, and extending to the sinotubular junction.
  • At the junction of the ascending aorta with the aortic arch, the caliber of the vessel increases with a bulging of its right wall.
  • This dilatation is termed the "bulb of the aorta."

• The Aorta and Its Branches

  • The aorta is the largest artery in the body and is divided into 3 parts: the ascending aorta, arch of the aorta, and descending aorta.
  • Blood is pumped from the left ventricle into the aorta and from there branches to all parts of the body.
  • The aorta is divided into three parts: the ascending aorta, where the aorta initially leaves the heart and points superiorly toward the head; the arch of the aorta where the aorta changes direction; and the descending aorta where the aorta points inferiorly toward the feet.
  • The descending aorta is the largest artery in the body; it runs from the heart down the length of the chest and abdomen.
  • This diagram of the human heart shows all the major vessels, and arrows indicate the direction of flow through the heart.

• Abdominal Aorta

  • The abdominal aorta is the largest artery in the abdominal cavity and supplies blood to most of the abdominal organs.
  • As part of the descending aorta, it is a direct continuation of the thoracic aorta.
  • The abdominal aorta travels down the posterior wall of the abdomen, anterior to the vertebral column, following the curvature of the lumbar vertebrae.
  • The abdominal aorta runs parallel to the inferior vena cava, located just to the right of the abdominal aorta.
  • The abdominal aorta lies slightly to the left of the midline of the body.

• Thoracic Aorta

  • The thoracic aorta is the section of the aorta that travels through the thoracic cavity to carry blood to the head, neck, thorax and arms.
  • The thoracic aorta forms part of the descending aorta and is continuous with the aortic arch at its origin before becoming the abdominal aorta.
  • The esophagus lies on the right side of the aorta for most of its length, but at the lower part of the thorax is placed in front of the aorta and close to the diaphragm, situated on its left side.
  • The posterior intercostal arteries are branches that originate throughout the length of the posterior aspect of the thoracic aorta.
  • The aorta, highlighted in red, includes the thoracic aorta, the section of the aorta which runs from the lower border of the fourth thoracic vertebra to the diaphragm.

• Arch of the Aorta

  • The arch of the aorta follows the ascending aorta and begins at the level of the second sternocostal articulation of the right side.
  • The arch of the aorta, or the transverse aortic arch, is continuous with the upper border of the ascending aorta and begins at the level of the upper border of the second sternocostal articulation of the right side.
  • The arch of the aorta runs at first upward, backward, and to the left in front of the trachea; it is then directed backward on the left side of the trachea and finally passes downward on the left side of the body of the fourth thoracic vertebra.
  • At the lower border, this vertebra becomes continuous with the descending aorta.
  • This diagram shows the arch of the aorta and its branches.

• Great Vessels of the Heart

  • The aorta is the largest of the arteries in systemic circulation.
  • The five components of the aorta are:
  • The ascending aorta lies between the heart and the arch of aorta.
  • The arch of aorta is the peak of the aorta, which breaks off into the left carotid artery, brachiocephalic trunk, and the left subclavian artery.
  • The thoracic aorta is  the part of the descending aorta above the diaphragm.

• Elastic Arteries

  • An elastic or conducting artery has a large number of collagen and elastin filaments in the tunica media.
  • The pulmonary arteries, the aorta, and its branches together comprise the body's system of elastic arteries.
  • Due to position as the first part of the systemic circulatory system closest to the heart and the resultant high pressures it will experience, the aorta is perhaps the most elastic artery, featuring an incredibly thick tunica media rich in elastic filaments.
  • When the left ventricle contracts to force blood into the aorta, the aorta expands.
  • The aorta makes up most of the elastic arteries in the body.

• Olfactory (I) Nerve

  • The olfactory nerve, or cranial nerve I, is the first of 12 cranial nerves and is responsible for the sense of smell.
  • The specialized olfactory receptor neurons of the olfactory nerve are located in the olfactory mucosa of the upper parts of the nasal cavity.
  • The olfactory nerves consist of a collection of many sensory nerve fibers that extend from the olfactory epithelium to the olfactory bulb, passing through the many openings of the cribriform plate of the ethmoid bone.
  • Olfactory receptor neurons continue to emerge throughout life and extend new axons to the olfactory bulb.
  • These interactions are transduced into electrical activity in the olfactory bulb, which then transmits the electrical activity to other parts of the olfactory system and the rest of the central nervous system via the olfactory tract.

• Development of the Heart

  • The development of the circulatory system occurs by the process of vasculogenesis followed by angiogenesis, the sprouting of new vessels from pre-existing ones.
  • The human arterial system originates from the aortic arches and from the dorsal aortae starting from week four of human development.
  • The dorsal aortae are initially bilateral and then fuse to form the definitive dorsal aorta.
  • The lateral branches of the aorta form the definitive renal, suprarenal, and gonadal arteries.
  • The ventral branches of the aorta consist of the vitelline arteries and umbilical arteries.

• Operation of Semilunar Valves

  • The semilunar valves allow blood to be pumped into the major arteries, but prevent backflow of blood from the arteries into the ventricles.
  • The aortic valve separates the left ventricle from the aorta and has three cusps .
  • When the pressure in the left ventricle exceeds the pressure in the aorta, the aortic valve opens, and blood flows from the left ventricle into the aorta.
  • This anterior view of the heart indicates the semilunar valves, the aortic and pulmonary valves.
  • Describe the operation of the semilunar valves, the aortic and pulmonary valves