What Is the Descending Aorta?

The aorta is the thickest arterial tube in the human body, emanating from the left ventricle of the heart, slightly arched up, to the right, and then down, and then down the spine, dividing a lot of smaller arteries in the chest and abdominal cavity. The aorta is the main conduit that delivers blood to all parts of the body. Also called aorta.

The aorta is the thickest arterial tube in the human body, emanating from the left ventricle of the heart, slightly arched up, to the right, and then down, and then down the spine, dividing a lot of smaller arteries in the chest and abdominal cavity. The aorta is the main conduit that delivers blood to all parts of the body. Also called aorta.

Chinese name

Aorta

Foreign name

Aorta

Department

Cardiology

Aortic anatomy:

1. Aorta:

The main artery of the systemic circulation, the arteries at all levels of the body, are issued directly or indirectly by the autonomous arteries. The aorta starts from the left ventricle and rises forward to the upper right, to the right second costal cartilage, turns to the left and back, and reaches to the left of the lower edge of the 4th thoracic vertebra, turning down and descending along the front of the spine. It is divided into the left and right common iliac arteries through the aortic hiatus to the abdominal cavity and to the front of the 4th lumbar vertebra. The aorta can be divided into ascending aorta, aortic arch and descending aorta. Among them, the descending aorta is divided by the aortic rupture of the iliac crest, and is divided into the aortic chest (thoracic aorta) and the aortic abdomen (abdominal aorta). The average diameter of the aorta at the beginning of the Chinese is 2.8 to 3.0 cm.

The aorta is the main artery of the systemic circulation, so it is called the aorta, which is also the largest artery in the body. From the left ventricle, travel from the right side of the pulmonary artery to the front right and up, to the height of the right thoracic rib joint on the right, turn in an arcuate direction to the left and back to the left side of the lower edge of the 4th thoracic vertebra, and then turn downward, along the spine. Anterior descend to the height of the 12th thoracic vertebra, the aortic puncture that penetrates the diaphragm enters the abdominal cavity, and continues to descend from the front of the spine to the lower edge of the 4th lumbar vertebra. The left and right common iliac arteries and a small middle iliac artery. According to the running and location of the aorta, it can be divided into three sections: ascending aorta (ascending aorta), aortic arch, and descending aorta (descending aorta). The descending aorta is divided into the aortic rupture of the iliac crest and is divided into the thoracic aorta (aortic chest) and abdominal aorta (aortic abdomen).

2. Artery:

Arteries are the type of blood vessels that carry blood from the heart to various parts of the body according to the direction of blood flow in the blood vessels. They are collectively called arteries. The arterial wall is composed of the inner layer, the middle layer and the outer layer, and the wall is thicker. The inner surface of the inner layer is a single layer of flat epithelium with a smooth surface; the middle layer is composed of elastic fibers and smooth muscle; the outer layer is mainly composed of connective tissue. There are two major arteries in the human body that start directly from the heart, the pulmonary artery and the aorta. The left ventricle is connected to the aorta, and the right ventricle is connected to the pulmonary artery. Pulmonary arteries carry dark red venous blood with a high carbon dioxide content from the whole body back to the heart from the right ventricle to the lungs. The aorta sends bright red arterial blood with more oxygen from the left ventricle to the body.

According to the size of the tube diameter, the arteries can be divided into three types: large, medium and small. The middle layer of the aorta is thick, and the circular smooth muscles and elastic fibers are developed, which can expand and contract with the increase and decrease of blood volume and the level of blood pressure. The smooth muscles of the middle wall of the middle artery are well developed; Under the dominance of the autonomic nervous system, the arteries perform diastolic exercises to regulate blood flow and blood pressure. Due to the elastic effect of the arterial wall, continuous blood flow is guaranteed in the blood vessels. Arterial wall tissue changes with age. The arterial elasticity of the elderly is reduced, and the ability to regulate blood pressure is reduced. Therefore, a person's blood pressure is higher in old age than in younger age.

Aortic morphology of the aorta:

The aorta is an elastic artery, also known as the conveying artery. Its structural characteristics are rich in elastic membrane and elastic fibers.

Intima: about 100-130 m thick, accounting for about one sixth of the thickness of the tube wall. Endothelial cells are rich in plasma membrane vesicles and contain varying numbers of microfilaments. The cells are connected by tight junctions and spaced sutures. Vesicles have the role of actively transporting multiple molecules. The base film is thin and finely meshed. The lower endothelium contains loose connective tissue, contains elastic fibers, scattered fibroblasts and some longitudinal smooth muscle cells. The inner elastic membrane has no obvious limit under the light microscope, and the first layer adjacent to the inner membrane under the electron microscope is an inner elastic membrane.

Medium film: This film is the thickest, about 500 m. It is mainly composed of 40 to 70 layers of elastic films arranged concentrically, and each layer of elastic films is 5 to 15 m apart, and each layer of elastic film is 2 to 3 m thick. Elastic fibers are connected between the elastic membranes. Elastic fibers and collagen fibers are scattered in the matrix, and there are slender branched smooth muscle cells, which are connected to the elastic membrane by collagen fibrils and collagen fibers. The matrix contains more chondroitin sulfate, which is basophilic and metachromatic.

Outer membrane: This membrane is relatively thin and contains longitudinally helical collagen fiber bundles and elastic fibers. There are fibroblasts, mast cells, and a few longitudinal smooth muscles. The outer elastic membrane is not easy to distinguish under the light microscope. Under the electron microscope, it is considered that a layer of intermittent elastic membrane adjacent to the middle membrane is the outer elastic membrane. Vegetative blood vessels and lymphatic vessels can distribute the outer layer of the media, sometimes with myeloid and unmyelinated nerves. The adventitia gradually moves around the connective tissue.