The upper lobe is the largest lobe of the right lung. It extends from the apex of the lung down to the horizontal and oblique fissures. It bears apical, anterior, and posterior bronchopulmonary segments. The middle lobe is the smallest lobe of the right lung, located between the horizontal and oblique fissures.
It bears medial and lateral bronchopulmonary segments. The lower lobe is the bottom lobe of the right lung. It lies beneath the oblique fissure. It bears medial, lateral, superior, anterior, and posterior bronchopulmonary segments. The Left Lung : This has a concave depression that accommodates the shape of the heart, called the cardiac notch. The human left lung is smaller and narrower that the right lung, and is divided into two lobes, an upper and a lower, by the oblique fissure.
The left lung has only two formal lobes because of the space taken up in the left side of the chest cavity by the heart, though it does have the lingula, which is similar to a lobe. The left lung has a depression on the medial side of its surface called the cardiac notch, a concave impression molded to accommodate the shape of the heart. The upper lobe of the left lung contains anterior and apicoposterior bronchopulmonary segments.
It is above the oblique fissure. The lower lobe of the left lung contains superior, anterior, posterior, medial, and lateral bronchopulmonary segments. The lingula is not formally considered to be a lobe. It is a small, tongue-like projection of the left lung that is analogous to the middle lobe of the right lung. It contains superior and inferior bronchopulmonary segments. Above and behind the cardiac impression is a triangular depression named the hilum.
The hilum is the root of the lung where that contains structures that supply the lungs with blood, lymph fluid, and innervation, such as the pulmonary vein, pulmonary artery, pulmonary nerves, and lymphatic vessels. These structures are enclosed by pleura. There is a hilium for each of the lungs found in the mediastinum backside of the lungs.
The hilium is thinner in the left lung compared to the right lung because it lies between the cardiac notch and the groove for the aorta. The hilium is important because it is the primary way in which the respiratory system links with the cardiovascular and nervous systems.
Pulmonary circulation transports oxygen-depleted blood away from the heart to the lungs and returns oxygenated blood back to the heart. Bronchial circulation by the bronchial arteries supplies blood to the tissues of the bronchi and the pleura, and is considered part of systemic circulation. The right side of the heart deals with pulmonary circulation.
At the end of systemic circulation, the veins take blood back to the heart through the vena cava. The vena cava fills the right atrium with blood, which then ejects blood into the right ventricle by passing through the tricuspid valve. After blood fills in the right ventricle, it contracts and pumps the blood through the pulmonary valve, and into the pulmonary arteries. There are two pulmonary arteries one for each lung that bring the deoxygenated blood to the lungs through the hilium.
The arteries branch into the capillaries of the alveoli. Capillaries are the thinnest and smallest type of blood vessel, and they supply oxygen to individual tissues everywhere in the human body.
Gas exchange occurs by passive diffusion in the alveoli, so that dissolved oxygen enters the capillaries, while carbon dioxide leaves pulmonary circulation. The oxygenated blood then leaves the lungs through pulmonary veins also contained in the hilium , which return the blood to the left side of the heart, completing the cycle of pulmonary circulation.
This blood then enters and fills inside the left atrium, which pumps it through the mitral valve also called bicuspid into the left ventricle. The blood fills inside the left ventricle and is then pumped through the aortic valve into the aorta, which marks the beginning of systemic circulation.
Systemic circulation and pulmonary circulation form the overall cycle of the circulatory system: transporting oxygen throughout the body. Pulmonary circuit : Diagram of pulmonary circulation. Oxygen-rich blood is shown in red; oxygen-depleted blood in blue.
While the cycle of pulmonary and systemic circulation is a well designed and effective system, it is not immune to certain problems. The most serious issue in pulmonary circulation is a pulmonary embolism, which is where a blood clot travels to the lung and causes an infarction of the lung tissue death from lack of oxygen.
These blood clots typically originate in the deep veins of the legs part of systemic circulation as a result of blood pooling from injury or immobilization. A bony cage commonly called the rib cage , which is formed by the sternum, ribs, and spine, protects the lungs and other organs in the chest.
The 12 pairs of ribs curve around the chest from the back. Each pair is joined to the bones vertebrae of the spine. In the front of the body, the upper seven pairs of ribs are attached to the sternum by cartilage. The eighth, ninth, and tenth pairs of ribs join the cartilage of the pair above. Breathing continues during sleep and usually even when a person is unconscious Merck and Co.
From developing new therapies that treat and prevent disease to helping people in need, we are committed to improving health and well-being around the world. The Manual was first published in as a service to the community. Learn more about our commitment to Global Medical Knowledge. These include the spinal cord, the meninges of the spinal cord, and the fluid-filled spaces between them.
This is the most narrow of all body cavities, sometimes described as threadlike. The ventral cavity, the interior space in the front of the body, contains many different organ systems. The organs within the ventral cavity are also called viscera.
The ventral cavity has anterior and posterior portions divided by the diaphragm, a sheet of skeletal muscle found beneath the lungs. The thoracic cavity is the anterior ventral body cavity found within the rib cage in the torso.
It houses the primary organs of the cardiovascular and respiratory systems, such as the heart and lungs, but also includes organs from other systems, such as the esophagus and the thymus gland.
The thoracic cavity is lined by two types of mesothelium, a type of membrane tissue that lines the ventral cavity: the pleura lining of the lungs, and the pericadium lining of the heart. The abdominoplevic cavity is the posterior ventral body cavity found beneath the thoracic cavity and diaphragm. It is generally divided into the abdominal and pelvic cavities. The abdominal cavity is not contained within bone and houses many organs of the digestive and renal systems, as well as some organs of the endocrine system, such as the adrenal glands.
The pelvic cavity is contained within the pelvis and houses the bladder and reproductive system.
0コメント