Search results
Results from the WOW.Com Content Network
Ventilation–perfusion coupling is the relationship between ventilation and perfusion processes, which take place in the respiratory system and the cardiovascular system. [1] Ventilation is the movement of gas during breathing, and perfusion is the process of pulmonary blood circulation , which delivers oxygen to body tissues. [ 2 ]
The control of ventilation is the physiological mechanisms involved in the control of breathing, which is the movement of air into and out of the lungs. Ventilation facilitates respiration. Respiration refers to the utilization of oxygen and balancing of carbon dioxide by the body as a whole, or by individual cells in cellular respiration. [1]
The volume of air that moves in or out (at the nose or mouth) during a single breathing cycle is called the tidal volume. In a resting adult human, it is about 500 ml per breath. At the end of exhalation, the airways contain about 150 ml of alveolar air which is the first air that is breathed back into the alveoli during inhalation.
Exchange of gases in the lung occurs by ventilation and perfusion. [1] Ventilation refers to the in-and-out movement of air of the lungs and perfusion is the circulation of blood in the pulmonary capillaries. [1] In mammals, physiological respiration involves respiratory cycles of inhaled and exhaled breaths.
Respiration is driven by different muscular systems in different species. Mammals, reptiles and birds use their musculoskeletal systems to support and foster breathing. In early tetrapods, air was driven into the lungs by the pharyngeal muscles via buccal pumping, a mechanism still seen in amphibians.
The ventilation/perfusion ratio (V/Q ratio) is higher in zone #1 (the apex of lung) when a person is standing than it is in zone #3 (the base of lung) because perfusion is nearly absent. However, ventilation and perfusion are highest in base of the lung, resulting in a comparatively lower V/Q ratio.
Respiration is the rhythmical process of breathing, in which air is drawn into the alveoli of the lungs via inhalation and subsequently expelled via exhalation. When a human being inhales, air travels down the trachea, through the bronchial tubes, and into the lungs. The entire tract is protected by the rib cage, spine, and sternum. In the ...
Oxygenated blood leaves the lungs through pulmonary veins, which return it to the left part of the heart, completing the pulmonary cycle. [3] [6] This blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. [3] [6] From the left ventricle, the blood passes through the aortic valve to the aorta.