Search results
Results from the WOW.Com Content Network
In radial section, two tracheids of a coniferous wood species are shown. A series of bordered pits are also appearing in each tracheid. A tracheid of oak shows pits along the walls. It has no perforation plates. Angiosperms have both tracheids and vessel elements. [1] A tracheid is a long and tapered lignified cell in the xylem of vascular ...
The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies greatly, depending on the size of the organism, the environment in which it lives and its evolutionary ...
Air enters the respiratory systems of insects through a series of external openings called spiracles. These external openings, which act as muscular valves in some insects, lead to the internal respiratory system, a densely networked array of tubes called tracheae. This network of transverse and longitudinal tracheae equalizes pressure ...
The breathing of all vertebrates with lungs consists of repetitive cycles of inhalation and exhalation through a highly branched system of tubes or airways which lead from the nose to the alveoli. [4] The number of respiratory cycles per minute is the breathing or respiratory rate, and is one of the four primary vital signs of life. [5]
The lungs can be included in the lower respiratory tract or as separate entity and include the respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli. [3] Adult and pediatric airway anatomy. The respiratory tract can also be divided into a conducting zone and a respiratory zone, based on the distinction of transporting gases or ...
In physiology, respiration is the transport of oxygen from the outside environment to the cells within tissues, and the removal of carbon dioxide in the opposite direction to the environment by a respiratory system. [1] The physiological definition of respiration differs from the biochemical definition, which refers to a metabolic process by ...
For the respiratory system to function properly, there need to be as few impediments as possible to the movement of air within the lungs. Inflammation of the lungs and excess mucus are common sources of breathing difficulties. [50] In asthma, the respiratory system is persistently inflamed, causing wheezing or shortness of breath.
The tracheal system branches into progressively smaller tubes, here supplying the crop of the cockroach. Scale bar, 2 mm. The word trachea is used to define a very different organ in invertebrates than in vertebrates. Insects have an open respiratory system made up of spiracles, tracheae, and tracheoles to transport metabolic gases to and from ...