query: which body structure provides actual diffusion of respiratory gases in lungs

pos: Gas exchange The gas exchangers are therefore frequently coupled to gas-distributing circulatory systems, which transport the gases evenly to all the body tissues regardless of their distance from the gas exchanger. Some multicellular organisms such as flatworms (Platyhelminthes) are relatively large but very thin, allowing their outer body surface to act as a gas exchange surface without the need for a specialised gas exchange organ. Flatworms therefore lack gills or lungs, and also lack a circulatory system. Other multicellular organisms such as sponges (Porifera) have an inherently high surface area, because they are very porous and/or branched. Sponges do not require a

neg: Inhalation exposure nitrogen oxide , ozone , sulfur dioxide , carbon monoxide (CO), and nonmethane hydrocarbons (NHMC). Particulate matter (PM) is divided into two sizes, PM which is called inhalable PM, and PM, which is called fine PM. The diffusion of from the air in the lungs to the bloodstream, and diffusion of from the bloodstream back out to the lungs is an essential part of human respiration. The absorption and diffusion of gases is a bidirectional process. Once the gases are absorbed into the mucus or surfactant layer, the dissolved gases can desorb back to the air in the lungs. Gases

neg: Respiratory tract zone and a respiratory zone, based on the distinction of transporting gases or exchanging them. The conducting zone includes structures outside of the lungs – the nose, pharynx, larynx, and trachea, and structures inside the lungs – the bronchi, bronchioles, and terminal bronchioles. The conduction zone conducts air breathed in that is filtered, warmed, and moistened, into the lungs. It represents the 1st through the 16th division of the respiratory tract. The conducting zone is most of the respiratory tract that conducts gases into and out of the lungs, but excludes the respiratory zone that exchanges gases. The conducting zone

neg: Exhalation abdominal muscles and internal intercostal muscles generate abdominal and thoracic pressure, which forces air out of the lungs. Exhaled air is rich in carbon dioxide, a waste product of cellular respiration during the production of energy, which is stored as ATP. Exhalation has a complementary relationship to inhalation which together make up the respiratory cycle of a breath. The main reason for exhalation is to rid the body of carbon dioxide, which is the waste product of gas exchange in humans. Air is brought in the body through inhalation. During this process air is taken in through the lungs. Diffusion

neg: Gas exchange as the pre-metamorphosis tadpole stage of frogs, also have external gills. The gills are absorbed into the body during metamorphosis, after which the lungs will then take over. The lungs are usually simpler than in the other land vertebrates, with few internal septa and larger alveoli; however, toads, which spend more time on land, have a larger alveolar surface with more developed lungs. To increase the rate of gas exchange by diffusion, amphibians maintain the concentration gradient across the respiratory surface using a process called buccal pumping. The lower floor of the mouth is moved in a "pumping" manner, which

neg: Breathing has little effect on the actual rate of inflow into the lungs and is easily compensated for by breathing slightly deeper. The lower viscosity of air at altitude allows air to flow more easily and this also helps compensate for any loss of pressure gradient. All of the above effects of low atmospheric pressure on breathing are normally accommodated by increasing the respiratory minute volume (the volume of air breathed in – "or" out – per minute), and the mechanism for doing this is automatic. The exact increase required is determined by the respiratory gases homeostatic mechanism, which regulates the

neg: Physiology of decompression and the partial pressures of the constituent gases will be increased proportionately. The inert gases from the breathing gas in the lungs diffuse into blood in the alveolar capillaries ("move down the pressure gradient") and are distributed around the body by the systemic circulation in the process known as perfusion. Perfusion is the mass flow of blood through the tissues. Dissolved materials are transported in the blood much faster than they would be distributed by diffusion alone (order of minutes compared to hours). The dissolved gas in the alveolar blood is transported to the body tissues by the blood circulation.

neg: Pathophysiology of acute respiratory distress syndrome Pathophysiology of acute respiratory distress syndrome The pathophysiology of acute respiratory distress syndrome involves fluid accumulation in the lungs not explained by heart failure (noncardiogenic pulmonary edema). It is typically provoked by an acute injury to the lungs that results in flooding of the lungs' microscopic air sacs responsible for the exchange of gases such as oxygen and carbon dioxide with capillaries in the lungs. Additional common findings in ARDS include partial collapse of the lungs (atelectasis) and low levels of oxygen in the blood (hypoxemia). The clinical syndrome is associated with pathological findings including pneumonia, eosinophilic pneumonia, cryptogenic organizing

neg: Respiratory system and forth within the body, drastically increasing the dead space ventilation. The purpose of this extraordinary feature is unknown. The anatomical structure of the lungs is less complex in reptiles than in mammals, with reptiles lacking the very extensive airway tree structure found in mammalian lungs. Gas exchange in reptiles still occurs in alveoli however. Reptiles do not possess a diaphragm. Thus, breathing occurs via a change in the volume of the body cavity which is controlled by contraction of intercostal muscles in all reptiles except turtles. In turtles, contraction of specific pairs of flank muscles governs inhalation and exhalation.

neg: Gas exchange flow of water across their cells, and they exchange gases by simple diffusion across their cell membranes. Pores called ostia draw water into the sponge and the water is subsequently circulated through the sponge by cells called choanocytes which have hair-like structures that move the water through the sponge. The cnidarians include corals, sea anemones, jellyfish and hydras. These animals are always found in aquatic environments, ranging from fresh water to salt water. They do not have any dedicated respiratory organs; instead, every cell in their body can absorb oxygen from the surrounding water, and release waste gases to it.

neg: Cardiorespiratory fitness to increase blood flow. As a result of increased vascular resistance, blood pressure rises throughout exercise and stimulates baroreceptors in the carotid arteries and aortic arch. “These pressure receptors are important since they regulate arterial blood pressure around an elevated systemic pressure during exercise”. Although all of the described adaptations in the body to maintain homeostatic balance during exercise are very important, the most essential factor is the involvement of the respiratory system. The respiratory system allows for the proper exchange and transport of gases to and from the lungs while being able to control the ventilation rate through neural

neg: Respiratory system between species, however they always come in pairs, one on each side of the body, and usually one pair per segment. Some of the Diplura have eleven, with four pairs on the thorax, but in most of the ancient forms of insects, such as Dragonflies and Grasshoppers there are two thoracic and eight abdominal spiracles. However, in most of the remaining insects there are fewer. It is at the level of the tracheoles that oxygen is delivered to the cells for respiration. Insects were once believed to exchange gases with the environment continuously by the simple diffusion of gases into

neg: Respiratory system have a high demand for oxygen, bringing the air closer to the active cells. This is probably brought about by the buildup of lactic acid in the active muscles causing an osmotic gradient, moving the water out of the tracheoles and into the active cells. Diffusion of gases is effective over small distances but not over larger ones, this is one of the reasons insects are all relatively small. Insects which do not have spiracles and trachaea, such as some Collembola, breathe directly through their skins, also by diffusion of gases. The number of spiracles an insect has is variable

neg: Apnea will then remain at the usual level and the normal functioning of the organs will not be affected. A detriment to this hyperoxygenation is possible nitrogen washout occurring which can lead to absorption atelectasis. However, no CO is removed during apnea. The partial pressure of CO in the airspace of the lungs will quickly equilibrate with that of the blood. As the blood is loaded with CO from the metabolism, more and more CO will accumulate and eventually displace oxygen and other gases from the airspace. CO will also accumulate in the tissues of the body, resulting in respiratory acidosis.

neg: Sea spider insects or crustaceans. This is in dispute, however, as genetic evidence suggests they may be the sister group to all other living arthropods. Sea spiders have long legs in contrast to a small body size. The number of walking legs is usually eight (four pairs), but species with five and six pairs exist. Because of their small size and thin body and legs, no respiratory system is necessary, with gases moving by diffusion. A proboscis allows them to suck nutrients from soft-bodied invertebrates, and their digestive tract has diverticula extending into the legs. Certain Pycnogonids are so small that each

neg: Pulmonary alveolus the alveoli where, through diffusion, carbon dioxide is released and oxygen absorbed. The alveoli are located in the respiratory zone of the lungs, at the ends of the alveolar ducts and alveolar sac, representing the smallest units in the respiratory tract. They provide total surface area of about 75m. A typical pair of human lungs contain about 480 million alveoli, producing 70m of surface area. Each alveolus is wrapped in a fine mesh of capillaries covering about 70% of its area. An adult alveolus has an average diameter of 200 µm, with an increase in diameter during inhalation. The alveoli

neg: Respiratory system lungs, thus providing an extremely large surface area (approximately 145 m) for gas exchange to occur. The air contained within the alveoli has a semi-permanent volume of about 2.5-3.0 liters which completely surrounds the alveolar capillary blood (Fig. 12). This ensures that equilibration of the partial pressures of the gases in the two compartments is very efficient and occurs very quickly. The blood leaving the alveolar capillaries and is eventually distributed throughout the body therefore has a partial pressure of oxygen of 13-14 kPa (100 mmHg), and a partial pressure of carbon dioxide of 5.3 kPa (40 mmHg) (i.e. the

neg: Lungfish number of larval features, which suggest paedomorphosis. They also demonstrate the largest genome among the vertebrates. Modern lungfish all have an elongate body with fleshy, paired pectoral and pelvic fins and a single unpaired caudal fin replacing the dorsal, caudal and anal fins of most fishes. Lungfish have a highly specialized respiratory system. They have a distinct feature that their lungs are connected to the larynx and pharynx without a trachea. While other species of fish can breathe air using modified, vascularized gas bladders, these bladders are usually simple sacs, devoid of complex internal structure. In contrast, the lungs of

neg: Common raven physiology lungs via ventilation 2. The diffusion of oxygen from the lungs into the blood stream 3. Oxygen-rich blood is transported to the peripheral tissues by convection 4. Oxygen diffuses into the mitochondria. Fick's laws of diffusion can be applied to oxygen cascade events in avian species. There is a proportional relationship between the tissue sheet and the surface area. Finally, in the avian respiratory system, the partial pressure of oxygen between the gas, lung, and the vascular capillaries depends upon the ventilation rate and air that is already inhaled. Like all avian species, the blood of the common raven transports

neg: Chronic obstructive pulmonary disease the connective tissue of the lungs by proteases that are insufficiently inhibited by protease inhibitors. The destruction of the connective tissue of the lungs leads to emphysema, which then contributes to the poor airflow, and finally, poor absorption and release of respiratory gases. General muscle wasting that often occurs in COPD may be partly due to inflammatory mediators released by the lungs into the blood. Narrowing of the airways occurs due to inflammation and scarring within them. This contributes to the inability to breathe out fully. The greatest reduction in air flow occurs when breathing out, as the pressure in

neg: Extracorporeal membrane oxygenation Extracorporeal membrane oxygenation Extracorporeal membrane oxygenation (ECMO), also known as extracorporeal life support (ECLS), is an extracorporeal technique of providing prolonged cardiac and respiratory support to persons whose heart and lungs are unable to provide an adequate amount of gas exchange or perfusion to sustain life. The technology for ECMO is largely derived from cardiopulmonary bypass, which provides shorter-term support with arrested native circulation. This intervention has mostly been used on children, but it is seeing more use in adults with cardiac and respiratory failure. ECMO works by removing blood from the person's body and artificially removing the carbon dioxide

neg: Physiology of decompression the capillaries of the lungs, which are around the alveoli and very near to the respiratory gas, where the gas will diffuse from the bubbles though the capillary and alveolar walls into the gas in the lung. If the number of lung capillaries blocked by these bubbles is relatively small, the diver will not display symptoms, and no tissue will be damaged (lung tissues are adequately oxygenated by diffusion). The bubbles which are small enough to pass through the lung capillaries may be small enough to be dissolved due to a combination of surface tension and diffusion to a lowered

neg: General anaesthetic by varying the partial pressure of the inspired anesthetic. A higher drug partial pressure in the lungs will drive diffusion more rapidly throughout the body and yield a higher maximum tissue concentration. Respiratory rate and inspiratory volume will also effect the promptness of anesthesia onset, as will the extent of pulmonary blood flow. The partition coefficient of a gaseous drug is indicative of its relative solubility in various tissues. This metric is the relative drug concentration between two tissues, when their partial pressures are equal (gas:blood, fat:blood, etc.). Inhalational anesthetics vary widely with respect to their tissue solubilities and partition

neg: Aurelia aurita the cavity by ciliated action. There, digestive enzymes from serous cell break down the food. There is little known about the requirements for particular vitamins and minerals, but due to the presence of some digestive enzymes, we can deduce in general that "A. aurita" can process carbohydrates, proteins and lipids. "Aurelia" does not have respiratory parts such as gills, lungs or trachea, it respires by diffusing oxygen from water through the thin membrane covering its body. Within the gastrovascular cavity, low oxygenated water can be expelled and high oxygenated water can come in by ciliated action, thus increasing the diffusion

neg: Acute respiratory distress syndrome include the following: ARDS is a form of fluid accumulation in the lungs not explained by heart failure (noncardiogenic pulmonary edema). It is typically provoked by an acute injury to the lungs that results in flooding of the lungs' microscopic air sacs responsible for the exchange of gases such as oxygen and carbon dioxide with capillaries in the lungs. Additional common findings in ARDS include partial collapse of the lungs (atelectasis) and low levels of oxygen in the blood (hypoxemia). The clinical syndrome is associated with pathological findings including pneumonia, eosinophilic pneumonia, cryptogenic organizing pneumonia, acute fibrinous organizing pneumonia, and

neg: Soil not just to allow the penetration of water, but also to allow gases to diffuse in and out. Movement of gases is by diffusion from high concentrations to lower, the diffusion coefficient decreasing with soil compaction. Oxygen from above atmosphere diffuses in the soil where it is consumed and levels of carbon dioxide in excess of above atmosphere diffuse out with other gases (including greenhouse gases) as well as water. Soil texture and structure strongly affect soil porosity and gas diffusion. It is the total pore space (porosity) of soil, not the pore size, and the degree of pore interconnection

neg: Decompression theory from the breathing gas in the lungs diffuse into blood in the alveolar capillaries and are distributed around the body by the systemic circulation in the process known as perfusion. Dissolved materials are transported in the blood much faster than they would be distributed by diffusion alone. From the systemic capillaries the dissolved gases diffuse through the cell membranes and into the tissues, where it may eventually reach equilibrium. The greater the blood supply to a tissue, the faster it will reach equilibrium with gas at the new partial pressure. This equilibrium is called saturation. Ingassing appears to follow a

neg: Artificial ventilation Artificial ventilation Artificial ventilation, (also called artificial respiration) is means of assisting or stimulating respiration, a metabolic process referring to the overall exchange of gases in the body by pulmonary ventilation, external respiration, and internal respiration. It may take the form of manually providing air for a person who is not breathing or is not making sufficient respiratory effort on their own, or it may be mechanical ventilation involving the use of a mechanical ventilator to move air in and out of the lungs when an individual is unable to breathe on their own, for example during surgery with general

neg: Respiratory tract trachea, bronchi (primary, secondary and tertiary), bronchioles (including terminal and respiratory), and lungs (including alveoli). It also sometimes includes the larynx. The lower respiratory tract is also called the respiratory tree or tracheobronchial tree, to describe the branching structure of airways supplying air to the lungs, and includes the trachea, bronchi and bronchioles. At each division point or generation, one airway branches into two or more smaller airways. The human respiratory tree may consist on average of 23 generations, while the respiratory tree of the mouse has up to 13 generations. Proximal divisions (those closest to the top of the

neg: Breathing Breathing Breathing (or respiration, or ventilation) is the process of moving air into and out of the lungs to facilitate gas exchange with the internal environment, mostly by bringing in oxygen and flushing out carbon dioxide. All aerobic creatures need oxygen for cellular respiration, which uses the oxygen to break down foods for energy and produces carbon dioxide as a waste product. Breathing, or "external respiration", brings air into the lungs where gas exchange takes place in the alveoli through diffusion. The body's circulatory system transports these gases to and from the cells, where "cellular respiration" takes place. The breathing

neg: Decompression (diving) pressure of the inert gas in the lungs. This process may be complicated by the formation of gas bubbles, and the modeling is more complex and varied. The combined concentrations of gases in any given tissue depend on the history of pressure and gas composition. Under equilibrium conditions, the total concentration of dissolved gases is less than the ambient pressure—as oxygen is metabolized in the tissues, and the carbon dioxide produced is much more soluble. However, during a reduction in ambient pressure, the rate of pressure reduction may exceed the rate at which gas is eliminated by diffusion and perfusion.

neg: Decompression sickness but do not reduce it to zero. One of the most significant breakthroughs in the prevention of altitude DCS is oxygen pre-breathing. Breathing pure oxygen significantly reduces the nitrogen loads in body tissues by reducing the partial pressure of nitrogen in the lungs, which induces diffusion of nitrogen from the blood into the breathing gas, and this effect eventually lowers the concentration of nitrogen in the other tissues of the body. If continued for long enough, and without interruption, this provides effective protection upon exposure to low-barometric pressure environments. However, breathing pure oxygen during flight alone (ascent, en route, descent)

neg: Inhalation exposure The deposition of particulate pollutants into the lungs is necessary before the particles can travel through the mucus into the lung tissue. There are four mechanisms of deposition: interception, impaction, gravitational settling, and Brownian diffusion. Interception happens when a particle is removed after brushing up against an obstacle. Impaction happens when the particle collides into the surface of the respiratory tract due to the high inertia. Gravitational settling is influenced by the force of gravity which causes the particle to settle on the respiratory tract. Brownian motion causes the random collision of gas molecules against the particle, until the particle

neg: Physiology of underwater diving reduction may exceed the rate at which gas can be eliminated by diffusion and perfusion, and if the concentration gets too high, it may reach a stage where bubble formation can occur in the supersaturated tissues. When the pressure of gases in a bubble exceed the combined external pressures of ambient pressure and the surface tension from the bubble - liquid interface, the bubbles will grow, and this growth can cause damage to tissues. Symptoms caused by this damage are known as Decompression sickness. The actual rates of diffusion and perfusion, and the solubility of gases in specific tissues are

neg: Diffusion 1948, Wendell H. Furry proposed to use the "form" of the diffusion rates found in kinetic theory as a framework for the new phenomenological approach to diffusion in gases. This approach was developed further by F.A. Williams and S.H. Lam. For the diffusion velocities in multicomponent gases ("N" components) they used Here, formula_65 is the diffusion coefficient matrix, formula_123 is the thermal diffusion coefficient, formula_124 is the body force per unite mass acting on the "i"th species, formula_125 is the partial pressure fraction of the "i"th species (and formula_126 is the partial pressure), formula_127 is the mass fraction of the

neg: Mouth-to-mouth resuscitation Mouth-to-mouth resuscitation Mouth-to-mouth resuscitation, a form of artificial ventilation, is the act of assisting or stimulating respiration, a metabolic process referring to the overall exchange of gases in the body, where a rescuer presses his or her mouth against that of the victim and blows air into the person's lungs. Assistance takes many forms, but generally entails providing air for a person who is not breathing or is not making sufficient respiratory effort on his/her own. It is used on a patient with a beating heart or as part of cardiopulmonary resuscitation (CPR) to achieve the internal respiration). Pulmonary ventilation

neg: Breathalyzer beer, or of wine.) Breath alcohol is a representation of the equilibrium of alcohol concentration as the blood gases (alcohol) pass from the (arterial) blood into the lungs to be expired in the breath. Arterial blood distributes oxygen throughout the body. Breath alcohol concentrations are generally lower than blood alcohol concentrations, because a true representation of blood alcohol concentration is only possible if the lungs were able to completely deflate. Vitreous (eye) fluid provides the most accurate account of blood alcohol concentration. A common defense to an impaired driving charge (in appropriate circumstances) is that the consumption of alcohol occurred

neg: Lung trachea and the structures below this including the lungs. The trachea receives air from the pharynx and travels down to a place where it splits (the carina) into a right and left bronchus. These supply air to the right and left lungs, splitting progressively into the secondary and tertiary bronchi for the lobes of the lungs, and into smaller and smaller bronchioles until they become the respiratory bronchioles. These in turn supply air through alveolar ducts into the alveoli, where the exchange of gases take place. Oxygen breathed in, diffuses through the walls of the alveoli into the enveloping capillaries

neg: Murray's law gas diffusion for breathing, the sum of radii squared of tracheal pores remains constant along the diffusion pathway, to maximize gases diffusion. From plants, animals and materials to industrial processes, the introduction of Murray material concept to industrial reactions can revolutionize the design of reactors with highly enhanced efficiency, minimum energy, time, and raw material consumption for a sustainable future. Murray's law Murray's law predicts the thickness of branches in transport networks, such that the cost for transport and maintenance of the transport medium is minimized. This law is observed in the vascular and respiratory systems of animals, xylem in

neg: Respiratory system tightly closed glottis, so that no air can escape from the lungs. Instead abdominal contents are evacuated in the opposite direction, through orifices in the pelvic floor. The abdominal muscles contract very powerfully, causing the pressure inside the abdomen and thorax to rise to extremely high levels. The Valsalva maneuver can be carried out voluntarily, but is more generally a reflex elicited when attempting to empty the abdomen during, for instance, difficult defecation, or during childbirth. Breathing ceases during this maneuver. The primary purpose of the respiratory system is the equilibration of the partial pressures of the respiratory gases in

neg: Atrial septal defect infections. ASDs, and particularly PFOs, are a predisposing venous blood carrying inert gases, such as helium or nitrogen does not pass through the lungs. The only way to release the excess inert gases from the body is to pass the blood carrying the inert gases through the lungs to be exhaled. If some of the inert gas-laden blood passes through the PFO, it avoids the lungs and the inert gas is more likely to form large bubbles in the arterial blood stream causing decompression sickness. If a net flow of blood exists from the left atrium to the right atrium,

neg: Fink effect combination of nitrous oxide and oxygen, is suitable for use by para-medical staff such as ambulance officers: it provides sufficient nitrous oxide for pain relief with sufficient oxygen to avoid hypoxia. Fink effect The Fink effect, also known as "diffusion anoxia", "diffusion hypoxia", or the "third gas effect", is a factor that influences the pO (partial pressure of oxygen) within the alveolus. When water-insoluble gases such as anesthetic agent NO (nitrous oxide) are breathed in large quantities they can be dissolved in body fluids rapidly. This leads to a temporary increase in both the concentrations and partial pressures of oxygen

neg: Graham's law escape through a small pinhole in a vessel at half the rate of the other (heavier gases diffuse more slowly). A complete theoretical explanation of Graham's law was provided years later by the kinetic theory of gases. Graham's law provides a basis for separating isotopes by diffusion—a method that came to play a crucial role in the development of the atomic bomb. Graham's law is most accurate for molecular effusion which involves the movement of one gas at a time through a hole. It is only approximate for diffusion of one gas in another or in air, as these processes

neg: General anaesthetic the lungs, and patient respiratory rate and inspiratory volume. For gases that have minimal tissue solubility, termination of anesthesia generally occurs as rapidly as the onset of anesthesia. For gases that have high tissue solubility, however, termination of anesthesia is generally context-dependent. As with intravenous anesthetic infusions, prolonged delivery of highly soluble anesthetic gases generally results in longer drug half-lives, slowed elimination from the brain and spinal cord, and delayed termination of anesthesia. Metabolism of inhaled anesthetics is generally not a major route of drug elimination. General anaesthetic General anaesthetics (or anesthetics, see spelling differences) are often defined as compounds

neg: Acute inhalation injury Acute inhalation injury Acute inhalation injury may result from frequent and widespread use of household cleaning agents and industrial gases (including chlorine and ammonia). The airways and lungs receive continuous first-pass exposure to non-toxic and irritant or toxic gases via inhalation. Irritant gases are those that, on inhalation, dissolve in the water of the respiratory tract mucosa and provoke an inflammatory response, usually from the release of acidic or alkaline radicals. Smoke, chlorine, phosgene, sulfur dioxide, hydrogen chloride, hydrogen sulfide, nitrogen dioxide, ozone, and ammonia are common irritants. Depending on the type and amount of irritant gas inhaled, victims can

neg: Parasitic pneumonia Parasitic pneumonia Parasitic pneumonia is an infection of the lungs by parasites. It is a rare cause of pneumonia, occurring almost exclusively in immunocompromised persons (persons with a weakened or absent immune system). This is a respiratory infection that may or may not be serious. There are a variety of parasites which can affect the lungs. In general, these parasites enter the body through the skin or by being swallowed. Once inside the body, these parasites travel to the lungs, most often through the blood. There, a similar combination of cellular destruction and immune response causes disruption of oxygen transportation.

neg: Parasitic pneumonia Depending on the type of parasite, antihelmynthic drugs can be prescribed. The most common parasites involved: Parasitic pneumonia Parasitic pneumonia is an infection of the lungs by parasites. It is a rare cause of pneumonia, occurring almost exclusively in immunocompromised persons (persons with a weakened or absent immune system). This is a respiratory infection that may or may not be serious. There are a variety of parasites which can affect the lungs. In general, these parasites enter the body through the skin or by being swallowed. Once inside the body, these parasites travel to the lungs, most often through the

neg: Human brain acidic pH, or low oxygen stimulate the respiratory centres. The desire to breathe in is also affected by pulmonary stretch receptors in the lungs which, when activated, prevent the lungs from overinflating by transmitting information to the respiratory centres via the vagus nerve. The hypothalamus in the diencephalon, is involved in regulating many functions of the body. Functions include neuroendocrine regulation, regulation of the circadian rhythm, control of the autonomic nervous system, and the regulation of fluid, and food intake. The circadian rhythm is controlled by two main cell groups in the hypothalamus. The anterior hypothalamus includes the suprachiasmatic nucleus

neg: Exhalation in the alveoli allows for the exchange of O into the pulmonary capillaries and the removal of CO and other gases from the pulmonary capillaries to be exhaled. In order for the lungs to expel air the diaphragm relaxes, which pushes up on the lungs. The air then flows through the trachea then through the larynx and pharynx to the nasal cavity and oral cavity where it is expelled out of the body. Exhalation takes longer than inhalation since it is believed to facilitate better exchange of gases. Parts of the nervous system help to regulate respiration in humans. The

neg: Diffusion Latin word, "diffundere", which means "to spread way out". A distinguishing feature of diffusion is that it depends on particle random walk, and results in mixing or mass transport without requiring directed bulk motion. Bulk motion, or bulk flow, is the characteristic of advection. The term convection is used to describe the combination of both transport phenomena. An example of a situation in which bulk motion and diffusion can be differentiated is the mechanism by which oxygen enters the body during external respiration known as breathing. The lungs are located in the thoracic cavity, which expands as the first step

neg: Breathing end of exhalation, and is the first air to breathed back into the alveoli, before any fresh air reaches the alveoli during inhalation. The dead space volume of a typical adult human is about 150 ml. The primary purpose of breathing is to bring atmospheric air (in small doses) into the alveoli where gas exchange with the gases in the blood takes place. The equilibration of the partial pressures of the gases in the alveolar blood and the alveolar air occurs by diffusion. At the end of each exhalation the adult human lungs still contain 2,500–3,000 mL of air, their

neg: Influenza the viral hemagglutinin protein by any one of several human proteases. In mild and avirulent viruses, the structure of the hemagglutinin means that it can only be cleaved by proteases found in the throat and lungs, so these viruses cannot infect other tissues. However, in highly virulent strains, such as H5N1, the hemagglutinin can be cleaved by a wide variety of proteases, allowing the virus to spread throughout the body. The viral hemagglutinin protein is responsible for determining both which species a strain can infect and where in the human respiratory tract a strain of influenza will bind. Strains that

neg: Ant or two nodes (the second alone, or the second and third abdominal segments). Like other insects, ants have an exoskeleton, an external covering that provides a protective casing around the body and a point of attachment for muscles, in contrast to the internal skeletons of humans and other vertebrates. Insects do not have lungs; oxygen and other gases, such as carbon dioxide, pass through their exoskeleton via tiny valves called spiracles. Insects also lack closed blood vessels; instead, they have a long, thin, perforated tube along the top of the body (called the "dorsal aorta") that functions like a heart,

neg: Respiratory system of insects Respiratory system of insects An insect's respiratory system is the biological system with which it introduces respiratory gases to its interior and performs gas exchange. 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 throughout the system. It is responsible for delivering sufficient oxygen (O) to all cells of the body and for removing carbon dioxide (CO) that is produced

neg: Hypoxemia volume of air entering the lungs (ventilation) or any cause that influences the transfer of air from the lungs to the blood may cause hypoxemia. As well as these respiratory causes, cardiovascular causes such as shunts may also result in hypoxaemia. Hypoxemia is caused by five categories of etiologies: hypoventilation, ventilation/perfusion mismatch, right-to-left shunt, diffusion impairment, and low PO. Low PO and hypoventilation are associated with a normal A-a gradient whereas the other categories are associated with an increased A-a gradient. If the alveolar ventilation is insufficient, there will not be enough oxygen delivered to the alveoli for the body's

neg: Horseshoe crab swimming, and moving food into the mouth, each with a claw at the tip, except for the last pair. Behind its legs, the horseshoe crab has book gills, which exchange respiratory gases, and are also occasionally used for swimming. As in other arthropods, a true endoskeleton is absent, but the body does have an endoskeletal structure made up of cartilaginous plates that support the book gills. They are more often found on the ocean floor searching for worms and molluscs, which are their main food. They may also feed on crustaceans and even small fish. Females are about 20–30% larger

neg: Respiratory tract the lung that exchanges oxygen and carbon dioxide with the blood. 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 lungs, oxygen from the inhaled air is transferred into the blood and circulated throughout the body. Carbon dioxide (CO) is transferred from returning blood back into gaseous form in the lungs and

neg: Alveolar–arterial gradient both. CO2 is very easily exchanged in the lungs and low P directly correlates with high minute ventilation; therefore a low arterial P indicates that extra respiratory effort is being used to oxygenate the blood. A low Pa indicates that the patient's current minute ventilation (whether high or normal) is not enough to allow adequate oxygen diffusion into the blood. Therefore, the A–a gradient essentially demonstrates a high respiratory effort (low arterial P) relative to the achieved level of oxygenation (arterial P). A high A–a gradient could indicate a patient breathing hard to achieve normal oxygenation, a patient breathing normally

neg: Decompression theory veins will pass into the right side of the heart, and from there they will normally enter the pulmonary circulation and pass through or be trapped in the capillaries of the lungs, which are around the alveoli and very near to the respiratory gas, where the gas will diffuse from the bubbles though the capillary and alveolar walls into the gas in the lung. If the number of lung capillaries blocked by these bubbles is relatively small, the diver will not display symptoms, and no tissue will be damaged (lung tissues are adequately oxygenated by diffusion). The bubbles which are

neg: Fick's laws of diffusion put in contact with a layer of pure solvent. (Bokstein, 2005) The length is called the "diffusion length" and provides a measure of how far the concentration has propagated in the -direction by diffusion in time (Bird, 1976). As a quick approximation of the error function, the first 2 terms of the Taylor series can be used: If is time-dependent, the diffusion length becomes This idea is useful for estimating a diffusion length over a heating and cooling cycle, where varies with temperature. The Chapman–Enskog formulae for diffusion in gases include exactly the same terms. These physical models of diffusion

neg: Feynman sprinkler sprinkler, even in its steady state. Such behavior could be explained by the diffusion of momentum in a non-ideal (i.e., viscous) flow. However, careful observations of the actual behavior of experimental setups show that this turning is associated with the formation of a vortex inside the body of the sprinkler. An analysis of the actual distribution of forces and pressure in a non-ideal reverse sprinkler provides the theoretical basis to explain this: Feynman sprinkler A Feynman sprinkler, also referred to as a Feynman inverse sprinkler or as a reverse sprinkler, is a sprinkler-like device which is submerged in a tank

neg: Respiratory system diffuses from a region of high concentration to one of low concentration, under standard conditions) of the respiratory gases is typically 10,000 faster in air than in water. Thus oxygen, for instance, has a diffusion coefficient of 17.6 mm/s in air, but only 0.0021 mm/s in water. The corresponding values for carbon dioxide are 16 mm/s in air and 0.0016 mm/s in water. This means that when oxygen is taken up from the water in contact with a gas exchanger, it is replaced considerably more slowly by the oxygen from the oxygen-rich regions small distances away from the exchanger than

neg: Respiratory system of insects insects from growing as large as the ones we see in horror movies. Periods in Earth's ancient history, however, such as the Carboniferous, featured much higher oxygen levels (up to 35%) that allowed horror movie sized insects, such as meganeura, along with arachnids, to exist. Insects were once believed to exchange gases with the environment continuously by the simple diffusion of gases into the tracheal system. More recently, large variation in insect ventilatory patterns have been documented, suggesting that insect respiration is highly variable. Some small insects do demonstrate continuous respiration and may lack muscular control of the spiracles. Others,

neg: Insect sclerotized to form the intromittent organ, the aedeagus. The remainder of the male reproductive system is derived from embryonic mesoderm, except for the germ cells, or spermatogonia, which descend from the primordial pole cells very early during embryogenesis. Insect respiration is accomplished without lungs. Instead, the insect respiratory system uses a system of internal tubes and sacs through which gases either diffuse or are actively pumped, delivering oxygen directly to tissues that need it via their trachea (element 8 in numbered diagram). In most insects, air is taken in through openings on the sides of the abdomen and thorax called

neg: Bronchus remainder the bronchus may exhibit branching and associated aerated lung parenchyma. The alveolar ducts and alveoli consist primarily of simple squamous epithelium, which permits rapid diffusion of oxygen and carbon dioxide. Exchange of gases between the air in the lungs and the blood in the capillaries occurs across the walls of the alveolar ducts and alveoli. Bronchial wall thickening, as can be seen on CT scan, generally (but not always) implies inflammation of the bronchi. Normally, the ratio of the bronchial wall thickness and the bronchial diameter is between 0.17 and 0.23. Bronchitis is defined as inflammation of the bronchi,

neg: Decompression theory pressure, the rate of pressure reduction may exceed the rate at which gas can be eliminated by diffusion and perfusion, and if the concentration gets too high, it may reach a stage where bubble formation can occur in the supersaturated tissues. When the pressure of gases in a bubble exceed the combined external pressures of ambient pressure and the surface tension from the bubble - liquid interface, the bubbles will grow, and this growth can cause damage to tissues. Symptoms caused by this damage are known as Decompression sickness. The actual rates of diffusion and perfusion, and the solubility of

neg: Leukostasis as opposed to particular organ damage. The lungs alone account for approximately 30 percent of leukostasis fatalities. All other organs combined attribute to 30 percent of deaths, with the major outliers being neurological and respiratory failure equating to 70 percent of all death rates. Damage to the microvasculature of the body is the primary cause of death by leukostasis. Microvasculatre damage to the lungs is only second to neurological damage because the body is already suffering from hypoxic conditions, which leads to lung tissue damage as the second leading cause of fatalities. Pulmonary signs - Dyspnea and hypoxia with or

neg: Respiratory exchange ratio Respiratory exchange ratio The respiratory exchange ratio (RER) is the ratio between the amount of carbon dioxide (CO) produced in metabolism and oxygen (O) used. The ratio is determined by comparing exhaled gases to room air. Measuring this ratio can be used for estimating the respiratory quotient (RQ), an indicator of which fuel (carbohydrate or fat) is being metabolized to supply the body with energy. This estimation is only valid if metabolism is in a steady state. RER is about 0.8 at rest with a modern diet. This value, however, can exceed 1 during intense exercise, as CO production by

neg: Physiology of decompression of gases in a bubble exceed the combined external pressures of ambient pressure and the surface tension from the bubble - liquid interface, the bubbles will grow, and this growth can cause damage to tissues. Symptoms caused by this damage are known as Decompression sickness. The actual rates of diffusion and perfusion, and the solubility of gases in specific tissues are not generally known, and vary considerably. However mathematical models have been proposed which approximate the real situation to a greater or lesser extent, and these models are used to predict whether symptomatic bubble formation is likely to occur for

neg: Coffin birth bacteria in the gastrointestinal tract proliferate and as a result of increased metabolic activity, release gases such as carbon dioxide, methane, and hydrogen sulfide. These bacteria secrete exoenzymes to break down body cells and proteins for ingestion which thus weakens organ tissues. Increasing pressure forces the diffusion of excessive gases into the weakened tissues where they enter the circulatory system and spread to other parts of the body, causing both torso and limbs to become bloated. These decompositional processes weaken the structural integrity of organs by separating necrotizing tissue layers. Bloating usually begins from two to five days after death,

neg: Lung other vertebrates. Some invertebrates have lung-like structures that serve a similar respiratory purpose as, but are not evolutionarily related to, vertebrate lungs. Some arachnids, such as spiders and scorpions, have structures called book lungs used for atmospheric gas exchange. Some species of spider have four pairs of book lungs but most have two pairs. Scorpions have spiracles on their body for the entrance of air to the book lungs. The coconut crab is terrestrial and uses structures called branchiostegal lungs to breathe air. They cannot swim and would drown in water, yet they possess a rudimentary set of gills. They

neg: Acute respiratory distress syndrome Acute respiratory distress syndrome Acute respiratory distress syndrome (ARDS) is type of respiratory failure characterized by rapid onset of widespread inflammation in the lungs. Symptoms include shortness of breath, rapid breathing, and bluish skin coloration. Among those who survive, a decreased quality of life is relatively common. Causes may include sepsis, pancreatitis, trauma, pneumonia, and aspiration. The underlying mechanism involves diffuse injury to cells which form the barrier of the microscopic air sacs of the lungs, surfactant dysfunction, activation of the immune system, and dysfunction of the body's regulation of blood clotting. In effect, ARDS impairs the lungs' ability to

neg: Bochdalek hernia normal lungs, Bochdalek hernias are life-threatening conditions due to respiratory distress. Also, if the invasion of the intestine or stomach punctures the lung, then the lungs cannot fill completely with air. The baby will not be healthy or stable with this condition because he or she cannot take in enough air and oxygen to keep the body operating properly. Like the lungs, the intestines may also have trouble developing correctly. If the intestines are trapped within the lungs, then the lungs and intestines may not be receiving the amount of blood they need to stay healthy and function properly. Bochdalek

neg: Insect morphology then eliminated through the anus (element 17), completing the process of digestion. The uric acid is formed using hemolymph waste products diffused from the Malpighian tubules (element 20). It is then emptied directly into the alimentary canal, at the junction between the midgut and hindgut. The number of Malpighian tubules possessed by a given insect varies between species, ranging from only two tubules in some insects to over 100 tubules in others. Insect respiration is accomplished without lungs. Instead, the insect respiratory system uses a system of internal tubes and sacs through which gases either diffuse or are actively pumped,

neg: Aquatic respiration all cases, oxygen is provided from air trapped by hairs around the animals body. All aquatic reptiles breathe air into lungs. The anatomical structure of the lungs is less complex in reptiles than in mammals, with reptiles lacking the very extensive airway tree structure found in mammalian lungs. Gas exchange in reptiles still occurs in alveoli however, reptiles do not possess a diaphragm. Thus, breathing occurs via a change in the volume of the body cavity which is controlled by contraction of intercostal muscles in all reptiles except turtles. In turtles, contraction of specific pairs of flank muscles governs inspiration

neg: Arterial blood gas test increase ("Pa"CO > 45 mmHg), a condition known as respiratory acidosis occurs. The body tries to maintain homeostasis by increasing the respiratory rate, a condition known as tachypnea. This allows much more carbon dioxide to escape the body through the lungs, thus increasing the pH by having less carbonic acid. If a person is in a critical setting and intubated, one must increase the number of breaths mechanically. Respiratory alkalosis ("Pa" CO < 35 mmHg) occurs when there is too little carbon dioxide in the blood. This may be due to hyperventilation or else excessive breaths given via a mechanical

neg: Gill slender, tufted processes that have a highly folded surface to increase surface area. The delicate nature of the gills is possible because the surrounding water provides support. The blood or other body fluid must be in intimate contact with the respiratory surface for ease of diffusion. A high surface area is crucial to the gas exchange of aquatic organisms, as water contains only a small fraction of the dissolved oxygen that air does. A cubic meter of air contains about 250 grams of oxygen at STP. The concentration of oxygen in water is lower than in air and it diffuses

neg: Dog anatomy the respiratory system also plays an important role in body thermoregulation. Dogs are mammals with two large lungs and lobes, with a spongy appearance due to the presence of a system of delicate branches of the bronchioles in each lung, ending in closed, thin-walled chambers (the points of gas exchange) called alveoli. The presence of a muscular structure, the diaphragm, exclusive of the mammals, divides the peritoneal cavity of the pleural cavity, besides assisting the ribs in the Inhale. The organs that make up the canine digestive system are: Like most predatory mammals, the dog has powerful muscles, a cardiovascular

neg: Ventral respiratory group nerve which excites the diaphragm and the intercostal nerve which excites the external intercostal muscle. This leads to expansion of the thorax and air rush into the lungs. When VRG expiratory neurons fire, the output stops, and expiration occurs passively, as the inspiration muscles relax and the lungs recoil. The two respiratory groups in the medulla – the ventral and the dorsal respiratory group are responsible for the control of the rhythm of respiration. Ventral respiratory group The ventral respiratory group (VRG) is a column of neurons located in the ventrolateral region of the medulla, extending from the caudal facial

neg: Lung bud bronchial tree. Lung bud The lung bud sometimes referred to as the respiratory bud forms from the respiratory diverticulum, an embryological endodermal structure that develops into the respiratory tract organs such as the larynx, trachea, bronchi and lungs. It arises from part of the laryngotracheal tube. In the fourth week of development, the respiratory diverticulum, starts to grow from the ventral (front) side of the foregut into the mesoderm that surrounds it, forming the lung bud. Around the 28th day, during the separation of the lung bud from the foregut it forms the trachea and splits into two bronchial buds,

neg: Lung bud Lung bud The lung bud sometimes referred to as the respiratory bud forms from the respiratory diverticulum, an embryological endodermal structure that develops into the respiratory tract organs such as the larynx, trachea, bronchi and lungs. It arises from part of the laryngotracheal tube. In the fourth week of development, the respiratory diverticulum, starts to grow from the ventral (front) side of the foregut into the mesoderm that surrounds it, forming the lung bud. Around the 28th day, during the separation of the lung bud from the foregut it forms the trachea and splits into two bronchial buds, one on

neg: Tradeoffs for locomotion in air and water open water can accommodate harder landings. Similar to having light bones, birds also have large respiratory systems with large air spaces that reduce body weight and allow more efficient oxygen exchange required for the high metabolic demands of flight. Birds also have specialized structures called air sacs closely associated with their lungs that store air when the animal inspires, further reducing body weight and maintaining the partial pressure of oxygen within the lungs equal to that of the surrounding environment. While highly beneficial for flight, decreasing body weight (and thus whole body density) increases buoyancy forces and makes maintaining submerged

neg: Equimolar counterdiffusion Equimolar counterdiffusion Equimolar counterdiffusion is an instance of molecular diffusion in a binary mixture, and occurs when equal numbers of molecules of the two substances are moving in opposite directions. There are three different types of diffusion: molecular, Brownian and turbulent. Molecular diffusion occurs in gases, liquids, and solids. Diffusion is a result of thermal motion of molecules. Usually, convection occurs as a result of the diffusion process. The rate at which diffusion occurs depends on the state of the molecules: it occurs at a high rate in gases, a slower rate in liquids, and an even slower rate in

neg: Occupational hazards of grain facilities be respiratory irritants such as nitrogen dioxide (NO) and nitrogen tetroxide (NO). While low NO concentrations can cause coughing, labored breathing, and/or nausea, high concentrations can cause fluid to fill the lungs, which can result in death. Exposure Conditions/Scenarios/Causal Pathways Hazardous gas concentrations are generally highest within the first 48 hours after silage has been added to the container, but may still be present for roughly four weeks. The hazardous gases produced from fermenting silage (NO and NO) are heavier than air and typically can be reduced in silos by means of opening the containers chute doors. Even when airing

neg: Scipionyx been drawn from the indirect evidence available. In 1999 John Ruben e.a. inferred that "Scipionyx" had a respiratory system different from birds, and more similar to crocodiles, based on an analysis of pictures of the fossil which seemed to indicate the presence of a diaphragm. The large liver would have completely divided the body cavity into an anterior section for the heart and lungs and a posterior section for the intestines. This would have indicated the presence of septate lungs, ventilated by a hepatic-piston diaphragm, driven by the liver and a "Musculus diaphragmaticus", which in the fossil was visibly attached

neg: Respiratory tract tract infections are probably the most common infections in the world. The respiratory system is very prone to developing infections in the lungs. Infants and older adults are more likely to develop infections in their lungs, because their lungs are not as strong in fighting off these infections. Most of these infections used to be fatal, but with new research and medicine, they are now treatable. With bacterial infections, antibiotics are prescribed, while viral infections are harder to treat, but still curable. The common cold/flu is the most common cause for the upper respiratory tract infection, which can cause more

neg: Pharynx General Pharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity and above the esophagus and larynx, or the tubes going down to the stomach and the lungs. It is found in vertebrates and invertebrates, though its structure varies across species. In humans, the pharynx is part of the digestive system and the conducting zone of the respiratory system. (The conducting zone—which also includes the nostrils of the nose, the larynx, trachea, bronchi, and bronchioles—filters, warms and moistens air and conducts it into the lungs.) The pharynx makes up the part of the

neg: Pharynx Pharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity and above the esophagus and larynx, or the tubes going down to the stomach and the lungs. It is found in vertebrates and invertebrates, though its structure varies across species. In humans, the pharynx is part of the digestive system and the conducting zone of the respiratory system. (The conducting zone—which also includes the nostrils of the nose, the larynx, trachea, bronchi, and bronchioles—filters, warms and moistens air and conducts it into the lungs.) The pharynx makes up the part of the throat

neg: Respiratory tract tree, such as the bronchi) mainly function to transmit air to the lower airways. Later divisions including the respiratory bronchiole, alveolar ducts and alveoli, are specialized for gas exchange. The trachea is the largest tube in the respiratory tract and consists of tracheal rings of hyaline cartilage. It branches off into two bronchial tubes, a left and a right main bronchus. The bronchi branch off into smaller sections inside the lungs, called bronchioles. These bronchioles give rise to the air sacs in the lungs called the alveoli. The lungs are the largest organs in the lower respiratory tract. The lungs

neg: Lung single bronchus running down the centre, from which numerous branches reach out to individual pockets throughout the lungs. These pockets are similar to alveoli in mammals, but much larger and fewer in number. These give the lung a sponge-like texture. In tuataras, snakes, and some lizards, the lungs are simpler in structure, similar to that of typical amphibians. Snakes and limbless lizards typically possess only the right lung as a major respiratory organ; the left lung is greatly reduced, or even absent. Amphisbaenians, however, have the opposite arrangement, with a major left lung, and a reduced or absent right lung.

neg: Diffusion in external respiration. This expansion leads to an increase in volume of the alveoli in the lungs, which causes a decrease in pressure in the alveoli. This creates a pressure gradient between the air outside the body at relatively high pressure and the alveoli at relatively low pressure. The air moves down the pressure gradient through the airways of the lungs and into the alveoli until the pressure of the air and that in the alveoli are equal i.e. the movement of air by bulk flow stops once there is no longer a pressure gradient. The air arriving in the

neg: Respiratory system Respiratory system 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 history. In land animals the respiratory surface is internalized as linings of the lungs. Gas exchange in the lungs occurs in millions of small air sacs called alveoli in mammals and reptiles, but atria in birds. These microscopic air sacs have a very rich blood supply,

neg: Diffusion Elder had previously described the cementation process, which produces steel from the element iron (Fe) through carbon diffusion. Another example is well known for many centuries, the diffusion of colors of stained glass or earthenware and Chinese ceramics. In modern science, the first systematic experimental study of diffusion was performed by Thomas Graham. He studied diffusion in gases, and the main phenomenon was described by him in 1831–1833: "...gases of different nature, when brought into contact, do not arrange themselves according to their density, the heaviest undermost, and the lighter uppermost, but they spontaneously diffuse, mutually and equally, through each

neg: Edgar Buckingham dependent significantly on the soil structure, compactness or water content of the soil. Using an empirical formula based on his data, Buckingham was able to give the diffusion coefficient as a function of air content. This relation is still commonly cited in many modern textbooks and used in modern research. The outcomes of his research on gas transport were to conclude that the exchange of gases in soil aeration takes place by diffusion and is "sensibly independent of the variations of the outside barometric pressure". Buckingham then worked on soil water, research for which he is now renowned. Buckingham’s work

neg: Gas kinetics through analysis of a gas’ viscosity except the molecules are stationary while only the temperatures of the gases are changing. Thermal conductivity is stated as the amount of heat transported across a specific area in a specific time. The thermal conductivity always flows opposite of the direction of the temperature gradient. Diffusion of gases is configured with a uniform concentration of gases and while the gases are stationary. Diffusion is the change of concentration between the two gases due to a weaker concentration gradient between the two gases. Diffusion is the transportation of mass over a period of time. A

neg: Sputum culture will most effectively treat the infection. This is called susceptibility or sensitivity testing. In a hospital setting, a sputum culture is most commonly ordered if a patient has a pneumonia. The Infectious Diseases Society of America recommends that sputum cultures be done in pneumonia requiring hospitalization, while the American College of Chest Physicians does not. One reason for such a discrepancy is that normal, healthy lungs have bacteria, and sputum cultures collect both normal and pathogenic bacteria. However, pure cultures of common respiratory pathogens in the absence of upper respiratory flora combined with symptoms of respiratory distress provides strong evidence

neg: Sexual selection in scaled reptiles While attempting cloacal alignment, a male entices a female by pressing his chin along the length of her body and continually attempting to intertwine his own tail with hers. At the same time, the male tries to prevent other males from breeding with the female, using his body to block their access. When copulation is achieved, a male implements a coercive mating strategy known as caudocephalic waving. The male garter snake strikes his own body against the female in quick repeated intervals. These strikes drive anoxic air from the non-respiratory lung of the female into her respiratory lungs, causing an

neg: Molecular diffusion osmosis. Metabolism and respiration rely in part upon diffusion in addition to bulk or active processes. For example, in the alveoli of mammalian lungs, due to differences in partial pressures across the alveolar-capillary membrane, oxygen diffuses into the blood and carbon dioxide diffuses out. Lungs contain a large surface area to facilitate this gas exchange process. Fundamentally, two types of diffusion are distinguished: The diffusion coefficients for these two types of diffusion are generally different because the diffusion coefficient for chemical diffusion is binary and it includes the effects due to the correlation of the movement of the different diffusing

neg: Respiratory system Both the lungs and the skin serve as respiratory organs in amphibians. The ventilation of the lungs in amphibians relies on positive pressure ventilation. Muscles lower the floor of the oral cavity, enlarging it and drawing in air through the nostrils into the oral cavity. With the nostrils and mouth closed, the floor of the oral cavity is then pushed up, which forces air down the trachea into the lungs. The skin of these animals is highly vascularized and moist, with moisture maintained via secretion of mucus from specialised cells, and is involved in cutaneous respiration. While the lungs are

neg: Frog and fused tailbones (urostyle or coccyx). Like other amphibians, oxygen can pass through their highly permeable skins. This unique feature allows them to remain in places without access to the air, respiring through their skins. The ribs are poorly developed, so the lungs are filled by buccal pumping and a frog deprived of its lungs can maintain its body functions without them. For the skin to serve as a respiratory organ, it must remain moist. This makes frogs susceptible to various substances they may encounter in the environment, some of which may be toxic and can dissolve in the water

neg: Respiratory system the lungs (Fig. 18). Birds also do not have diaphragms or pleural cavities. Bird lungs are smaller than those in mammals of comparable size, but the air sacs account for 15% of the total body volume, compared to the 7% devoted to the alveoli which act as the bellows in mammals. Inhalation and exhalation are brought about by alternately increasing and decreasing the volume of the entire thoraco-abdominal cavity (or coelom) using both their abdominal and costal muscles. During inhalation the muscles attached to the vertebral ribs (Fig. 17) contract angling them forwards and outwards. This pushes the sternal ribs,