As water moves over the surface of the gills, oxygen is absorbed - like lungs in land creatures. The water that passes over the gill lamellae flows in the opposite direction to the blood within the gill lamellae. In adult lampreys, a separate respiratory tube develops beneath the pharynx proper, separating food and water from respiration by closing a valve at its anterior end. The adolescent protagonists of the sequence, Enrique and Rosa, are Arturos son and , The payout that goes with the Nobel Prize is worth $1.2 million, and its often split two or three ways. This jet propulsion also provides the locomotion. The water flow through the fish's mouth as well as the blood in gill capillaries follow the countercurrent principle. The tips meet to form a sieve like arrangement for flow of water. Previously, the evolution of gills was thought to have occurred through two diverging lines: gills formed from the endoderm, as seen in jawless fish species, or those form by the ectoderm, as seen in jawed fish. 3.1.5 Adaptations of Gas Exchange Surfaces. On this Wikipedia the language links are at the top of the page across from the article title. The 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. Gills are branching organs located on the side of fish heads that have many, many small blood vessels called capillaries. Juvenile bichirs have external gills, a very primitive feature that they share with larval amphibians. Why is large surface area important for gas exchange? , Does Wittenberg have a strong Pre-Health professions program? Explain. The gas exchange organs of fish are called gills. Gills of fishes consist of several gill arches on either side. These adaptations are gills. What happens when alveoli lose their elasticity? The gill cover is open when the mouth is closed. This means that theconcentration gradient is maintained the whole way through, allowing the maximum amount of oxygen to diffuse into the blood from the water. A cubic meter of air contains about 250 grams of oxygen at STP. After many, many years, you will have some intuition for the physics you studied. (Just keep swimming) State 4 ways that gas exchange in fish is efficient. But opting out of some of these cookies may affect your browsing experience. 2023 Owlgen India. But instead of lungs, they use gills. Learn how leaves and fish gills are adapted for efficient gas exchange with evulpo. In some fish, capillary blood flows in the opposite direction to the water, causing counter-current exchange. Another way in which a steep concentration gradient is maintained is by ensuring water flows in one direction only. Gas exchange in fish occurs in their gills which is supported by a bony arch. 1. Why does reduced elasticity of the lungs cause breathing difficulty? The gaseous exchange takes place between alveoli in the lungs and blood capillaries. lamellae thin so short (diffusion) pathway to blood/capillaries; The rows of gill filaments have many protrusions called gill lamellae. This massively increases the fish's ability to absorb oxygen from the water as a diffusion gradient is always maintained. This allows for more efficient gas exchange than if the water had to go in and out the same way. Use evidence from the table to explain how mackerel are able to swim faster than toadfish. In this video, Head of Biology Mr May carries out a fish head dissection and explains how the gills of a fish are adapted for efficient gas exchange. Protects your airways from harmful substances and irritants. Because of poor elastic recoil, such patients have high lung compliance. Fish exchange gases by pulling oxygen-rich water through their mouths and pumping it over their gills. What are the 4 main functions of the lungs? They continuously pump their jaws and opercula to draw water in through the mouth and then force it over the gills and out through the opercular valve behind the gills. How do gills promote rapid gas exchange by having a large surface area? Just a click away. Mudskippers breathe by absorbing oxygen across the skin (similar to frogs). 1. mouth opens, operculum/opercular valve shuts; There is a one-way flow of water over the gills of a fish whereas there is a two-way flow of air in the lungs of a mammal. In six adult human lungs, the mean alveolar number was 480 million (range: 274-790 million; coefficient of variation: 37%). Solid arrows show the flow of water. The large muscles of the body actually do most of the work, but the fins help with balance and turning. 3 Tips for Beginner Players. Which part is directly involved in gas exchange in plant? The second mechanism includes the moving of water over the gill. One of the ways in which gas exchange is carried out efficiently is by the countercurrent flow principle. Objective, Importance and Limitations of Animal Breeding. How do gills promote rapid gas exchange by having a good oxygen supply? 8 study hacks, 3 revision templates, 6 revision techniques, 10 exam and self-care tips. (a) Determine the distance from the positive plate at which the two pass each other. the large surface area of the blood capillaries in each gill filament. It is spherical in shape and has a diameter of 20m. Which ion helps plants with gas exchange? Gar and bowfin have a vascularized swim bladder that functions in the same way. Explain how these young fish get enough oxygen to their cells without having gills. Fish also have an efficient transport system within the lamellae which maintains the concentration gradient across the lamellae. Earthworms must keep their skin moist to absorb oxygen and give off carbon dioxide; they satisfy this requirement in two ways. Then would one team of nine horses succeed if the other team were replaced with a strong tree? Explain how a fish is adapted for gas exchange? Ram ventilation is efficient because the fish does not need to use the muscles around its buccal and opercular cavities to move water through the gills. per mm of gill length Most air breathing fish are facultative air breathers that avoid the energetic cost of rising to the surface and the fitness cost of exposure to surface predators.[4]. This one-way ventilation is necessary because water is denser and more viscous than air, so it cannot be contained in delicate sac-like lungs found in air-breathing animals. The vertebrate ancestor no doubt had more arches, as some of their chordate relatives have more than 50 pairs of gills. There is therefore a very large concentration gradient and oxygen diffuses out of the water and into the blood. This means that the maximum number of dissolves water molecules can enter into the blood. Fish take water in through their mouths. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. [7], A smaller opening, the spiracle, lies in the back of the first gill slit. d Hallucination. [8] Rather than using lungs "Gaseous exchange takes place across the surface of highly vascularised gills over which a one-way current of water is kept flowing by a specialised pumping mechanism. Ventilation-perfusion inequality always causes hypoxemia, that is, an abnormally low PO2 in arterial blood. ), Keys to the Trematoda, Vol. [21] Various protists and Myxosporea are also parasitic on gills, where they form cysts. Gills are simply layers of tissue adapted specifically to gas exchange. 4. Rich blood supply of lamellae. Suggest one advantage to a fish of this one-way flow of water over its gills. The gills are composed of comb-like filaments, the gill lamellae, which help increase their surface area for oxygen exchange. The great majority of bony fish species have five pairs of gills, although a few have lost some over the course of evolution. Gills have numerous folds that give them a very large surface area. Use the combined gas law to complete the table Because of this reason large amount of energy is required to move the gill. The Fins help the fish swim. Their alveolar sacs have a high residual volume, which in turn causes difficulty in exhaling the excess air out of the lung, and patients develop shortness of breath. Fish maintains water flow over the gills by holding their mouth open relying on continual movement to ventilate. You also have the option to opt-out of these cookies. So that maximum oxygen can enter the blood at the gils and maximum carbon dioxide can leave by diffusion. Describe the relationships between gill surface area, mass and swimming speed shown in the diagram. Two teams of eight horses each were unable to pull the Magdeburg hemispheres apart (shown on the opening page of this chapter). Water enters via a fish's open mouth, its opercula close and stop water from leaving before being forced through the gill filaments. Valves inside the mouth keep the water from escaping. You need to ask yourself questions and then do problems to answer those questions. [8] The use of sac-like lungs to remove oxygen from water would not be efficient enough to sustain life. Gills have numerous folds that give them a very large surface area. [6] When a fish breathes, it draws in a mouthful of water at regular intervals. b Delusion of grandeur [7], Chimaeras differ from other cartilagenous fish, having lost both the spiracle and the fifth gill slit. Hence, oxygen diffusing into the blood is rapidly removed by the circulating blood supply and more oxygen is able to difuse into the blood. Suppose that two teams of nine horses each could pull them apart. This mucus also helps to trap and dissolve oxygen from the air. We also use third-party cookies that help us analyze and understand how you use this website. Wittenberg is a nationally ranked liberal arts institution with a particular strength in the sciences. When the mouth closes, the gill cover opens and this forces the water into the gill chamber. Yes! Fish gills have many lamellae so larger surface area. Why are elastic Fibres important in gas exchange? The folds are kept supported and moist by the water that is continually pumped through the mouth and over the gills. Unlimited number of exercises. [13], Sharks and rays typically have five pairs of gill slits that open directly to the outside of the body, though some more primitive sharks have six or seven pairs. Each gill consists of many fine gill lamellae, supported by a bony gill bar. Considering Fick's law, in order to maximise the rate of gas exchange, fish have many gill filaments covered in lamellae, maximising the surface area available.In order to maximise the concentration gradient, the gills have a good blood supply to ensure that oxygenated blood is removed from the gills as quickly as possible. Explain why this arrangement is important for efficient oxygen uptake. Teleost fish use a buccal-opercular pump to ventilate the gills. The remaining slits are covered by an operculum, developed from the septum of the gill arch in front of the first gill. Necessary cookies are absolutely essential for the website to function properly. Oxygen is a product of photosynthesis it is needed as a reactant during aerobic respiration within a plant. This is a counter current flow. Choose a suitable coordinate system and express the components of the displacement vector in that system in unit-vector notation. The gills are a fish's gas exchange system. Family Didymozoidae Monticelli, 1888. The gill filaments have many protrusions called gill lamellae. The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. Thickness of [7], The gill arches of bony fish typically have no septum, so that the gills alone project from the arch, supported by individual gill rays. Very active, flying insects need a more rapid supply/intake of oxygen. \end{array} [18] Endoparasites (parasites living inside the gills) include encysted adult didymozoid trematodes,[19] a few trichosomoidid nematodes of the genus Huffmanela, including Huffmanela ossicola which lives within the gill bone,[20] and the encysted parasitic turbellarian Paravortex. Enable registration in settings - general, Why GTA San Andreas is Still One of the Most Popular Games Today, Atomy Business Tips and Tricks: How to Succeed in Atomy E-commerce, Is Having A Friends With Benefits Relationship Actually Sustainable In Todays Time? Delivers oxygen to the cells in your body. In some cases, the openings may be fused together, effectively forming an operculum. Gills are tissues that are like short threads, protein structures called filaments. Genetics, Populations, Evolution & Ecosystems (A Level only), 7.1.2 Predicting Inheritance: Monohybrid Crosses, 7.1.3 Predicting Inheritance: Dihybrid Crosses, 7.1.4 Predicting Inheritance: Test Crosses, 7.3.8 Investigating the Effects of Random Sampling on Allele Frequencies, 7.4 Populations in Ecosystems (A Level only), 7.4.4 Estimating the Size of a Population, 8. Image showing the structure of a leaf from a dicotyledonous plant. This strategy is called ram ventilation, and is used by many active fish species. Remember, the blood capillaries must be in contact with the respiratory surface for gas exchange to take place. This means the water flows through the gills in one direction, allowing for more efficient gas exchange than if the water had to go in and out the same way. #gcsebiology #gcsefishgills #biologydissection #AlevelbiologyTimestamps: 0:00 - introduction 0:20 - Ram Ventilation0:55 - Drawing Water Through The Gills1:55 - Gill Structure2:39 - Counter Current Mechanism3:41 - Gills UnderwaterExam Questions:A-level Biology - Gas Exchange Questions - shorturl.at/bLYZ4 Mark Scheme - shorturl.at/otyLW Why must gaseous exchange structures hvave all these requirements? Image showing the structure of fish gills and the counter-current system within gills. The flattened shape of structures such as leaves. 5.51 \mathrm{~atm}& 0.879 \mathrm{~L}& 22.1^{\circ} \mathrm{C} & -& 1.05\mathrm{~L} & 38.3 { }^{\circ} \mathrm{C}\\ 3. This device is used by fishes and crabs with the help of their locomotary organs for circulating the water. P111.21atm721torr5.51atmV11.58L141mL0.879LT112.2C135K22.1CP21.54atm801torrV2152mL1.05LT232.3C38.3C, Circle the BEST answer. [7][11], In some primitive bony fishes and amphibians, the larvae bear external gills, branching off from the gill arches. (2002): Gaining ground: the origin and evolution of tetrapods. 3 (pp. The gills are a fish's gas exchange system. A few other fish have structures resembling labyrinth organs in form and function, most notably snakeheads, pikeheads, and the Clariidae catfish family. The gills' large surface area tends to create a problem for fish that seek to regulate the osmolarity of their internal fluids. Breathing air is primarily of use to fish that inhabit shallow, seasonally variable waters where the water's oxygen concentration may seasonally decline. Search. Examples of air-breathing fish include the mudskipper, lungfish, bowfin, and gar. Table of Contents show The operculum has been lifted to show the arch. Stomata are tiny holes found in the underside of leaves. In the hagfish, the pouches connect with the pharynx internally. Fish have gills that extract or take oxygen out of the water. These filaments have many functions including the transfer of ions and water, as well as the exchange of oxygen, carbon dioxide, acids and ammonia. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". (1) REFER TO DIAGRAM, Explain the relationship between gill surface area and swimming speed. He also shares personal stories and insights from his own journey as a scientist and researcher. A woman believes she is married to a rock singer. Obligate air breathers, such as the African lungfish, are obligated to breathe air periodically or they suffocate. 8 study hacks, 3 revision templates, 6 revision techniques, 10 exam and self-care tips. [7], Although most fish respire primarily using gills, some fish can at least partially respire using mechanisms that do not require gills. Part I-systematics, middle ear evolution, and jaw suspension. Mackerel 5 32 Oxygen passes from the water into the blood at the gills. Efficient gas exchange in fish is due to: -large surface area of gills due to gill lamellae, -water being able to flow in one direction only. Fish use gills for gas exchange. This is important because there isn't much oxygen in the water, and fish need to absorb enough oxygen to survive. Dordrecht: Springer. The upper row is the oxygen concentration in the blood, while the lower is the one in the water. Key points Gill filaments have lamellae which increase the surface area available for diffusion, while keeping the diffusion pathway short. Laurin M. (1998): The importance of global parsimony and historical bias in understanding tetrapod evolution. Alveoli in the lungs, fish gills and the villi in the small intestine are adapted so that they have short diffusion distance, big concentration difference and large surface area. They also contain elastic fibres which expand to allow air in and recoil to help force out air. About 80% of the dissolved oxygen is extracted from the water. [7], Gills usually consist of thin filaments of tissue, branches, or slender tufted processes that have a highly folded surface to increase surface area. Countercurrent exchange means the flow of water over the gills is in the opposite direction to the flow of blood through the capillaries in the lamellae. The complexity of the gills depends on the animal's requirement for oxygen. Patients who have increased physiological dead space (eg, emphysema) will have decreased effective ventilation. Therefore, the greater the surface area, the more gas exchange can occur. A number of fish have evolved so-called accessory breathing organs that extract oxygen from the air. Gas exchange is really important so that we take oxygen for aerobic respiration and get rid of the carbon dioxide so that it doesnt accumulate inside of us. In your lungs, the main airways (bronchi) branch off into smaller and smaller passageways the smallest, called bronchioles, lead to tiny air sacs (alveoli). [14], Most sharks rely on ram ventilation, forcing water into the mouth and over the gills by rapidly swimming forward. Explain how the gills of a fish are adapted for efficient gas exchange (6) 1 Large surface area provided by lamellae/filaments; Q Candidates are required to refer to lamellae or filaments. What is rotational grazing, and how does it mimic natural processes? The base of the arch may also support gill rakers, small projecting elements that help to filter food from the water. This is important for fish becaus of the low oxygen concentration in water. Ignore the electrical attraction between the proton and electron. These cookies will be stored in your browser only with your consent. At the same time carbon dioxide passes from the blood to the lungs. Explain the Mechanism of Stomatal Opening. Large surface area of gills due to gill lamellae. To understand countercurrent flow, it is easiest to start by looking at concurrent flow where water and blood flow over and through the lamellae in the same direction. These adaptations aregills. Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors. Clack, J. This system maximises the amount of oxygen diffusinginto the blood by having the most oxygenated blood meet the most oxygenated water, and the least oxygenated blood meet the least oxygenated water. Oxygenated blood is continuously removed from the gills by the circulation to the rest of the body. A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water and excretes carbon dioxide. Lra has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning. Removal of carbon dioxide also occurs, as the blood containing high concentrations of the waste gas goes to the gills, and the carbon dioxide diffuses out into the water down a diffusion gradient (external water has lower concentrations of carbon dioxide than levels in the blood, so this sets up a diffusion gradient.). Do NOT follow this link or you will be banned from the site! Fish also have an efficient transport system within the . As , EL NORTE is a melodrama divided into three acts. Fish dependent solely on dissolved oxygen, such as perch and cichlids, quickly suffocate, while air-breathers survive for much longer, in some cases in water that is little more than wet mud. To regain the water, marine fishes drink large amounts of sea water while simultaneously expend energy to excrete salt through the Na+/K+-ATPase ionocytes (formerly known as mitochondrion-rich cells and chloride cells). Make sure you know how and why each system above is adapted for efficient gas exchange. maintains diffusion / concentration gradient / equilibrium not reached; Describe and explain how fish maintain a flow of water over their gills. These cookies ensure basic functionalities and security features of the website, anonymously. Fish and many other aquatic organisms have evolved gills (outgrowths of the body used for gas exchange) to take up the dissolved oxygen from water. They control water loss and gas exchange by opening and closing. the short distance required for diffusion - the outer layer of the gill filaments and the capillary walls are just one cell thick. This website uses cookies to improve your experience while you navigate through the website. In this method, much force is needed to overcome the resistance of water in order to permit the movement. The skin of anguillid eels may absorb oxygen directly. describe the structure of the components of the fish gas exchange system, including the filaments and lamellae, describe how fish gills are adapted for efficient gas exchange, describe the countercurrent flow of blood and oxygenated water in fish gills, explain the advantages of the countercurrent flow for efficient gas exchange. Gills have lamellae which increase surface area for increased diffusion of oxygen Thin epithelium walls which decreases diffusion distance into capillaries which increases the rate of diffusion Alveolar number was closely related to total lung volume, with larger lungs having considerably more alveoli. Always. Repeat part (a) for a sodium ion (Na+)\left(\mathrm{Na}^{+}\right)(Na+) and a chloride ion (Cl).\left(\mathrm{Cl}^{-}\right).(Cl). This bears a small pseudobranch that resembles a gill in structure, but only receives blood already oxygenated by the true gills. A. Along the flow, oxygen enters the bloodstream from the water, so that the concentration in blood increases, while the concentration in water decreases, Fish extract dissolved oxygen molecules from the surrounding water. We will be very happy to hear from you. You have two lungs, but they arent the same size the way your eyes or nostrils are. Fish transfer oxygen from the sea water to their blood using a highly efficient mechanism called countercurrent exchange. In his writing, Alexander covers a wide range of topics, from cutting-edge medical research and technology to environmental science and space exploration. Gills in fish Exchange of gases in fish is very efficient because of: the large surface area of the gills. (b) What If? During gas exchange oxygen moves from the lungs to the bloodstream. This allows for more efficient gas exchange than if the water had to go in and out the same way. Fish ventilate their gills to maintain the gas concentration gradient. In this video, Head of Biology Mr May carries out a fish head dissection and explains how the gills of a fish are adapted for efficient gas exchange. The Control of Gene Expression (A Level only), 8.2 Regulation of Gene Expression (A Level only), 8.2.4 Producing Tissue Cultures of Explants, 8.2.6 Evaluating Data about Genetic Expression, 8.4.3 Investigating the Specificity of Restriction Enzymes, 8.4.9 Genetic Counselling & Personalised Medicine. A uniform electric field of magnitude 640 N/c exists between two parallel plates that are 4.00 cm apart. One-to-one online tuition can be a great way to brush up on your Biology knowledge. (1). [11] Conversely, freshwater has less osmolytes than the fish's internal fluids. \hline 11.21 \mathrm{~atm} & 1.58 \mathrm{~L} & 12.2{ }^{\circ} \mathrm{C} & 1.54 \mathrm{~atm} &- & 32.3{ }^{\circ} \mathrm{C} \\ However, if a fish swims forward with its mouth open, water will flow across the gills without active pumping by the muscles surrounding the buccal and opercular cavities. A fish had gills, made up of gill filaments containing lamellae, which provide a very large surface area for oxygen to diffuse out of the water as it moves over them. Adjacent slits are separated by a cartilaginous gill arch from which projects a long sheet-like septum, partly supported by a further piece of cartilage called the gill ray. Many fishes like shark breathe by pumping at low speed and change to ram ventilation at high speed. 1 Large surface area provided by lamellae/filaments; Mackerel live in the surface waters of the sea. [9][10], In bony fish, the gills lie in a branchial chamber covered by a bony operculum (branchia is an Ancient Greek word for gills). Some fish, like sharks and lampreys, possess multiple gill openings. This maintains a high concentration gradient, making gas exchange more efficient. Removes waste gases, including carbon dioxide, from the body when you exhale. By far the commonest cause of impaired gas exchange in patients with lung disease is ventilation-perfusion inequality. To see how the gas exchange happens, we need to zoom right in on a single lamella. This cookie is set by GDPR Cookie Consent plugin. [8] Water is 777 times more dense than air and is 100 times more viscous. Then it draws the sides of its throat together, forcing the water through the gill openings, so that it passes over the gills to the outside. This movement is aided by ciliary action as in gills of mussels and clams. Fish gills are made up of thin plates called gill filaments, which are covered in structures called lamallae. Detailed learning statistics . Decreased PO2 levels are associated with: Decreased oxygen levels in the inhaled air. However, the fish needs to be swimming, which is energetically costly, and its body position with the mouth open may increase drag on the fish and increase the cost of locomotion. the large surface area of the blood capillaries in each gill filament. They allow water vapour and oxygen out of the leaf and carbon dioxide into the leaf. What is the main function of gas exchange? What are 3 ways that exchange surfaces are adapted to their function? 1.1.10 Biochemical Tests: Sugars & Starch, 1.1.11 Finding the Concentration of Glucose, 1.3.7 The Molecular Structure of Haemoglobin, 1.3.8 The Molecular Structure of Collagen, 1.4.4 Required Practical: Measuring Enzyme Activity, 1.4.5 Maths Skill: Drawing a Graph for Enzyme Rate Experiments, 1.4.6 Maths Skill: Using a Tangent to Find Initial Rate of Reaction, 1.4.7 Limiting Factors Affecting Enzymes: Temperature, 1.4.8 Limiting Factors Affecting Enzymes: pH, 1.4.10 Limiting Factors Affecting Enzymes: Enzyme Concentration, 1.4.11 Limiting Factors Affecting Enzymes: Substrate Concentration, 1.4.12 Limiting Factors Affecting Enzymes: Inhibitors, 1.4.13 Models & Functions of Enzyme Action, 1.4.14 Practical Skill: Controlling Variables & Calculating Uncertainty, 1.5 Nucleic Acids: Structure & DNA Replication, 1.5.2 Nucleotide Structure & the Phosphodiester Bond, 1.5.6 The Origins of Research on the Genetic Code, 1.5.8 The Process of Semi-Conservative Replication, 1.5.9 Calculating the Frequency of Nucleotide Bases, 2.2.2 Microscopy & Drawing Scientific Diagrams, 2.2.6 Cell Fractionation & Ultracentrifugation, 2.2.7 Scientific Research into Cell Organelles, 2.3 Cell Division in Eukaryotic & Prokaryotic Cells, 2.3.7 Uncontrolled Cell Division & Cancer, 2.4.2 Components of Cell Surface Membranes, 2.4.8 Comparing Osmosis in Animal & Plant Cells, 2.4.13 Factors Affecting Membrane Fluidity, 2.5.5 The Role of Antigen-Presenting Cells, 2.6 Vaccines, Disease & Monoclonal Antibodies, 2.6.6 Ethical Issues with Vaccines & Monoclonal Antibodies, 3.2.3 Looking at the Gas Exchange under the Microscope, 3.2.11 Correlations & Causal Relationships - The Lungs, 3.4.7 Animal Adaptations For Their Environment, 3.5.8 Interpreting Data on the Cardiovascular System, 3.5.9 Correlations & Causal Relationships - The Heart, 3.5.10 Required Practical: Dissecting Mass Transport Systems, 4.2.6 Nucleic Acid & Amino Acid Sequence Comparison, 4.3 Genetic Diversity: Mutations & Meiosis, 4.3.5 Meiosis: Sources of Genetic Variation, 4.3.7 The Outcomes & Processes of Mitosis & Meiosis, 4.4.2 Maths Skill: Using Logarithms When Investigating Bacteria, 4.4.4 Directional & Stabilising Selection, 4.6.7 Quantitative Investigations of Variation, 4.6.9 Genetic Relationships Between Organisms, 5. The gills push the oxygen-poor water out through openings in the sides of the pharynx. Many invertebrates such that octopus or squid ventilates its gills by taking water in the mantle cavity and ejecting it out through the siphon. What happens to oxygen during gas exchange? A proton is released from rest at the positive plate at the same instant an electron is released from rest at the negative plate. Ventilation is the fast movement of a fluid such that water through a medium like gills. How do gills promote rapid gas exchange by having a thin barrier between water and blood? The water moves through the mouth over the branched gills. The operculum can be important in adjusting the pressure of water inside of the pharynx to allow proper ventilation of the gills, so that bony fish do not have to rely on ram ventilation (and hence near constant motion) to breathe.