How many gill arches are there?
All modern fishes have four respiratory gill arches and a 5th non-respiratory arch on each side of the buccal cavity. Each respiratory arch is composed of a cartilaginous supporting structure which bears gill rakers in the front and respiratory tissue in the rear.
How many gill does a fish have?
The fish gill is arguably the most physiologically diversified and anatomically complex vertebrate organ. Bony fish have eight gill arches, four on each side of the mouth cavity.
What is a gill arch in fish?
Branchial arches, or gill arches, are a series of bony "loops" present in fish, which support the gills. As gills are the primitive condition of vertebrates, all vertebrate embryos develop pharyngeal arches, though the eventual fate of these arches varies between taxa.
How many gill filaments are there?
Gills in fish are arranged as a series of cartilaginous gill arches, each of which has two rows of gill filaments forming a corrugated structure through which the water flows (Fig. 25.4).
How many gills do most fish have?
Bony fish generally have four gill arches on each side, covered and protected by a single external bony plate. Sharks do not have a protective bony covering over their gill slits, which leaves gills more vulnerable to injury.
How many pairs of gills are there?
Bony fishes are the fishes which have bones as an endoskeleton. They have 4 gill pairs whereas cartilaginous fish have five to seven pairs and primitive jawless fish have seven.
Where is gill arches in fish?
branchial arch, also called Visceral Arch, or Gill Arch, one of the bony or cartilaginous curved bars on either side of the pharynx (throat) that support the gills of fishes and amphibians; also, a corresponding rudimentary ridge in the embryo of higher vertebrates, which in some species may form real but transitory ...
How many gill arches does a perch have?
There should be two pairs of gills on each side of the perch (4 total gills).
What is the function of gill arches?
The gill arches offer support for the gills as well as the blood vessels. 2 Arteries that enter the gills bring blood with low oxygen and a high concentration of wastes. Arteries that leave the gills contain blood with little waste that's rich with oxygen.
What are the three parts of gill?
The gills are composed of three main parts: filaments, rakers, and arches. The arches are the structural component of the gill, rakers prevent debris from entering the fish through the gills, and the filaments absorb oxygen.
Is there a fish without gills?
Unlike other fish with gills alone, lungfish can surface, take a breath and survive when other fish might be lacking air. In fact, much like many sea mammals, lungfish are obligate air breathers—they have to breathe air above water periodically to survive.
Do any fish not have gills?
All fish have gills to filter oxygen from their water environment.
Do all fish have gills?
All fish have gills to filter oxygen from their water environment. 3. All fish have fins to help them move through the water.
How many gills does a shark have?
Most shark species have five gill slits on each side such as the frilled sharks, cow sharks, however, some species can have up to six or seven like the sixgill sawshark. As part of their respiratory system, sharks also have an accessory respiratory opening called a spiracle behind their eyes.
What are fish gills called?
The gill filaments of bony fishes are also called "primary lamellae."2 They are intricate structures that have a large surface area. Smaller "secondary lamellae" are offshoots of the primary filaments. The secondary lamellae contain small blood capillaries and the blood flows in the opposite direction of the water.
Do fish have gills or lungs?
Like us, fish also need to take in oxygen and expel carbon dioxide in order to survive. But instead of lungs, they use gills. Gills are branching organs located on the side of fish heads that have many, many small blood vessels called capillaries.
1. How do fishes breathe?
To survive, humans and fish both need oxygen. The difference, however, is that we get ours through the air, and fish get theirs through the water....
2. What are the functions of fish gills?
Fish breathe underwater through their gills, which are protected by a membrane called an operculum. An operculum allows fish to exchange carbon dio...
3. What is the role of gills in gas exchange?
In fish, the gills play an essential role in oxygenation and carbon dioxide removal from the body. Aerobic metabolic pathways convert ATP into ener...
4. What is a complete gill called?
Gills with a complete structure are called holobranch. Halo Branches have cartilaginous or bony arches, and the anterior and posterior part of each...
5. How to check the gills of a fish to determine its freshness?
Ensure that the gills of the whole fish are pink or reddish in color, and slightly wet rather than slimy and dry. Check for discolorations on the s...
How many pairs of gills are there in bony fish?
The great majority of bony fish species have five pairs of gills, although a few have lost some over the course of evolution.
How many gills does a vertebrate have?
The vertebrate ancestor no doubt had more arches, as some of their chordate relatives have more than 50 pairs of gills. Pharynx and gill rakers in an estuary cod. Gills usually consist of thin filaments of tissue, branches, or slender tufted processes that have a highly folded surface to increase surface area.
How do fish breathe?
Respiratory mechanism in bony fish. The fish draws oxygen-rich water in through the mouth (left). It then pumps it over gills so oxygen enters the bloodstream, and allows oxygen-depleted water to exit through the gill slits (right ) Fish gills are organs that allow fish to breathe underwater. Most fish exchange gases like oxygen ...
What are the organs that fish use to breathe?
Fish gills are organs that allow fish to breathe underwater. Most fish exchange gases like oxygen and carbon dioxide using gills that are protected under gill covers (operculum) on both sides of the pharynx (throat). Gills are tissues that are like short threads, protein structures called filaments. These filaments have many functions ...
Why do gills have a countercurrent exchange system?
Most species employ a counter-current exchange system to enhance the diffusion of substances in and out of the gill, with blood and water flowing in opposite directions to each other. The gills are composed of comb-like filaments, the gill lamellae, which help increase their surface area for oxygen exchange.
What keeps water from escaping from bony fish?
Valves inside the mouth keep the water from escaping. The gill arches of bony fish typically have no septum, so that the gills alone project from the arch, supported by individual gill rays. Some species retain gill rakers.
What are the functions of a gill?
Gills are tissues that are like short threads, protein structures called filaments. These filaments have many functions including the transfer of ions and water, as well as the exchange of oxygen, carbon dioxide, acids and ammonia. Each filament contains a capillary network that provides a large surface area for exchanging oxygen ...
What are the gill filaments of bony fish called?
The gill filaments of bony fishes are also called "primary lamellae.". 2 They are intricate structures that have a large surface area. Smaller "secondary lamellae" are offshoots of the primary filaments. The secondary lamellae contain small blood capillaries and the blood flows in the opposite direction of the water.
What are the functions of the gill filaments in fish?
The gill filaments in fish have functions like lungs in people: it's the organ responsible for absorbing oxygen and expelling carbon dioxide. The gills also regulate levels of mineral ions and the pH of the blood , as well as being the primary site of nitrogenous waste excretion, in the form of ammonia.
What do the gills do?
The gills take oxygen from the water and let water whisk away carbon dioxide and ammonia from the blood vessels in the gills. Gill filaments are the red, fleshy part of the gills; they take oxygen into the blood. Each filament has thousands of fine branches (lamellae) that are exposed to the water. The branches contain blood capillaries beneath ...
Why do fish have gill filaments?
Actively swimming fish have gill filaments that are highly developed to maximize the absorption of oxygen. Sedentary fish that live on the bottom usually have gill filaments that absorb smaller volumes, since they are less active and don't use the oxygen as quickly.
How do fish breathe underwater?
In order to breathe underwater, fish have to extract dissolved oxygen from the water. They do this using their gills. 1 Water enters the fish's mouth and then the fish forces water across its gills, past many tiny blood vessels, and out the gill slits. The gills take oxygen from the water and let water whisk away carbon dioxide ...
What are gill rakers?
Gill rakers are bony projections that help the fish feed. 3 They point forward and inward from the gill arches. Their number and shape vary based on the diet of the fish: widely spaced gill rakers are evident on fish that eat large prey, such as other fish, which prevent the prey item from getting free and escaping between the gills. A larger number of thinner, longer gill rakers are seen on fish that eat smaller prey. Species that consume plankton and tiny matter suspended in the water sport gill rakers that are extremely long and thin. Some fish have more than 150 just on the lower arch.These help to collect food particles in the throat that can be swallowed, while water is passed out through the gill slits.
Why do fish drown?
Others have lungs or other accessory air chambers that have developed to breathe air from the surface of the water, and these species of fish may drown if they don't have access to the water's surface.
What are the gill arches?
The gill arches form as pharyngeal arches during embryogenesis, and lay the basis of essential structures such as jaws, the thyroid gland, the larynx, the columella (corresponding to the stapes in mammals) and in mammals the malleus and incus.
How many gills do fish have?
Each gill is supported by a cartilaginous or bony gill arch. Bony fish have three pairs of arches, cartilaginous fish have five to seven pairs, and primitive jawless fish have seven .
How many arches are there in the primitive arrangement?
The primitive arrangement is 7 (possibly 8) arches, each consisting of the same series of paired (left and right) elements. In order from dorsal-most to ventral-most, these are the pharyngobranchial, epibranchial, ceratobranchial, hypobranchial, and basibranchial. The pharyngobranchials may articulate with the neurocranium, while the left and right basibranchials connect to each other (often fusing into a single bone). When part of the hyoid system, the names of the bones are altered by replacing "-branchial" with "-hyal", thus "ceratobranchial" becomes "ceratohyal".
What is the branchial arch?
Branchial arch. Branchial arches, or gill arches, are a series of bony "loops" present in fish, which support the gills. As gills are the primitive condition of vertebrates, all vertebrate embryos develop pharyngeal arches, though the eventual fate of these arches varies between taxa. In jawed fish, the first arch develops into the jaws, ...
What is the basihyal?
In tetrapods, the basihyal is known as the hyoid bone. Basibranchials, which are most common in osteichthyans, have the form of one or more rod-like bones projecting backwards along the throat. The Ceratohyals and Ceratobranchials lie above their respective basi- components, slanting backwards and upwards.
Where is the basihyal bone?
The Basihyal and Basibranchials lie at the midline of the lower edge of the throat. Almost all modern chondrichthyans have a single midline basihyal, as do many teleosts, lungfish, and tetrapodomorphs. In tetrapods, the basihyal is known as the hyoid bone. Basibranchials, which are most common in osteichthyans, have the form of one or more rod-like bones projecting backwards along the throat.
What are the bones that connect the basi and cerato?
Small connecting bones known as Hypophyals or Hypobranchials may link the basi- and cerato- components. Paired hypophyals are characteristic of living osteichthyans.
Overview
Breathing with gills
Air breathing fish can be divided into obligate air breathers and facultative air breathers. Obligate air breathers, such as the African lungfish, are obligated to breathe air periodically or they suffocate. Facultative air breathers, such as the catfish Hypostomus plecostomus, only breathe air if they need to and can otherwise rely on their gills for oxygen. Most air breathing fish are facultative air breathers that avoid the energetic cost of rising to the surface and the fitness cos…
Bony fish
• Fish gill respiration
• Fish gill structure
In bony fish, the gills lie in a branchial chamber covered by a bony operculum (branchia is an Ancient Greek word for gills). The great majority of bony fish species have five pairs of gills, although a few have lost some over the course of evolution. The operculum can be important in …
Cartilaginous fish
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. 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. The individual lamellae of the gills lie on either side of the septum. The base of the arch may also support gill rakers, small projecting elements that help t…
Lampreys and hagfish
Lampreys and hagfish do not have gill slits as such. Instead, the gills are contained in spherical pouches, with a circular opening to the outside. Like the gill slits of higher fish, each pouch contains two gills. In some cases, the openings may be fused together, effectively forming an operculum. Lampreys have seven pairs of pouches, while hagfishes may have six to fourteen, depending on the species. In the hagfish, the pouches connect with the pharynx internally. In ad…
Breathing without gills
Although most fish respire primarily using gills, some fish can at least partially respire using mechanisms that do not require gills. In some species cutaneous respiration accounts for 5 to 40 percent of the total respiration, depending on temperature. Cutaneous respiration is more important in species that breathe air, such as mudskippers and reedfish, and in such species can account for nearly half the total respiration.
Parasites on gills
Fish gills are the preferred habitat of many ectoparasites (parasites attached to the gill but living out of it); the most commons are monogeneans and certain groups of parasitic copepods, which can be extremely numerous. Other ectoparasites found on gills are leeches and, in seawater, larvae of gnathiid isopods. Endoparasites (parasites living inside the gills) include encysted adult didymozoid trematodes, a few trichosomoidid nematodes of the genus Huffmanela, including Huffmanela ossi…
See also
• Aquatic respiration
• Book lung
• Gill raker
• Gill slit
• Lung