Structures and functions related to the excretory system - class-XII

Malpighian tubules are the excretory organs in all insects. The tubules often occur in two’s or multiples of two. As insects belong to the phylum Arthropoda, the organism must be placed under it. 

The excretory organs of grasshopper are the malpighian tubules which are coiled about in the haemocoel and open into the anterior end of the hindgut. The malpighian tubules have a wall of a single layer of cells with striated inner border. Their free ends are completely closed. In the majority of Arthropods, Malpighian tubules are the excretory organs. So, the correct option is 'Malpighian tubule'.

On the basis of development, there three types of kidneys as pronephric kidney, mesonephric kidney and the metanephric kidney.

The excretory product of freshwater fishes is 'ammonia'.

• Amphibians have mesonephric type of kidneys which are primitive compared to metanephric kidneys. 
• Mesonephric kidneys do not have nephrons but their nephrons do not contain a loop of Henle.

Nephridia is the earthworm's excretory organ. Earthworms are called septal, integumentary, and pharyngeal nephridia in three kinds of nephridial structures. These three nephridial structures are present in various body positions and differ in structures as well. Septal and pharyngeal nephridia are both enteronephric, i.e. they expel nitrogen products to the gut. Integumentary nephridia is exonephric, i.e. products of nitrogen waste are discharged outside straigh

Amphioxus or Branchiostoma is a peculiar chordate animal, which does not have excretory organs in the form of mesodermal kidneys but are in the form of protonephridia. They are similar to protonephridia of flat worms or polychaete, annelids and they are ectodermal in origin. In Amphioxus there are 90 to 100 pairs of protonephridia present segmentally on dorso-lateral pharyngeal wall one above each gill slit on either side. Simply, they are ciliated, thin walled, closed ectodermal tubules like structures.

The original nephrostomes remain in the adult frog on the ventral face of the kidney as ciliated peritoneal funnels. These convey coelomic fluids directly into the blood sinuses of the kidney. They are regarded as accessory excretory structures.

The excretory organs of earthworm are coiled tubular structures, known as nephridia. A nephridium consists of a ciliated nephridial canal, that opens into the coelom by nephrostome and to the exterior or in the gut by nephridiopore. The walls of nephridia are glandular and richly supplied with blood vessels, they extract solutes and water from the blood by ultra filtration, and discharge the filtrate into the nephridial canal. 

In most of the invertebrates, the excretory structures are simple tubular forms whereas vertebrates have complex tubular organs called kidneys. Shark is a vertebrate and has kidneys as excretory structures.
Protonephridia or flame cells are the excretory structures in Platyhelminthes (Flatworms, e.g., Planaria), rotifers, some annelids and the cephalochordate Amphioxus. Protonephridia are primarily concerned with ionic and fluid volume regulation, i.e., osmoregulation.
Nephridia are the tubular excretory structures of earthworms and other annelids like Leech. Nephridia help to remove nitrogenous wastes and maintain a fluid and ionic balance.
Malpighian tubules are the excretory structures of most of the insects including cockroaches. Malpighian tubules help in the removal of nitrogenous wastes and osmoregulation.

Nephridial organs, or nephridia, are excretory structures that evolved in many invertebrates, including flatworms, nemerteans, rotifers, annelids, mollusks, and lancelets. Each nephridial organ consists of simple or branching tubes that typically open to the outside of the body through excretory pores, called nephridiopores. Two types of nephridial organs are protonephridia and metanephridia. The excretory system of insects and spiders consists of several hundred Malpighian tubules. Malpighian tubules are slender extensions of the gut wall. Their blind ends lie in the hemocoel (blood cavity) and are bathed in hemolymph. The mammalian urinary system consists of the kidneys, the urinary bladder, and associated ducts. Each kidney has more than 1 million functional units called nephrons. A nephron consists of a cuplike Bowmans capsule connected to a long, partially coiled renal tubule.
In option A typhlosole is an intestinal fold for absorption but contractile vacuole is meant for osmoregulation. In option C antennae of cockroach are sensory but clitellum of earth worm forms cocoon. In option D tube feet of starfish are meant for locomotion and not related to other structures mentioned which have a role in digestion of food.

'Green Gland' is one of the pair of excretory organs in each side of the head region of decapod crustaceans, emptying at the base of the antennae. Prawns have green glands for excretion.

Solenocytes are a type of long, narrow, flagellated cell that functions in excretion of nitrogenous wastes and occurs in a variety of organisms, including certain annelids and molluscs.

Wolffian duct is also called as archinephric duct, is a pair of tubes that carry urine from primitive or embryonic kidneys to the exterior or to a primitive bladder. 

Various animals of animal kingdom presents a variety of excretory structures. In most of the invertebrates, these structures are simple tubular forms. Protonephridia or flame cells are the excretory structures in Platyhelminthes (Flatworms, e.g., Planaria), rotifers, some annelids and the cephalochordate Amphioxus. Protonephridia are primarily concerned with ionic and fluid volume regulation, i.e., osmoregulation. Nephridia are the tubular excretory structures of earthworms and other annelids. Nephridia help to remove nitrogenous wastes and maintain a fluid and ionic balance. Malpighian tubules are the excretory structures of most of the insects including cockroaches. Malpighian tubules help in the removal of nitrogenous wastes and osmoregulation. Antennal glands or green glands perform the excretory function in crustaceans like prawns. Vertebrates have complex tubular organs called kidneys as primary excretory organ. Towards the centre of the inner concave surface of the kidney is a notch called hilum through which ureter, blood vessels and nerves enter. Inner to the hilum is a broad funnel shaped space called the renal pelvis with projections called calyces. The outer layer of kidney is a tough capsule. Inside the kidney, there are two zones, an outer cortex and an inner medulla. The medulla is divided into a few conical masses (medullary pyramids) projecting into the calyces (sing.: calyx). The cortex extends in between the medullary pyramids as renal columns called Columns of Bertini.

Mammals like humans and rabbit, many terrestrial amphibians and marine fishes mainly excrete urea and are called ureotelic animals. Ammonia produced by metabolism is converted into urea in the liver of these animals and released into the blood, which is filtered and excreted out by the kidneys. Some amount of urea may be retained in the kidney matrix of some of these animals to maintain a desired osmolarity.

The ductus deferens, also known as the vas deferens, is a tiny muscular tube in the male reproductive system that carries sperm from the epididymis to the ejaculatory duct. 

In the substrate eaters like Balanoglossus, the excretory organ is glomerulus or proboscis gland lying in front of the central sinus and projecting into the proboscis coelom.

Green glands are excretory organs in crustaceans. The excretory organ in annelids is nephridia. The column of bertini is an extension of renal cortex between the renal pyramids.

Freshwater and marine organisms are adapted to specific osmotic environments. Moving them between these environments causes osmotic stress, leading to cell swelling or dehydration, which is fatal.

The metanephric kidneys are a paired compact organ whose functional units are nephrons. The nephrons filter initial urine from the blood, reabsorbing water and nutrients, and secrete wastes, producing the final urine, which is expelled. In adult Frog, The kidney is Metanephros.

Planarians are one of the types of flatworms belonging to the class Turbellaria. The excretory organs of planarians are flame cells. The flame cells work like a kidney and remove excretory wastes from the body.

Sea gulls are marine birds belonging to the family Laridae. They drink salt water as a result to maintain their osmotic balance they excrete salts through nasal gland or salt gland present in the nostrils and assist kidney in maintaining electrolyte balance.

Amoeba is a fresh water unicellular organism. In amoeba the excretory waste is ammonia. The excretory waste present in the cytoplasm is collected by contractile vacuole then this excretory waste i.e NH$ _3$ is excreted through plasma membrane by diffusion.

Hydra is a freshwater sessile organism belonging to the phylum Cnidaria and class Hydrozoa. They are found in lakes, pond, and stream. Hydra is ammonotelic i.e they secrete ammonia as chief excretory nitrogenous waste. In hydra specialized excretory organs are absent hence in hydra, wastes of food digestion and nitrogenous wastes are removed from mouth and body wall.

The excretory system of frog consists of a pair of kidney, ureters, urinary bladder and cloaca. On the ventral surface of the kidney in the frog, there are ciliated funnels present called as nephrostome. The nephrostome is internally lined with cilia, its function is to push water, metabolic wastes and other substances into metanephridium (Kidney).

The frogs which are highly aquatic belongs to the genus xenopus. They are usually found in lakes, rivers, swamps. The xenopus excretes ammonia as nitrogenous waste hence ammonotelic.

For many chordates, the urinary system is a critical component of the excretory system. It is made up of organs such as the kidneys and bladder, structures such as a urethra or cloaca, and even arteries such as the aorta. The urinary system is responsible for both creating and excreting urine, which it does to regulate the amount of water and solutes within the body. Amazingly enough, the urinary system also works closely with hormones in your body that signal when you start to become dehydrated or when there is too much fluid in your body.

So, the correct option is 'All chordates'.

In decapod crustaceans, the excretory organs are known as antennary glands or green glands. These glands are opaque-white, pea seed sized structures, enclosed in the coxa of each second antenna. These glands play an important role in the process of excretion.

Earthworms (annelids) have slightly more evolved excretory structures called nephridia. A pair of nephridia is present on each segment of the earthworm. Malpighian tubules are found lining the gut of some species of arthropods, such as the bee. They are usually found in pairs and the number of tubules varies with the species of insect.

Green glands are excretory organs of some arthropods like crustaceans. They are also called antennal glands because these glands are located near the base of larger antennae. Each gland has three parts end sac, labyrinth and bladder. The labyrinth is the proper excretory gland. Hence green glands help in excretion.

Green glands are excretory organs of some arthropods like crustaceans.  For example, prawns, crayfishes, lobsters etc. They are also called antennal glands because these glands are located near the base of larger antennae. Each gland has three parts end sac, labyrinth and bladder. The labyrinth is the proper excretory gland. Hence antennal gland functions as the excretory organ in prawn.

Earthworms (annelids) have slightly more evolved excretory structures called nephridia. A pair of nephridia is present on each segment of the earthworm. Excretion occurs through a pore called the nephridiopore. Malpighian tubules are found lining the gut of some species of arthropods, such as the bee. They are usually found in pairs and the number of tubules varies with the species of insect.

Hepatopancreas is not an excretory organ of vertebrates. It is a glandular excretory organ present in many invertebrates like arthropods and molluscs. It shows functions similar to liver and pancreas of vertebrates.

Salamander belongs to the phylum Chordata and class amphibia. Just like humans, the salamander has two kidneys which excrete urea as the nitrogenous waste product. Two kidneys are extremely important in excreting nitrogenous waste, and the urinary bladder stores waste in the form of urea before it is released into the environment.

Hydra is sessile and cylindrical in shape belonging to the phylum Cnidaria and class Hydrozoa. It has no specialized excretory organs hence excretion in hydra occurs by diffusion through the general body surface.

Green glands are excretory organs of crustaceans. For example, prawn. They are also called antennal glands because these glands are located near the base of larger antennae. Each gland has three parts end sac, labyrinth and bladder. The labyrinth is the proper excretory gland. Hence green glands help in excretion.

Green glands are excretory organs of crustaceans. They are also called antennal glands because these glands are located near the base of larger antennae. Each gland has three parts end sac, labyrinth and bladder. The labyrinth is the proper excretory gland.

Rotifers are microscopic aquatic animals belonging to phylum rotifera. They eat dead bacteria, algae and protozoans. The excretory structures of rotifers are Flame cells. The flame cells function like a kidney, removing nitrogenous waste.

Birds excrete nitrogenous wastes as uric acid in the form of a pellet or paste with a minimum loss of water. Therefore they are called uricotelic animals. 

(A) The process of excreting ammonia is Ammonotelism. Many bony fishes, aquatic amphibians and aquatic insects are ammonotelic. 

Ureotelic organisms produce ammonia as a metabolic byproduct, which is then converted into urea in the liver via the urea cycle. Therefore, the statement that ammonia is not a product of metabolism in these organisms is false.

Malpighian tubules are excretory structures in most insects, including cockroaches, but in crustaceans such as prawns, green glands conduct excretory functions, whereas all other statements are true.

Gymnophiona, also called apoda, is one of the three major extant orders of the class amphibia. Its members are known as caecilians. Their skin is smooth but some species have colourful skins. Inside the skin are calcite scales. Because of these scales, the caecilians were once thought to be related to the fossil Stegocephalia.

The renal gland is a relatively wide tube opening from a sac (the pericardium) surrounding the heart, at one end, and to the mantle cavity (effectively to the exterior) at the other. The anatomical form of the renal gland varies from one class of molluscs to another.

The Bowman's capsule and the glomerulus together constitute the malpighian corpuscle (pygmalion corpuscle or renal corpuscle). The malphigian corpuscles were first described by Morcello Malpighi in the year 1966.

Birds and reptiles urinate in a way to conserve their water. Unlike mammals, which excrete waste fluid as urine and solid waste as faeces, birds and reptiles mix both liquid waste and solid waste into the semi-solid paste (nitrogen containing waste) formed from the breakdown of proteins. Hence snakes, crocodiles, birds and most lizards lack a urinary bladder.

Bright's disease is a classification for nephritis, a kidney condition. Nephritis is caused by inflammation of part of the kidneys, usually either the glomeruli or the spaces in between the renal tubules. Symptoms most commonly associated with Bright's disease are intense pain on either or both sides of the lower back along with a fever and nausea. Cloudy, dark, or bloody urine containing blood plasma proteins is also a hallmark sign of kidney problems. 

The excretory system of earthworm contains a pair of nephridia in every segment, except for the first three and the last ones. The three types of nephridia are: integumentary, septal, and pharyngeal. The integumentary nephridia lie attached to the inner side of the body wall in all segments except the first two. The septal nephridia are attached to both sides of the septa behind the 15th segment. The pharyngeal nephridia are attached to fourth, fifth and sixth segments.

In many higher crustaceans the excretory glands are located in the head. They are called antennal glands or maxillary glands, depending on whether they open at the base of the antennae or at the maxillae.

Chloragogen cells in annelids function similarly to the liver in vertebrates. The cells store glycogen and neutralize toxins, are yellowish in colour due to the presence of yellow granules, called as chloragosomes and are present in coelomic fluid of some annelids.

A flame cell is a specialized excretory cell, found in the simplest freshwater invertebrates, including flatworms, rotifers and nemerteans. These are the simplest animals to have a dedicated excretory system. Flame cells function like a kidney, removing waste materials.

The loop of Henle is incompletely developed or absent in many nephrons of the bird kidney. Hence, the concentrating capacity of the bird kidney is considerably less than that of the mammal. 

The term pelage is used to refer to the body hair of an animal as a complete coat. Its principal function is thermoregulation, it maintains a layer of dry air next to the skin and repels water, thus providing thermal insulation.

The excretory organ of cockroach is the Malpighian tubules. It is found at the junction of the midgut and hindgut and are about 150 in number. 

A kidney stone is a solid cluster made up of tiny crystals. 

Mesonephric kidney- Develop from middle part (mesonephros) of nephrotome plate and remaining part of nephrotome is destroyed. Only Bowman's capsule is found in nephrons, while remaining part is simple tubular, e.g., most of the fishes and adult amphibians.

Porifera (sponges), Platyhelminthes (flatworms) and Cnidaria (Hydra) do not have a well-developed digestive system. They have 'blind-sac' body plan, with an opening that serves as both the mouth and the anus, and a gastrovascular cavity where digestion takes place.

Birds and reptiles have uric acid as their nitrogenous waste.