Endocrine System Anatomy and Physiology

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Urinary System
Cut out everything that is crap, literally crap: Or another medical condition that makes you retain water since you barely eat. Just as your appetite for food fluctuates, so does your thirst for water, and staying tuned to your body's signal for water is the best way to ensure you drink enough, especially since the amount of water you lose every day pivots on how much you perspire and excrete through urine and bowel movements. Read more about Gold. I am so much more free.

Think Like A Cop

The Function of the Circulatory System Lesson for Kids

The size of an adult kidney is approximately 4 inches 10 centimeters long and 2 inches 5 centimeters wide. To maintain human life, it is necessary for at least one of the kidneys to function properly. Blood carries waste products to the kidneys via the renal artery. Inside each kidney, blood is transported to 1. The cells in nephrons take in the liquid portion of the blood and filter out impurities urea, mineral salts, and other toxins. Necessary substances such as certain salts, water, glucose sugar , and other nutrients are returned to the blood stream via the renal vein.

Chemical secreted by the pituitary gland that regulates the amount of water excreted by the kidneys. Process of separating wastes from the blood by passage through a semipermeable membrane.

Chemical compound of carbon, hydrogen, nitrogen, and oxygen produced as waste by cells that break down protein. Tube that carries urine from a kidney to the urinary bladder. Duct leading from the urinary bladder to outside the body through which urine is eliminated.

The waste-containing fluid that remains in the nephrons is called urine. Urine is 95 percent water, in which the waste products are dissolved. A pair of tubes called ureters carry urine from the kidneys to the urinary bladder. Each ureter is about 16 to 18 inches 40 to 45 centimeters long. The bladder is a hollow muscular sac located in the pelvis that is collapsed when empty, but pear-shaped and distended when full. The bladder in an adult can hold more than 2 cups 0. The bladder empties urine into the urethra, a duct leading to outside the body.

In males, the urethra is about 8 inches 20 centimeters long. In females, it is less than 2 inches 5 centimeters long. A sphincter muscle around the urethra at the base of the bladder controls the flow of urine between the two. The volume of urine excreted is controlled by the antidiuretic hormone ADH , which is released by the pituitary gland a small gland lying at the base of the skull.

If an individual perspires a lot or fails to drink enough water, special nerve cells in the hypothalamus a region of the brain controlling body temperature, hunger, and thirst detect the low water concentration in the blood. They then signal the pituitary gland to release ADH into the blood, where it travels to the kidneys. With ADH present, the kidneys reabsorb more water from the urine and return it to the blood. The volume of urine is thus reduced.

On the other hand, if an individual takes in too much water, production of ADH decreases. The kidneys do not reabsorb as much water, and the volume of urine is increased. Alcohol inhibits ADH production and therefore increases the output of urine. Disorders of the urinary tract kidneys, ureters, bladder, and urethra include urinary tract infections UTI. An example is cystitis, a disease in which bacteria infect the urinary bladder, causing inflammation.

Most UTIs are treated with antibiotics. Sometimes kidney stones, solid salt crystals, form in the urinary tract. Kidney stones can obstruct the urinary passages and cause severe pain and bleeding. If they do not pass out of the body naturally, a physician may remove them surgically or disintegrate them using shock waves. Chronic renal failure is the permanent loss of kidney function. Hemodialysis and kidney transplant are two medical treatments for this condition.

In hemodialysis, an artificial kidney device cleans the blood of wastes. During the procedure, blood is taken out of an artery in the patient's arm and passed through a tubing that is semipermeable allows certain materials to pass through its sides. The tubing is immersed in a solution. As the blood passes through the tubing, wastes pass out of the tubing and into the surrounding solution. The cleansed blood then returns to the body. In a kidney transplant, a surgeon replaces a diseased kidney with a closely matched donor kidney.

There are about 11, species, more than all other platyhelminthes combined, and second only to roundworms among parasites on metazoans. The intermediate stages transfer the parasites from one host to another. The definitive host in which adults develop is a land vertebrate; the earliest host of juvenile stages is usually a snail that may live on land or in water, whilst in many cases a fish or arthropod is the second host.

Schistosomes, which cause the devastating tropical disease bilharzia , belong to this group. Adults range between 0. Individual adult digeneans are of a single sex, and in some species slender females live in enclosed grooves that run along the bodies of the males, partially emerging to lay eggs. In all species the adults have complex reproductive systems, capable of producing between 10, and , times as many eggs as a free-living flatworm. In addition, the intermediate stages that live in snails reproduce asexually.

Adults of different species infest different parts of the definitive host - for example the intestine , lungs , large blood vessels, [3] and liver. In both the adult and snail-inhabiting stages, the external syncytium absorbs dissolved nutrients from the host. Adult digeneans can live without oxygen for long periods. Members of this small group have either a single divided sucker or a row of suckers that cover the underside.

These parasites attach themselves to their hosts by means of disks that bear crescent-shaped hooks. They are divided into the Monogenea and Cestoda groupings. Of about 1, species of monogeneans, most are external parasites that require particular host species - mainly fish, but in some cases amphibians or aquatic reptiles.

However, a few are internal parasites. They often have flattened bodies. In some species, the pharynx secretes enzymes to digest the host's skin, allowing the parasite to feed on blood and cellular debris.

Others graze externally on mucus and flakes of the hosts' skins. The name "Monogenea" is based on the fact that these parasites have only one nonlarval generation. These are often called tapeworms because of their flat, slender but very long bodies — the name "cestode" is derived from the Latin word cestus , which means "tape". The adults of all 3, cestode species are internal parasites. Cestodes have no mouths or guts, and the syncitial skin absorbs nutrients — mainly carbohydrates and amino acids — from the host, and also disguises it chemically to avoid attacks by the host's immune system.

Their metabolisms generally use simple but inefficient chemical processes, compensating for this inefficiency by consuming large amounts of food relative to their physical size. In the majority of species, known as eucestodes "true tapeworms" , the neck produces a chain of segments called proglottids via a process known as strobilation. As a result, the most mature proglottids are furthest from the scolex. Each proglottid has both male and female reproductive organs.

If the host's gut contains two or more adults of the same cestode species they generally fertilize each other, however proglottids of the same worm can fertilize each other and even themselves.

When the eggs are fully developed, the proglottids separate and are excreted by the host. The eucestode life cycle is less complex than that of digeneans , but varies depending on the species. A members of the smaller group known as Cestodaria have no scolex, do not produce proglottids, and have body shapes similar to those of diageneans. Cestodarians parasitize fish and turtles. The relationships of Platyhelminthes to other Bilateria are shown in the phylogenetic tree: The internal relationships of Platyhelminthes are shown below.

The tree is not fully resolved. Neodermata flukes , tapeworms. The oldest confidently identified parasitic flatworm fossils are cestode eggs found in a Permian shark coprolite , but helminth hooks still attached to Devonian acanthodians and placoderms might also represent parasitic flatworms with simple life cycles.

This makes it difficult to work out their relationships with other groups of animals, as well as the relationships between different groups that are described as members of the Platyhelminthes. The "traditional" view before the s was that Platyhelminthes formed the sister group to all the other bilaterians, which include, for instance, arthropods , molluscs , annelids and chordates. Since then, molecular phylogenetics , which aims to work out evolutionary "family trees" by comparing different organisms' biochemicals such as DNA , RNA and proteins , has radically changed scientists' view of evolutionary relationships between animals.

Xenoturbella , a bilaterian whose only well-defined organ is a statocyst , was originally classified as a "primitive turbellarian". The Platyhelminthes excluding Acoelomorpha contain two main groups - Catenulida and Rhabditophora - both of which are generally agreed to be monophyletic each contains all and only the descendants of an ancestor that is a member of the same group.

Other molecular phylogenetics analyses agree the redefined Platyhelminthes are most closely related to Gastrotricha , and both are part of a grouping known as Platyzoa. Platyzoa are generally agreed to be at least closely related to the Lophotrochozoa , a super phylum that includes molluscs and annelid worms.

The majority view is that Platyzoa are part of Lophotrochozoa, but a significant minority of researchers regard Platyzoa as a sister group of Lophotrochozoa. It has been agreed since that each of the wholly parasitic platyhelminth groups Cestoda , Monogenea and Trematoda is monophyletic, and that together these form a larger monophyletic grouping, the Neodermata , in which the adults of all members have syncitial skins.

An outline of the origins of the parasitic life style has been proposed; [29] epithelial feeding monopisthocotyleans on fish hosts are basal in the Neodermata and were the first shift to parasitism from free living ancestors. The next evolutionary step was a dietary change from epithelium to blood. Cestodes tapeworms and digeneans flukes cause diseases in humans and their livestock , whilst monogeneans can cause serious losses of stocks in fish farms.

The condition has a low mortality rate , but usually presents as a chronic illness that can damage internal organs. It can impair the growth and cognitive development of children, increasing the risk of bladder cancer in adults. The disease is caused by several flukes of the genus Schistosoma , which can bore through human skin; those most at risk use infected bodies of water for recreation or laundry. Infection of humans by the broad fish tapeworm Diphyllobothrium latum occasionally causes vitamin B 12 deficiency and, in severe cases, megaloblastic anemia.

The threat to humans in developed countries is rising as a result of social trends: In less-developed countries, inadequate sanitation and the use of human feces night soil as fertilizer or to enrich fish farm ponds continues to spread parasitic platyhelminths, whilst poorly designed water-supply and irrigation projects have provided additional channels for their spread. People in these countries usually cannot afford the cost of fuel required to cook food thoroughly enough to kill parasites.

Controlling parasites that infect humans and livestock has become more difficult, as many species have become resistant to drugs that used to be effective, mainly for killing juveniles in meat. There is concern in northwest Europe including the British Isles regarding the possible proliferation of the New Zealand planarian Arthurdendyus triangulatus and the Australian flatworm Australoplana sanguinea , both of which prey on earthworms.

In Hawaii, the planarian Endeavouria septemlineata has been used to control the imported giant African snail Achatina fulica , which was displacing native snails; Platydemus manokwari , another planarian, has been used for the same purpose in Philippines, Indonesia, New Guinea and Guam.

The ability of planarians to take different kinds of prey and to resist starvation may account for their ability to decimate A. However, these abilities have raised concerns that planarians may themselves become a serious threat to native snails.

A study [39] in La Plata , Argentina, shows the potential for planarians such as Girardia anceps , Mesostoma ehrenbergii , and Bothromesostoma evelinae to reduce populations of the mosquito species Aedes aegypti and Culex pipiens. The experiment showed that G. The ability for these flatworms to live in artificial containers demonstrated the potential of placing these species in popular mosquito breeding sites, which would ideally reduce the amount of mosquito-borne diseases.

From Wikipedia, the free encyclopedia. List of bilateral animal orders. The Diversity of Living Organisms. Invertebrate Zoology 7 ed. Encyclopaedia of Life Sciences. Annual Review of Ecology, Evolution, and Systematics. Acoela and Nemertodermatida are separate early bilaterian clades". Assembling the Tree of Life. Oxford University Press US. Neotropical Biology and Conservation. In Kenneth De Baets and D. Molecular Biology and Evolution. Biological Journal of the Linnean Society. Bulletin of the World Health Organization.

Natural Enemies of Terrestrial Molluscs. Turbellaria on mosquitoes Diptera: Cnidaria jellyfish and relatives. Xenacoelomorpha Xenoturbellida Xenoturbella Acoelomorpha acoels nemertodermatids. Echinodermata starfish and relatives Hemichordata acorn worms pterobranchs.

Kinorhyncha mud dragons Priapulida penis worms. Nematoda roundworms Nematomorpha horsehair worms. Arthropoda arthropods Tardigrada waterbears. Chaetognatha arrow worms Gnathostomulida jaw worms.