Menstruation known as a period or monthly, is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. The first period begins between twelve and fifteen years of age, a point in time known as menarche. However, periods may start as young as eight years old and still be considered normal; the average age of the first period is later in the developing world, earlier in the developed world. The typical length of time between the first day of one period and the first day of the next is 21 to 45 days in young women, 21 to 31 days in adults. Bleeding lasts around 2 to 7 days. Menstruation stops occurring after menopause, which occurs between 45 and 55 years of age. Periods stop during pregnancy and do not resume during the initial months of breastfeeding. Up to 80% of women report having some symptoms prior to menstruation. Common signs and symptoms include acne, tender breasts, feeling tired and mood changes; these may interfere with normal life, therefore qualifying as premenstrual syndrome, in 20 to 30% of women.
In 3 to 8%, symptoms are severe. A lack of periods, known as amenorrhea, is when periods do not occur by age 15 or have not occurred in 90 days. Other problems with the menstrual cycle include painful periods and abnormal bleeding such as bleeding between periods or heavy bleeding. Menstruation in other animals occur in primates; the menstrual cycle occurs due to the fall of hormones. This cycle results in the thickening of the lining of the uterus, the growth of an egg; the egg is released from an ovary around day fourteen in the cycle. If pregnancy does not occur, the lining is released in; the first menstrual period occurs after the onset of pubertal growth, is called menarche. The average age of menarche is 12 to 15. However, it may start as early as eight; the average age of the first period is later in the developing world, earlier in the developed world. The average age of menarche has changed little in the United States since the 1950s. Menstruation is the most visible phase of the menstrual cycle and its beginning is used as the marker between cycles.
The first day of menstrual bleeding is the date used for the last menstrual period. The typical length of time between the first day of one period and the first day of the next is 21 to 45 days in young women, 21 to 31 days in adults. Perimenopause is when fertility in a female declines, menstruation occurs less in the years leading up to the final menstrual period, when a female stops menstruating and is no longer fertile; the medical definition of menopause is one year without a period and occurs between 45 and 55 in Western countries. During pregnancy and for some time after childbirth, menstruation does not occur; the average length of postpartum amenorrhoea is longer. In most women, various physical changes are brought about by fluctuations in hormone levels during the menstrual cycle; this includes muscle contractions of the uterus that can accompany menstruation. Some may notice water retention, changes in sex drive, breast tenderness, or nausea. Breast swelling and discomfort may be caused by water retention during menstruation.
Such sensations are mild, some females notice few physical changes associated with menstruation. A healthy diet, reduced consumption of salt and alcohol, regular exercise may be effective for women in controlling some symptoms. Severe symptoms that disrupt daily activities and functioning may be diagnosed as premenstrual dysphoric disorder. Symptoms before menstruation are known as premenstrual molimina. Many women experience painful cramps known as dysmenorrhea, during menstruation. Pain results from muscle contractions. Spiral arteries in the secretory endometrium constrict, resulting in ischemia to the secretory endometrium; this allows the uterine lining to slough off. The myometrium contracts spasmodically in order to push the menstrual fluid through the cervix and out of the vagina; the contractions are mediated by a release of prostaglandins. Painful menstrual cramps that result from an excess of prostaglandin release are referred to as primary dysmenorrhea. Primary dysmenorrhea begins within a year or two of menarche with the onset of ovulatory cycles.
Treatments that target the mechanism of pain include non-steroidal anti-inflammatory drugs and hormonal contraceptives. NSAIDs inhibit prostaglandin production. With long-term treatment, hormonal birth control reduces the amount of uterine fluid/tissue expelled from the uterus, thus resulting in shorter, less painful menstruation. These drugs are more effective than treatments that do not target the source of the pain. Risk factors for primary dysmenorrhea include: early age at menarche, long or heavy menstrual periods, a family history of dysmenorrhea. Regular physical activity may limit the severity of uterine cramps. For many women, primary dysmenorrhea subsides in late second generation. Pregnancy has been demonstrated to lessen the severity of dysmenorrhea, when menstruation resumes. However, dysmenorrhea can continue until menopause. 5–15% of women with dysmenorrhea experience symptoms severe enough to interfere with daily activities. Secondary dysmenorrhea is the diagnosis given when menstruation pain is a secondary cause to another disorder.
An intrauterine device known as intrauterine contraceptive device or coil, is a small T-shaped birth control device, inserted into a woman's uterus to prevent pregnancy. IUDs are one form of long-acting reversible birth control. Among birth control methods, IUDs, along with contraceptive implants, result in the greatest satisfaction among users. One study found that female family planning providers choose LARC methods more than the general public. IUDs are safe and effective in adolescents as well as those who have not had children. Once an IUD is removed after long-term use, fertility returns to normal rapidly. Copper devices have a failure rate of about 0.8% while hormonal devices fail about 0.2% of the time within the first year of use. In comparison, male sterilization and male condoms have a failure rate of about 0.15% and 15%, respectively. Copper IUDs can be used as emergency contraception within 5 days of unprotected sex. Although copper IUDs may increase menstrual bleeding and result in painful cramps, hormonal IUDs may reduce menstrual bleeding or stop menstruation altogether.
However, women can have daily spotting for several months and it can take up to three months for there to be a 90% decrease in bleeding. Cramping can be treated with NSAIDs. More serious potential complications include expulsion and perforation of the uterus. IUDs do not affect breastfeeding and can be inserted after delivery, they may be used after an abortion. The use of IUDs has increased within the United States from 0.8% in 1995 to 5.6% from the period of 2006 to 2010. The use of IUDs as a form of birth control dates from the 1800s. A previous model known as the Dalkon shield was associated with an increased risk of pelvic inflammatory disease. However, current models do not affect PID risk in women without sexually transmitted infections during the time of insertion; the types of intrauterine devices available, the names they go by, differ by location. In the United States, there are two types available: Nonhormonal: Copper-containing IUD Hormonal: Progestogen-releasing IUD The WHO ATC labels both copper and hormonal devices as IUDs.
In the United Kingdom, there are more than 10 different types of copper IUDs. In the United Kingdom, the term IUD refers only to these copper devices. Hormonal intrauterine contraception is considered to be a different type of birth control and is labeled with the term intrauterine system. Most copper IUDs have a T-shaped frame, wound around with pure electrolytic copper wire and/or has copper collars; the arms of the frame hold the IUD in place near the top of the uterus. The Paragard TCu 380a measures 32 mm horizontally, 36 mm vertically. Copper IUDs have a first year failure rate ranging from 0.1 to 2.2%. They work by disrupting their motility so that they are not able to join an egg. Copper acts as a spermicide within the uterus by increasing levels of copper ions and white blood cells within the uterine and tubal fluids; the increased copper ions in the cervical mucus inhibit the sperm's motility and viability, preventing sperm from traveling through the cervical mucus, or destroying it as it passes through.
Copper can alter the endometrial lining, but studies show that while this alteration can prevent implantation of a fertilized egg, it cannot disrupt one, implanted. Advantages of the copper IUD include its ability to provide emergency contraception up to five days after unprotected sex, it is the most effective form of emergency contraception available. It works by preventing fertilization or implantation but does not affect implanted embryos, it contains no hormones, so it can be used while breastfeeding, fertility returns after removal. Copper IUDs last longer and are available in a wider range of sizes and shapes compared to hormonal IUDs. Disadvantages include the possibility of heavier menstrual periods and more painful cramps. IUDs that contain gold or silver exist. Other shapes of IUD include the so-called U-shaped IUDs, such as the Load and Multiload, the frameless IUD that holds several hollow cylindrical minuscule copper beads, it is held in place by a suture to the fundus of the uterus.
It is available in China and Europe. A framed copper IUD called the IUB SCu300 coils when deployed and forms a three-dimensional spherical shape, it is based on a nickel titanium shape memory alloy core. In addition to copper, noble metal and progestogen IUDs; this non-hormonal compound reduces the severity of menstrual bleeding, these coils are popular. Inert IUDs do not have a bioactive component, they are made of inert materials like stainless plastic. They are less effective than copper or hormonal IUDs, with a side effect profile similar to copper IUDs, their primary mechanism of action is inducing a local foreign body reaction, which makes the uterine environment hostile both to sperm and to implantation of an embryo. They may have higher rates of preventing pregnancy after fertilization, instead of before fertilization, compared to copper or hormonal IUDs. Inert IUDs are not yet approved for use in UK, or Canada. In China, where IUDs are the most common form of contraception, copper IUD production rep
Obstetrics is the field of study concentrated on pregnancy and the postpartum period. As a medical specialty, obstetrics is combined with gynecology under the discipline known as obstetrics and gynecology, a surgical field. Prenatal care is important in screening for various complications of pregnancy; this includes routine office visits with physical exams and routine lab tests: Complete blood count Blood type General antibody screen for HDN Rh D negative antenatal patients should receive RhoGam at 28 weeks to prevent Rh disease. Rapid plasma reagin to screen for syphilis Rubella antibody screen Hepatitis B surface antigen Gonorrhea and Chlamydia culture PPD for tuberculosis Pap smear Urinalysis and culture HIV screenGenetic screening for Down syndrome and trisomy 18, the national standard in the United States, is evolving away from the AFP-Quad screen for Down syndrome, done in the second trimester at 16–18 weeks; the newer integrated screen can be done at 10 plus weeks to 13 plus weeks with an ultrasound of the fetal neck and two chemicals PAPP-A and βHCG.
It gives an accurate risk profile early. A second blood screen at 15 to 20 weeks refines the risk more accurately; the cost is higher than an "AFP-quad" screen due to the ultrasound and second blood test, but it is quoted to have a 93% pick up rate as opposed to 88% for the standard AFP/QS. This is an evolving standard of care in the United States. MSAFP/quad. Screen – elevations, low numbers or odd patterns correlate with neural tube defect risk and increased risks of trisomy 18 or trisomy 21 Ultrasound either abdominal or transvaginal to assess cervix, placenta and baby Amniocentesis is the national standard for women over 35 or who reach 35 by mid pregnancy or who are at increased risk by family history or prior birth history. Hematocrit Group B Streptococcus screen. If positive, the woman receives IV penicillin or ampicillin while in labor—or, if she is allergic to penicillin, an alternative therapy, such as IV clindamycin or IV vancomycin. Glucose loading test – screens for gestational diabetes.
Most doctors do a sugar load in a drink form of 50 grams of glucose in cola, lime or orange and draw blood an hour later. The standard modified criteria have been lowered to 135 since the late 1980s. Obstetric ultrasonography is used for dating the gestational age of a pregnancy from the size of the fetus, determine the number of fetuses and placentae, evaluate for an ectopic pregnancy and first trimester bleeding, the most accurate dating being in first trimester before the growth of the foetus has been influenced by other factors. Ultrasound is used for detecting congenital anomalies and determining the biophysical profiles, which are easier to detect in the second trimester when the foetal structures are larger and more developed. Specialised ultrasound equipment can evaluate the blood flow velocity in the umbilical cord, looking to detect a decrease/absence/reversal or diastolic blood flow in the umbilical artery. X-rays and computerized tomography are not used in the first trimester, due to the ionizing radiation, which has teratogenic effects on the foetus.
No effects of magnetic resonance imaging on the foetus have been demonstrated, but this technique is too expensive for routine observation. Instead, obstetric ultrasonography is the imaging method of choice in the first trimester and throughout the pregnancy, because it emits no radiation, is portable, allows for realtime imaging; the safety of frequent ultrasound scanning has not be confirmed. Despite this, increasing numbers of women are choosing to have additional scans for no medical purpose, such as gender scans, 3D and 4D scans. A normal gestation would reveal a gestational sac, yolk sac, fetal pole; the gestational age can be assessed by evaluating the mean gestational sac diameter before week 6, the crown-rump length after week 6. Multiple gestation is evaluated by the number of placentae and amniotic sacs present. Other tools used for assessment include: Fetal screening is used to help assess the viability of the fetus, as well as congenital abnormalities. Fetal karyotype can be used for the screening of genetic diseases.
This can be obtained via amniocentesis or chorionic villus sampling Foetal haematocrit for the assessment of foetal anemia, Rh isoimmunization, or hydrops can be determined by percutaneous umbilical blood sampling, done by placing a needle through the abdomen into the uterus and taking a portion of the umbilical cord. Fetal lung maturity is associated with. Reduced production of surfactant indicates decreased lung maturity and is a high risk factor for infant respiratory distress syndrome. A lecithin:sphingomyelin ratio greater than 1.5 is associated with increased lung maturity. Nonstress test for fetal heart rate Oxytocin challenge test A pregnant woman may have intercurrent diseases, that is, other diseases or conditions that may become worse or be a potential risk to the pregnancy. Diabetes mellitus and pregnancy deals with the interactions of diabetes mellitus and pregnanc
Chlamydia trachomatis known as chlamydia, is a bacterium that can replicate only in human cells. It causes chlamydia, which can manifest in various ways, including: trachoma, lymphogranuloma venereum, nongonococcal urethritis, salpingitis, pelvic inflammatory disease. C. trachomatis is the most common infectious cause of blindness and the most common sexually transmitted bacterium. Different types of C. trachomatis cause different diseases. The most common strains cause disease in the genital tract, while other strains cause disease in the eye or lymph nodes. Like other Chlamydia species, the C. trachomatis life cycle consists of two morphologically distinct life stages: elementary bodies and reticulate bodies. Elementary bodies are infectious. Reticulate bodies are seen only within host cells. Chlamydia trachomatis is a gram-negative bacterium. Over the course of the C. trachomatis life cycle, the bacteria take on two distinct forms. Elementary bodies are 200 to 400 nanometers across, are surrounded by a rigid cell wall that allows them to survive outside of a host cell.
This form can initiate a new infection. Reticulate bodies are 600 to 1500 nanometers across, are found only within host cells. Neither form is motile; the C. trachomatis genome is smaller than that of many other bacteria at 1.04 megabases, encoding 900 genes. A number of important metabolic functions are not encoded in the C. trachomatis genome, instead are scavenged from the host cell. In addition to the chromosome that contains most of the genome, nearly all C. trachomatis strains carry a 7.5 kilobase plasmid that contains 8 genes. The role of this plasmid is unknown, though strains without the plasmid have been isolated, suggesting it is not required for survival of the bacterium. Like other Chlamydia species, C. trachomatis has a life cycle consisting of two morphologically distinct forms. First, C. trachomatis attaches to a new host cell as a small spore-like form called the elementary body. The elementary body enters. Within the inclusion, C. trachomatis transforms into a larger, more metabolically active form called the reticulate body.
The reticulate body modifies the inclusion, making it a more hospitable environment for rapid replication of the bacteria, which occurs over the following 30 to 72 hours. The massive number of intracellular bacteria transition back to resistant elementary bodies, before causing the cell to rupture and being released into the environment; these new elementary bodies are shed in the semen or released from epithelial cells of the female genital tract, attach to new host cells. C. trachomatis are bacteria in the genus Chlamydia, a group of obligate intracellular parasites of eukaryotic cells. Chlamydial cells cannot carry out energy metabolism and they lack biosynthetic pathways. C. Trachomatis strains are divided into three biovars based on the type of disease they cause; these are further subdivided into several serovars based on surface antigens recognized by the immune system. Serovars A through C cause trachoma, the worlds leading cause of preventable infectious blindness. Serovars D through K infect the genital tract, causing pelvic inflammatory disease, ectopic pregnancies, infertility.
Serovars L1 through L3 cause an invasive infection of the lymph nodes near the genitals, called lymphogranuloma venereum. C. Trachomatis is thought to have diverged from other Chlamydia species around 6 million years ago; this genus contains a total of nine species: C. trachomatis, C. muridarum, C. pneumoniae, C. pecorum, C. suis, C. abortus, C. felis, C. caviae, C. psittaci. The closest relative to C. trachomatis is C. muridarum. C. trachomatis along with C. pneumoniae have been found to infect humans to a greater extent. C. trachomatis infects human beings. C. pneumoniae is found to infect horses and frogs. Some of the other species can have a considerable impact on human health due to their known zoonotic transmission. Clinical signs and symptoms of C. trachomatis infection and gonorrhea infection are indistinguishable. Both are common causes of urethritis. C. trachomatis is the single most important infectious agent associated with blindness. Elementary bodies are present in the semen of infected men and vaginal secretions of infected women.
When they come into contact with a new host cell, the elementary bodies bind to the cell via interaction between adhesins on their surface and several host receptor proteins and heparan sulfate proteoglycans. Once attached, the bacteria inject various effector proteins into the host cell using a type three secretion system; these effectors trigger the host cell to take up the elementary bodies and prevent the cell from triggering apoptosis. Within 6 to 8 hours after infection, the elementary bodies transition to reticulate bodies and a number of new effectors are synthesized; these effectors include a number of proteins that modify the inclusion membrane, called Inc proteins, as well as proteins that redirect host vesicles to the inclusion. 8 to 16 hours after infection, another set of effectors are synthesized, driving acquisition of nutrients from the host cell. At this stage, the reticulate bodies begin to divide. If several elemenary bodies have infected a single cell, their inclusions will fuse at this point to create a single large inclusion in the host cell.
From 24 to 72 hours after infection
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" sound in its physical properties, except that humans cannot hear it; this limit varies from person to person and is 20 kilohertz in healthy young adults. Ultrasound devices operate with frequencies from 20 kHz up to several gigahertz. Ultrasound is used in many different fields. Ultrasonic devices are used to detect objects and measure distances. Ultrasound imaging or sonography is used in medicine. In the nondestructive testing of products and structures, ultrasound is used to detect invisible flaws. Industrially, ultrasound is used for cleaning and accelerating chemical processes. Animals such as bats and porpoises use ultrasound for locating prey and obstacles. Scientists are studying ultrasound using graphene diaphragms as a method of communication. Acoustics, the science of sound, starts as far back as Pythagoras in the 6th century BC, who wrote on the mathematical properties of stringed instruments.
Echolocation in bats was discovered by Lazzaro Spallanzani in 1794, when he demonstrated that bats hunted and navigated by inaudible sound, not vision. Francis Galton in 1893 invented the Galton whistle, an adjustable whistle that produced ultrasound, which he used to measure the hearing range of humans and other animals, demonstrating that many animals could hear sounds above the hearing range of humans; the first technological application of ultrasound was an attempt to detect submarines by Paul Langevin in 1917. The piezoelectric effect, discovered by Jacques and Pierre Curie in 1880, was useful in transducers to generate and detect ultrasonic waves in air and water. Ultrasound is defined by the American National Standards Institute as "sound at frequencies greater than 20 kHz". In air at atmospheric pressure, ultrasonic waves have wavelengths of 1.9 cm or less. The upper frequency limit in humans is due to limitations of the middle ear. Auditory sensation can occur if high‐intensity ultrasound is fed directly into the human skull and reaches the cochlea through bone conduction, without passing through the middle ear.
Children can hear some high-pitched sounds that older adults cannot hear, because in humans the upper limit pitch of hearing tends to decrease with age. An American cell phone company has used this to create ring signals that are only audible to younger humans, but many older people can hear the signals, which may be because of the considerable variation of age-related deterioration in the upper hearing threshold; the Mosquito is an electronic device that uses a high pitched frequency to deter loitering by young people. Bats use a variety of ultrasonic ranging techniques to detect their prey, they can detect frequencies beyond 100 kHz up to 200 kHz. Many insects have good ultrasonic hearing, most of these are nocturnal insects listening for echolocating bats; these include many groups of moths, praying mantids and lacewings. Upon hearing a bat, some insects will make evasive manoeuvres to escape being caught. Ultrasonic frequencies trigger a reflex action in the noctuid moth that causes it to drop in its flight to evade attack.
Tiger moths emit clicks which may disturb bats' echolocation, in other cases may advertise the fact that they are poisonous by emitting sound. Dogs and cats' hearing range extends into the ultrasound; the wild ancestors of cats and dogs evolved this higher hearing range to hear high-frequency sounds made by their preferred prey, small rodents. A dog whistle is a whistle that emits ultrasound, used for calling dogs; the frequency of most dog whistles is within the range of 23 to 54 kHz. Toothed whales, including dolphins, can hear ultrasound and use such sounds in their navigational system to orient and to capture prey. Porpoises have the highest known upper hearing limit at around 160 kHz. Several types of fish can detect ultrasound. In the order Clupeiformes, members of the subfamily Alosinae have been shown to be able to detect sounds up to 180 kHz, while the other subfamilies can hear only up to 4 kHz. Ultrasound generator/speaker systems are sold as electronic pest control devices, which are claimed to frighten away rodents and insects, but there is no scientific evidence that the devices work.
An ultrasonic level or sensing system requires no contact with the target. For many processes in the medical, pharmaceutical and general industries this is an advantage over inline sensors that may contaminate the liquids inside a vessel or tube or that may be clogged by the product. Both continuous wave and pulsed systems are used; the principle behind a pulsed-ultrasonic technology is that the transmit signal consists of short bursts of ultrasonic energy. After each burst, the electronics looks for a return signal within a small window of time corresponding to the time it takes for the energy to pass through the vessel. Only a signal received during this window will qualify for additional signal processing. A popular consumer application of ultrasonic ranging was the Polaroid SX-70 camera, which included a lightweight transducer system to focus the camera automatically. Polaroid licensed this ultrasound technology and it became the basis of a variety of ultrasonic products. A common ultrasound application is an automatic door opener, where an ultrasonic sensor detects a person's approach and opens the door.
Ultrasonic sensors are used to detect intruders. The flow in pipes or open channels can be measured by ultrasonic flowmeters, which measure the average veloci
The myometrium is the middle layer of the uterine wall, consisting of uterine smooth muscle cells, but of supporting stromal and vascular tissue. Its main function is to induce uterine contractions; the myometrium is located between the endometrium, the serosa or perimetrium. Myometrium has 3 layers: outer longitudinal smooth muscles, middle crisscrossing muscle fibres, inner circular fibres. Middle crisscross fibres act as living ligature during involution of the uterus and prevent blood loss; the inner one-third of the myometrium appears to be derived from the Müllerian duct, while the outer, more predominant layer of the myometrium appears to originate from non-Müllerian tissue, is the major contractile tissue during parturition and abortion. The junctional layer appears to function like a circular muscle layer, capable of peristaltic and anti-peristaltic activity, equivalent to the muscular layer of the intestines; the molecular structure of the smooth muscle of myometrium is similar to that of smooth muscle in other sites of the body, with myosin and actin being the predominant proteins.
In uterine smooth muscle, there is 6-fold more actin than myosin. A shift in the myosin expression of the uterine smooth muscle may be responsible for changes in the directions of uterine contractions during the menstrual cycle; the myometrium stretches during pregnancy to allow for the uterus to become several times its non-gravid size, contracts in a coordinated fashion, via a positive feedback effect on the "Ferguson reflex", during the process of labor. After delivery the myometrium contracts to expel the placenta, crisscrossing fibres of middle layer compress the blood vessels to minimize blood loss. A positive benefit to early breastfeeding is a stimulation of this reflex to reduce further blood loss and facilitate a swift return to prepregnancy uterine and abdominal muscle tone. Uterine smooth muscle has a phasic pattern, shifting between a contractile pattern and maintenance of a resting tone with discrete, intermittent contractions of varying frequency and duration; as noted for the macrostructure of uterine smooth muscle, the junctional layer appears be capable of both peristaltic and anti-peristaltic activity.
The resting membrane potential of uterine smooth muscle has been recorded to be between -35 and -80 mV. As with the resting membrane potential of other cell types, it is maintained by a Na+/K+ pump that causes a higher concentration of Na+ ions in the extracellular space than in the intracellular space, a higher concentration of K+ ions in the intracellular space than in the extracellular space. Subsequently, having K+ channels open to a higher degree than Na+ channels results in an overall efflux of positive ions, resulting in a negative potential; this resting potential undergoes rhythmic oscillations, which have been termed slow waves, reflect intrinsic activity of slow wave potentials. These slow waves are caused by changes in the distribution of Ca2+, Na+, K+ and Cl− ions between the intracellular and extracellular spaces, which, in turn, reflects the permeability of the plasma membrane to each of those ions. K+ is the major ion responsible for such changes in ion flux, reflecting changes in various K+ channels.
The excitation-contraction coupling of uterine smooth muscle is very similar to that of other smooth muscle in general, with intracellular increase in calcium leading to contraction. However, the stimulating factors for uterine smooth muscle differs from other types of muscles in the body. Removal of Ca2+ after contraction induces relaxation of the smooth muscle, restores the molecular structure of the sarcoplasmic reticulum for the next contractile stimulus. Lack of contraction at this stage is termed uterine atony. After pregnancy the uterus returns to its nonpregnant size by a process of myometrial involution. Benign neoplasms of the myometrium are common, termed uterine leiomyomata or fibroids, their malignant version, leiomyosarcoma, is rare
Cattle—colloquially cows—are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, are most classified collectively as Bos taurus. Cattle are raised as livestock for meat, for milk, for hides, which are used to make leather, they are used as riding animals and draft animals. Another product of cattle is dung, which can be used to create fuel. In some regions, such as parts of India, cattle have significant religious meaning. Cattle small breeds such as the Miniature Zebu, are kept as pets. Around 10,500 years ago, cattle were domesticated from as few as 80 progenitors in central Anatolia, the Levant and Western Iran. According to an estimate from 2011, there are 1.4 billion cattle in the world. In 2009, cattle became one of the first livestock animals to have a mapped genome; some consider cattle the oldest form of wealth, cattle raiding one of the earliest forms of theft. Cattle were identified as three separate species: Bos taurus, the European or "taurine" cattle.
The aurochs is ancestral to both taurine cattle. These have been reclassified as one species, Bos taurus, with three subspecies: Bos taurus primigenius, Bos taurus indicus, Bos taurus taurus. Complicating the matter is the ability of cattle to interbreed with other related species. Hybrid individuals and breeds exist, not only between taurine cattle and zebu, but between one or both of these and some other members of the genus Bos – yaks and gaur. Hybrids such as the beefalo breed can occur between taurine cattle and either species of bison, leading some authors to consider them part of the genus Bos, as well; the hybrid origin of some types may not be obvious – for example, genetic testing of the Dwarf Lulu breed, the only taurine-type cattle in Nepal, found them to be a mix of taurine cattle and yak. However, cattle cannot be hybridized with more distantly related bovines such as water buffalo or African buffalo; the aurochs ranged throughout Europe, North Africa, much of Asia. In historical times, its range became restricted to Europe, the last known individual died in Mazovia, Poland, in about 1627.
Breeders have attempted to recreate cattle of similar appearance to aurochs by crossing traditional types of domesticated cattle, creating the Heck cattle breed. The noun cattle encompasses both sexes; the singular, technically means the female, the male being bull. The plural form cows is sometimes used colloquially to refer to both sexes collectively, as e.g. in a herd, but that usage can be misleading as the speaker's intent may indeed be just the females. The bovine species per se is dimorphic. Cattle did not originate as the term for bovine animals, it was borrowed from Anglo-Norman catel, itself from medieval Latin capitale'principal sum of money, capital', itself derived in turn from Latin caput'head'. Cattle meant movable personal property livestock of any kind, as opposed to real property; the word is a variant of chattel and related to capital in the economic sense. The term replaced earlier Old English feoh ` property', which survives today as fee; the word "cow" came via Anglo-Saxon cū, from Common Indo-European gʷōus = "a bovine animal", compare Persian: gâv, Sanskrit: go-, Welsh: buwch.
The plural cȳ became ki or kie in Middle English, an additional plural ending was added, giving kine, but kies and others. This is the origin of the now archaic English plural, "kine"; the Scots language singular is coo or cou, the plural is "kye". In older English sources such as the King James Version of the Bible, "cattle" refers to livestock, as opposed to "deer" which refers to wildlife. "Wild cattle" may refer to undomesticated species of the genus Bos. Today, when used without any other qualifier, the modern meaning of "cattle" is restricted to domesticated bovines. In general, the same words are used in different parts of the world, but with minor differences in the definitions; the terminology described here contrasts the differences in definition between the United Kingdom and other British-influenced parts of the world such as Canada, New Zealand and the United States. An "intact" adult male is called a bull. A wild, unmarked bull is known as a micky in Australia. An unbranded bovine of either sex is called a maverick in the Canada.
An adult female that has had a calf is a cow. A young female before she has had a calf of her own and is under three years of age is called a heifer. A young female that has had only one calf is called a first-calf heifer. Young cattle of both sexes are called calves until they are weaned weaners until they are a year old in some areas. After that, they are referred to as stirks if between one and two years of age. A castrated male is called a steer in the United States.