Perspiration , also known as sweat , is the fluid secreted by sweat glands in the skin of mammals .
108-496: Two types of sweat glands can be found in humans: eccrine glands and apocrine glands . The eccrine sweat glands are distributed over much of the body and are responsible for secreting the watery, brackish sweat most often triggered by excessive body temperature. Apocrine sweat glands are restricted to the armpits and a few other areas of the body and produce an odorless, oily, opaque secretion which then gains its characteristic odor from bacterial decomposition. In humans , sweating
216-415: A Rasmussen aneurysm , resulting in massive bleeding. Tuberculosis may become a chronic illness and cause extensive scarring in the upper lobes of the lungs. The upper lung lobes are more frequently affected by tuberculosis than the lower ones. The reason for this difference is not clear. It may be due to either better air flow, or poor lymph drainage within the upper lungs. In 15–20% of active cases,
324-432: A duct . There are two main types of sweat glands that differ in their structure, function, secretory product, mechanism of excretion, anatomic distribution, and distribution across species: Ceruminous glands (which produce ear wax), mammary glands (which produce milk ), and ciliary glands in the eyelids are modified apocrine sweat glands. Generally, sweat glands consist of a secretory unit that produces sweat, and
432-460: A 1:20 ratio of follicles with apocrine glands versus follicles without. They have eccrine glands between hairs over most of their body (while humans have them between the hairs on their scalp ). The overall distribution of sweat glands varies among primates: the rhesus and patas monkeys have them on the chest; the squirrel monkey has them only on the palms and soles; and the stump-tailed macaque , Japanese monkey , and baboon have them over
540-627: A combination of glycoproteins that either bind directly to, or prevent the binding of microbes to, the skin and seem to form part of the innate immune system . In 2001, researchers at Eberhard-Karls University in Tübingen, Germany , isolated a large protein called dermcidin from skin. This protein, which could be cleaved into other antimicrobial peptides , was shown to be effective at killing some species of bacteria and fungi that affect humans, including Escherichia coli , Enterococcus faecalis , Staphylococcus aureus , and Candida albicans . It
648-560: A common ancestor, remains unclear. A comparison of the genes of M. tuberculosis complex (MTBC) in humans to MTBC in animals suggests humans did not acquire MTBC from animals during animal domestication, as researchers previously believed. Both strains of the tuberculosis bacteria share a common ancestor, which could have infected humans even before the Neolithic Revolution . Skeletal remains show some prehistoric humans (4000 BC ) had TB, and researchers have found tubercular decay in
756-515: A decrease in core temperature through evaporative cooling at the skin surface. As high energy molecules evaporate from the skin, releasing energy absorbed from the body, the skin and superficial vessels decrease in temperature. Cooled venous blood then returns to the body's core and counteracts rising core temperatures. There are two situations in which the nerves will stimulate the sweat glands, causing perspiration: during physical heat and during emotional stress. In general, emotionally induced sweating
864-448: A duct that carries the sweat away. The secretory coil or base, is set deep in the lower dermis and hypodermis , and the entire gland is surrounded by adipose tissue . In both sweat gland types, the secretory coils are surrounded by contractile myoepithelial cells that function to facilitate excretion of secretory product. The secretory activities of the gland cells and the contractions of myoepithelial cells are controlled by both
972-440: A large role in axillary sweating. Apoeccrine glands are sensitive to cholinergic activity, though they can also be activated via adrenergic stimulation. Like eccrine glands, they continuously secrete a thin, watery sweat. Specialized sweat glands, including the ceruminous glands , mammary glands , ciliary glands of the eyelids, and sweat glands of the nasal vestibulum , are modified apocrine glands. Ceruminous glands are near
1080-680: A microscope. Since MTB retains certain stains even after being treated with acidic solution, it is classified as an acid-fast bacillus . The most common acid-fast staining techniques are the Ziehl–Neelsen stain and the Kinyoun stain , which dye acid-fast bacilli a bright red that stands out against a blue background. Auramine-rhodamine staining and fluorescence microscopy are also used. The M. tuberculosis complex (MTBC) includes four other TB-causing mycobacteria : M. bovis , M. africanum , M. canettii , and M. microti . M. africanum
1188-439: A narrow portion similar to secretory coils in eccrine glands as well as a wide section reminiscent of apocrine glands. Apoeccrine glands, found in the armpits and perianal region, have ducts opening onto the skin surface. They are presumed to have developed in puberty from the eccrine glands, and can comprise up to 50% of all axillary glands. Apoeccrine glands secrete more sweat than both eccrine and apocrine glands, thus playing
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#17328588276081296-549: A small amount (0.2–1%) of solute . When a person moves from a cold climate to a hot climate, adaptive changes occur in the sweating mechanisms of the person. This process is referred to as acclimatization : the maximum rate of sweating increases and its solute composition decreases. The volume of water lost in sweat daily is highly variable, ranging from 100 to 8,000 millilitres per day (0.041 to 3.259 imp fl oz/ks). The solute loss can be as much as 350 mmol/d (or 90 mmol/d acclimatised) of sodium under
1404-407: A small decrease in case numbers. Some countries have legislation to involuntarily detain or examine those suspected to have tuberculosis, or involuntarily treat them if infected. The only available vaccine as of 2021 is bacillus Calmette-Guérin (BCG). In children it decreases the risk of getting the infection by 20% and the risk of infection turning into active disease by nearly 60%. It
1512-401: A tuberculosis infection does become active, it most commonly involves the lungs (in about 90% of cases). Symptoms may include chest pain and a prolonged cough producing sputum. About 25% of people may not have any symptoms (i.e., they remain asymptomatic). Occasionally, people may cough up blood in small amounts, and in very rare cases, the infection may erode into the pulmonary artery or
1620-474: A wide range of symptoms. Tuberculosis is spread from one person to the next through the air when people who have active TB in their lungs cough, spit, speak, or sneeze . People with latent TB do not spread the disease. Active infection occurs more often in people with HIV/AIDS and in those who smoke . Diagnosis of active TB is based on chest X-rays , as well as microscopic examination and culture of bodily fluids. Diagnosis of latent TB relies on
1728-398: Is Mycobacterium tuberculosis (MTB), a small, aerobic , nonmotile bacillus . The high lipid content of this pathogen accounts for many of its unique clinical characteristics. It divides every 16 to 20 hours, which is an extremely slow rate compared with other bacteria, which usually divide in less than an hour. Mycobacteria have an outer membrane lipid bilayer. If a Gram stain
1836-404: Is a non-specific symptom or sign, which means that it has many possible causes. Some causes of diaphoresis include physical exertion, menopause , fever, ingestion of toxins or irritants, and high environmental temperature. Strong emotions (anger, fear, anxiety) and recall of past trauma can also trigger sweating. This is sometimes referred to as flop sweat. The vast majority of sweat glands in
1944-497: Is a classic symptom of a pheochromocytoma , a rare tumor of the adrenal gland . Acetylcholinesterase inhibitors (e.g. some insecticides ) also cause contraction of sweat gland smooth muscle leading to diaphoresis. Mercury is well known for its use as a diaphoretic, and was widely used in the 19th and early 20th century by physicians to "purge" the body of an illness. However, due to the high toxicity of mercury, secondary symptoms would manifest, which were erroneously attributed to
2052-491: Is a growing problem, with increasing rates of multiple drug-resistant tuberculosis (MDR-TB). In 2018, one quarter of the world's population was thought to have a latent infection of TB. New infections occur in about 1% of the population each year. In 2022, an estimated 10.6 million people developed active TB, resulting in 1.3 million deaths, making it the second leading cause of death from an infectious disease after COVID-19 . As of 2018, most TB cases occurred in
2160-445: Is able to reproduce inside the macrophage and will eventually kill the immune cell. The primary site of infection in the lungs, known as the Ghon focus , is generally located in either the upper part of the lower lobe, or the lower part of the upper lobe . Tuberculosis of the lungs may also occur via infection from the blood stream. This is known as a Simon focus and is typically found in
2268-613: Is accompanied by unexplained weight loss , fever / chills , or by palpitations , shortness of breath , unconsciousness , fatigue , dizziness , muscle pain , nausea , vomiting , diarrhea , and chest discomfort, it suggests serious illness. Diaphoresis is also seen in an acute myocardial infarction (heart attack), from the increased firing of the sympathetic nervous system , and is frequent in serotonin syndrome , which can result in serious sickness or even death. Diaphoresis can also be caused by many types of infections, often accompanied by high fever and/or chills which can trigger
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#17328588276082376-653: Is also rare and is seen almost only in immunodeficient people, although its prevalence may be significantly underestimated. Other known pathogenic mycobacteria include M. leprae , M. avium , and M. kansasii . The latter two species are classified as " nontuberculous mycobacteria " (NTM) or atypical mycobacteria. NTM cause neither TB nor leprosy , but they do cause lung diseases that resemble TB. When people with active pulmonary TB cough, sneeze, speak, sing, or spit, they expel infectious aerosol droplets 0.5 to 5.0 μm in diameter. A single sneeze can release up to 40,000 droplets. Each one of these droplets may transmit
2484-533: Is another common area for hyperhidrosis to be an issue. Sweating uncontrollably is not always expected and may be embarrassing to people with the condition. It can cause both physiological and emotional problems in patients. It is generally inherited. It is not life-threatening, but it is threatening to a person's quality of life. Treatments for hyperhidrosis include antiperspirants , iontophoresis, and surgical removal of sweat glands. In severe cases, botulinum toxin injections or surgical cutting of nerves that stimulate
2592-425: Is created by apocrine glands and contains a wetting agent, the protein latherin which transfers from the skin to the surface of their coats. Sweat contributes to body odor when it is metabolized by bacteria on the skin . Medications that are used for other treatments and diet also affect odor. Some medical conditions, such as kidney failure and diabetic ketoacidosis , can also affect sweat odor. Diaphoresis
2700-444: Is difficult, as is diagnosing the disease in those who have a weakened immune system. A diagnosis of TB should, however, be considered in those with signs of lung disease or constitutional symptoms lasting longer than two weeks. A chest X-ray and multiple sputum cultures for acid-fast bacilli are typically part of the initial evaluation. Interferon-γ release assays (IGRA) and tuberculin skin tests are of little use in most of
2808-416: Is directly controlled by the hypothalamus . Thermal sweating is stimulated by a combination of internal body temperature and mean skin temperature. In eccrine sweat glands, stimulation occurs via activation by acetylcholine , which binds to the gland's muscarinic receptors . Emotional sweating is stimulated by stress, anxiety, fear, and pain; it is independent of ambient temperature. Acetylcholine acts on
2916-432: Is likely to increase because the body must exert more energy to function and there is more body mass to cool down. On the other hand, a fit person will start sweating earlier and more readily. As someone becomes fit, the body becomes more efficient at regulating the body's temperature and sweat glands adapt along with the body's other systems. Human sweat is not pure water ; though it contains no protein, it always contains
3024-455: Is mostly water, but it does contain some electrolytes , since it is derived from blood plasma . The presence of sodium chloride gives sweat a salty taste. The total volume of sweat produced depends on the number of functional glands and the size of the surface opening. The degree of secretory activity is regulated by neural and hormonal mechanisms (men sweat more than women). When all of the eccrine sweat glands are working at maximum capacity,
3132-500: Is not widespread, but it is a significant cause of tuberculosis in parts of Africa. M. bovis was once a common cause of tuberculosis, but the introduction of pasteurized milk has almost eliminated this as a public health problem in developed countries. M. canettii is rare and seems to be limited to the Horn of Africa , although a few cases have been seen in African emigrants. M. microti
3240-479: Is often used to screen people at high risk for TB. Those who have been previously immunized with the Bacille Calmette-Guerin vaccine may have a false-positive test result. The test may be falsely negative in those with sarcoidosis , Hodgkin's lymphoma , malnutrition , and most notably, active tuberculosis. Interferon gamma release assays , on a blood sample, are recommended in those who are positive to
3348-507: Is oily, cloudy, viscous, and originally odorless; it gains odor upon decomposition by bacteria. Because both apocrine glands and sebaceous glands open into the hair follicle, apocrine sweat is mixed with sebum . Both apocrine and eccrine sweat glands use merocrine secretion , where vesicles in the gland release sweat via exocytosis , leaving the entire cell intact. It was originally thought that apocrine sweat glands use apocrine secretion due to histological artifacts resembling "blebs" on
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3456-501: Is performed, MTB either stains very weakly "Gram-positive" or does not retain dye as a result of the high lipid and mycolic acid content of its cell wall. MTB can withstand weak disinfectants and survive in a dry state for weeks. In nature, the bacterium can grow only within the cells of a host organism, but M. tuberculosis can be cultured in the laboratory . Using histological stains on expectorated samples from phlegm (also called sputum), scientists can identify MTB under
3564-423: Is poor as of 2019 . The Centers for Disease Control and Prevention (CDC) stopped recommending yearly testing of health care workers without known exposure in 2019. Tuberculosis prevention and control efforts rely primarily on the vaccination of infants and the detection and appropriate treatment of active cases. The World Health Organization (WHO) has achieved some success with improved treatment regimens, and
3672-429: Is primarily a means of thermoregulation , which is achieved by the water-rich secretion of the eccrine glands. Maximum sweat rates of an adult can be up to 2–4 litres (0.53–1.06 US gal) per hour or 10–14 litres (2.6–3.7 US gal) per day, but is less in children prior to puberty. Evaporation of sweat from the skin surface has a cooling effect due to evaporative cooling . Hence, in hot weather, or when
3780-483: Is restricted to palms , soles , armpits , and sometimes the forehead , while physical heat-induced sweating occurs throughout the body. People have an average of two to four million sweat glands, but how much sweat is released by each gland is determined by many factors, including sex, genetics, environmental conditions, age and fitness level. Two of the major contributors to sweat rate are an individual's fitness level and weight. If an individual weighs more, sweat rate
3888-424: Is small enough to make sweat hypotonic at the skin surface. Eccrine sweat is clear, odorless, and is composed of 98–99% water; it also contains NaCl , fatty acids , lactic acid , citric acid , ascorbic acid , urea, and uric acid . Its pH ranges from 4 to 6.8. On the other hand, the apocrine sweat has a pH of 6 to 7.5; it contains water, proteins, carbohydrate waste material, lipids, and steroids . The sweat
3996-464: Is termed caseous necrosis . If TB bacteria gain entry to the blood stream from an area of damaged tissue, they can spread throughout the body and set up many foci of infection, all appearing as tiny, white tubercles in the tissues. This severe form of TB disease, most common in young children and those with HIV, is called miliary tuberculosis. People with this disseminated TB have a high fatality rate even with treatment (about 30%). In many people,
4104-476: Is the most widely used vaccine worldwide, with more than 90% of all children being vaccinated. The immunity it induces decreases after about ten years. As tuberculosis is uncommon in most of Canada, Western Europe, and the United States, BCG is administered to only those people at high risk. Part of the reasoning against the use of the vaccine is that it makes the tuberculin skin test falsely positive, reducing
4212-442: The epidermal ridges . There are no pores between the ridges, though sweat tends to spill into them. The thick epidermis of the palms and soles causes the sweat glands to become spirally coiled. Non-primate mammals have eccrine sweat glands only on the palms and soles. Apocrine glands cover the rest of the body, though they are not as effective as humans' in temperature regulation (with the exception of horses '). Prosimians have
4320-623: The keratin fibrils in the ducts; the ducts then close and form a "horny plug". The main active ingredients in modern antiperspirants are aluminum chloride , aluminum chlorohydrate , aluminum zirconium chlorohydrate, and buffered aluminum sulfate . On apocrine glands, antiperspirants also contain antibacterial agents such as trichlorocarbanilide , hexamethylene tetramine , and zinc ricinoleate . The salts are dissolved in ethanol and mixed with essential oils high in eugenol and thymol (such as thyme and clove oils). Antiperspirants may also contain levomethamphetamine . Some diseases of
4428-434: The lungs , but it can also affect other parts of the body. Most infections show no symptoms, in which case it is known as latent tuberculosis . Around 10% of latent infections progress to active disease that, if left untreated, kill about half of those affected. Typical symptoms of active TB are chronic cough with blood-containing mucus , fever , night sweats , and weight loss . Infection of other organs can cause
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4536-454: The lymphatic system (in scrofula of the neck), the genitourinary system (in urogenital tuberculosis ), and the bones and joints (in Pott disease of the spine), among others. A potentially more serious, widespread form of TB is called "disseminated tuberculosis"; it is also known as miliary tuberculosis . Miliary TB currently makes up about 10% of extrapulmonary cases. The main cause of TB
4644-420: The tuberculin skin test (TST) or blood tests. Prevention of TB involves screening those at high risk, early detection and treatment of cases, and vaccination with the bacillus Calmette-Guérin (BCG) vaccine. Those at high risk include household, workplace, and social contacts of people with active TB. Treatment requires the use of multiple antibiotics over a long period of time. Antibiotic resistance
4752-543: The German anatomist Karl Krause. Sweat glands were first separated into kinds by the French histologist Louis-Antoine Ranvier , who separated them in 1887 regarding their type of secretion into holocrine glands ( sebaceous glands ) and the merocrine glands (sweat glands), the latter were then in 1917 divided into apocrine and eccrine sweat glands. In 1987, apoeccrine glands were identified. Eccrine sweat glands are everywhere except
4860-693: The Mantoux test. These are not affected by immunization or most environmental mycobacteria , so they generate fewer false-positive results. However, they are affected by M. szulgai , M. marinum , and M. kansasii . IGRAs may increase sensitivity when used in addition to the skin test, but may be less sensitive than the skin test when used alone. The US Preventive Services Task Force (USPSTF) has recommended screening people who are at high risk for latent tuberculosis with either tuberculin skin tests or interferon-gamma release assays . While some have recommend testing health care workers, evidence of benefit for this
4968-511: The United States test positive via the tuberculin test. Tuberculosis has been present in humans since ancient times . Tuberculosis has existed since antiquity . The oldest unambiguously detected M. tuberculosis gives evidence of the disease in the remains of bison in Wyoming dated to around 17,000 years ago. However, whether tuberculosis originated in bovines, then transferred to humans, or whether both bovine and human tuberculosis diverged from
5076-601: The WHO regions of South-East Asia (44%), Africa (24%), and the Western Pacific (18%), with more than 50% of cases being diagnosed in seven countries: India (27%), China (9%), Indonesia (8%), the Philippines (6%), Pakistan (6%), Nigeria (4%), and Bangladesh (4%). By 2021, the number of new cases each year was decreasing by around 2% annually. About 80% of people in many Asian and African countries test positive, while 5–10% of people in
5184-584: The acrid odor. Apocrine sweat glands are most active in times of stress and sexual excitement. In mammals (including humans), apocrine sweat contains pheromone -like compounds to attract other organisms within their species. Study of human sweat has revealed differences between men and women in apocrine secretions and bacteria. Some human sweat glands cannot be classified as either apocrine or eccrine, having characteristics of both; such glands are termed apoeccrine . They are larger than eccrine glands, but smaller than apocrine glands. Their secretory portion has
5292-688: The active disease. Use of certain medications, such as corticosteroids and infliximab (an anti-αTNF monoclonal antibody), is another important risk factor, especially in the developed world . Other risk factors include: alcoholism , diabetes mellitus (3-fold increased risk), silicosis (30-fold increased risk), tobacco smoking (2-fold increased risk), indoor air pollution , malnutrition, young age, recently acquired TB infection, recreational drug use, severe kidney disease, low body weight, organ transplant, head and neck cancer, and genetic susceptibility (the overall importance of genetic risk factors remains undefined ). Tobacco smoking increases
5400-458: The arrival of streptomycin and other antibiotics, although the disease remained a significant threat. In 1946, the development of the antibiotic streptomycin made effective treatment and cure of TB a reality. Prior to the introduction of this medication, the only treatment was surgical intervention, including the " pneumothorax technique", which involved collapsing an infected lung to "rest" it and to allow tuberculous lesions to heal. Because of
5508-529: The autonomic nervous system and by the circulating hormones. The distal or apical part of the duct that opens to the skin's surface is known as the acrosyringium . Each sweat gland receives several nerve fibers that branch out into bands of one or more axons and encircle the individual tubules of the secretory coil. Capillaries are also interwoven among sweat tubules. The number of active sweat glands varies greatly among different people, though comparisons between different areas (ex. axillae vs. groin) show
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#17328588276085616-423: The bacterium is enveloped by the macrophage and stored temporarily in a membrane-bound vesicle called a phagosome. The phagosome then combines with a lysosome to create a phagolysosome. In the phagolysosome, the cell attempts to use reactive oxygen species and acid to kill the bacterium. However, M. tuberculosis has a thick, waxy mycolic acid capsule that protects it from these toxic substances. M. tuberculosis
5724-552: The body are innervated by sympathetic cholinergic neurons. Sympathetic postganglionic neurons typically secrete norepinephrine and are named sympathetic adrenergic neurons; however, the sympathetic postganglionic neurons that innervate sweat glands secrete acetylcholine and hence are termed sympathetic cholinergic neurons. Sweat glands, piloerector muscles, and some blood vessels are innervated by sympathetic cholinergic neurons. Diaphoresis may be associated with some abnormal conditions, such as hyperthyroidism and shock. If it
5832-425: The cattle and human tuberculosis diseases were similar, which delayed the recognition of infected milk as a source of infection. During the first half of the 1900s, the risk of transmission from this source was dramatically reduced after the application of the pasteurization process. Koch announced a glycerine extract of the tubercle bacilli as a "remedy" for tuberculosis in 1890, calling it "tuberculin". Although it
5940-480: The cause of pulmonary tuberculosis. J. L. Schönlein first published the name "tuberculosis" (German: Tuberkulose ) in 1832. Between 1838 and 1845, John Croghan, the owner of Mammoth Cave in Kentucky from 1839 onwards, brought a number of people with tuberculosis into the cave in the hope of curing the disease with the constant temperature and purity of the cave air; each died within a year. Hermann Brehmer opened
6048-449: The cell surface, however, recent electron micrographs indicate that the cells use merocrine secretion. In both apocrine and eccrine sweat glands, the sweat is originally produced in the gland's coil, where it is isotonic with the blood plasma there. When the rate of sweating is low, salt is conserved and reabsorbed by the gland's duct; high sweat rates, on the other hand, lead to less salt reabsorption and allow more water to evaporate on
6156-700: The declaration of a global health emergency by the World Health Organization (WHO) in 1993. There is a popular misconception that tuberculosis is purely a disease of the lungs that manifests as coughing . Tuberculosis may infect many organs, even though it most commonly occurs in the lungs (known as pulmonary tuberculosis). Extrapulmonary TB occurs when tuberculosis develops outside of the lungs, although extrapulmonary TB may coexist with pulmonary TB. General signs and symptoms include fever, chills , night sweats, loss of appetite , weight loss, and fatigue . Significant nail clubbing may also occur. If
6264-640: The developing world. IGRA have similar limitations in those with HIV. A definitive diagnosis of TB is made by identifying M. tuberculosis in a clinical sample (e.g., sputum, pus , or a tissue biopsy ). However, the difficult culture process for this slow-growing organism can take two to six weeks for blood or sputum culture. Thus, treatment is often begun before cultures are confirmed. Nucleic acid amplification tests and adenosine deaminase testing may allow rapid diagnosis of TB. Blood tests to detect antibodies are not specific or sensitive , so they are not recommended. The Mantoux tuberculin skin test
6372-596: The disease became common among the urban poor. In 1815, one in four deaths in England was due to "consumption". By 1918, TB still caused one in six deaths in France. After TB was determined to be contagious, in the 1880s, it was put on a notifiable-disease list in Britain. Campaigns started to stop people from spitting in public places, and the infected poor were "encouraged" to enter sanatoria that resembled prisons. The sanatoria for
6480-620: The disease, since the infectious dose of tuberculosis is very small (the inhalation of fewer than 10 bacteria may cause an infection). People with prolonged, frequent, or close contact with people with TB are at particularly high risk of becoming infected, with an estimated 22% infection rate. A person with active but untreated tuberculosis may infect 10–15 (or more) other people per year. Transmission should occur from only people with active TB – those with latent infection are not thought to be contagious. The probability of transmission from one person to another depends upon several factors, including
6588-614: The duct (see Fig. 9 of the reference). Many other trace elements are also excreted in sweat, again an indication of their concentration is (although measurements can vary fifteenfold) zinc ( 0.4 milligrams/litre ), copper ( 0.3–0.8 mg/L ), iron ( 1 mg/L ), chromium ( 0.1 mg/L ), nickel ( 0.05 mg/L ), and lead ( 0.05 mg/L ). Probably many other less-abundant trace minerals leave the body through sweating with correspondingly lower concentrations. Some exogenous organic compounds make their way into sweat as exemplified by an unidentified odiferous "maple syrup" scented compound in several of
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#17328588276086696-404: The ear canals, and produce cerumen (earwax) that mixes with the oil secreted from sebaceous glands . Mammary glands use apocrine secretion to produce milk. Sweat glands are used to regulate temperature and remove waste by secreting water, sodium salts , and nitrogenous waste (such as urea) onto the skin surface. The main electrolytes of sweat are sodium and chloride , though the amount
6804-463: The eccrine glands and adrenaline acts on both eccrine and apocrine glands to produce sweat. Emotional sweating can occur anywhere, though it is most evident on the palms, soles of the feet, and axillary regions. Sweating on the palms and soles is thought to have evolved as a fleeing reaction in mammals: it increases friction and prevents slipping when running or climbing in stressful situations. Gustatory sweating refers to thermal sweating induced by
6912-440: The eccrine sweat gland provides details on what solutes partition into sweat, their mechanisms of partitioning, and their fluidic transport to the skin surface. Dissolved in the water are trace amounts of minerals , lactic acid , and urea . Although the mineral content varies, some measured concentrations are: sodium ( 0.9 gram/litre ), potassium ( 0.2 g/L ), calcium ( 0.015 g/L ), and magnesium ( 0.0013 g/L ). Relative to
7020-463: The emergence of multidrug-resistant tuberculosis (MDR-TB), surgery has been re-introduced for certain cases of TB infections. It involves the removal of infected chest cavities ("bullae") in the lungs to reduce the number of bacteria and to increase exposure of the remaining bacteria to antibiotics in the bloodstream. Hopes of eliminating TB ended with the rise of drug-resistant strains in the 1980s. The subsequent resurgence of tuberculosis resulted in
7128-594: The entire body. Domestic animals have apocrine glands at the base of each hair follicle, but eccrine glands only in foot pads and snout. Their apocrine glands, like those in humans, produce an odorless oily milky secretion evolved not to evaporate and cool but rather coat and stick to hair so odor-causing bacteria can grow on it. Eccrine glands on their foot pads, like those on palms and soles of humans, did not evolve to cool either but rather increase friction and enhance grip. Dogs and cats have apocrine glands that are specialized in both structure and function located at
7236-434: The environment". Some of the underlying medical conditions and infections that cause these severe night sweats can be life-threatening and should promptly be investigated by a medical practitioner. Sweating allows the body to regulate its temperature. Sweating is controlled from a center in the preoptic and anterior regions of the brain's hypothalamus , where thermosensitive neurons are located. The heat-regulatory function of
7344-421: The excessive sweating ( endoscopic thoracic sympathectomy ) may be an option. Night sweats, also known as nocturnal hyperhidrosis, is the occurrence of excessive sweating during sleep. The person may or may not also perspire excessively while awake. One of the most common causes of night sweats in women over 40 is the hormonal changes related to menopause and perimenopause. This is a very common occurrence during
7452-517: The eyelids ( Moll's glands ), ears ( ceruminous glands ), anal sac , clitoral hood , and circumanal area . The pores of eccrine sweat pores were first identified by the Italian physiologist Marcello Malpighi . Sweat glands themselves were first discovered by the Czech physiologist, Johannes Purkinjé in 1833. The differing densities of sweat glands in different body regions was first investigated in 1844 by
7560-541: The first TB sanatorium in 1859 in Görbersdorf (now Sokołowsko ) in Silesia . In 1865, Jean Antoine Villemin demonstrated that tuberculosis could be transmitted, via inoculation, from humans to animals and among animals. (Villemin's findings were confirmed in 1867 and 1868 by John Burdon-Sanderson . ) Robert Koch identified and described the bacillus causing tuberculosis, M. tuberculosis , on 24 March 1882. In 1905, he
7668-615: The first genuine success in immunization against tuberculosis in 1906, using attenuated bovine-strain tuberculosis. It was called bacille Calmette–Guérin (BCG). The BCG vaccine was first used on humans in 1921 in France, but achieved widespread acceptance in the US, Great Britain, and Germany only after World War II. By the 1950s mortality in Europe had decreased about 90%. Improvements in sanitation, vaccination, and other public-health measures began significantly reducing rates of tuberculosis even before
7776-417: The former disease that was being treated with mercurials. Infantile acrodynia (childhood mercury poisoning) is characterized by excessive perspiration. A clinician should immediately consider acrodynia in an afebrile child who is sweating profusely. Some people can develop a sweat allergy . The allergy is not due to the sweat itself but instead to an allergy-producing protein secreted by bacteria found on
7884-431: The host's immune system. Macrophages and dendritic cells in the granulomas are unable to present antigen to lymphocytes; thus the immune response is suppressed. Bacteria inside the granuloma can become dormant, resulting in latent infection. Another feature of the granulomas is the development of abnormal cell death ( necrosis ) in the center of tubercles . To the naked eye, this has the texture of soft, white cheese and
7992-455: The hypothalamus is also affected by inputs from temperature receptors in the skin . High skin temperature reduces the hypothalamic set point for sweating and increases the gain of the hypothalamic feedback system in response to variations in core temperature . Overall, however, the sweating response to a rise in hypothalamic ('core') temperature is much larger than the response to the same increase in average skin temperature. Sweating causes
8100-466: The individual's muscles heat up due to exertion, more sweat is produced. Animals with few sweat glands, such as dogs , accomplish similar temperature regulation results by panting, which evaporates water from the moist lining of the oral cavity and pharynx . Although sweating is found in a wide variety of mammals, relatively few (apart from humans, horses , some primates and some bovidae ) produce sweat in order to cool down. In horses, such cooling sweat
8208-400: The infected macrophages. When other macrophages attack the infected macrophage, they fuse together to form a giant multinucleated cell in the alveolar lumen. The granuloma may prevent dissemination of the mycobacteria and provide a local environment for interaction of cells of the immune system. However, more recent evidence suggests that the bacteria use the granulomas to avoid destruction by
8316-439: The infection spreads outside the lungs, causing other kinds of TB. These are collectively denoted as extrapulmonary tuberculosis. Extrapulmonary TB occurs more commonly in people with a weakened immune system and young children. In those with HIV, this occurs in more than 50% of cases. Notable extrapulmonary infection sites include the pleura (in tuberculous pleurisy), the central nervous system (in tuberculous meningitis ),
8424-613: The infection waxes and wanes. Tissue destruction and necrosis are often balanced by healing and fibrosis . Affected tissue is replaced by scarring and cavities filled with caseous necrotic material. During active disease, some of these cavities are joined to the air passages ( bronchi ) and this material can be coughed up. It contains living bacteria and thus can spread the infection. Treatment with appropriate antibiotics kills bacteria and allows healing to take place. Upon cure, affected areas are eventually replaced by scar tissue. Diagnosing active tuberculosis based only on signs and symptoms
8532-757: The ingestion of food. The increase in metabolism caused by ingestion raises body temperature, leading to thermal sweating. Hot and spicy foods also lead to mild gustatory sweating in the face, scalp and neck: capsaicin (the compound that makes spicy food taste "hot"), binds to receptors in the mouth that detect warmth. The increased stimulation of such receptors induces a thermoregulatory response. Unlike deodorant , which simply reduces axillary odor without affecting body functions, antiperspirant reduces both eccrine and apocrine sweating. Antiperspirants, which are classified as drugs, cause proteins to precipitate and mechanically block eccrine (and sometimes apocrine) sweat ducts. The metal salts found in antiperspirants alters
8640-425: The lathering that often occurs on the coats of sweating horses, especially when rubbed. In hot conditions, horses during three hours of moderate-intensity exercise can lose 30 to 35 litres (6.6 to 7.7 imp gal; 7.9 to 9.2 US gal) of water and 100 grams (3.5 oz) of sodium, 198 grams (7.0 oz) of chloride and 45 grams (1.6 oz) of potassium. Sweat is mostly water . A microfluidic model of
8748-487: The life from the other family members. Although Richard Morton established the pulmonary form associated with tubercles as a pathology in 1689, due to the variety of its symptoms, TB was not identified as a single disease until the 1820s. Benjamin Marten conjectured in 1720 that consumptions were caused by microbes which were spread by people living close to each other. In 1819, René Laennec claimed that tubercles were
8856-410: The lips, ear canal , foreskin , glans penis , labia minora , clitoral hood , and clitoris . They are ten times smaller than apocrine sweat glands, do not extend as deeply into the dermis, and excrete directly onto the surface of the skin. The proportion of eccrine glands decreases with age. The clear secretion produced by eccrine sweat glands is termed sweat or sensible perspiration . Sweat
8964-547: The menopausal transition years. While night sweats might be relatively harmless, it can also be a sign of a serious underlying disease. It is important to distinguish night sweats due to medical causes from those that occur simply because the sleep environment is too warm, either because the bedroom is unusually hot or because there are too many covers on the bed. Night sweats caused by a medical condition or infection can be described as "severe hot flashes occurring at night that can drench sleepwear and sheets, which are not related to
9072-525: The middle and upper classes offered excellent care and constant medical attention. What later became known as the Alexandra Hospital for Children with Hip Disease (tuberculous arthritis) was opened in London in 1867. Whatever the benefits of the "fresh air" and labor in the sanatoria, even under the best conditions, 50% of those who entered died within five years ( c. 1916). Robert Koch did not believe
9180-401: The most abundant minerals and metabolites in sweat. There is interest in its use in wearable technology . Sweat can be sampled and sensed non-invasively and continuously using electronic tattoos, bands, or patches. However, sweat as a diagnostic fluid presents numerous challenges as well, such as very small sample volumes and filtration (dilution) of larger-sized hydrophilic analytes. Currently
9288-444: The most extreme conditions. During average intensity exercise, sweat losses can average up to 2 litres (0.44 imp gal; 0.53 US gal) of water/hour. In a cool climate and in the absence of exercise , sodium loss can be very low (less than 5 mmol/d). Sodium concentration in sweat is 30–65 mmol/L, depending on the degree of acclimatisation. Horses have a thick, waterproofed, hairy coat that would normally block
9396-596: The newly infected person becomes infectious enough to transmit the disease to others. A number of factors make individuals more susceptible to TB infection and/or disease. The most important risk factor globally for developing active TB is concurrent HIV infection; 13% of those with TB are also infected with HIV. This is a particular problem in sub-Saharan Africa , where HIV infection rates are high. Of those without HIV infection who are infected with tuberculosis, about 5–10% develop active disease during their lifetimes; in contrast, 30% of those co-infected with HIV develop
9504-599: The number of infectious droplets expelled by the carrier, the effectiveness of ventilation, the duration of exposure, the virulence of the M. tuberculosis strain , the level of immunity in the uninfected person, and others. The cascade of person-to-person spread can be circumvented by segregating those with active ("overt") TB and putting them on anti-TB drug regimens. After about two weeks of effective treatment, subjects with nonresistant active infections generally do not remain contagious to others. If someone does become infected, it typically takes three to four weeks before
9612-480: The only major commercial application for sweat diagnostics is for infant cystic fibrosis testing based on sweat chloride concentrations. Sweat gland Sweat glands , also known as sudoriferous or sudoriparous glands , from Latin sudor 'sweat', are small tubular structures of the skin that produce sweat . Sweat glands are a type of exocrine gland , which are glands that produce and secrete substances onto an epithelial surface by way of
9720-447: The plasma and extracellular fluid, the concentration of Na ions is much lower in sweat (~40 mM in sweat versus ~150 mM in plasma and extracellular fluid). Initially, within eccrine glands sweat has a high concentration of Na ions. In the sweat ducts, the Na ions are re-absorbed into tissue by epithelial sodium channels (ENaC) that are located on the apical membrane of epithelial cells that form
9828-447: The rapid translocation of sweat water from the skin to the surface of the hair required for evaporative cooling. To solve this, horses have evolved a detergent-like protein, latherin , that they release at high concentrations in their sweat. Their perspiration unlike humans is created by apocrine glands. This protein, by wetting the horses' coat hairs facilitate water flow for cooling evaporation. The presence of this protein can be seen in
9936-458: The rate of perspiration for a human being may exceed three liters per hour, and dangerous losses of fluids and electrolytes can occur. Eccrine glands have three primary functions: Apocrine sweat glands are found in the armpit, areola (around the nipples), perineum (between the anus and genitals), in the ear, and the eyelids. The secretory portion is larger than that of eccrine glands (making them larger overall). Rather than opening directly onto
10044-902: The result of hyperthermia . Most infections can cause some degree of diaphoresis and it is a very common symptom in some serious infections such as malaria and tuberculosis . In addition, pneumothorax can cause diaphoresis with splinting of the chest wall. Neuroleptic malignant syndrome and other malignant diseases (e.g. leukemias) can also cause diaphoresis. Diabetics relying on insulin shots or oral medications may have low blood sugar ( hypoglycemia ), which can also cause diaphoresis. Drugs (including caffeine , morphine , alcohol , antidepressants and certain antipsychotics) may be causes, as well as withdrawal from alcohol , benzodiazepines , nonbenzodiazepines or narcotic painkiller dependencies. Sympathetic nervous system stimulants such as cocaine and amphetamines have also been associated with diaphoresis. Diaphoresis due to ectopic catecholamine
10152-435: The risk of developing active TB increases to nearly 10% a year. If effective treatment is not given, the death rate for active TB cases is up to 66%. TB infection begins when the mycobacteria reach the alveolar air sacs of the lungs, where they invade and replicate within endosomes of alveolar macrophages . Macrophages identify the bacterium as foreign and attempt to eliminate it by phagocytosis . During this process,
10260-414: The risk of infections (in addition to increasing the risk of active disease and death). Additional factors increasing infection susceptibility include young age. About 90% of those infected with M. tuberculosis have asymptomatic , latent TB infections (sometimes called LTBI), with only a 10% lifetime chance that the latent infection will progress to overt, active tuberculous disease. In those with HIV,
10368-437: The same directional changes (certain areas always have more active sweat glands while others always have fewer). According to Henry Gray 's estimates, the palm has around 370 sweat glands per cm ; the back of the hand has 200 per cm ; the forehead has 175 per cm ; the breast, abdomen, and forearm have 155 per cm ; and the back and legs have 60–80 per cm . In the finger pads, sweat glands pores are somewhat irregularly spaced on
10476-597: The skin (via osmosis ) to increase evaporative cooling . Secretion of sweat occurs when the myoepithelial cell cells surrounding the secretory glands contract. Eccrine sweat increases the rate of bacterial growth and volatilizes the odor compounds of apocrine sweat, strengthening the latter's acrid smell. Normally, only a certain number of sweat glands are actively producing sweat. When stimuli call for more sweating, more sweat glands are activated, with each then producing more sweat. Both eccrine and apocrine sweat glands participate in thermoregulatory sweating, which
10584-401: The skin. Tannic-acid has been found to suppress the allergic response along with showering. Millions of people are affected by hyperhidrosis , but more than half never receive treatment due to embarrassment, lack of awareness, or lack of concern. While it most commonly affects the armpits , feet, and hands, it is possible for someone to experience this condition over their whole body. The face
10692-406: The species in the mushroom genus Lactarius . In humans, sweat is hypoosmotic relative to plasma (i.e. less concentrated ). Sweat is found at moderately acidic to neutral pH levels, typically between 4.5 and 7.0. Sweat contains many glycoproteins . Sweat may serve an antimicrobial function, like that of earwax or other secretory fluids (e.g., tears, saliva, and milk). It does this through
10800-535: The spines of Egyptian mummies dating from 3000 to 2400 BC. Genetic studies suggest the presence of TB in the Americas from about AD 100. Before the Industrial Revolution , folklore often associated tuberculosis with vampires . When one member of a family died from the disease, the other infected members would lose their health slowly. People believed this was caused by the original person with TB draining
10908-408: The surface of the skin, apocrine glands secrete sweat into the pilary canal of the hair follicle . Before puberty, the apocrine sweat glands are inactive; hormonal changes in puberty cause the glands to increase in size and begin functioning. The substance secreted is thicker than eccrine sweat and provides nutrients for bacteria on the skin: the bacteria's decomposition of sweat is what creates
11016-431: The sweat glands include: Sweat gland tumors include: Adenolipomas are lipomas associated with eccrine sweat glands. Many diseases cause sweat gland dysfunction: Tuberculosis Tuberculosis ( TB ), also known colloquially as the " white death ", or historically as consumption , is an infectious disease usually caused by Mycobacterium tuberculosis (MTB) bacteria . Tuberculosis generally affects
11124-465: The test's usefulness as a screening tool. Several vaccines are being developed. Intradermal MVA85A vaccine in addition to BCG injection is not effective in preventing tuberculosis. Public health campaigns which have focused on overcrowding, public spitting and regular sanitation (including hand washing) during the 1800s helped to either interrupt or slow spread which when combined with contact tracing, isolation and treatment helped to dramatically curb
11232-565: The top of the lung. This hematogenous transmission can also spread infection to more distant sites, such as peripheral lymph nodes, the kidneys, the brain, and the bones. All parts of the body can be affected by the disease, though for unknown reasons it rarely affects the heart , skeletal muscles , pancreas , or thyroid . Tuberculosis is classified as one of the granulomatous inflammatory diseases. Macrophages , epithelioid cells , T lymphocytes , B lymphocytes , and fibroblasts aggregate to form granulomas, with lymphocytes surrounding
11340-462: The transmission of both tuberculosis and other airborne diseases which led to the elimination of tuberculosis as a major public health issue in most developed economies. Other risk factors which worsened TB spread such as malnutrition were also ameliorated, but since the emergence of HIV a new population of immunocompromised individuals was available for TB to infect. During the HIV/AIDS epidemic in
11448-410: Was active at high salt concentrations and in the acidity range of human sweat, where it was present at concentrations of 1–10 mg/ml. Artificial skin capable of sweating similar to natural sweat rates and with the surface texture and wetting properties of regular skin has been developed for research purposes. Artificial perspiration is also available for in-vitro testing, and contains 19 amino acids and
11556-514: Was awarded the Nobel Prize in Physiology or Medicine for this discovery. In Europe, rates of tuberculosis began to rise in the early 1600s to a peak level in the 1800s, when it caused nearly 25% of all deaths. In the 18th and 19th century, tuberculosis had become epidemic in Europe , showing a seasonal pattern. Tuberculosis caused widespread public concern in the 19th and early 20th centuries as
11664-468: Was not effective, it was later successfully adapted as a screening test for the presence of pre-symptomatic tuberculosis. World Tuberculosis Day is marked on 24 March each year, the anniversary of Koch's original scientific announcement. When the Medical Research Council formed in Britain in 1913, it initially focused on tuberculosis research. Albert Calmette and Camille Guérin achieved
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