How many sweat glands are there in the human body?



Humans have 2,000,000 to 5,000,000 eccrine sweat glands, with an average distribution of 150 to 340 per square centimetre. They are most numerous on the palms and soles and then, in decreasing order, on the head, trunk, and extremities. Some individuals have more glands than others, but there is no difference in number between men and women.



The specific function of sweat glands is to secrete water upon the surface so that it can cool the skin when it evaporates. The purpose of the glands on the palms and soles, however, is to keep these surfaces damp, to prevent flaking or hardening of the horny layer, and thus to maintain tactile sensibility. A dry hand does not grip well and is minimally sensitive.



The glands on the palms and soles develop at about 3 1/2 months of gestation, whereas those in the hairy skin are the last skin organs to take shape, appearing at five to 5 1/2 months, when all the other structures are already formed. This separation of events over time may represent a fundamental difference in the evolutionary history of the two types of glands. Those on palms and soles, which appear first and are present in all but the hooved mammals, may be more ancient; those in the hairy skin, which respond to thermal stimuli, may be more recent organs.



 



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What is gustatory sweating?



Gustatory sweating is sweating that occurs on the forehead, scalp, neck, and upper lip while eating, talking, or thinking about food.



Gustatory sweating can occur for no apparent reason or as a result of an underlying condition, such as diabetes or Parkinson’s disease. These diseases can also cause damage to the nerves in the mouth. When the nerves become injured, they can become confused and cause sweating.



Gustatory sweating may cause some people distress, as thinking about food can trigger the reactions of sweating. Since there is often an underlying cause, a person should talk to their doctor to find out what may be causing the sweating.



People do not necessarily need to see a doctor after sweating from eating food. Those who only sweat while eating either very hot or spicy foods have no reason to be concerned.



Some people who experience Frey’s syndrome may consider it to be a nuisance but do not consider it significant enough to seek help.



 



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Sweat is made of 99% water. What is the remaining 1%?



A body has between two and four million sweat glands lying deep in the skin. They are connected to the surface by coiled tubes called ducts. You perspire constantly, even without exercise. Sweat is a liquid made from 99% water and 1% salt and fat. Up to a quart of sweat evaporates each day.



When your body becomes overheated, you sweat more. The evaporation of sweat from your skin cools your body down.



When you're frightened or nervous (imagine being pinned under heavy weights) you also sweat more. Your palms and forehead begin to sweat. So do the soles of your feet and your armpits. These are sites where sweat glands are most abundant.



So why do you smell when you sweat? You may notice the smell mostly comes from our pits (hence why we put deodorant there). This is because the apocrine glands produce the bacteria that break down our sweat into “scented” fatty acids.



“Apocrine sweat by itself does not have an odor, but when the bacteria that lives on our skin mixes with apocrine secretions, it can produce a foul-smelling odor,” Haimovic says.



 



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What is perspiration?



Perspiration, also known as sweating, is the production of fluids secreted by the sweat glands in the skin of mammals.



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. The 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.



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. Areas that produce excessive sweat usually appear pink or white, but, in severe cases, may appear cracked, scaly, and soft.



 



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What disease in children do Rotavirus vaccines address?



Rotavirus spreads easily among infants and young children. The virus can cause severe watery diarrhea, vomiting, fever, and abdominal pain. Children who get rotavirus disease can become dehydrated and may need to be hospitalized.



Good hygiene like handwashing and cleanliness are important, but are not enough to control the spread of the disease. Rotavirus vaccine is the best way to protect your child against rotavirus disease. Most children (about 9 out of 10) who get the vaccine will be protected from severe rotavirus disease. About 7 out of 10 children will be protected from rotavirus disease of any severity.



Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how severe the condition is. Antibiotics are not used to treat this illness. Medicines for diarrhea are also not recommended. Some healthcare providers may recommend probiotics. But their effectiveness is unclear.



The goal of treatment is to help reduce symptoms. Treatment may include:




  • Giving your child plenty of water, formula, breastmilk, or fluids with electrolytes (sugars and salts). Don't give young children soda, juice, or sports drinks.

  • Feeding your child solid foods if he or she can eat. Don’t restrict food if your child is able to eat. Not having food may cause the diarrhea to last longer.



If your child loses too much water, he or she may need to be in the hospital. Treatment there may include:




  • Intravenous (IV) fluids.  A thin, flexible tube is put into your child’s vein. Fluids are given through this tube.

  • Blood tests. These are done to measure the levels of sugar, salt, and other chemicals (electrolytes) in your child’s blood.



 



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Which was the first disease against which vaccination was developed?



The story of vaccines did not begin with the first vaccine–Edward Jenner’s use of material from cowpox pustules to provide protection against smallpox. Rather, it begins with the long history of infectious disease in humans, and in particular, with early uses of smallpox material to provide immunity to that disease.



Evidence exists that the Chinese employed smallpox inoculation (or variolation, as such use of smallpox material was called) as early as 1000 CE. It was practiced in Africa and Turkey as well, before it spread to Europe and the Americas.



Edward Jenner’s innovations, begun with his successful 1796 use of cowpox material to create immunity to smallpox, quickly made the practice widespread. His method underwent medical and technological changes over the next 200 years, and eventually resulted in the eradication of smallpox.



Louis Pasteur’s 1885 rabies vaccine was the next to make an impact on human disease. And then, at the dawn of bacteriology, developments rapidly followed. Antitoxins and vaccines against diphtheria, tetanus, anthrax, cholera, plague, typhoid, tuberculosis, and more were developed through the 1930s.



The middle of the 20th century was an active time for vaccine research and development. Methods for growing viruses in the laboratory led to rapid discoveries and innovations, including the creation of vaccines for polio. Researchers targeted other common childhood diseases such as measles, mumps, and rubella, and vaccines for these diseases reduced the disease burden greatly.



Innovative techniques now drive vaccine research, with recombinant DNA technology and new delivery techniques leading scientists in new directions. Disease targets have expanded, and some vaccine research is beginning to focus on non-infectious conditions such as addiction and allergies.



 



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Who is known as the father of vaccinology?



Edward Jenner was an English physician and scientist who pioneered the concept of vaccines including creating the smallpox vaccine, the world's first vaccine. The terms vaccine and vaccination are derived from Variolae vaccinae (smallpox of the cow), the term devised by Jenner to denote cowpox. He used it in 1798 in the long title of his Inquiry into the Variolae vaccinae known as the Cow Pox, in which he described the protective effect of cowpox against smallpox.



He still remembered the Bristol milkmaid's remark and acquired the reputation of a bore because of his constant harping on cowpox and its preventive use. Eventually, and totally unethically, he took lymph from a pustule on the hand of a milkmaid and inoculated a healthy child, who developed cowpox in the normal fashion but proved immune to subsequent inoculation with smallpox. Both the medical profession and the Royal Society were hostile to these unorthodox practices so Jenner published his observations in 1798 and travelled to London to publicize them. His reception was so unenthusiastic that he returned to Gloucestershire leaving some lymph with Mr Cline, a surgeon at St Thomas's Hospital. Cline used it to inoculate a child who also proved immune to a later attempt at smallpox inoculation and this popularized the practice.



 



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Which part of a girl’s body produces and releases eggs at the mid-point of each menstrual cycle?



The ovaries form part of the female reproductive system. Each woman has two ovaries. They are oval in shape, about four centimetres long and lie on either side of the womb (uterus) against the wall of the pelvis in a region known as the ovarian fossa. They are held in place by ligaments attached to the womb but are not directly attached to the rest of the female reproductive tract, e.g. the fallopian tubes.  



The major hormones secreted by the ovaries are oestrogen and progesterone, both important hormones in the menstrual cycle. Oestrogen production dominates in the first half of the menstrual cycle before ovulation, and progesterone production dominates during the second half of the menstrual cycle when the corpus luteum has formed. Both hormones are important in preparing the lining of the womb for pregnancy and the implantation of a fertilised egg, or embryo.



If conception occurs during any one menstrual cycle, the corpus luteum does not lose its ability to function and continues to secrete oestrogen and progesterone, allowing the embryo to implant in the lining of the womb and form a placenta. At this point, development of the foetus begins. 



 



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Which are group hormones that primarily influence the growth and development of the male reproductive system?



Androgen, any of a group of hormones that primarily influence the growth and development of the male reproductive system. The predominant and most active androgen is testosterone, which is produced by the male testes.



In males the interstitial cells of Leydig, located in the connective tissue surrounding the sperm-producing tubules of the testes, are responsible for the production and secretion of testosterone. In male animals that breed only seasonally, such as migratory birds and sheep, Leydig cells are prevalent in the testes during the breeding season but diminish considerably in number during the nonbreeding season. The actual secretion of androgens by these cells is controlled by luteinizing hormone (LH) from the pituitary gland.



The adrenal production of androgens is of importance to several physiological processes. Certain adrenal androgens—androstenedione, dehydroepiandrosterone (DHEA), and dehydroepiandrosterone sulfate (DHEA sulfate)—can be converted to testosterone in other tissues.



 



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Which gland in the hypothalamus of your brain is responsible for releasing special hormones that trigger the onset of puberty?



The hypothalamus is a small but important area in the center of the brain. It plays an important role in hormone production and helps to stimulate many important processes in the body and is located in the brain, between the pituitary gland and thalamus.



The hypothalamus is responsible for the regulation of certain metabolic processes and other activities of the autonomic nervous system. It synthesizes and secretes certain neurohormones, called releasing hormones or hypothalamic hormones, and these in turn stimulate or inhibit the secretion of hormones from the pituitary gland. The hypothalamus controls body temperature, hunger, important aspects of parenting and attachment behaviours, thirst, fatigue, sleep, and circadian rhythms.



The hypothalamus is a divided into 3 regions (supraoptic, tuberal, mammillary) in a parasagittal plane, indicating location anterior-posterior; and 3 areas (periventricular, medial, lateral) in the coronal plane, indicating location medial-lateral. Hypothalamic nuclei are located within these specific regions and areas. It is found in all vertebrate nervous systems. In mammals, magnocellular neurosecretory cells in the paraventricular nucleus and the supraoptic nucleus of the hypothalamus produce neurohypophysial hormones, oxytocin and vasopressin. These hormones are released into the blood in the posterior pituitary. Much smaller parvocellular neurosecretory cells, neurons of the paraventricular nucleus, release corticotropin-releasing hormone and other hormones into the hypophyseal portal system, where these hormones diffuse to the anterior pituitary.



 



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Who is Govind Swarup, and how is he connected to radio telescopes?



Govind Swarup was a radio astronomer and one of the pioneers of radio astronomy, known not only for his many important research contributions in several areas of astronomy and astrophysics, but also for his outstanding achievements in building ingenious, innovative and powerful observational facilities for front-line research in radio astronomy. He was the key scientist behind concept, design and installation of the Ooty Radio Telescope (India) and the Giant Metrewave Radio Telescope (GMRT) near Pune. Under his leadership, a strong group in radio astrophysics has been built at Tata Institute of Fundamental Research that is comparable to the best in the world.



Prof Swarup was born in Thakurdwara, now in the state of Uttar Pradesh, on March 23, 1929. He obtained his undergraduate education at Allahabad University and then joined the National Physical Laboratory in Delhi. After a stint in Australia building telescopes at Pott’s Hill near Sydney, Prof Swarup moved to the US, where he obtained a PhD from Stanford University. At the back of his mind, always, was the thought to return to India to establish the newly emerging field of radio astronomy.



Initially he joined National Physical laboratory for two years. Returning from Stanford to India in March 1963, he joined TIFR as a Reader at the request of Dr. Homi Bhabha. In 1965, he became Associate Professor, Professor in 1970, and Professor of Eminence in 1989. He became Project Director of the GMRT in 1987, Centre Director of the National Centre for Radio Astrophysics (NCRA) of TIFR in 1993 and retired from TIFR in 1994.



 



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Who is Jocelyn Bell, and how is she linked to Radio Astronomy?



Dame Susan Jocelyn Bell Burnell is an astrophysicist from Northern Ireland who, as a postgraduate student, discovered the first radio pulsars in 1967.[9] She was credited with "one of the most significant scientific achievements of the 20th century".



Burnell was a PhD student at Cambridge at the time and was working with her supervisor Hewish to make radio observations of the universe. She ended up discovering a pulsar using a vast radio telescope occupying an area of 4.5 acres that was designed by Hewish and joined him and the team of five when the construction of the telescope was about to begin. The telescope was built to measure the random brightness flickers of a different category of celestial objects called quasars.



The telescope took over two years to build and the team started operating it in July 1967. As per Burnell, she had the sole responsibility of operating the telescope and analysing its data output, which amounted to 96-feet of chart paper everyday, which she analysed by hand.



In the 1977 article, titled, “Little Green Men, White Dwarfs or Pulsars?”, Burnell wrote that the story of the discovery of pulsars began in the middle of 1960s when the technique of interplanetary scintillation (IPS) was discovered. This technique involved the fluctuation in the emission of radio signals from a compact radio source such as a quasar and was chosen by Hewish to pick out quasars. While analysing the telescope’s output, Burnell saw that there were unexpected markings on the chart that were recorded approximately every 1.33 seconds.



 



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Who is considered to be the founder of the field called Radio Astronomy?



Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The first detection of radio waves from an astronomical object was in 1932, when Karl Jansky at Bell Telephone Laboratories observed radiation coming from the Milky Way. Subsequent observations have identified a number of different sources of radio emission. These include stars and galaxies, as well as entirely new classes of objects, such as radio galaxies, quasars, pulsars, and masers. The discovery of the cosmic microwave background radiation, regarded as evidence for the Big Bang theory, was made through radio astronomy.



Radio astronomers use different techniques to observe objects in the radio spectrum. Instruments may simply be pointed at an energetic radio source to analyze its emission. To "image" a region of the sky in more detail, multiple overlapping scans can be recorded and pieced together in a mosaic image. The type of instrument used depends on the strength of the signal and the amount of detail needed.



Observations from the Earth's surface are limited to wavelengths that can pass through the atmosphere. At low frequencies, or long wavelengths, transmission is limited by the ionosphere, which reflects waves with frequencies less than its characteristic plasma frequency. Water vapor interferes with radio astronomy at higher frequencies, which has led to building radio observatories that conduct observations at millimeter wavelengths at very high and dry sites, in order to minimize the water vapor content in the line of sight. Finally, transmitting devices on earth may cause radio-frequency interference. Because of this, many radio observatories are built at remote places.



 



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What are pulsars used for?



Pulsars are spherical, compact objects that are about the size of a large city but contain more mass than the sun. Scientists are using pulsars to study extreme states of matter, search for planets beyond Earth's solar system and measure cosmic distances. Pulsars also could help scientists find gravitational waves, which could point the way to energetic cosmic events like collisions between supermassive black holes. Discovered in 1967, pulsars are fascinating members of the cosmic community. 



Pulsars radiate two steady, narrow beams of light in opposite directions. Although the light from the beam is steady, pulsars appear to flicker because they also spin. It's the same reason a lighthouse appears to blink when seen by a sailor on the ocean: As the pulsar rotates, the beam of light may sweep across the Earth, then swing out of view, then swing back around again. To an astronomer on the ground, the light goes in and out of view, giving the impression that the pulsar is blinking on and off. The reason a pulsar's light beam spins around like a lighthouse beam is that the pulsar's beam of light is typically not aligned with the pulsar's axis of rotation.



Some pulsars also prove extremely useful because of the precision of their pulses. There are many known pulsars that blink with such precise regularity; they are considered the most accurate natural clocks in the universe. As a result, scientists can watch for changes in a pulsar's blinking that could indicate something happening in the space nearby. 



It was with this method that scientists began to identify the presence of alien planets orbiting these dense objects. In fact, the first planet outside Earth's solar system ever found was orbiting a pulsar. 



Because pulsars are moving through space while also blinking a regular number of times per second, scientists can use many pulsars to calculate cosmic distances. The changing position of the pulsar means the light it emits takes more or less time to reach Earth. Thanks to the exquisite timing of the pulses, scientists have made some of the most accurate distance measurements of cosmic objects.



 



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The Arecibo Observatory, a massive telescope, collapsed on December 1, 2020. What kind of a telescope was it?



The Arecibo Observatory in Puerto Rico has collapsed, after weeks of concern from scientists over the fate of what was once the world's largest single-dish radio telescope.



The telescope was built in the early 1960s, with the intention of studying the ionised upper part of Earth's atmosphere, the ionosphere. But it was soon being used as an all-purpose radio observatory.



Radio astronomy is a field within the larger discipline that observes objects in the Universe by studying them at radio frequencies. A number of cosmic phenomena such as pulsars - magnetised, rotating stars - show emission at radio wavelengths.



The observatory provided the first solid evidence for a type of object known as a neutron star. It was also used to identify the first example of a binary pulsar (two magnetised neutron stars orbiting around a common centre of mass), which earned its discoverers the Nobel Prize in Physics.



The telescope helped to make the first definitive detection of exoplanets, planetary bodies orbiting other stars, in 1992.



It has also been used to listen for signals from intelligent life elsewhere in the cosmos and to track near-Earth asteroids.



Over the years, the main dish appeared as a location in movies, including GoldenEye, Pierce Brosnan's first outing as James Bond in 1995, and the 1997 science fiction drama Contact, starring Jodie Foster and Matthew McConaughey.



 



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