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Paper Cut
A paper cut occurs when a piece of paper or other thin, sharp material slices a person's skin, often the upper part of the finger, and often the index finger. Notably, "paper" cuts can also be caused by other thin, stiff, and abrasive materials other than just paper. Paper cuts can be highly painful, even though they may bleed very little, if at all. Although a loose sheet of paper is usually too soft to cut, it can be very thin (sometimes as thin as a razor edge), thus being able to exert high levels of pressure, enough to cause a cut. Paper cuts are most often caused by paper sheets that are strongly fastened together (such as brand new sheet of paper out of a ream), because one single sheet might be dislocated from the rest. Thus all the other sheets are holding this dislocated sheet in position, making it stiff enough to act as a razor. Paper cuts can be painful as they can stimulate a large number of skin surface nociceptors (pain receptors) in a very small area of the skin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paper
Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distributed on the surface, followed by pressing and drying. Although paper was originally made in single sheets by hand, almost all is now made on large machines—some making reels 10 metres wide, running at 2,000 metres per minute and up to 600,000 tonnes a year. It is a versatile material with many uses, including printing, painting, graphics, signage, design, packaging, decorating, writing, and cleaning. It may also be used as filter paper, wallpaper, book endpaper, conservation paper, laminated worktops, toilet tissue, or currency and security paper, or in a number of industrial and construction processes. The papermaking process developed in east Asia, probably China, at least as early as 105 CE, by the Han court eunuch Cai Lun, al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Skin
The human skin is the outer covering of the body and is the largest organ of the integumentary system. The skin has up to seven layers of ectodermal tissue guarding muscles, bones, ligaments and internal organs. Human skin is similar to most of the other mammals' skin, and it is very similar to pig skin. Though nearly all human skin is covered with hair follicles, it can appear hairless. There are two general types of skin, hairy and glabrous skin (hairless). The adjective ''cutaneous'' literally means "of the skin" (from Latin ''cutis'', skin). Because it interfaces with the environment, skin plays an important immunity role in protecting the body against pathogens and excessive water loss. Its other functions are insulation, temperature regulation, sensation, synthesis of vitamin D, and the protection of vitamin B folates. Severely damaged skin will try to heal by forming scar tissue. This is often discoloured and depigmented. In humans, skin pigmentation (a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Finger
A finger is a limb of the body and a type of digit, an organ of manipulation and sensation found in the hands of most of the Tetrapods, so also with humans and other primates. Most land vertebrates have five fingers ( Pentadactyly). Chambers 1998 p. 603 Oxford Illustrated pp. 311, 380 Land vertebrate fingers The five-rayed anterior limbs of terrestrial vertebrates can be derived phylogenetically from the pectoral fins of fish. Within the taxa of the terrestrial vertebrates, the basic pentadactyl plan, and thus also the fingers and phalanges, undergo many variations. Morphologically the different fingers of terrestrial vertebrates are homolog. The wings of birds and those of bats are not homologous, they are analogue flight organs. However, the phalanges within them are homologous. Chimpanzees have lower limbs that are specialized for manipulation, and (arguably) have fingers on their lower limbs as well. In the case of Primates in general, the digits of the hand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Index Finger
The index finger (also referred to as forefinger, first finger, second finger, pointer finger, trigger finger, digitus secundus, digitus II, and many other terms) is the second digit of a human hand. It is located between the thumb and the middle finger. It is usually the most dextrous and sensitive digit of the hand, though not the longest. It is shorter than the middle finger, and may be shorter or longer than the ring finger (see digit ratio). Anatomy " Index finger" literally means "pointing finger", from the same Latin source as '' indicate;'' its anatomical names are "index finger" and "second digit". The index finger has three phalanges. It does not contain any muscles, but is controlled by muscles in the hand by attachments of tendons to the bones. Uses A lone index finger held vertically is often used to represent the number 1 (but finger counting differs across cultures), or when held up or moved side to side (finger-wagging), it can be an admonitory gesture. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Razor
A razor is a bladed tool primarily used in the removal of body hair through the act of shaving. Kinds of razors include straight razors, safety razors, disposable razors, and electric razors. While the razor has been in existence since before the Bronze Age (the oldest razor-like object has been dated to 18,000 BC), the most common types of razors currently used are the safety razor and the electric razor. History Razors have been identified from many Bronze Age cultures. These were made of bronze or obsidian and were generally oval-shaped, with a small tang protruding from one of the short ends.Warwickshire County Council: New Prehistoric Archaeology Objects "Even further away ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pressure
Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and even by industry. Further, both spellings are often used ''within'' a particular industry or country. Industries in British English-speaking countries typically use the "gauge" spelling. is the pressure relative to the ambient pressure. Various #Units, units are used to express pressure. Some of these derive from a unit of force divided by a unit of area; the International System of Units, SI unit of pressure, the Pascal (unit), pascal (Pa), for example, is one newton (unit), newton per square metre (N/m2); similarly, the Pound (force), pound-force per square inch (Pounds per square inch, psi) is the traditional unit of pressure in the imperial units, imperial and United States customary units, U.S. customary systems. Pressure may also be e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paper Ream
Various measures of paper quantity have been and are in use. Although there are no S.I. units such as quires and bales, there are ISO''ISO 4046-3:2002 Paper, board, pulps and related terms – Vocabulary – Part 3: Paper-making terminology'' (2002), quoted in ''ISO 22414:2004(E) Paper – Cut-size office paper – Measurement of edge quality'' (2004) Geneva:ISO. and DIN''Papier und Pappe: DIN 6730:2011-02: Begriffe'' (''Paper and board: vocabulary'') (2011) (in German). Berlin: Beuth Verlag. standards for the ream. Expressions used here include U.S. Customary Units. Units ; Writing paper measurements : 25 sheets = 1 quire : 500 sheets = 20 quires = 1 ream : 1,000 sheets = 40 quires = 2 reams = 1 bundle : 5,000 sheets = 200 quires = 10 reams = 5 bundles = 1 bale : 200,000 sheets = 8,000 quires = 400 reams = 200 bundles = 40 bales = 1 pallet ; 'Short' paper measurements : 24 sheets = 1 'short' quire : 480 sheets = 20 'short' quires = 1 'short' ream : 960 sheets = 40 'short' qui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nociceptor
A nociceptor ("pain receptor" from Latin ''nocere'' 'to harm or hurt') is a sensory neuron that responds to damaging or potentially damaging stimuli by sending "possible threat" signals to the spinal cord and the brain. The brain creates the sensation of pain to direct attention to the body part, so the threat can be mitigated; this process is called nociception. History Nociceptors were discovered by Charles Scott Sherrington in 1906. In earlier centuries, scientists believed that animals were like mechanical devices that transformed the energy of sensory stimuli into motor responses. Sherrington used many different experiments to demonstrate that different types of stimulation to an afferent nerve fiber's receptive field led to different responses. Some intense stimuli trigger reflex withdrawal, certain autonomic responses, and pain. The specific receptors for these intense stimuli were called nociceptors. Location In mammals, nociceptors are found in any area of the body th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bleach
Bleach is the generic name for any chemical product that is used industrially or domestically to remove color (whitening) from a fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers specifically, to a dilute solution of sodium hypochlorite, also called "liquid bleach". Many bleaches have broad spectrum bactericidal properties, making them useful for disinfecting and sterilizing. They are used in swimming pool sanitation to control bacteria, viruses, and algae, and in many places where sterile conditions are required. They are also used in many industrial processes, notably in the bleaching of wood pulp. Bleaches also have other minor uses like removing mildew, killing weeds, and increasing the longevity of cut flowers. Bleaches work by reacting with many colored organic compounds, such as natural pigments, and turning them into colorless ones. While most bleaches are oxidizing agents (chemicals that can remove electrons from othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensory Receptor
Sensory neurons, also known as afferent neurons, are neurons in the nervous system, that convert a specific type of stimulus, via their receptors, into action potentials or graded potentials. This process is called sensory transduction. The cell bodies of the sensory neurons are located in the dorsal ganglia of the spinal cord. The sensory information travels on the afferent nerve fibers in a sensory nerve, to the brain via the spinal cord. The stimulus can come from ''exteroreceptors'' outside the body, for example those that detect light and sound, or from ''interoreceptors'' inside the body, for example those that are responsive to blood pressure or the sense of body position. Types and function Different types of sensory neurons have different sensory receptors that respond to different kinds of stimuli. There are at least six external and two internal sensory receptors: External receptors External receptors that respond to stimuli from outside the body are ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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