Tobacco smoking is the practice of smoking tobacco and inhaling tobacco smoke. The practice is believed to have begun as early as 5000 -- 3000 BC in South America. Tobacco was introduced to Eurasia in the late 17th century by European colonists, where it followed common trade routes; the practice encountered criticism from its first import into the Western world onwards but embedded itself in certain strata of a number of societies before becoming widespread upon the introduction of automated cigarette-rolling apparatus. German scientists identified a link between smoking and lung cancer in the late 1920s, leading to the first anti-smoking campaign in modern history, albeit one truncated by the collapse of Nazi Germany at the end of World War II. In 1950, British researchers demonstrated a clear relationship between cancer. Evidence continued to mount in the 1980s. Rates of consumption declined. However, they continue to climb in the developing world. Smoking is the most common method of consuming tobacco, tobacco is the most common substance smoked.
The agricultural product is mixed with additives and combusted. The resulting smoke is inhaled and the active substances absorbed through the alveoli in the lungs or the oral mucosa. Combustion was traditionally enhanced by addition of potassium or nitrates. Many substances in cigarette smoke trigger chemical reactions in nerve endings, which heighten heart rate and reaction time, among other things. Dopamine and endorphins are released, which are associated with pleasure; as of 2008 to 2010, tobacco is used by about 49% of men and 11% of women aged 15 or older in fourteen low-income and middle-income countries, with about 80% of this usage in the form of smoking. The gender gap tends to be less pronounced in lower age groups. Many smokers begin during early adulthood. During the early stages, a combination of perceived pleasure acting as positive reinforcement and desire to respond to social peer pressure may offset the unpleasant symptoms of initial use, which include nausea and coughing. After an individual has smoked for some years, the avoidance of withdrawal symptoms and negative reinforcement become the key motivations to continue.
A study of first smoking experiences of seventh-grade students found out that the most common factor leading students to smoke is cigarette advertisements. Smoking by parents and friends encourages students to smoke. Smoking's history dates back to as early as 5000–3000 BC, when the agricultural product began to be cultivated in Mesoamerica and South America; the practice worked its way into shamanistic rituals. Many ancient civilizations – such as the Babylonians, the Indians, the Chinese – burnt incense during religious rituals. Smoking in the Americas had its origins in the incense-burning ceremonies of shamans but was adopted for pleasure or as a social tool; the smoking of tobacco and various hallucinogenic drugs was used to achieve trances and to come into contact with the spirit world. To stimulate respiration, tobacco smoke enemas were used. Eastern North American tribes would carry large amounts of tobacco in pouches as a accepted trade item and would smoke it in ceremonial pipes, either in sacred ceremonies or to seal bargains.
Adults as well as children enjoyed the practice. It was believed that tobacco was a gift from the Creator and that the exhaled tobacco smoke was capable of carrying one's thoughts and prayers to heaven. Apart from smoking, tobacco had a number of uses as medicine; as a pain killer it was used for earache and toothache and as a poultice. Smoking was said by the desert Indians to be a cure for colds if the tobacco was mixed with the leaves of the small Desert sage, Salvia dorrii, or the root of Indian balsam or cough root, Leptotaenia multifida, the addition of, thought to be good for asthma and tuberculosis. In 1612, six years after the settlement of Jamestown, John Rolfe was credited as the first settler to raise tobacco as a cash crop; the demand grew as tobacco, referred to as "brown gold", revived the Virginia joint stock company from its failed gold expeditions. In order to meet demands from the Old World, tobacco was grown in succession depleting the soil; this became a motivator to settle west into the unknown continent, an expansion of tobacco production.
Indentured servitude became the primary labor force up until Bacon's Rebellion, from which the focus turned to slavery. This trend abated following the American Revolution as slavery became regarded as unprofitable. However, the practice was revived in 1794 with the invention of the cotton gin. Frenchman Jean Nicot introduced tobacco to France in 1560, tobacco spread to England; the first report of a smoking Englishman is of a sailor in Bristol in 1556, seen "emitting smoke from his nostrils". Like tea and opium, tobacco was just one of many intoxicants, used as a form of medicine. Tobacco was introduced around 1600 by French merchants in what today is modern-day Gambia and Senegal. At the same time, caravans from Morocco brought tobacco to the
Arnold Rice Rich
Arnold Rice Rich was an American pathologist. Born March 28, 1893 in Birmingham, Rich attended the University of Virginia, majoring in biology, the Johns Hopkins Medical School in Baltimore, Maryland from which he received his M. D. degree in 1919. He remained associated with Hopkins the rest of his career, he was appointed Chairman of the Department of Pathology and pathologist-in-chief of the Johns Hopkins Hospital in 1944, until he retired in 1958. Rich had broad interests in medicine. Among his many contributions, he classified jaundice, helped understand the formation of bile pigment, studied the relationship between hypersensitivity and immunity in tuberculosis and discovered the phagocytic function of the Gaucher cell, the hallmark of Gaucher's disease. A number of diseases or conditions are named after Rich, including: Hamman-Rich syndrome and the Rich focus Rich was Jewish. In 1925 he married composer Helen Jones, they had the writer Cynthia Rich. Arnold Rice Rich died April 1968 in Baltimore, Maryland.
Brief biography of Rich in WhoNamedIt? Arnold Rice Rich, A Biographical Memoir by Ella H. Oppenheimer
Louis Virgil Hamman was recognized as one of the great clinicians in his time. He was graduated M. D. from Johns Hopkins and after interning at New York Hospital he returned in 1903 to his alma mater to become head of the new Phipps Tuberculosis Clinic. He said: "The physician, consciously or otherwise, depends for success in his practice on his abilities as a psychiatrist." Conditions which carry his name: Hamman's sign, Hamman's syndrome and Hamman-Rich syndrome
In human anatomy, the head is at the top of the human body. It is maintained by the skull, which itself encloses the brain; the human head consists of a fleshy outer portion. The brain is enclosed within the skull; the head rests on the neck, the seven cervical vertebrae support it. The human head weighs between 5 and 11 pounds The face is the anterior part of the head, containing the eyes and mouth. On either side of the mouth, the cheeks provide a fleshy border to the oral cavity; the ears sit to either side of the head. The head receives blood supply through the external carotid arteries; these supply the area outside of the inside of the skull. The area inside the skull receives blood supply from the vertebral arteries, which travel up through the cervical vertebrae; the twelve pairs of cranial nerves provide the majority of nervous control to the head. The sensation to the face is provided by the branches of the trigeminal nerve, the fifth cranial nerve. Sensation to other portions of the head is provided by the cervical nerves.
Modern texts are in agreement about which areas of the skin are served by which nerves, but there are minor variations in some of the details. The borders designated by diagrams in the 1918 edition of Gray's Anatomy are similar but not identical to those accepted today; the cutaneous innervation of the head is as follows: Ophthalmic nerve Maxillary nerve Mandibular nerve Cervical plexus Dorsal rami of cervical nerves and others are in picture which show following in upper column The head contains sensory organs: two eyes, two ears, a nose and tongue inside of the mouth. It houses the brain. Together, these organs function as a processing center for the body by relaying sensory information to the brain. Humans can process information faster by having this central nerve cluster. For humans, the front of the head is the main distinguishing feature between different people due to its discernible features, such as eye and hair colors, shapes of the sensory organs, the wrinkles. Humans differentiate between faces because of the brain's predisposition toward facial recognition.
When observing a unfamiliar species, all faces seem nearly identical. Human infants are biologically programmed to recognize subtle differences in anthropomorphic facial features. People who have greater than average intelligence are sometimes depicted in cartoons as having bigger heads as a way of notionally indicating that they have a "larger brain". Additionally, in science fiction, an extraterrestrial having a big head is symbolic of high intelligence. Despite this depiction, advances in neurobiology have shown that the functional diversity of the brain means that a difference in overall brain size is only to moderately correlated to differences in overall intelligence between two humans; the head is a source for many metaphors and metonymies in human language, including referring to things near the human head, things physically similar to the way a head is arranged spatially to a body and things that represent some characteristics associated with the head, such as intelligence. Ancient Greeks had a method for evaluating sexual attractiveness based on the Golden ratio, part of which included measurements of the head.
Headpieces can signify status, religious/spiritual beliefs, social grouping, team affiliation, occupation, or fashion choices. In many cultures, covering the head is seen as a sign of respect; some or all of the head must be covered and veiled when entering holy places or places of prayer. For many centuries, women in Europe, the Middle East, South Asia have covered their hair as a sign of modesty; this trend has changed drastically in Europe in the 20th century, although is still observed in other parts of the world. In addition, a number of religions require men to wear specific head clothing—such as the Islamic Taqiyah, Jewish yarmulke, or the Sikh turban; the same goes for Christian nun's habit. A hat is a head covering. Hats may be worn as part of a uniform or used as a protective device, such as a hard hat, a covering for warmth, or a fashion accessory. Hats can be indicative of social status in some areas of the world. While numerous charts detailing head sizes in infants and children exist, most do not measure average head circumference past the age of 21.
Reference charts for adult head circumference generally feature homogeneous samples and fail to take height and weight into account. One study in the United States estimated the average human head circumference to be 55 centimetres in females and 57 centimetres in males. A British study by Newcastle University showed an average size of 55.2 cm for females and 57.2 cm for males with average size varying proportionally with height Macrocephaly can be an indicator of increased risk for some types of cancer in individuals who carry the genetic mutation that causes Cowden syndrome. For adults, this refers to head sizes greater than 58 centimeters in men or greater than 57 centimeters in women. Human body Head and neck anatomy 8. Human head Campbell, Bernard Grant. Human Evolution: An Introduction to Man's Adaptations, 4th edition
Hematoxylin and eosin stain or haematoxylin and eosin stain is one of the principal stains in histology. It is the most used stain in medical diagnosis and is the gold standard. A combination of hematoxylin and eosin, it produces blues and reds; the staining method involves application of hemalum, a complex formed from aluminium ions and hematein. Hemalum colors nuclei of cells blue, along with a few other objects, such as keratohyalin granules and calcified material, which turns blue when exposed to alkaline water; the nuclear staining is followed by counterstaining with an aqueous or alcoholic solution of eosin Y, which colors eosinophilic structures in various shades of red and orange. The staining of nuclei by hemalum is ordinarily due to binding of the dye-metal complex to DNA, but nuclear staining can be obtained after extraction of DNA from tissue sections; the mechanism is different from that of nuclear staining by basic dyes such as thionine or toluidine blue. Staining by basic dyes occurs only from solutions that are less acidic than hemalum, it is prevented by prior chemical or enzymatic extraction of nucleic acids.
There is evidence to indicate that co-ordinate bonds, similar to those that hold aluminium and hematein together, bind the hemalum complex to DNA and to carboxy groups of proteins in the nuclear chromatin. The eosinophilic structures are composed of intracellular or extracellular protein; the Lewy bodies and Mallory bodies are examples of eosinophilic structures. Most of the cytoplasm is eosinophilic. Red blood cells are stained intensely red; the structures do not have to be basic to be called basophilic and eosinophilic. Other colors, e.g. yellow and brown, can be present in the sample. Some structures do not stain well. Basal laminae need to be stained by PAS stain or some silver stains, if they have to be well visible. Reticular fibers require silver stain. Hydrophobic structures tend to remain clear. Hematoxylin is a dark blue or violet stain, basic/positive, it binds to basophilic substances. DNA/RNA in the nucleus, RNA in ribosomes in the rough endoplasmic reticulum are both acidic because the phosphate backbones of nucleic acids are negatively charged.
These backbones form salts with basic dyes containing positive charges. Therefore, dyes stain them violet. Eosin is a red or pink stain, acidic and negative, it binds to acidophilic substances such as positively charged amino-acid side chains. Most proteins in the cytoplasm of some cells are basic because they are positively charged due to the arginine and lysine amino-acid residues; these form salts with acid dyes containing negative charges, like eosin. Therefore, eosin stains them pink; this includes cytoplasmic filaments in muscle cells, intracellular membranes, extracellular fibers. So, in optical microscopy, one can observe: Nuclei in blue/purple Basophils in purplish red Cytoplasm in red Muscles in dark red Erythrocytes in cherry red Collagen in pale pink Mitochondria in pale pink Papanicolaou stain, another popular staining technique Cytopathology Acid-fast Baker JR Experiments on the action of mordants. 2. Aluminium-haematein. Quart. J. Microsc. Sci. 103: 493–517. Kiernan JA Histological and Histochemical Methods: Theory and Practice.
4th ed. Bloxham, UK: Scion. Lillie RD, Pizzolato P, Donaldson PT Nuclear stains with soluble metachrome mordant lake dyes; the effect of chemical endgroup blocking reactions and the artificial introduction of acid groups into tissues. Histochemistry 49: 23–35. Llewellyn BD Nuclear staining with alum-hematoxylin. Biotech. Histochem. 84: 159–177. Marshall PN, Horobin RW The mechanism of action of "mordant" des – a study using preformed metal complexes. Histochemie 35: 361–371. Puchtler H, Meloan SN, Waldrop FS Application of current chemical concepts to metal-haematein and -brazilein stains. Histochemistry 85: 353–364. SIGMA-ALDRICH H&E Informational Primer Routine Mayer's Hematoxylin and Eosin Stain Hematoxylin & Eosin Staining Protocol Rosen Lab, Department of Molecular and Cellular Biology, Baylor College of Medicine) Step by step protocol
A micrograph or photomicrograph is a photograph or digital image taken through a microscope or similar device to show a magnified image of an object. This is opposed to a macrograph or photomacrograph, an image, taken on a microscope but is only magnified less than 10 times. Micrography is the art of using microscopes to make photographs. A micrograph contains extensive details of microstructure. A wealth of information can be obtained from a simple micrograph like behavior of the material under different conditions, the phases found in the system, failure analysis, grain size estimation, elemental analysis and so on. Micrographs are used in all fields of microscopy. A light micrograph or photomicrograph is a micrograph prepared using an optical microscope, a process referred to as photomicroscopy. At a basic level, photomicroscopy may be performed by connecting a camera to a microscope, thereby enabling the user to take photographs at reasonably high magnification. Scientific use began in England in 1850 by Prof Richard Hill Norris FRSE for his studies of blood cells.
Roman Vishniac was a pioneer in the field of photomicroscopy, specializing in the photography of living creatures in full motion. He made major developments in light-interruption photography and color photomicroscopy. Photomicrographs may be obtained using a USB microscope attached directly to a home computer or laptop. An electron micrograph is a micrograph prepared using an electron microscope. Micrographs have micron bars, or magnification ratios, or both. Magnification is a ratio between the size of an object on its real size. Magnification can be a misleading parameter as it depends on the final size of a printed picture and therefore varies with picture size. A scale bar, or micron bar, is a line of known length displayed on a picture; the bar can be used for measurements on a picture. When the picture is resized the bar is resized making it possible to recalculate the magnification. Ideally, all pictures destined for publication/presentation should be supplied with a scale bar. All but one of the micrographs presented on this page do not have a micron bar.
The microscope has been used for scientific discovery. It has been linked to the arts since its invention in the 17th century. Early adopters of the microscope, such as Robert Hooke and Antonie van Leeuwenhoek, were excellent illustrators. After the invention of photography in the 1820s the microscope was combined with the camera to take pictures instead of relying on an artistic rendering. Since the early 1970s individuals have been using the microscope as an artistic instrument. Websites and traveling art exhibits such as the Nikon Small World and Olympus Bioscapes have featured a range of images for the sole purpose of artistic enjoyment; some collaborative groups, such as the Paper Project have incorporated microscopic imagery into tactile art pieces as well as 3D immersive rooms and dance performances. Close-up Digital microscope Macro photography Microphotograph Microscopy USB microscope Make a Micrograph – This presentation by the research department of Children's Hospital Boston shows how researchers create a three-color micrograph.
Shots with a Microscope – a basic, comprehensive guide to photomicrography Scientific photomicrographs – free scientific quality photomicrographs by Doc. RNDr. Josef Reischig, CSc. Micrographs of 18 natural fibres by the International Year of Natural Fibres 2009 Seeing Beyond the Human Eye Video produced by Off Book - Solomon C. Fuller bio Charles Krebs Microscopic Images Dennis Kunkel Microscopy Andrew Paul Leonard, APL Microscopic Cell Centered Database - Montage Nikon Small World Olympus Bioscapes Other examples
A pulmonary alveolus is a hollow cavity found in the lung parenchyma, is the basic unit of ventilation. Lung alveoli are the ends of the respiratory tree, branching from either alveolar sacs or alveolar ducts, which like alveoli are both sites of gas exchange with the blood as well. Alveoli are particular to mammalian lungs. Different structures are involved in gas exchange in other vertebrates; the alveolar membrane is the gas exchange surface. Carbon dioxide rich blood is pumped from the rest of the body into the capillaries that surround the alveoli where, through diffusion, carbon dioxide is released and oxygen is absorbed; the alveoli are located in the respiratory zone of the lungs, at the ends of the alveolar ducts and alveolar sac, representing the smallest units in the respiratory tract. They provide total surface area of about 75m2. A typical pair of human lungs contain about 480 million alveoli; each alveolus is wrapped in a fine mesh of capillaries covering about 70% of its area. An adult alveolus has an average diameter of 200 µm, with an increase in diameter during inhalation.
The alveoli consist of an epithelial layer and an extracellular matrix surrounded by small blood vessels called capillaries. In some alveolar walls there are pores between alveoli called Pores of Kohn; the alveoli contain elastic fibers. The elastic fibres allow the alveoli to stretch, they spring back during exhalation in order to expel the carbon dioxide-rich air. There are three major types of cell in the alveolar wall: two types of alveolar cell and a large phagocyte known as an alveolar macrophage. Type I cells form the structure of the alveoli. Type I alveolar cells are squamous and cover 90–95% of the alveolar surface. Type I cells are involved in the process of gas exchange between blood; these cells are thin – the electron microscope was needed to prove that all alveoli are covered with an epithelial lining. These cells need to be so thin to be permeable for enabling an easy gas exchange between the alveoli and the blood. Organelles of type I alveolar cells such as the endoplasmic reticulum, Golgi apparatus and mitochondria are clustered around the nucleus.
The nuclei occupy large areas of free cytoplasm. This reduces the thickness of the cell; the cytoplasm in the thin portion contains pinocytotic vesicles which may play a role in the removal of small particulate contaminants from the outer surface. In addition to desmosomes, all type I alveolar cells have occluding junctions that prevent the leakage of tissue fluid into the alveolar air space. Type I pneumocytes are susceptible to toxic insults. In the event of damage, type II cells can proliferate and differentiate into type I cells to compensate. Type II cells secrete pulmonary surfactant to lower the surface tension of water and allows the membrane to separate, therefore increasing its capability to exchange gases; the surfactant is continuously released by exocytosis. It forms an underlying aqueous protein-containing hypophase and an overlying phospholipid film composed of dipalmitoyl phosphatidylcholine. Type II alveolar cells cover a small fraction of the alveolar surface area. Type II cells are capable of cellular division, giving rise to more type I and II alveolar cells when the lung tissue is damaged.
These cells are granular and cuboidal. Type II alveolar cells are found at the blood-air barrier. Although they only make up <5% of the alveolar surface, they are numerous. The alveolar macrophages called dust cells, destroy foreign materials and microbes such as bacteria. Type I cells are flat cells lining the alveolar walls; each alveolus is surrounded by numerous capillaries, is the site of gas exchange, which occurs by diffusion. The low solubility of oxygen necessitates the large internal surface area and thin walls of the alveoli. Weaving between the capillaries and helping to support them is an extracellular matrix, a meshlike fabric of elastic and collagenous fibres; the collagen fibres, being more rigid, give the wall firmness, while the elastic fibres permit expansion and contraction of the walls during breathing. Type II cells in the alveolar wall contain secretory granular organelles known as lamellar bodies that fuse with the cell membranes and secrete pulmonary surfactant; this surfactant is a film of fatty substances, a group of phospholipids that reduce alveolar surface tension.
The phospholipid are stored in the lamellar bodies. Without this coating, the alveoli would collapse and large forces would be required to re-expand them. Type II cells start to develop at about 26 weeks of gestation, secreting small amounts of surfactant. However, adequate amounts of surfactant are not secreted until about 35 weeks of gestation - this is the main reason for increased rates of infant respiratory distress syndrome, which drastically reduces at ages above 35 weeks gestation. Type II pneumocytes will replicate to replace damaged type I cells. MUC1, a human gene associated with type II pneumocytes, has been identified as a marker in lung cancer. Another type of cell, known as an alveolar macrophage, resides on the internal surfaces of the air cavities of the alveoli, the alveolar ducts, the bronchioles, they are mobile scavengers that serve to engulf