Sunday, April 27, 2008

Human Anatomy

Human anatomy is primarily the scientific study of the morphology of the adult human body.Anatomy is subdivided into gross anatomy and microscopic anatomy.Gross anatomy (also called topographical anatomy, regional anatomy, or anthropotomy) is the study of anatomical structures that can be seen by unaided vision.Microscopic anatomy is the study of minute anatomical structures assisted with microscopes, which includes histology (the study of the organization of tissues),and cytology (the study of cells). Anatomy, physiology (the study of function) and biochemistry (the study of the chemistry of living structures) are complementary basic medical sciences where are usually tought together (or in tandem).
In some of its facets human anatomy is closely related to embryology, comparative anatomy and comparative embryology, through common roots in evolution; for example, much of the human body maintains the ancient segmental pattern that is present in all vertebrates with basic units being repeated, which is particularly obvious in the vertebral column and in the ribcage, and can be traced from very early embryos.
The human body consists of biological systems, that consist of organs, that consist of tissues, that consist of cells and connective tissue.
The history of anatomy has been characterized, over time, by a continually developing understanding of the functions of organs and structures in the body. Methods have also advanced dramatically, advancing from examination of animals through dissection of preserved cadavers (dead human bodies) to technologically complex techniques developed in the 20th century

Evolution

In biology, evolution is the process of change in the inherited traits of a population of organisms from one generation to the next. The genes that are passed on to an organism's offspring produce the inherited traits that are the basis of evolution. Mutations in genes can produce new or altered traits in individuals, resulting in the appearance of heritable differences between organisms, but new traits also come from the transfer of genes between populations, as in migration, or between species, in horizontal gene transfer. In species that reproduce sexually, new combinations of genes are produced by genetic recombination, which can increase the variation in traits between organisms. Evolution occurs when these heritable differences become more common or rare in a population.
There are two major mechanisms driving evolution. The first is natural selection, which is a process causing heritable traits that are helpful for survival and reproduction to become more common in a population, and harmful traits to become more rare. This occurs because individuals with advantageous traits are more likely to reproduce successfully, so that more individuals in the next generation inherit these traits. Over many generations, adaptations occur through a combination of successive, small, random changes in traits, and natural selection of those variants best-suited for their environment.In contrast, genetic drift produces random changes in the frequency of traits in a population. Genetic drift results from the role chance plays in whether a given individual will survive and reproduce. Though the changes produced in any one generation by drift and selection are small, differences accumulate with each subsequent generation and can, over time, cause substantial changes in the organisms.
One definition of a species is a group of organisms that can reproduce with one another and produce fertile offspring. When a species is separated into populations that are prevented from interbreeding, mutations, genetic drift, and natural selection cause the accumulation of differences over generations and the emergence of new species The similarities between organisms suggest that all known species are descended from a common ancestor (or ancestral gene pool) through this process of gradual divergence.

Human Body

The human body is the entire physical structure of a human organism. The human body consists of a head, neck, torso, two arms and two legs. The average height of an adult human is about 1.7 m (5 to 6 feet) tall. This size is largely determined by genes. Body type and body composition are influenced by postnatal factors such as diet and exercise. By the time the human reaches adult-hood, the body consists of close to 100 trillion cells. Each is part of an organ system designed to perform essential life functions. The body's organ systems include: the circulatory system, immune system, respiratory system, digestive system, excretory system, urinary system, musculoskeletal system, nervous system, endocrine system and the male and / or female reproductive system.
The human body is often called a "body". The body of a dead person is called a "corpse" or "cadaver

Biochemistry

Biochemistry is the study of the chemical processes in living organisms. It deals with the structure and function of cellular components, such as proteins, carbohydrates, lipids, nucleic acids, and other biomolecules. Chemical biology aims to answer many questions arising from biochemistry by using tools developed within chemical synthesis.
Although there are a vast number of different biomolecules, many are complex and large molecules (called polymers) that are composed of similar repeating subunits (called monomers). Each class of polymeric biomolecule has a different set of subunit types. For example, a protein is a polymer made up of 20 or more amino acids. Biochemistry studies the chemical properties of important biological molecules, like proteins, in particular the chemistry of enzyme-catalyzed reactions.
The biochemistry of cell metabolism and the endocrine system has been extensively described. Other areas of biochemistry include the genetic code (DNA, RNA), protein synthesis, cell membrane transport, and signal transduction.
This article only discusses terrestrial biochemistry (carbon- and water-based), as all the life forms we know are on Earth. Since life forms alive today descended from the same common ancestor, they have similar biochemistries, even for matters that seem to be

History Of Anatomy

The history of anatomy as a science extends from the earliest examinations of sacrificial victims to the sophisticated analyses of the body performed by modern scientists. It has been characterized, over time, by a continually developing understanding of the functions of organs and structures in the body. The field of Human Anatomy has a prestigious history, and is considered to be the most prominent of the biological sciences of the 19th and early 20th centuries. Methods have also advanced dramatically, advancing from examination of animals through dissection of cadavers to technologically complex techniques developed in the 20th century.

Physiology

Physiology talk about the nature (of things)") is the study of the mechanical, physical, and biochemical functions of living organisms.
Physiology has traditionally been divided between plant physiology and animal physiology but the principles of physiology are universal, no matter what particular organism is being studied. For example, what is learned about the physiology of yeast cells may also apply to human cells.
The field of animal physiology extends the tools and methods of human physiology to non-human animal species. Plant physiology also borrows techniques from both fields. Its scope of subjects is at least as diverse as the tree of life itself. Due to this diversity of subjects, research in animal physiology tends to concentrate on understanding how physiological traits changed throughout the evolutionary history of animals. Other major branches of scientific study that have grown out of physiology research include biochemistry, biophysics, paleobiology, biomechanics, and pharmacology

Histology

Histology is the study of tissue sectioned as a thin slice, using a microtome. It can be described as microscopic anatomy. The photographing of stained cells is called histography. Histology is an essential tool of biology.
Histopathology, the microscopic study of diseased tissue, is an important tool in anatomical pathology, since accurate diagnosis of cancer and other diseases usually requires histopathological examination of samples.
The trained scientists who perform the preparation of histological sections are histotechnicians, histology technicians (HT), histology technologists (HTL), medical scientists, medical laboratory technicians, or biomedical scientists. Their field of study is called histotechnology.Histology is the study of tissue sectioned as a thin slice, using a microtome. It can be described as microscopic anatomy. The photographing of stained cells is called histography. Histology is an essential tool of biology.
Histopathology, the microscopic study of diseased tissue, is an important tool in anatomical pathology, since accurate diagnosis of cancer and other diseases usually requires histopathological examination of samples.
The trained scientists who perform the preparation of histological sections are histotechnicians, histology technicians (HT), histology technologists (HTL), medical scientists, medical laboratory technicians, or biomedical scientists. Their field of study is called histotechnology.

Tissue

Biological tissue is a collection of interconnected cells that perform a similar function within an organism.
In other words it is a group of cells working together mainly inside an organ.
The study of tissue is known as histology, or, in connection with disease, histopathology.
The classical tools for studying the tissues are the wax block, the tissue stain, and the optical microscope, though developments in electron microscopy, immunofluorescence, and frozen sections have all added to the sum of knowledge in the last couple of decades.With these tools, the classical appearances of the tissues can be examined in health and disease, enabling considerable refinement of clinical diagnosis and prognosis.

Animal

Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile - they can move spontaneously and independently. Animals are heterotrophs - they are dependent on other organisms (e.g. plants) for sustenance.
Most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago.

Vertebrate

Vertebrates are members of the subphylum Vertebrata, chordates with backbones or spinal columns. The grouping sometimes includes the hagfish which have no vertebrae, but are genetically quite closely related to lampreys, which do have vertebrae.. For this reason, the sub-phylum is sometimes referred to as "Craniata", as all members do possess a cranium. About 58,000 species of vertebrates have been described.[2Vertebrata is the largest subphylum of chordates, and contains many familiar groups of large land animals. Vertebrates comprise cyclostomes, bony fish, sharks and rays, amphibians, reptiles, mammals, and birds. Extant vertebrates range in size from the carp species Paedocypris, at as little 7.9 mm (0.3 inch), to the Blue Whale, at up to 33 m (110

Cell

The cell is the structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as living, and is sometimes called the building block of life. Some organisms, such as most bacteria, are unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion or 1014 cells; a typical cell size is 10 µm; a typical cell mass is 1 nanogram.) The largest known cell is an ostrich egg. In 1837 before the final cell theory was developed, a Czech Jan Evangelista Purkyně observed small "granules" while looking at the plant tissue through a microscope. The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells. All cells come from preexisting cells. Vital functions of an organism occur within cells, and all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.
The word cell comes from the Latin cellula, meaning, a small room. The descriptive name for the smallest living biological structure was chosen by Robert Hooke in a book he published in 1665 when he compared the cork cells he saw through his microscope to the small rooms monks lived in.

Morphology

The term morphology in biology refers to the outward appearance (shape, structure, color, pattern) of an organism or taxon and its component parts. This is in contrast to physiology, which deals primarily with function.
Also in use is the term "gross morphology", which refers to the prominent or principal aspects of an organism or taxon's morphology. A description of an organism's gross morphology would include, for example, its overall shape, overall colour, main markings etc. but not finer details.
Most taxa differ morphologically from other taxa. Typically, closely related taxa differ much less than more distantly related ones, but there are exceptions to this. Cryptic species are species which look very similar, or perhaps even outwardly identical, but are reproductively isolated. Conversely, sometimes unrelated taxa acquire similar appearance through convergent evolution or even through mimicry. A further problem with relying on morphological data is that what may appear, morphologically speaking, to be two distinct species, may in fact be shown by DNA analysis to be a single species

Organ anatomy

In biology, an organ, is a group of tissues that perform a specific function or group of functions. Usually there is a main tissue and sporadic tissues. The main tissue is the one that is unique for the specific organ. For example, main tissue in the heart is the myocardium, while sporadic are the nervous, blood, connective etc.

Phylogenetic

In biology, phylogenetics is the study of evolutionary relatedness among various groups of organisms (e.g., species, populations). Also known as phylogenetic systematics or cladistics, phylogenetics treats each species as a group of lineage-connected individuals Taxonomy, the classification of organisms according to similarity, has been richly informed by phylogenetics but remains methodologically and logically distinct.
Evolution is regarded as a branching process, whereby populations are altered over time and may speciate into separate branches, hybridize together, or terminate by extinction. This may be visualized as a multidimensional character-space that a population moves through over time. The problem posed by phylogenetics is that genetic data are only available for the present, and fossil records (osteometric data) are sporadic and less reliable. Our knowledge of how evolution operates is used to reconstruct the full tree.
Cladistics provides a simplified method of understanding phylogenetic trees. There are some terms that describe the nature of a grouping. For instance, all birds and reptiles are believed to have descended from a single common ancestor, so this taxonomic grouping (yellow in the diagram) is called monophyletic. "Modern reptile" (cyan in the diagram) is a grouping that contains a common ancestor, but does not contain all descendents of that ancestor (birds are excluded). This is an example of a paraphyletic group. A grouping such as warm-blooded animals would include only mammals and birds (red/orange in the diagram) and is called polyphyletic because the members of this grouping do not include the most recent common ancestor.

Connective tissue

Connective tissue is one of the four types of tissue in traditional classifications (the others being epithelial, muscle, and nervous tissue.) It is largely a category of exclusion rather than one with a precise definition, but all or most tissues in this category are similarly:
Involved in structure and support.
Derived from mesoderm, usually.
Characterized largely by the traits of non-living tissue.
Blood, cartilage, and bone are usually considered connective tissue, but because they differ so substantially from the other tissues in this class, the phrase "connective tissue proper" is commonly used to exclude those three. There is also variation in the classification of embryonic connective tissues; on this page they will be treated as a third and separate category.
Collagen is the main protein of connective tissue in animals and the most abundant protein in mammals, making up about 25% of the total protein content.

Systems biology

Systems biology is a relatively new biological study field that focuses on the systematic study of complex interactions in biological systems, thus using a new perspective (integration instead of reduction) to study them. Particularly from year 2000 onwards, the term is used widely in the biosciences, and in a variety of contexts. Because the scientific method has been used primarily toward reductionism, one of the goals of systems biology is to discover new emergent properties that may arise from the systemic view used by this discipline in order to understand better the entirety of processes that happen in a biological system.

Microscope

A microscope is an instrument for viewing objects that are too small to be seen by the naked or unaided eye. The science of investigating small objects using such an instrument is called microscopy. The term microscopic means minute or very small, not visible with the eye unless aided by a microscope. The microscopes used in schools and homes trace their history back almost 400 years.
The first useful microscope was developed in the Netherlands in the early 1600s.Three different eyeglass makers have been given credit for the invention: Hans Lippershey (who also developed the first real telescope); Hans Janssen; and his son, Zacharias. The coining of the name "microscope" has been credited to Giovanni Faber, who gave that name to Galileo Galilei's compound microscope in 1625. (Galileo had called it the "occhiolino" or "little eye".)
The most common type of microscope—and the first to be invented—is the optical microscope. This is an optical instrument containing one or more lenses that produce an enlarged image of an object placed in the focal plane of the lens(es). There are, however, many other microscope designs

Paramedic

A paramedic is a medical professional, usually a member of the emergency medical service, who primarily provides pre-hospital advanced medical and trauma care. A paramedic is charged with providing emergent on-scene treatment, crisis intervention, life-saving stabilization and, when appropriate, transport of ill or injured patients to definitive emergency medical and surgical treatment facilities, such as a hospitals and trauma centers.
The use of the specific term paramedic varies by jurisdiction, and in some places is used to refer to any member of an ambulance crew. In countries such as the United States and the United Kingdom, the use of the word paramedic is restricted by law, and the person claiming the title must have passed a specific set of examinations and clinical placements, and hold a valid registration, certification, or license with a governing body. Even in countries where the law restricts the title, popular media has created a culture where lay persons may incorrectly refer to all emergency medical personnel as 'paramedics', even if they officially hold a different qualification, such as emergency medical technician-basic.

Radiology

Radiology is the specialty directing medical imaging technologies to diagnose and sometimes treat diseases. Originally it was the aspect of medical science dealing with the medical use of electromagnetic energy emitted by X-ray machines or other such radiation devices for the purpose of obtaining visual information as part of medical imaging. Radiology that involves use of x-ray is called roentgenology.
Wilhelm Conrad Roentgen first discovered x-radiation on 8 November 1895 at the Physical Institute of Wuerzburg University. He named the radiation he had discovered "X-radiation". This term is still in use today in the anglo-american region. His work was first published in a meeting protocol of the Wuerzburg Physical-Medical Society in the 1895 volume; the article was submitted by W.C. Roentgen on 28 December 1895.
Today, following extensive training, radiologists direct an array of imaging technologies (such as ultrasound, computed tomography (CT) and magnetic resonance imaging) to diagnose or treat disease. Interventional radiology is the performance of (usually minimally invasive) medical procedures with the guidance of imaging technologies. The acquisition of medical imaging is usually carried out by the radiographer or radiologic technologist. Outside of the medical field, radiology also encompasses the examination of the inner structure of objects using X-rays or other penetrating radiation.

Physical therapy

Physical therapyis a healthcare profession concerned with prevention, treatment and management of movement disorders arising from conditions and diseases occurring throughout the lifespan. Physical therapy is performed by either a physical therapist (PT) or a physical therapist assistant (PTA) acting under the direction of a PT.However, various non-PT health professionals (e.g., chiropractors, Doctors of Osteopathy) employ the use of some physical therapeutic modalities in practice. A program of physical therapy will typically also involve a patient's caregivers.
PTs utilize a patient's history and physical examination in diagnosis and treatment, and if necessary, PTs will also incorporate the results of laboratory and imaging studies. Electrodiagnostic testing (e.g., electromyograms, nerve conduction velocity testing) may also be of assistance.PTs practice in many settings, such as outpatient clinics or offices, inpatient rehabilitation facilities, extended care facilities, patient homes, education or research centers, schools, hospices, industrial workplaces or other occupational environments, fitness centers and sports training facilities.
For decades, physical therapy practice has been the subject of criticism for its lack of a research base, and "most physical therapists continued to base practice decisions largely on anecdotal evidence."The World Confederation for Physical Therapy, has called on the profession to adopt and adhere to evidence-based practices formally based on the best available scientific sources

Biology

Biology , also referred to as Life Science, is the scientific study of life. Biology examines the structure, Biologyfunction, growth, origin, evolution, and distribution of living things. It classifies and describes organisms, their functions, how species come into existence, and the interactions they have with each other and with the natural environment. Four unifying principles form the foundation of modern biology: cell theory, evolution, genetics and homeostasis.
Biology as a separate science was developed in the nineteenth century as scientists discovered that organisms shared fundamental characteristics. Biology is now a standard subject of instruction at schools and universities around the world, and over a million papers are published annually in a wide array of biology and medicine journals.
Most biological sciences are specialized disciplines. Traditionally, they are grouped by the type of organism being studied: botany, the study of plants; zoology, the study of animals; and microbiology, the study of microorganisms. The fields within biology are further divided based on the scale at which organisms are studied and the methods used to study them: biochemistry examines the fundamental chemistry of life; molecular biology studies the complex interactions of systems of biological molecules; cellular biology examines the basic building block of all life, the cell; physiology examines the physical and chemical functions of the tissues and organ systems of an organism; and ecology examines how various organisms and their environment interrelate.

Study

Generally, medical students, dentists, physiotherapists, nurses, paramedics, radiographers, artists, and students of certain biological sciences, learn gross anatomy and microscopic anatomy from anatomical models, skeletons, textbooks, diagrams, photographs, lectures, and tutorials. The study of microscopic anatomy (or histology) can be aided by practical experience examining histological preparations (or slides) under a microscope; and in addition, medical and dental students generally also learn anatomy with practical experience of dissection and inspection of cadavers (dead human bodies). A thorough working knowledge of anatomy is required by all medical doctors, especially surgeons, and doctors working in some diagnostic specialities, such as histopathology and radiology.
Human anatomy, physiology and, biochemistry are complementary basic medical sciences, which are generally taught to medical students in their first year at medical school. Human anatomy can be taught regionally or systemically; that is, respectively, studying anatomy by bodily regions such as the head and chest, or studying by specific systems, such as the nervous or respiratory systems. The major anatomy textbook, Gray's Anatomy, has recently been reorganized from a systems format to a regional format,in line with modern teaching methods.

Circulatory system

The circulatory system is an organ system that moves nutrients, gases, and wastes to and from cells, helps fight diseases and helps stabilize body temperature and pH to maintain homeostasis. This system may be seen strictly as a blood distribution network, but some consider the circulatory system as composed of the cardiovascular system, which distributes blood, and the lymphatic system, which distributes lymph. While humans, as well as other vertebrates, have a closed cardiovascular system (meaning that the blood never leaves the network of arteries, veins and capillaries), some invertebrate groups have an open cardiovascular system. The most primitive animal phyla lack circulatory systems. The lymphatic system, on the other hand, is an open system.

Nervous system

The nervous system is a highly specialized network whose principal components are nerves called neurons. Neurons are interconnected to each other in complex arrangements, and have the property of conducting, using electrochemical signals, a great variety of stimuli both within the nervous tissue as well as from and towards most of the other tissues. Thus, neurons coordinate multiple functions in organisms. Nervous systems are found in many multicellular animals but differ greatly in complexity between species.

Bone

Bones are rigid organs that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red and white blood cells and store minerals. Because bones come in a variety of shapes and have a complex internal and external structure, they are lightweight, yet strong and hard, in addition to fulfilling their many other functions. One of the types of tissues that makes up bone is the mineralized osseous tissue, also called bone tissue, that gives it rigidity and honeycomb-like three-dimensional internal structure. Other types of tissue found in bones include marrow, endosteum and periosteum, nerves, blood vessels and cartilage. There are 206 bones in the adult body and about 300 bones in the infant body.

Human skeleton

The human skeleton consists of both fused and individual bones supported and supplemented by ligaments, tendons, muscles and cartilage. It serves as a scaffold which supports organs, anchors muscles, and protects organs such as the brain, lungs and heart.
The longest and heaviest bone in the body is the femur and the smallest is the stapes bone in the middle ear. In an adult, the skeleton comprises around 20% of the total body weight.
Fused bones include those of the pelvis and the cranium. Not all bones are interconnected directly: There are six bones in the middle ear called the ossicles (three on each side) that articulate only with each other. The hyoid bone, which is located in the neck and serves as the point of attachment for the tongue, does not articulate with any other bones in the body, being supported by muscles and ligaments.

Immune system

An immune system is a collection of mechanisms within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own healthy cells and tissues in order to function properly. Detection is complicated as pathogens adapt and evolve new ways to successfully infect the host organism.

Major organ systems

Circulatory system: pumping and channeling blood to and from the body and lungs with heart, blood, and blood vessels.
Digestive system: digestion and processing food with salivary glands, esophagus, stomach, liver, gallbladder, pancreas, intestines, rectum, and anus.
Endocrine system: communication within the body using hormones made by endocrine glands such as the hypothalamus, pituitary or pituitary gland, pineal body or pineal gland, thyroid, parathyroids, and adrenals or adrenal glands
Immune system: protecting against disease by identifying and killing pathogens and tumor cells.
Integumentary system: skin, hair and nails
Lymphatic system: structures involved in the transfer of lymph between tissues and the blood stream, the lymph and the nodes and vessels that transport it including the Immune system: defending against disease-causing agents with leukocytes, tonsils, adenoids, thymus, and spleen
Muscular system: movement with muscles.
Nervous system: collecting, transferring and processing information with brain, spinal cord, peripheral nerves, and nerves
Reproductive system: the sex organs, such as ovaries, fallopian tubes, uterus, vagina, mammary glands, testes, vas deferens, seminal vesicles, prostate, and penis.
Respiratory system: the organs used for breathing, the pharynx, larynx, trachea, bronchi, lungs, and diaphragm.
Skeletal system: structural support and protection with bones, cartilage, ligaments, and tendons.

Superficial anatomy

Superficial anatomy or surface anatomy is important in human anatomy being the study of anatomical landmarks that can be readily identified from the contours or other reference points on the surface of the body. With knowledge of superficial anatomy, physicians gauge the position and anatomy of the associated deeper structures.