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Skeletal structure frames the overall shape of the body and does not alter much over a lifetime. General body shape (and female body shape) is influenced by the distribution of muscle and fat tissue and also affected by various hormones. The average height of an adult male human (in developed countries) is about 1.7–1.8 m (5'7" to 5'11") and the adult female is about 1.6–1.7 m (5'2" to 5'7") .[3] Height is largely determined by genes and diet. Body type and composition are influenced by factors such as genetics, diet, and exercise. Composition Main article: Composition of the human body The main elements that compose the human body are shown from most abundant to least abundant. The average adult body contains between 5 and 5½ litres of blood. The composition of the human body can be referred to in terms of its water content, elements content, tissue types or material types. The adult human body contains approximately 60% water, and so makes up a significant proportion of the body, both in terms of weight and volume. Water content can vary from a high 75% in a newborn infant to a lower 45% in an obese person. (These figures are necessarily statistical averages). Composition by tissue type can refer to the cells of the human body where the vast majority of cells are not human but bacterial cells and also archaea cells, particularly methanogens such as Methanobrevibacter smithii. The whole population of microbiota include microorganisms of the skin and other body parts and these in total are also termed the human microbiome the largest proportion of these form the gut flora. The proportions of the elements of the body can be referred to in terms of the main elements, minor ones and trace elements. Material type may also be referred to as including water, protein, connective tissue, fats, carbohydrates and bone. Human anatomy Anatomical study by Leonardo da Vinci Human anatomy (gr. ἀνατομία, "dissection", from ἀνά, "up", and τέμνειν, "cut") is primarily the scientific study of the morphology of the human body.[4] Anatomy is subdivided into gross anatomy and microscopic anatomy (histology)[4] Gross anatomy (also called topographical anatomy, regional anatomy, or anthropotomy) is the study of anatomical structures that can be seen by the naked eye.[4] Microscopic anatomy involves the use of microscopes to study minute anatomical structures, and is the field of histology which studies the organization of tissues at all levels, from cell biology (previously called cytology), to organs.[4] Anatomy, human physiology (the study of function), and biochemistry (the study of the chemistry of living structures) are complementary basic medical sciences that are generally taught together (or in tandem) to students studying medical sciences. Front view of viscera In some of its facets human anatomy is closely related to embryology, comparative anatomy and comparative embryology,[4] 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 which can be traced from the somitogenesis stage in very early embryos. Generally, physicians, dentists, physiotherapists, nurses, paramedics, radiographers, 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 in 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 (corpses). A thorough working knowledge of anatomy is required for all medical doctors, especially surgeons, and doctors working in some diagnostic specialities, such as histopathology and radiology. Human anatomy, physiology, and biochemistry are 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;[4] 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.[5][6] Anatomical variations Further information: List of anatomical variations Question book-new.svg This section does not cite any references or sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (June 2012) In human anatomy, the term anatomical variation refers to a non-pathologic anatomic structure that is different from the norm. The possible anatomic variations in each organ and its arterial and venous supply must be known by physicians, such as surgeons or radiologists, in order to identify them. Unlike congenital anomalies, anatomic variations are typically inconsequential and do not constitute a disorder. Accessory muscles are rare anatomical duplicates of muscle that can occur and only require treatment where function is impaired. The accessory soleus muscle in the ankle, is one such variation and one which does not need to be rectified.[7][8] Human physiology Main article: Physiology Human physiology is the science of the mechanical, physical, bioelectrical, and biochemical functions of humans in good health, their organs, and the cells of which they are composed. Physiology focuses principally at the level of organs and systems. Most aspects of human physiology are closely homologous to corresponding aspects of animal physiology, and animal experimentation has provided much of the foundation of physiological knowledge. Anatomy and physiology are closely related fields of study: anatomy, the study of form, and physiology, the study of function, are intrinsically related and are studied in tandem as part of a medical curriculum. The study of how physiology is altered in disease is pathophysiology. |
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