Military roentgenology / War Department.

Date:
[1944]
Catalogue details

Licence: Public Domain Mark

Credit: Military roentgenology / War Department. Source: Wellcome Collection.

    117/470 page 107
    SECTION I. INTRODUCTION 145. GENERAL. a. Basically, all things as they exist In nature are classified into three general groups: animal, vegetable, and mineral. The mineral objects are characterized as inorganic. They contain inorganic matter and are nonliving. The animal and vegetable groups are referred to as organic since they are composed of organic matter and possess life. (1) An organism is defined as any living thing, plant, or animal. The fundamental difference be- tween plants and animals is distinguished by the process of life each follows. Plants are capable, in most instances, of producing their own food. By a process called photosynthesis (action of sunlight causing the formation of carbohydrates from carbon dioxide in the tissues of the plants in the presence of a green substance called chlorophyl) plants remain fixed in one location. Animals, lacking the mechanism for the production of food, must seek food in order to live. (2) Animals are classified according to the organi- zation and characteristics of their structure. They are divided into the invertebrates (lacking a back- bone) and the vertebrates (with a backbone). Included as vertebrates, from the simplest to the more com- plicated, are: fishes, amphibians, reptiles, birds, and mammals. The highest class of vertebrates is the mammal. Man is an example of a mammal. This class is subdivided into the order of primates includ- ing in order of evolutional development: lemurs, tarsioids, monkeys, baboons, gibbons, orang-utan, chimpanzee, gorilla, and man. Man (homo sapiens) is composed of many races; these being classified on the basis of skull and body measurements as well as superficial characteristics. (3) Commonly, man is spoken of as a “human being” for it is in him that specialization and differentiation of function has attained its highest degree. Man is the only animal capable of speech and the ability to reason and integrate intelligently the many complex problems which confront him. It is in man that the nervous system has reached a high state of development which allows him to engage in complicated mental activities. b. The human body is composed of various types of tissue and organs coordinated into a complex mechanism supported by a bony framework. The basic knowledge of the human body is essentially the result of many painstaking contributions from various allied scientific fields. The science dealing with the structure of the human body and the rela- tion of its parts is human anatomy. This knowledge is based upon countless dissections of human bodies. The subject of anatomy is divided into the study of systems such as: osteology, the study of the bones or skeleton; artbrology, the study of the joints or articu- lations; myology, the study of muscles; angiology, the study of the blood-vascular system comprising the heart, blood vessels and lymphatic system; neurology, the study of the nervous system and the organs of special sense; and splanchnology, the study of visceral anatomy, including the respiratory, the digestive and urogenital system. c. Embryology treats of the origin and develop- ment of the structures of the human body. It is con- cerned with the investigation of the minute and intricate formulation of the body cells, tissues, and organs. d. Histology is a science which deals with studies of minute portions of the component parts of the human body and the composition of tissues—as pro- vided with the use of a microscope. e. Physiology is the study of the functions and activity of the various anatomical structures of the body. Primarily, it assists in formulating a clearer understanding of the reactions that take place within the body under certain conditions and enables the body to function as an integrated organism rela- tive to chemical, physical, and mechanical stimuli. f. Pathology is a science which deals with varia- tions in the structure and functions of the body as caused by disease. 146. ANATOMICAL TERMS. a. For descriptive purposes, the body is considered to be in the erect position when the arms are hanging by the sides and the palms of the hands are directed forward. This is referred to as the normal anatomical position. (See fig. 85.) (1) Anterior is the front or ventral part of the body.
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