HUMAN ANATOMY – VOLUME 1

M.R. Sapin

L.L. Kolesnikov

D.B. Nikitjuk

TEXTBOOK OF

HUMAN

ANATOMY

For medical students

In 2 volumes

Volume 1

Edited by prof. M.R. Sapin

Рекомендовано Учебно-методическим объединением по медицинскому и фармацевтическому образованию вузов России

в качестве учебного пособия для студентов медицинских вузов, обучающихся на английском языке

Moscow

New Wave Publishing Agency

2019

PREFACE

This book consists of two parts and contains the most contemporary and fairly detailed data on the structure of the human body from the macroanatomic level to the microscopic one. The book also contains information about submicroscopic organization of cells and tissues. A lot of attention is given to topographic anatomy, correlation between the organs and bones of the skeleton and nearby organs, which brings theoretical anatomy to its practical purpose. This textbook provides a detailed description of the origin of the organs, their age peculiarities, variations and congenital malformation. As a whole, this book is structured in accordance with a plan, traditional in functional human anatomy.

In the first book a comprehensive introduction, in which necessary general anatomical terms and concepts are brought up, is followed by a detailed account of the structure of cells and tissues. Then follows the section on the anatomy of the skeletal and muscular system, in which the structure of skeletal bones, bone junctions, joints and skeletal muscles is expounded. Here information on topography of connective tissue structures, muscles of the head, body and limbs is also given. And finally, the functional anatomy of digestive and respiratory organs is presented.

The second book includes sections on the anatomy of the urinary organs, male and female genitals, endocrine glands and also organs of the immune system, which protect the organism from foreign substances. This book also contains a description of the heart and blood vessels (arteries, capillaries, veins), nervous system and sensory organs.

Part of the information is presented in well-designed informative tables.

Both books are richly illustrated with colorful anatomical pictures of organs, their parts, microscopic details. As is customary for anatomical textbooks the organs, their larger parts and anatomical objects that have a clinical significance are named both in English and Latin.

The Authors

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INTRODUCTION

Human anatomy is a science about the genesis, development and structure of the human body. It studies external forms and proportions of the human body and its parts, separate organs, their constitution and microscopic structure. Anatomy also studies the main stages of human development, particularities of structure of the body and separate organs at different age periods.

Anatomy studies the structure of the human body taking into consideration biological patterns, natural for all living organisms. At the same time human beings differ very much from animals due to their living in society. Mankind was formed by labor and social needs, an increase in which led to changes in structure, to biological progress. The environment has an influence on the human organism as well.

In studying the structure of the human body it is important to consider age, sexual and individual differences. During infancy, adolescence and even juvenile age the growth of organs and differentiation of tissues still continues. In adulthood the structure of the body is more or less stable. Even during this period, however, alterations take place within organs under the influence of living conditions and the environment.

It is impossible to understand the distinctions of form and structure of the human body without an analysis of its functions, as it is impossible to imagine the function of any organ without an understanding of its structure.

The human body consists of many organs and a tremendous amount of cells, however it is not a sum of separate parts but a whole coordinated living organism. This is why it is impossible to examine organs without considering at their relationship with each other and without taking into account the integrative role of the nervous and vascular systems and the endocrine apparatus. The main methods of anatomical research are the following: observation, examination of the body, dissection and studying of separate organs and groups of organs (macroscopic, or gross anatomy), including their internal fine structure (microscopic anatomy).

With the appearance of microscopes anatomy gave start to histology (the study of tissues) and cytology (the science of structure and functions of the cell).

The structure of the skeleton, internal organs, the disposition of blood and lymphatic vessels are examined with the help of x-rays. In the clinic the internal surface of many internal organs is studied by means of endoscopy. Antropometrical methods are used for studying external forms and proportions of the body.

The study of the human body by the systems (skeletal, muscular, digestive, etc.) is called systematic (descriptive) anatomy.

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Systematic anatomy studies the structure of «normal» that is, healthy human beings, whose organs have not been altered by disease or disturbance of development. The structure of the body is considered normal if it can provide the functions of a healthy organism. The standard values (for weight, height, shape, etc.) stand within a maximum and minimum and reflect individual structural features. Individuality of every human being is determined by hereditary and environmental factors. Recently the term «conditional standard» has often been used which indicates the relativity of this concept. Individual variability gives reason to discuss variants (variations) of structure of the organism and its organs. Variants are expressed as deflections from most frequently met cases, which are accepted as standard.

Strongly expressed congenital deflections from norm are called anomalies. Some anomalies do not change the external appearance (right-sided position of the heart, of all or some internal organs). Others have external manifestations and are called deformities (underdevelopment of the skull, limbs, etc.). Deformities are studied by teratology.

Topographic (surgical) anatomy studies the structure of the human body by regions, as well as the location of organs and their interrelation with each other and with the skeleton. External forms of the body and its proportions are studied by surface anatomy. Modern anatomy is called functional, as it examines the structure of the body in correlation with its functions.

Anatomy examines the structure and functions of organs taking into account the developments the human being goes through from birth to death (during ontogenesis). Developments that take place before birth (the prenatal period) are examined by embryology. After birth (the postnatal period) the human being is studied by developmental anatomy. Peculiarities of body structure of elderly and senile people are studied by gerontology — the science of aging.

In accordance with the length and width of the body and other anthropometric features anatomy distinguishes the dolichomorphic, brachymorphic and mesomorphic types of constitution. The dolichomorphic constitutional type is defined by a narrow long trunk and long extremities (asthenic); the brachymorphic type is characterized by a short wide trunk and short extremities (hypersthenic). The intermediate type of constitution is called mesomorphic. This type is close to an «ideal» (normal) human being (normosthenic).

While analyzing the peculiarities of structure of the human body (analytical approach), anatomy studies the organism as a whole, using the synthetic approach. That is why anatomy is not only an analytical science, but also a synthetic one.

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a standing human being. The vertical column and nearby organs (spinal cord, thoracic and abdominal parts of the aorta, thoracic duct) are located along this axis. The vertical axis coincides with the lengthwise axis, which is oriented along the human body independently of its position in space, or along extremities (leg, arm), or along an organ the length of which prevails over its other proportions. The direction of the frontal (transverse) axis coincides with that of the frontal plane. This axis is oriented from right to left or from left to right. The sagittal axis is oriented from front to back like the sagittal plane.

The following is a list of anatomical terms used to define the location of organs and parts of the body: medialis, i.e. medial, if an organ (organs) lies closer to the median plane; lateralis, i.e. lateral (side), if an organ is situated further (to the right or left) from the middle plane; intermedius, i.e. intermediate, if an organ lies between two nearby formations; internus, i.e. internal (lying within) and externus, i.e. external (lying outside) when we are speaking about organs which are situated within the cavity of the body and outside of it; profundus, i.e. deep (lying deeper) and superficialis, i.e. superficial (situated at the surface) for defining the location of organs which lie at different depths.

Special terms are used for describing upper and lower extremities. For designation of the beginning of an extremity, that is, the part located closer to the trunk, the term proximalis, i.e. proximal (closest to the trunk), is used. Parts distant from the trunk are called distalis, i.e. distal. The anterior surface of the upper extremity is described by the term palmaris, i.e. palmar or volaris, i.e. located on the palm side; the lower extremity on the side of the sole is described as plantaris, i.e. plantar. The edge of the forearm at the side of the ulna is called ulnaris, i.e. ulnar. On the shin, the edge, at which the fibula is located, is called fibularis, i.e. fibular; the opposite edge, where the tibia is located is called tibialis.

For determining the projections of borders of the heart, lungs, liver, pleura and other organs provisory vertical lines oriented along the body are drawn on its surface. The front middle line (linea mediana anterior) passes along the front surface of the body, on the border between its right and left halves. The posterior middle line (linea mediana posterior) passes along the vertebral column, above the apexes of the spinous processes of the vertebrae. Several other provisory lines may be drawn between these two lines at each side, passing over anatomical structures on the surface of the body. The sternal line (linea sternalis) passes along the edge of the sternum; the mid-clavicular line (linea medioclavicularis) is drawn though the middle of the clavicle. This line often coincides with the papilla of the mammary gland and thus is also called linea mammillaris (mammillary

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THE STRUCTURE OF THE HUMAN BODY

The human organism is a unified, complexly organized system. It consists of cells, tissues and organs. Organs, which are made of tissues, make up systems and apparatuses, which in combination form an entire human organism.

CELLS AND TISSUES

Each cell is a universal structural and functional unit of all living beings. Cells of all living organisms are similar in structure. Cells reproduce by division only.

CELLS

The cell (cellula), as an elementary well-organized unit, carries out the functions of reproduction, growth, metabolism, adaptation to changes in the environment and regeneration. Cells vary in shape, structure and chemical composition. In the human body there are flat, spherical, ovoid, cuboid, prismatic, pyramidal and stellate cells. The size of cells varies from several micrometers (small lymphocyte) to 200 micrometers (oocyte).

All cells have a plasma membrane, or cytolemma (which consists of hyaloplasm, containing organelles and inclusions), and a nucleus.

The cytolemma (plasmalemma) is 9–10 nm thick; it separates the content of the cell from its external (extracellular) environment (Fig. 2). The cytolemma performs functions of segregation, protection, transport and receiving impacts from the surrounding environment. It carries out the transfer of various molecules (particles) from outside into the cell and vice versa. The process of carrying substances inside the cell is called endocytosis, which can be differentiated into phagocytosis and pinocytosis. During phagocytosis the cell engulfs large particles (parts of dead cells, microorganisms). During pinocytosis the cytolemm forms vesicles, which involve small particles dissolved or suspended in the tissue fluid. These vesicles transport their content into the cell.

The cytolemma also takes part in excretion of substances out of the cell (exocytosis). Exocytosis is performed by means of vesicles or vacuoles, in which substances are excreted out of the cell.

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