Нормальная физиология = Normal physiology

            Нормальная физиология


Утверждено
Министерством образования Республики Беларусь в качестве учебника для иностранных студентов учреждений высшего образования по специальности «Лечебное дело»

Под редакцией профессора В. В. Зинчука


             Normal physiology


             Approved by
             the Ministry of Education of the Republic of Belarus as a textbook for international students of higher education institutions on specialty "General Medicine"
             Under the editorship of professor V. V. Zinchuk







               Минск «Вышэйшая школа» 2020

УДК 612(075.8)
ББК 28.707.3я73
     Н83
   Авторы: В. В. Зинчук, О. А. Балбатун, С. Д. Орехов, С. В. Глуткин, Ю. М. Емельянчик
   Р е це нз е нты: кафедра нормальной физиологии УО «Белорусский государственный медицинский университет» (заведующий кафедрой доктор медицинских наук, профессор В.А. Переверзев)
         Нормальная физиология : учебник = Normal physiology :
Н83 textbook / В.В. Зинчук [и др.]; под ред. проф. В.В. Зинчука. — Минск : Вышэйшая школа, 2020. — 496 с. : ил.
         ISBN 978-985-06-3245-6.
         Представлен теоретический материал об основных физиологических закономерностях и процессах организма человека, приведены физиологические термины и определения, вопросы для самоконтроля, ситуационные задачи.
         Для изучения (на английском языке) нормальной физиологии иностранными студентами медицинских учреждений высшего образования, может быть полезна всем, кто изучает данную дисциплину.
         This textbook is designed to study (in English) normal physiology by international students of medical higher education institutions and can be used by others who study this discipline as well.
УДК 612(075.8)
ББК 28.707.3я73
Учебное издание
Зинчук Виктор Владимирович
Балбатун Олег Александрович Орехов Сергей Дмитриевич и др.
НОРМАЛЬНАЯ ФИЗИОЛОГИЯ
NORMAL PHYSIOLOGY

Учебник на английском языке

      Редактор Ю.И. Варакса. Художественный редактор В.А. Ярошевич. Технический редактор Н.А. Лебедевич. Компьютерная верстка Н.В. Шабуни. Корректор В.И. Канопа
  Подписано в печать 20.07.2020. Формат 60x84/16. Бумага офсетная. Офсетная печать.
Усл. печ. л. 28,83. Уч.-изд. л. 31,5. Тираж 400 экз. Заказ 2391.
   Республиканское унитарное предприятие «Издательство “Вышэйшая школа”». Свидетельство о государственной регистрации издателя, изготовителя, распространителя печатных изданий № 1/3 от 08.07.2013. Пр. Победителей, 11, 220004, Минск. e-mail: market@vshph.com http://vshph.com
Открытое акционерное общество «Типография “Победа”». Свидетельство о государственной регистрации издателя, изготовителя, распространителя печатных изданий № 2/38 от 29.01.2014.
Ул. Тавлая, 11, 222310, Молодечно.
ISBN 978-985-06-3245-6                    © Оформление. УП «Издательство
“Вышэйшая школа”», 2020

ABBREVIATIONS


ACTH — adrenocorticotropic hormone
ADP       —   adenosine diphosphate
ANS       —   autonomic nervous system
AP        —   action potential
ATP       —   adenosine triphosphate
BOC       —   blood oxygen capacity
BP        —   blood pressure
CNS       —   central nervous system
CO        —   cardiac output
СО2       —   carbon dioxide
ECG       —   electrocardiography
EEG       —   electroencephalography
ESR       —   erythrocyte sedimentation rate
GABA      —   gamma-aminobutyric acid  (Y-aminobutyric acid)
GH — growth hormone (somatotropin)
GIT — gastrointestinal tract
Hb — reduced or deoxyhemoglobin
HbO2      —  oxyhemoglobin
HbCO — carboxyhemoglobin
HbCO2 — carbhemoglobin
HNA — higher nervous activity
HR — heart rate
MP — membrane potential
О2        —  oxygen
рСО2     — partial pressure of carbon dioxide
pH — potential of hydrogen
рО2       —   partial pressure of oxygen
Rh        —   rhesus factor
RMP — resting membrane potential
TV        —   tidal volume
VC        —   vital capacity
VR        —   ventilation rate

PREFACE


   This textbook is designed to study normal physiology by the 2ⁿd year international students of the Faculty of Medecine of medical higher education institutions with English as a medium of instruction and can be used by others who study this discipline as well. While creating the textbook, the authors used their own experience in teaching the discipline, as well as modern achievements in physiological science, and materials of national and foreign textbooks.
   The textbook consists of 12 chapters, which contain information on the basic physiological laws and processes of the human body. For material presentation, conventional terminology and a modern standard of the discipline are used. Normal physiology information is presented in a short comprehensive style, taking into account the fact that the target audience has basic biological education. The textbook contains situational tasks with answers. To structure students’ knowledge in each chapter the key definitions are presented.
   The authors are thankful to all lecturers teaching at the Department of Normal Physiology of Grodno State Medical University who have contributed to the development of the textbook. We owe our gratitude to the computer operator O.V. Tsuprianchik for the tremendous job on the technical design of the book script. We would like to thank the staff of the Department of Foreign Languages (head of the department — Ya.V Razvodovskaya, associate professor — L.N. Gushchyna) for their help in language correction of the script.
   The authors will be grateful for any constructive comments and suggestions (dpfizio@mail.ru).

INTRODUCTION

        Physiology as a discipline

   Normal physiology (from Ancient Greek physis — “nature, origin” and loyos — “word, doctrine”) is a science that studies the basic laws and mechanisms of the regulation of the organism functioning as a unit and its individual components in interaction with the environment, the organization of life processes at various structural and functional levels.
   The discipline of Physiology is important in the formation of medical specialties of various profiles. It is based on the integration of modern data obtained at the molecular, organ, systemic and organism levels that view the human body as an integral system being in constant interaction with the variety of impacts of the surrounding environment including the social one. This discipline is dynamic and systematically updated. Physiology occupies a special position between biophysics, biochemistry and other rapidly developing sciences.
   The classical approach to the teaching of normal physiology in the 20th century involved the experimental use of a large number of animals. Currently, the international standard of “three R” experiments is used:
   ♦ replacing animals by other methods;
   ♦ reducing the number of experiments;
   ♦ improving the conditions of research.
   Alternative methods include, first of all, special commercial programs of virtual and interactive physiology. An effective way to reduce the number of animal experiments is to conduct demonstrational laboratory investigations using modern recording equipment, as well as the use of non-invasive techniques involving volunteer students.
   The optimal ratio between traditional classical techniques and modern teaching technologies, humanization of the teaching process is especially important in training medical professionals.

        Basic concepts of the discipline

   One of the fundamental concepts is a function (from Latin functio — “activity”), which is considered as specific activity of various structures that provide vitality of the entire human body.
   The physiological mechanism is a set of different processes that ensure the formation of a specific function.

5

   Regulation of functions is a directed change in the activity of the organs, tissues, cells to achieve a useful result according to the needs of the organism in various life conditions. There are different types of regulation:
   ♦     Error-controlled regulation is a mechanism in which any change from the optimal level of the regulated parameter initiates the activity of the corresponding components of the functional system to restore its value to the initial level.
   ♦     Feed-forward regulation is a mechanism in which the regulatory processes are activated before the change of the relevant parameter begins on the basis of information entering the nervous center of the functional system and signaling its possible change.
   ♦     Autoregulation (self-regulation) of functions is a kind of regulation in which the body, with the help of its own mechanisms, changes the intensity of the functioning of organs and systems in accordance with their needs in various environmental conditions.
   Homeostasis (from Ancient Greek omoios — “same”, stasis — “steady”) — a relative dynamical, genetically based stability of internal environment and stability of the basic physiological body functions. The term was in-roduced by W. Cannon (1929), theoretical foundations were developed by C. Bernard (1879). Homeostatic constant is a specific parameter of the internal environment (рН, osmotic pressure, blood pressure, etc.), which in the body changes into a narrow (rigid constant) or in a wide (labile constant) range. Homeokinesis is a dynamic process of continual changes in a number of body constants, their interaction during metabolism and a return to the normal level for particular conditions.
   Functional system is a self-regulating organization, dynamically and selectively integrating the central nervous system and peripheral organs, tissues, based on nervous and humoral regulation to achieve a useful adaptive result. The functional system includes the following components: a useful adaptive result, receptors for result, feedback afferentation (coming from the receptors), central regulatory mechanisms, executive somatic, vegetative and endocrine components. Feedback in the functional system ensures the transmission of information about the actual parameters of the object’s state to the control systems.
Ш Key definitions
physiology, experiment, observation, technique, analytical-synthetic research method, function, physiological mechanism, regulation, reflex, reflex arc, homeostasis, homeostasis constant, homeokinesis, homeorhesis, functional system, feedback, adaptation, chronophysiology, biological rhythms, desynchronosis, circadian rhythms, valeology, health, growth-weight ratio, genome, genomics, genetic engineering, aging, age-related physiology

6

DEVELOPMENT OF PHYSIOLOGY IN BELARUS

   The discovery by W. Harvey of the systemic circulation in 1628 can be considered as a starting point in the history of physiology. In Russia, the date of its emerging was 1725, when the Department of Anatomy and Physiology at St. Petersburg Academy of Sciences was founded. Yet, its real formation as an independent discipline started at the beginning of the 19th century. Physiology development on the territory of Belarus up to the 1920s occurred sporadically. Here J.E. Gilibert (1741—1814), the first rector of the Grodno Medical Academy and J. Jodko-Narkiewicz (1848— 1905), a Polish-Belarusian naturalist, are worth mentioning.
   However, the foundation of the Department of Normal Physiology at Belarusian State University in 1922 could be considered a real starting point. It became the basis for a similar department at the current Belarusian State Medical University. The first steps in its development were associated with such scientists as L.P. Rozanov and I.A. Vetokhin.
   The foundation of the Institute of Physiology at the Academy of Sciences in 1953 was a true milestone event (its first director was I. A. Bulygin (1953-1984), then V N. Gurin (1984-2005), VS. Ulashchik (20052010), I.V Zalutskiy (2010-2018), S.V Gubkin (since 2018).
   The establishment of medical universities in Vitebsk (1934), Grodno (1958), Gomel (1990) gave an impetus to the development of physiology in the regions of Belarus as well. Today, in all regional cities there are classical universities in which the departments of physiology are organized. For several decades the I.P. Pavlov’s society of physiologists of Belarus has been functioning, bringing together more than 200 scientists.
   The most famous Belarusian physiologists are I.A. Bulygin, N.I. Arin-chin, V.N. Gurin, M.V. Borysiuk et al.

                Chapter 1





            BLOOD PHYSIOLOGY



   The internal environment is a group of fluids (blood, lymph, interstitial fluid, etc.) that directly participate in metabolic processes and in the maintenance of the body’s homeostasis. The internal environment is characterized by a relative constancy of composition and conditions. “The fixity of the internal environment is the condition for free life” (C. Bernard, 1813—1878). It is provided by various mechanisms. They include not only the physiological processes that maintain the stable state of the organism but also the mechanisms of regulation that, in certain limits, change these states.
   There are the following types of the internal environment:
   ♦  Intracellular;
   ♦  Extracellular:
      Ф extravascular (interstitial fluid, joint fluid, pleural fluid, cerebrospinal fluid, etc.);
      Ф intravascular (blood, lymph).

        General characteristics

   Blood as a tissue of the internal environment has a number of features: its components are synthesized outside it; the main portion of the blood tissue is liquid; it moves constantly. In 1939, G.F. Lang introduced the concept of the blood system, which includes blood circulating in vessels, the organs of blood formation, destruction and regulatory apparatus.
   There is also another concept: erythron — an aggregation of erythrocytes of peripheral blood, organs of erythrocyte formation (erythropoiesis) and organs of erythrocyte destruction.
   Blood functions:
   ♦      transport (nutrition, transport of gases, excretion, water and salt balance, osmotic concentration, acid and base balance (рН);
   ♦  regulation;
   ♦  defense;
   ♦  thermoregulation;
   ♦  homeostasis.

8

   These functions reflect the contribution of the blood system to the homeostasis formation. Thereby the main blood parameters are rigid homeostatic constants (Table 1.1).


Table 1.1. Main parameters of the blood system of a healthy adult

             Parameters              Gender       Range, units       
Hemoglobin                             М           130-160 g/L       
                                       F           120-140 g/L       
Erythrocytes                           М        (4.0-5.0)-1012/L     
                                       F        (3.9-4.7)-1012/L     
Average erythrocyte volume                          75-95 mm3        
Average erythrocyte diameter                       7.2-7.5 mm        
Hematocrit ratio (Ht or Hct)           М             40-48 %         
                                       F             36-42 %         
Color index                                         0.85-1.05        
Average Hb content in 1 erythrocyte                 27-33 pkg        
Reticulocytes                                       0.2-1.0 %        
Platelets                                        (180-320)-109/L     
Leukocytes                                       (4.0-9.0)-109/L     
Erythrocyte sedimentation rate (ESR)   М            2-10 mm/h        
                                       F            2-15 mm/h        
Total blood volume in the organism          6-8% of total body weight
Blood density                                   1.050-1.064 g/cm3    
Plasma density                                  1.024-1.030 g/cm3    
Blood cells density                             1.089-1.097 g/cm3    
Blood pH --- arterial                               7.37-7.45        
--- venous                                          7.34-7.43        
Plasma osmotic pressure                        5,780 mmHg/7.6 atm    
Plasma oncotic pressure                            25-35 mmHg        
Total plasma protein                                65-85 g/L        
Blood ions concentration                           0.9-0.95 %        
Blood viscosity                                       5 cP           
Plasma viscosity                                     1.7 cP          

9

    The blood volume in the body is 6—8% of total body weight, i.e. 4—6 L in an average man. Most of the blood moves constantly, about 30% of its volume is in a deposited state.
    Blood depots (venules and veins):
    ♦  spleen;
    ♦  liver;
    ♦  lungs;
    ♦  skin.


        Blood plasma properties

   Blood consists of plasma of a pale yellow color and formed elements (erythrocytes or red blood cells, leukocytes or white blood cells, thrombocytes or platelets). Plasma from which fibrinogens have been removed is called serum. Hematocrit is the ratio of formed elements volume (mostly red blood cells) to the total volume of blood (Figure 1.1). Its value is 40— 48% for men and 36—42% for women. This blood parameter can vary significantly depending on the conditions of the internal and external environments.


Figure 1.1. Hematocrit ratio determination:
hi — blood volume; h₂ — formed elements volume; h3 — plasma volume; h4 — leukocytes volume

    Plasma is composed of (90—92%) water, (6.5—8.5%) proteins and (about 2%) organic and inorganic substances (Table 1.2). Due to the latter, the osmotic pressure of plasma is formed (5,780 mmHg or 7.6 atm). The simplest blood substitute is a 0.95% solution of NaCl (normal saline). This isotonic solution has the same osmotic pressure as plasma, but its compo


10