levels of organization of life. Biology. Levels of organization of the human body 8 what levels of organization of the body do you know

In the course of this lesson, we will get acquainted with the levels of organization of our body and its organ systems.

Topic: General overview of the human body

Lesson: Organ systems in the body. Organization levels

Our body. This definition seems so familiar and understandable that we rarely think about its essence. And to the question: “what is it all the same?” many may find it difficult to answer.

organism is a specific complex or system that reacts as a whole to various changes in the external environment. This system is relatively stable, despite the fact that it consists of many organs. Organs are made up of tissues, tissues are made up of cells, and cells are made up of molecules.

Molecules, cells, tissues, organs, organ systems - all these floors, or different levels of the living, are united in the human body into a single and inseparable whole.

Living organisms are built from special chemical compounds - organic matter(proteins, fats, carbohydrates, nucleic acids). They are part of every living cell. These large molecules act as building blocks that create complex complexes. The substances of the cell are not located randomly, but form ordered structures - organelles, which provide the processes of the cell's vital activity. The human body is a multicellular state. The cells of the human body are not the same, they differ in their specialization. Cells of the same specialty are combined into groups. Together with the intercellular substance, they form tissues. Organs are made up of multiple tissues. Organs that perform a single function and have a common plan of structure and development will unite into organ systems. All organ systems are interconnected and form a single organism.

There are 10 major organ systems in the human body.

integumentary system-consists of the skin and mucous membranes lining the cavities of the internal organs, respiratory tract, digestive tract. The function of this system is to protect the body from mechanical damage, drying out, temperature fluctuations, and the penetration of pathogenic bacteria.

1. Kolesov D.V., Mash R.D., Belyaev I.N. Biology 8 M.: Bustard - p. 49, tasks and question 1.

2. What is included in the urinary system?

3. What is included in the digestive system?

4. Prepare an abstract about one of the organ systems.

All living organisms in nature consist of the same levels of organization; this is a characteristic biological pattern common to all living organisms.
The following levels of organization of living organisms are distinguished - molecular, cellular, tissue, organ, organism, population-species, biogeocenotic, biospheric.

Rice. 1. Molecular genetic level

1. Molecular genetic level. This is the most elementary level characteristic of life (Fig. 1). No matter how complex or simple the structure of any living organism, they all consist of the same molecular compounds. An example of this are nucleic acids, proteins, carbohydrates and other complex molecular complexes of organic and inorganic substances. They are sometimes called biological macro- molecular substances. At the molecular level, various life processes of living organisms take place: metabolism, energy conversion. Transmission is carried out at the molecular level hereditary information, separate organelles are formed and other processes occur.

Rice. 2. Cellular level

2. Cellular level. The cell is structural and functional unit all living organisms on Earth (Fig. 2). Individual organelles in a cell have characteristic structure and perform a specific function. The functions of individual organelles in the cell are interconnected and perform common life processes. In unicellular organisms (unicellular algae and protozoa), all life processes take place in one cell, and one cell exists as a separate organism. Remember unicellular algae, chlamydomonas, chlorella and protozoa - amoeba, infusoria, etc. In multicellular organisms, one cell cannot exist as a separate organism, but it is an elementary structural unit of the organism.

Rice. 3. Tissue level

3. Tissue level. A set of cells and intercellular substances similar in origin, structure and functions forms a tissue. The tissue level is typical only for multicellular organisms. Also, individual tissues are not an independent integral organism (Fig. 3). For example, the bodies of animals and humans are made up of four different tissues (epithelial, connective, muscle, and nervous). Plant tissues are called: educational, integumentary, supporting, conductive and excretory. Recall the structure and functions of individual tissues.

Rice. 4. Organ level

4. Organ level. In multicellular organisms, the union of several identical tissues, similar in structure, origin, and functions, forms the organ level (Fig. 4). Each organ contains several tissues, but among them one is the most significant. A separate organ cannot exist as a whole organism. Several organs, similar in structure and function, unite to form an organ system, for example, digestion, respiration, blood circulation, etc.

Rice. 5. Organism level

5. Organism level. Plants (chlamydomonas, chlorella) and animals (amoeba, infusoria, etc.), whose bodies consist of one cell, are an independent organism (Fig. 5). A separate individual of multicellular organisms is considered as a separate organism. In each individual organism, all the vital processes characteristic of all living organisms take place - nutrition, respiration, metabolism, irritability, reproduction, etc. Each independent organism leaves behind offspring. In multicellular organisms, cells, tissues, organs and organ systems are not a separate organism. Only an integral system of organs specialized in performing various functions, forms a separate independent organism. The development of an organism, from fertilization to the end of life, takes a certain period of time. This individual development of each organism is called ontogeny. An organism can exist in close relationship with environment.

Rice. 6. Population-species level

6. Population-species level. A set of individuals of one species or group that exists for a long time in a certain part of the range relatively apart from other sets of the same species constitutes a population. At the population level, the simplest evolutionary transformations are carried out, which contributes to the gradual emergence of a new species (Fig. 6).

Rice. 7 Biogeocenotic level

7. Biogeocenotic level. Set of organisms different types and varying complexity of the organization, adapted to the same conditions natural environment, is called biogeocenosis, or natural community. The composition of biogeocenosis includes numerous types of living organisms and environmental conditions. In natural biogeocenoses, energy is accumulated and transferred from one organism to another. Biogeocenosis includes inorganic, organic compounds and living organisms (Fig. 7).

Rice. 8. Biosphere level

8. Biosphere level. The totality of all living organisms on our planet and their common natural habitat constitutes the biospheric level (Fig. 8). At the biospheric level modern biology decides global problems, for example, determining the intensity of the formation of free oxygen by the Earth's vegetation cover or changes in the concentration of carbon dioxide in the atmosphere associated with human activities. main role at the biospheric level, "living substances" perform, that is, the totality of living organisms that inhabit the Earth. Also at the biosphere level, "bio-inert substances" are important, formed as a result of the vital activity of living organisms and "inert" substances (i.e., environmental conditions). At the biospheric level, the circulation of substances and energy on Earth takes place with the participation of all living organisms of the biosphere.

levels of organization of life. population. Biogeocenosis. Biosphere.

Currently, there are several levels of organization of living organisms: molecular, cellular, tissue, organ, organism, population-species, biogeocenotic and biospheric.
At the population-species level, elementary evolutionary transformations are carried out.
The cell is the most elementary structural and functional unit of all living organisms.
A set of cells and intercellular substances similar in origin, structure and functions forms a tissue.
The totality of all living organisms on the planet and their common natural habitat constitutes the biospheric level.

List the levels of organization in order.
What is fabric?
What are the main parts of a cell?

What organisms are characterized by the tissue level?
Describe the organ level.
What is a population?

Describe the organism level.
Name the features of the biogeocenotic level.
Give examples of the interconnectedness of the levels of organization of life.

Complete the table showing the structural features of each level of the organization:

Serial number	Organization levels	Peculiarities

1 Levels of organization of the human body

3. Ontogeny, its age periods

The structure and functions of the body are studied in such sections of biology as anatomy, physiology and hygiene.

Human anatomy is a science that studies the structure of the human body, its organs and systems.

Human physiology is the science of life processes (functions) and the mechanisms of their regulation in cells, tissues, opianax. organ systems and the whole body.

Human hygiene is the science of the influence of physical, chemical, biological and social environmental factors on human health, its performance and life expectancy.

These sciences are closely interrelated and form the basis of modern medicine, pedagogy, psychology and valueology.

Structure and life various bodies and the whole organism are inseparable from each other (unity of structure and function). Knowledge of the structure and functions of the human body allows everyone to consciously observe the scientifically based rules of personal and public hygiene, avoid various diseases and be healthy, physically developed.

An organism is an independently existing unit of the organic world, which is a self-regulating system that reacts as a whole to various changes in the external environment.

Each organism has a set of features and properties that distinguish it from inanimate nature: metabolism and energy, self-reproduction, heredity, variability, growth and development, irritability, self-regulation.

Man, with his complex anatomical structure, physiological and mental characteristics, represents the highest stage in the evolution of the organic world.

1. Levels of organization of the human body

Each organism is characterized by a certain organization of its structures. There are six levels of organization of the human body: 1) molecular; 2) cellular: 3) tissue; 4) organ; 5) systemic; 6) organismic.

Molecular level of organization. Any living system, no matter how complex it is organized, manifests itself at the level of functioning of biological macromolecules (biopolymers): nucleic acids, proteins, fats (lipids), polysaccharides, vitamins, enzymes and other organic substances. Protein molecules, in turn, are broken down in the body into monomer molecules - amino acids, fats - into glycerol molecules and fatty acids, carbohydrates - into glucose molecules, etc. The most important life processes of an organism begin at the molecular level.

Cellular level of organization. A cell is an elementary structural, functional and genetic unit of a multicellular organism. In the human body, there are approximately K) "4 cells. The cells of a complex organism are specialized

Every cell has a cell membrane, cytoplasm and nucleus. The membrane limits the internal environment of the cell, protects it from damage. regulates the metabolism between the cell and the environment, provides an interconnection with other cells. Cytoplasm - the internal semi-liquid environment of the cell, to which the organelles of the cell are located, including the nucleus, which performs the functions of storing and transmitting hereditary information, regulating protein synthesis; nuclear division is the basis of cell reproduction

Tissue, level of organization. Tissues are groups of cells and intercellular substance, united general structure, function and origin. There are four main groups of tissues: epithelial, connective, muscle and nervous.

Epithelial (boundary) tissue is located on surfaces bordering the external environment, and lines the walls of hollow organs, blood vessels from the inside, and is part of the glands of the body. The epithelium has a high ability to restore (regenerate), serves as a material for hair, nails, tooth enamel.

Connective tissues (tissues of the internal environment) perform nutritional, transport and protective (blood, lymph), as well as supporting (tendon, cartilage, bone) functions. A type of connective tissue is adipose tissue.

Muscle tissue is divided into three types:

Striated (skeletal muscles, muscles of the tongue, pharynx, larynx);

Smooth (forms the walls of internal organs);

Cardiac (like skeletal it has a striated structure, but like smooth muscles it contracts involuntarily).

Nervous tissue, consisting of nerve cells (neurons), is involved in the conduction of a nerve impulse from various organs and tissues to the central nervous system and vice versa.

Organ level of organization. Various tissues, connecting with each other, form organs: the heart, kidneys, lungs, brain, spinal cord, muscle, bladder, uterus, breast, stomach, eye, ear, etc. The organ occupies a permanent position, has a certain structure, shape and functions Organs similar in structure, function and development are combined into organ systems

The system level of the organization. A set of organs involved in the performance of any complex act of activity, forming anatomical and functional associations - organ systems. There are nine major body systems.

1. The system of organs of movement or the musculoskeletal system combines all the bones (skeleton), their connections (joints, ligaments) and skeletal muscles. Thanks to this system, the body moves in the external environment; the bones of the skeleton protect the internal organs from mechanical damage (the skull protects the brain, the chest protects the heart and lungs).

2 The digestive system combines organs that perform the functions of eating, processing it mechanically and chemically, absorbing nutrients into the blood and lymph, and removing undigested parts of food. The digestive system consists of the mouth, pharynx, esophagus, stomach, small intestine, and large intestine. The digestive system includes the salivary glands, liver and pancreas.

3. The respiratory system carries out the consumption of oxygen by the body and the release of carbon dioxide. those. the function of gas exchange between the body and the environment. The respiratory system includes the nasal cavity, larynx, trachea, bronchi and lungs.

4. The urinary system performs the function of excreting the end products of metabolism from the body and the function of maintaining the constancy of the internal environment of the body (homeostasis). in particular the water-salt balance. The urinary system includes the kidneys, bladder, ureters, and urethra.

5 The reproductive system combines the organs of reproduction and performs the function of prolonging the human race. There are male and female reproductive systems, which include external and internal genital organs (gonads).

The male genital organs include external (penis, scrotum) and internal (testicles with appendages, vas deferens and ejection ducts, seminal vesicles, prostate and Cooper glands). The testicles are paired male sex glands that produce male sex cells (spermatozoa) and secrete male sex hormones - androgens into the blood. The process of rest and development of male germ cells is called spermatogenesis.

The female genital organs include external (large and small labia, clitoris) and internal (ovaries, uterine rough, uterus, vagina). The uterus is a hollow muscular organ designed to bear a fetus. Its inner layer (endometrium) is lined with mucous epithelium, which is updated in each menstrual cycle. The ovary is a steamy female gonad, in which the development and maturation of female germ cells (eggs) occur, as well as the formation of female sex hormones - estrogen and progesterone. The process of release of a mature egg from the ovary is called ovulation.

6. The endocrine system consists of endocrine glands, which include the pituitary, pineal, thymus, thyroid, pancreas, parathyroid. sex glands, adrenal glands. They produce special active substances (hormones) that are directly absorbed into the blood. Hormones are carried by the blood throughout the body and have a regulatory effect on various functions, primarily on metabolism, gene activity, ontogenetic development, tissue differentiation, sex formation, reproduction, tone of the cerebral cortex, etc.

7. The cardiovascular system (CVS) provides continuous movement of blood in the body (blood circulation), due to which the transport functions of blood are carried out: delivery of oxygen, nutrients and hormones to tissues and removal of substances resulting from metabolic processes from tissues. The cardiovascular system includes the heart, blood vessels (arteries, veins and capillaries) and lymphatic vessels. CCC plays an important role in the integration of the body into a single whole. Communication between organs is carried out through blood and lymph.

8. The system of sense organs combines the organs of sight, hearing, smell, taste and touch. They perceive information from the external environment, play an important role in the exchange of information between the organism and the environment.

0. The nervous system plays a leading role in uniting the body into a single whole, regulates the activity of all internal organs and systems of orks. It connects the organism with the external environment on the basis of conditioned and unconditioned reflexes, providing adaptation to the changing conditions of life, and also carries out the mental activity of a person that arises on the basis of the physiological processes of sensation, perception and thinking.

The nervous system includes the brain and spinal cord, nerves extending from them and all their branches. The brain and spinal cord form the central nervous system (CNS). The highest division of the CNS is the cerebral cortex. All nerves arising from the brain and spinal cord make up the peripheral nervous system. The activity of the spinal cord and peripheral nervous system is regulated by the overlying parts of the central nervous system. those. brain.

The brain is located in the skull. It contains nerve centers that provide the most important functions of the body and mental activity of a person. The mass of the brain of men is on average 1400 g, and women - 1300 g. These differences do not reflect mental ability, and the ratio of brain mass to body mass.

In the brain, the cerebral hemispheres and the brain stem are distinguished. In the brainstem there are centers of respiration, cardiac activity, digestion, psoas, coordination of movements and regulation of muscle tone, regulation of sensations by the sense organs, etc. These are the centers of unconditioned reflexes - innate responses of the body that provide important vital functions of the body: breathing, heartbeat, digestion, thermoregulation, maintaining muscle tone.

The cerebral hemispheres (left and right) are composed of gray and white matter. The gray matter, consisting of the bodies of nerve cells, forms the cerebral cortex about 3-4 mm thick. White matter, formed by the processes of nerve cells, is located under the cortex. There is an interhemispheric asymmetry between the right and left hemispheres of the brain. This means that the functions of both hemispheres are not exactly the same. For example, in right-handed people (people whose main active hand is right) the center of speech is in the left hemisphere. The left hemisphere in right-handed people is the main nerve substrate of human consciousness and is called dominant.

The frontal lobes of the cerebral hemispheres in humans are the largest areas of the cortex in terms of area (they are absent in animals!, except for chimpanzees). One of the functions of the frontal lobe is to manage innate behavioral responses with the help of accumulated experience. For patients with affected frontal lobes of the cortex, impulsivity, incontinence, irritability and other manifestations of mental instability are characteristic. Such patients often become rude, tactless, although their intelligence is preserved, they often come into conflict with other people.

The cerebral cortex influences all the functions of the body and provides the connection of the body with the external environment, causing the highest nervous activity organism (mental activity, thinking, memory, speech, etc.). The centers of conditioned reflexes are located in the cerebral cortex. Conditioned reflexes- this is knowledge acquired in the process of learning, during life - skills and abilities. If the cells of the cerebral cortex die under damaging influences, then a person is completely or partially deprived of the knowledge, skills and abilities acquired by him earlier. Such an effect is possible with clinical death when the cells of the cerebral cortex die from lack of oxygen. Memory has great value In human life. One can only roughly estimate the information capacity of the human brain. Inhabited information capacity of the brain! and a person is approximately equal to 3x10xbit (a bit is a unit of information). Of all the information that surrounds a person, only 1% enters long-term memory.

Whole body level. The human body functions as a whole and is a self-regulating system. Interconnected, coordinated work of all organs and physiological systems is provided by humoral and nervous regulation.

2. The main functions of ensuring the vital activity of the body

Humoral (chemical) regulation of functions is carried out due to the transfer of hormones and inorganic substances by the blood or lymph flow. gases, metabolic products and other active substances. This type of regulation, from the point of view of evolutionary development, is more ancient than nervous regulation. However, due to moral regulation, a rapid restructuring of the body's activity is impossible, because this type of regulation is limited by the speed of blood movement through the vessels.

Nervous regulation provides a rapid restructuring of the functions of organs and the body as a whole in accordance with the conditions of existence. This is possible because the speed of propagation of nerve impulses along the nerve conductors significantly exceeds the speed of blood movement through the vessels, nerve impulses always have an exact direction to certain cells, tissues, organs. Various reflexes can serve as an example of nervous regulation: knee, pupillary, sneezing, swallowing, indicative and others.

In the whole organism, there is a "single neurohumoral regulation of functions. For example, breathing is regulated by the respiratory center located in the medulla oblongata. When the respiratory center is excited, inhalation occurs, and when inhibited, exhalation occurs. The respiratory center is excited both by the nervous (reflex) and humoral ways. Specific The chemical irritant of the respiratory center is CO: An increase in the content of CO2 in the blood is accompanied by excitation of the respiratory center (inhalation occurs), a decrease - by its inhibition (exhalation occurs).

permanence chemical composition and physical and chemical properties internal environment is called homeostasis. It is supported by the continuous work of the systems of the organs of blood circulation, respiration, digestion, excretion, etc. Due to this, self-regulation of physiological functions occurs in the body, which turns on whenever there is a deviation from a certain constant level of any vital factor of the external or internal environment. For example, due to the mechanisms of homeostasis in human blood, a constant level of glucose, sodium chloride, acid-base balance, etc. is continuously maintained.

The relationship of the organism with the environment is carried out through the metabolism and energy. Metabolism (metabolism) is the main function of living matter and is a combination of physical, chemical and physiological processes of the transformation of substances and energy in the human body. The main types of metabolism include: protein, lipid, carbohydrate, mineral and water 3. Ontogeny, its age periods

The process of individual development of an organism from the moment of birth (conception) to its death is called ontogeny. The following periods of human life are distinguished (according to N.P. Gundobin, 1982):

1. Newborn (1-30 days);

2. Breast age (30 days - 1 year);

3. Early childhood (1-3 years);

4. First childhood (4 - 7 years old);

5. Second childhood (8-12 years old boys, 8-11 years old girls);

6. Adolescence (13-16 years old boys, 12-15 years old girls);

7. Youth age (17-21 years old boys, 16-20 years old girls):

8. Mature age: 1 period (22-35 years old men, 21-35 years old women); II period (36-60 years old men, 36-55 years old women);

9. Old age (61-74 years old men, 56-74 years old women);

10. Old age (75-90 years);

11. Long-livers (90 years and above).

1. So, consideration of all sections and subsections of the chapter on the human body allows us to make sure that the human body is a universal single integral biological system, adequately responding to various changes both in the organism itself and in its natural, technogenic and social environment.

The following levels of life organization are distinguished: molecular, cellular, organ-tissue (sometimes they are separated), organismic, population-species, biogeocenotic, biospheric. Live nature is a system, and the various levels of its organization form its complex hierarchical structure, when the underlying simpler levels determine the properties of the overlying ones.

So complicated organic molecules are part of the cells and determine their structure and vital activity. In multicellular organisms, cells are organized into tissues, and several tissues form an organ. A multicellular organism consists of organ systems, on the other hand, the organism itself is an elementary unit of a population and biological species. The community is represented by interacting populations of different species. The community and the environment form a biogeocenosis (ecosystem). The totality of ecosystems of the planet Earth forms its biosphere.

At each level, new properties of living things arise, which are absent at the underlying level, their own elementary phenomena and elementary units are distinguished. At the same time, the levels largely reflect the course of the evolutionary process.

The allocation of levels is convenient for studying life as a complex natural phenomenon.

Let's take a closer look at each level of organization of life.

Molecular level

Although molecules are made up of atoms, the difference between living matter and non-living matter begins to manifest itself only at the level of molecules. Only found in living organisms a large number of complex organic substances - biopolymers (proteins, fats, carbohydrates, nucleic acids). However molecular level The organization of living things also includes inorganic molecules that enter cells and play an important role in their life activity.

The functioning of biological molecules underlies the living system. At the molecular level of life, metabolism and energy conversion are manifested as chemical reactions, the transfer and change of hereditary information (reduplication and mutations), as well as a number of other cellular processes. Sometimes the molecular level is called the molecular genetic level.

Cellular level of life

It is the cell that is the structural and functional unit of the living. There is no life outside the cell. Even viruses can exhibit the properties of a living being only once they are in the host cell. Biopolymers fully show their reactivity when organized into a cell, which can be considered as complex system interconnected in the first place by various chemical reactions molecules.

On this cellular level the phenomenon of life manifests itself, the mechanisms of transmission of genetic information and the transformation of substances and energy are conjugated.

Organ tissue

Only multicellular organisms have tissues. Tissue is a collection of cells similar in structure and function.

Tissues are formed in the process of ontogenesis by differentiation of cells that have the same genetic information. At this level, cell specialization occurs.

Plants and animals produce different types fabrics. So in plants it is a meristem, a protective, basic and conductive tissue. In animals - epithelial, connective, muscular and nervous. The fabrics may include a list of subfabrics.

An organ usually consists of several tissues, united among themselves in a structural and functional unity.

Organs form organ systems, each of which is responsible for an important function for the body.

The organ level in unicellular organisms is represented by various cell organelles that perform the functions of digestion, excretion, respiration, etc.

Organismal level of organization of living

Along with the cellular at the organismal (or ontogenetic) level, separate structural units are distinguished. Tissues and organs cannot live independently, organisms and cells (if it is a unicellular organism) can.

Multicellular organisms are made up of organ systems.

At the organismic level, such phenomena of life as reproduction, ontogeny, metabolism, irritability, neuro-humoral regulation, homeostasis are manifested. In other words, its elementary phenomena constitute regular changes in the organism in individual development. The elementary unit is the individual.

population-species

Organisms of the same species, united by a common habitat, form a population. A species usually consists of many populations.

Populations share a common gene pool. Within a species, they can exchange genes, that is, they are genetically open systems.

In populations, elementary evolutionary phenomena occur, ultimately leading to speciation. Living nature can evolve only in supra-organismal levels.

At this level, the potential immortality of the living arises.

Biogeocenotic level

Biogeocenosis is an interacting set of organisms of different species with different environmental factors. Elementary phenomena are represented by matter-energy cycles, provided primarily by living organisms.

The role of the biogeocenotic level consists in the formation of stable communities of organisms of different species, adapted to living together in a certain habitat.

Biosphere

The biospheric level of life organization is a higher-order system of life on Earth. The biosphere encompasses all manifestations of life on the planet. At this level, the global circulation of substances and the flow of energy (covering all biogeocenoses) take place.

In the course of this lesson, we will get acquainted with the levels of organization of our body and its organ systems.

Topic: General overview of the human body

Lesson: Organ systems in the body. Organization levels

1. Levels of organization

Our body. This definition seems so familiar and understandable that we rarely think about its essence. And to the question: “what is it all the same?” many may find it difficult to answer.

Molecules, cells, tissues, organs, organ systems - all these floors, or different levels of the living, are united in the human body into a single and inseparable whole.

Living organisms are built from special chemical compounds - organic substances (proteins, fats, carbohydrates, nucleic acids). They are part of every living cell. These large molecules act as building blocks that create complex complexes. The substances of the cell are not located randomly, but form ordered structures - organelles, which provide the processes of the cell's vital activity. The human body is a multicellular state. The cells of the human body are not the same, they differ in their specialization. Cells of the same specialty are combined into groups. Together with the intercellular substance, they form tissues. Organs are made up of multiple tissues. Organs that perform a single function and have a common plan of structure and development will unite into organ systems. All organ systems are interconnected and form a single organism.

There are 10 major organ systems in the human body.

2. Integumentary system

3. Musculoskeletal system

The musculoskeletal system consists of the skeleton and the muscles attached to it. It allows a person to stand, move, perform complex work, protects internal organs from damage.

4. Digestive system

The digestive system consists of the digestive tract (oral cavity, pharynx, esophagus, stomach and intestines) and digestive glands: salivary glands, glands of the stomach and intestines, pancreas, liver. The functions of the digestive system are the digestion of food and the absorption of nutrients into the blood.

5. Circulatory system

Circulatory system consists of the heart and blood vessels. This system supplies the organs of our body with nutrients and oxygen, removes from them carbon dioxide and other waste products of vital activity, performs a protective function, participating in immunity.

6. Lymphatic system

lymphatic system formed by lymph nodes and lymphatic vessels. It takes part in the formation of immunity and maintaining the constancy of the internal environment of the body.

7. Respiratory system

System bodies breathing consists of the respiratory tract (nasal cavity, nasopharynx, pharynx, larynx, trachea and bronchi) and the respiratory part - the lungs. The function of the respiratory system is to provide gas exchange between the external environment and the body.

8. Excretory system

The excretory system is formed by the kidneys, which produce urine containing harmful metabolic products, and the urinary organs - the ureters, bladder and urethra.

9. Reproductive system

reproductive system consists of the sex glands, internal and external genital organs. The function of the reproductive system is to ensure the process of childbearing.

10. Nervous system

The nervous system consists of the brain and spinal cord and nerves and ganglions extending from them. It regulates the work of organs, ensures their coordinated activity and adaptation to environmental conditions. Through the sense organs, it communicates with the environment. Thanks to nervous system mental activity of a person is carried out, his behavior is determined.

11. Endocrine system

Similar functions are performed by endocrine system, formed by the endocrine glands, such as the pituitary, thyroid, adrenal glands and some other glands. They secrete hormones.