Human Anatomy and Physiology - I. V. Gayvoronsky 2011

The human body as an integrated whole. Fundamentals of cytology and histology
The human body as a single entity

The highest form of integration in Human Body Structure is the integration of Organ Systems. It provides the highest level of Organization—the Organism as a single, unified whole.

The Human Body as a living biological system exists solely through continuous interaction with the environment. Certain characteristic properties are inherent to the human body as a living system. The primary ones include METABOLISM, irritability, the capacity for GROWTH AND REPRODUCTION, mobility, the maintenance of a stable internal environment, plasticity, and integrity.

The Emergence of these properties became possible only As a result of structural integration at all levels of the human body's organization. Integration is a process of unification that gives rise to a new quality and a higher level of organization.

Four types of integration are distinguished: mechanical, humoral, chemical, and neural.

At THE TISSUE LEVEL, mechanical integration is mediated by intercellular substances and junctions; at the organ level, by Connective Tissue; and at the system level, by accessory Organs. Humoral integrators are Blood AND Lymph, which perform an integrative role at the organ, intersystem, and organismal levels. Chemical integration refers to endocrine regulation mediated by Hormones secreted by Endocrine glands. Hormones exert their integrative effects across all levels: cellular, tissue, organ, intersystem, and organismal.

The highest level of integration is neural integration. Over the course of evolution, a specialized system—The Nervous system—emerges. It coordinates and regulates The activity of individual organs and body systems, ensuring the organism's adaptation to continuously changing environmental conditions.

Thus, a living, integrated human organism is a biological system capable of self-development, self-Replication, and self-regulation, distinguished by high plasticity, mobility, and resilience.

An integral characteristic of the external form of the human body as a unified, holistic system is constitution (habitus).

Body constitution (from the Greek habitus) is the aggregate of structural features, shape, dimensions, and proportions of individual PARTS OF THE human body. In other words, constitution refers to body shape, the proportionality of its individual parts, and their proper structural arrangement.

Since the time of Hippocrates, three main constitutional types have been distinguished:

1) the asthenic (dolichomorphic) type, characterized by tall stature, weakly developed musculature and Skeleton, and scant fat deposition;

2) the normosthenic (mesomorphic) type, characterized by medium stature, well-developed skeleton and musculature, prominent facial features, and minimal subcutaneous fat deposition;

3) the hypersthenic (brachymorphic) type, characterized by medium or short stature, a short neck, large HEAD size, short limbs, a broad chest, and a predisposition to subcutaneous fat accumulation.

Body build is associated not only with differences in The structure of organs (bones, Muscles, and subcutaneous adipose tissue accessible to external inspection and Palpation) but also determines the varying position, shape, and size of Internal Organs. For instance, the brachymorphic constitution corresponds to such features as a high position of the Diaphragm, a horizontal position of The Heart, an oblique and high position of The Stomach, a high position of the cecum, and a relatively long Small Intestine (6–8 m). Conversely, the dolichomorphic constitution corresponds to a low position of the diaphragm, a vertical position of the heart, an elongated stomach, a low position of the cecum, and a relatively short small intestine (4–5 m).

Body constitution exhibits pronounced age-related and sexual characteristics. During the organism's growth, There is a relative decrease in the size of the head and trunk, alongside an increase in the length of the neck and limbs. A specific ratio of body proportions is characteristic of each age group, from birth through old age.

In medical practice, the following age periodicity is adopted:

✵ newborn—from birth to 28 days;

✵ infancy—from 28 days to 1 year;

✵ early childhood—from 1 to 3 years;

✵ first childhood—from 3 to 7 years;

✵ second childhood—from 8 to 12 years (boys), from 7 to 11 years (girls);

✵ adolescence—from 12 to 16 years (boys), from 11 to 15 years (girls);

✵ youth—from 16 to 21 years (young men), from 15 to 20 years (young women);

✵ adulthood: period I—from 21 to 35 years (men), from 20 to 35 years (women); period II—from 35 to 60 years (men), from 35 to 55 years (women);

✵ elderly age—from 60 to 74 years (men), from 55 to 74 years (women);

✵ old age — from 74 to 90 years (men and women);

✵ centenarians — 90 years and older.

Review Questions

1. List the Levels of organization of the human body.

2. What are the main Functions performed by The Cell?

3. List the Organelles and describe their functions.

4. What is the Cell Cycle? What phases does it consist of?

5. What types of tissues exist?

6. List the types of epithelium and name their functions.

7. What types of connective tissue do you know and what is their localization in the human body?

8. List the types of Muscle tissue and characterize their functions.

9. What function does Nervous Tissue perform in the body?

10. Define an organ and an organ system.

11. Describe the Structural Features of hollow and parenchymatous organs.

12. Which organ systems make up the human body?

13. What types of integration in the human body do you know?

14. What are the main body types?