Sports science in English
from A to Z

The basic building block of human body is the cell, which is organized into more complex structures, in order to best perform its functions. These structures are called tissues and they differ according to their role within the body.

• Epithelial tissue: it covers and protects internal and external surfaces of the body; it prevents the passage of substances between the inside and outside of the cells.
• Connective tissue: it supports and connects different types of tissue, and it protects and covers organs. Examples of connective tissue are the tendons and ligaments (see articular system), as well as blood and lymph (see circulatory system), which is made of substances formed by various types of cells circulating in blood vessels within the body and transporting nutrients that are essential for the life of all cells.
• Muscle tissue: it contracts in response to nerves stimulus and it determines the movement.
• Nervous tissue: it perceives changes in the environment; it elaborates and quickly transmits electrical and chemical signals to the body.
• Bone tissue: it forms the rigid part of the bones (see skeletal system) and it supports and protects the body.
• Cartilaginous tissue: it constitutes the terminal part of the bones. Cartilage creates a very flexible, smooth surface, which protects the end of the bones avoiding the friction between them and allowing articular heads to slide over one another.

The tissues that are made of cells of the same type are called systems; the main systems of the human body are as follows: nervous system, muscular system, lymphatic system and endocrine system.

An organ is made from a group of different tissues giving rise to more complex structures, which in turn make up one functional unit. Together different organs make up different systems, which play a vital function. The main systems of the human body are: skeletal system, articular system, circulatory system, respiratory system, digestive system, excretory system, urogenital system.

The perfect harmony and cooperation between the different systems allows the proper functioning of the human body, making life possible.