Introduction to human body
Anatomy is a Greek word (anatomē) that means “to cut apart”. It is a branch of science concerned with the identification and description of the body structures of living things. Anatomy can be defined as a branch of science that deals with the structures of the body and the relationship of various parts to each other.
Physiology is the study of the functioning of living organisms, animal or plant, and of the functioning of their constituent tissues or cells. In short the way in which the bodies of living things work.
Organizations of living systems
Living systems theory is a general theory about the existence of all living systems, their structure, interaction, behavior and development. This work is created by James Grier Miller, which was intended to formalize the concept of life.
At the chemical level, atoms, molecules (combinations of atoms), and the chemical bonds between atoms provide the framework upon which all living activity is based.
Cell is the smallest structural, functional unit of life. Organelles within the cell are specialized bodies performing specific cellular functions. Cells themselves may be specialized. Thus, there are nerve cells, bone cells, and muscle cells.
Tissue is a group of similar cells performing a common function. Muscle tissue, for example, consists of muscle cells.
Organ is a group of different kinds of tissues working together to perform a particular activity. The heart is an organ composed of muscle, nervous, connective, and epithelial tissues.
Organ system is two or more organs working together to accomplish a particular task. The digestive system, for example, involves the coordinated activities of many organs, including the mouth, stomach, small and large intestines, pancreas, and liver.
Organism is any individual entity that embodies the properties of life like the ability to obtain and process energy, the ability to respond to environmental changes, and the ability to reproduce.
Homeostasis – The phenomenon in which the body regulates its process to keep internal conditions as well as possible is termed as homeostasis. Homeostasis is necessary because the body cells need to have suitable conditions around them for proper functioning. Inside the cell these conditions include – presence of proper concentration of chemicals, temperature, and a suitable pH etc.
Descriptive terms used in Anatomy:
Symmetric - limbs, eyes, ears, and lungs.
Asymmetric - Spleen, liver
Following are a few important terms which are used to describe the human body:
Median line (mid sagittal plane) - The central plane which divides the body into two halves,
(right and left).
Medial : Nearer to the median line
Lateral : Away from the median line
Superior : Towards head
Inferior : Towards foot (nearer foot)
Posterior : Back surface of the body
Proximal : Near the origin of structure
Distal : Away from the origin of structure
Superficial : Skin surface