The Basic Anatomy,Tissues and Organs

There are many different types of cells in the human body. None of these cells work well in their own, are part of the larger organism is called - that.

Fabrics
Cells group together in the body to form tissues - a collection of similar cells are grouped to perform a specialized function. There are 4 primary tissue types in the human body: epithelial tissue, connective tissue, muscle and nervous tissue.

Epithelial tissue - cells of epithelial tissue pack tightly together and form continuous sheets that serve as linings in different parts of the body. Epithelial tissue serve as membranes that line the organs and help maintain the body's organs separate, in place and protected. Examples of epithelial tissue are the outer layer of skin inside the mouth and stomach, and the tissue surrounding the organs of the body.
Fabric - There are many types of connective tissue in the body. In general, connective tissue adds support and structure to the body. Most types of connective tissue contain fibrous strands of the protein collagen that add strength to connective tissue. Some examples of connective tissue include the inner layers of the skin, tendons, ligaments, cartilage, bone and fat tissue. In addition to these more recognizable forms of connective tissue, blood is also considered a form of connective tissue.
Muscle tissue - muscle tissue is a specialized tissue that can contract. Muscle tissue contains actin and myosin specialized proteins that slide over one another and allow movement. Samples of muscle tissue found in muscles throughout your body.
Nerve Tissue - Nerve tissue contains two types of cells: neurons and glial cells. Nerve tissue has the capacity to generate and conduct electrical signals in the body. These electrical messages are managed by nerve tissue in the brain and transmitted down the spinal cord to the body.

Organs
Organs are the next level of organization in the body. An organ is a structure containing at least two different types of tissue functioning together for a common purpose. There are many different organs in the body: the liver, kidneys, heart, though his skin is an organ. In fact, the skin is the largest organ in the human body and provides an excellent example for explanation purposes. The skin is composed of three layers: the epidermis, dermis and subcutaneous layer. The epidermis is the outermost layer of skin. It consists of epithelial tissue in which cells are tightly packed together providing a barrier between the inside of the body and the outside world. Beneath the epidermis is a layer of connective tissue called the dermis. In addition to providing support to the skin, the dermis has many other purposes. The dermis contains blood vessels that nourish the skin cells. It contains nerve tissue that provides feeling in the skin. And it contains muscle tissue that is responsible for giving "goose bumps" when you are cold or frightened. The subcutaneous layer is beneath the dermis and consists mainly of a type of connective tissue called adipose tissue. Adipose tissue is more commonly known as fat and helps smooth the skin and provide protection against low temperatures.
A cross-section of skin

Organ Systems
Organ systems are composed of two or more different organs that work together to provide a common function. There are 10 major organ systems in the human body, they are the:

Skeletal System:

Image courtesy of A. McGann

Muscular System:

Circulatory System:

Nervous System:

Respiratory System:

Digestive System:

Excretory System:

Reproductive System:

Male

For more information on human anatomy, try these other sites:

The National Library of Medicine has an excellent page that includes links to Medline, a searchable medical research database, and the Visible Human Project's animations, which include anatomical illustrations from human cadavers and an animated trip through the Visible Human male cryosections (770k movie linked here).
The Informative Graphics Corp. has put together a wonderful Human Anatomy On-line program.
The University of Washington's Digital Anatomist Interactive Atlas has some interesting computer generated illustrations of the brain, the heart and a knee cross-section.
Andrew McGann's Look Inside the Human Body has more information on some organ systems.
The Upper Freehold Regional School District's AP Biology class has put together a nice summary of the Human Organ Systems.
The Indianapolis-Marion County Public Library's Inside the Human Body site has organ system info.