Nursing foundations of biology

• Anatomy is the science of structure and the relationship among structures.
• Physiology is the science of the body functions, that is, how the body parts work.
• The chemical level:

  Atoms – the smallest units of matter that participate in chemical reactions.

  Molecules – two or more atoms joined together.
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  The cellular level – 

  Cells are the basic structural and functional units of an organism. 

  Types of cells in the human body are muscle cells, nerve cells, and blood cells.
• The tissue level- 

  Tissues are groups of cells and the materials surrounding them that work together to perform a particular function. 

  Cells join together to form tissues
• There are four basic types of tissue in the body:

  -       Epithelial tissue

  -       Connective tissue

  -       Muscular tissue

  -       Nervous tissue
• Organ level-

  Organs are composed of two or more different types of tissues, and have specific functions.

  Examples of organs are: Stomach, heart, liver, lungs and brain.
• System level:

  System consists of related organs that have a common function.

  Example is the digestive system, which breaks down and absorbs molecules in food.
• The organismal level:

  Organismal level is the largest level of organisation.

  All the systems of the body combine to make up an organism.