Systemic approach to anatomy

body study is organized around organ systems, such as circulatory, digestive,..     

Regional approach to anatomy

body study is organized around body regions, such as head and neck, thorax, ...

Organismal level

the result of all simpler levels working in unison

Organ system 

organs working together for a common purpose

Organ level 

a discrete structure made up of more than one tissue

Tissue level 

a group of cells performing a common function

Cellular level 

cells and their functional subunits

Chemical Level 

atoms form molecules

Hierarchy of structural organization

Organismal level, Organ system, Organ level, Tissue level, Cell level, Chemical level

Organelles

“little organs” – carry on essential functions of cells

Enzymes 

direct chemical reactions in cells

Metabolism 

the sum of all chemical reactions in the cell

Three main components of cells

Plasma membrane, Cytoplasm, Nucleus

Nucleus

“central core” or “kernel” – control center of cell

Nuclear envelope 

two parallel membranes separated by fluid-filled space

Chromatin 

composed of DNA and histone proteins

Condensed chromatin 

contains tightly coiled strands of DNA

Extended chromatin 

contains uncoiled strands of DNA

Chromosomes 

highest level of organization of chromatin

Nucleolus 

Plasma membrane

defines the extent of the cell