1. The Hierarchy… Alveolar cells Alveolar tissue Lung (organ)
Respiratory system

2. From Cell to Tissue Cells are organized into tissues
A tissue is a groups of similar cells that have a common function
Ex: endothelial cells  endothelial tissue (skin)
brain cells  brain tissue
There are 4 types of tissue:
Epithelial Tissue
Connective Tissue
Nerve Tissue
Muscle Tissue

3. Epithelial Tissue Epithelial tissue: Ex: covers and protects organs
Secretes, absorbs and filters substances
Ex:
Epithelial tissue of salivary glands contains cells that secretes saliva
Epithelial cells of the digestive system contains cells that absorb nutrients

4. Connective Tissue Connective tissue: EX:
Provides organs in the body with protection and nutrients
EX:
Bone tissue supports and protects the body
Fatty tissue stores nutrients as fat

5. Nerve Tissue Nerve tissue:
Allows messages to sent and received between the brain and body
Nerves, spinal cord and brain are made up of nerve tissue

6. Muscle Tissue
Muscle tissue is composed of fibers capable of contracting to allow bodily movement. There are 3 types of muscle tissue:
a) Skeletal: Makes up the muscles that are attached to the bones.
b) Smooth: Makes up the lining of organs that contract (stomach, bladder)
c) Cardiac: Found in the heart

7. From Tissue to Organ
An organ is a structure composed of two or more tissue types performing one or more specific functions.
Ex: The stomach is an organ made up of four types of tissue.

8. From Organ to System
An system is made up of groups of organs that work together to perform a set of related tasks
Ex: mouth, esophagus, stomach, intestines = digestive system
Each organ performs a specific function and all organs work together