1. Cellular Specialization

2. Start of Life
Fertilization- sperm + ova = ZYGOTE (single cell, full set DNA)
Zygote – divides by mitosis into 2 cells, then 4 cells…….full organism!
Cells DIVIDE AND SPECIALIZE

3. Tissue Types Specialized cells: perform common function called tissues
Tissues: group of similar cells that have a common structure and function.

4. 1. EPITHELIAL TISSUE
Covers and protects organs, inside (lining of organs) & outside (skin)
Also Secretes, absorbs, filters

5. Ex. Skin
Protects underlying tissues

6. Salivary glands
Secrete saliva

7. Ex. Small intestine
Cells that absorb nutrients

8. Ex. Kidneys
Cells in kidneys that filter blood

9. 2. Connective Tissues
Binds and supports tissues & organs for protection & nutrients
Most abundant, widely distributed

10. Ex. Cartilage
Protects bone extremities

11. Ex. Blood tissue
Transports substances like oxygen, carbon dioxide

12. Ex. Bone tissues
Supports and protects body

13. Ex. Fatty tissues
Stores nutrients as fats

14. 3. Nerve Tissue Helps to control and guide the body
Receive, process, and transmit messages between the brain & body
Ex. Nerves, spinal cord, brain

15. 4. Muscle Tissue Tissues that contract & relax (spring like)
Make body or parts move

16. Skeletal (voluntary): attached to bones
Smooth (involuntary) : lining of organs
ex. Stomach, bladder, uterus, blood vessels
3. Cardiac(involuntary): only in heart

17. Structure of Body
Tissue: group of cells that have common structure and function
Organs: composed of two or more tissue types performing one or more specific functions. Ex. Stomach (fig 5.17)
Muscle tissues: contract and relax crushing food
Epithelial tissues: secrete gastric juices
Connective tissues: hold stomach together (shape)
Nerve Tissues: control activity in stomach

19. 3. Systems
Group of organs & tissues working together to accomplish a common function.
ex. Digestive system: esophagus, Stomach, small intestine, large intestines
Many systems (see fig. 5.19)