Specialization and Stem cells

1. Specialization and Stem cells

3. Why Specialize?? • A single celled organism performs all required functions all in one cell. • Ex. An Amoeba

4. Why Specialize?? • Multicellular organisms are much more complex. • Allocated cells , tissues and organs perform certain bodily functions. • Ex. Supply food and nutrients, transport materials, remove waste and fight infections

5. Specialized Cells The structure matches the function!!

6. Stem Cell • Stem cell: an unspecialized cell • Scientists study stem cells to learn more about specialization and differentiation • Stem cells can be used to treat injuries and diseases by regenerating organs • Stem cells can differentiate into any cell type of a plant or animal such as nerve, blood, or muscle cells of humans • Every cell in you body originally came from a small group of stem cells • These stem cells specialize when exposed to certain conditions such as hormones or can remain unspecialized and actively dividing for long periods of time

7. Animal Stem Cells • Animal stem cells - two types • Embryonic stem cells can differentiate into other cell types http://www.hhmi.org/biointeractive/stemcells/human_emb_dev.html • Adult stem cells are mature specialized cells mostly involved in replacement of damaged tissue

8. Plant Stem Cells • Called meristematic cells • Found in growing tips of roots and stems Meristematic cells in an onion root tip (magnification 25x)

9. Regeneration • Cell Regeneration: the process of replacing or regrowing a body tissue or organ • Salamanders - have unique ability to not only to regrow limbs that have been amputated but also tails, lenses in eyes, and parts of the heart. http://www.dnatube.com/video/504/Newt-Limb-Regeneration • Humans - the liver is the only organ that has the ability to naturally regenerate, and in young children, fingertips can also regenerate.

10. Regeneration of a newt’s limb over 6 to 8 weeks. The newt is a type of salamander. The axoloti is a type of salamander that can regrow amputated limbs videos.howstuffworks.com/science-channel/29246-kapow-superhero-science-limb-regeneration-video.htm?sort=most_watched&page=2

11. Current Research • Pig extracellular matrix applied to severed fingertip of human stimulates regrowth http://news.bbc.co.uk/2/hi/health/7354279.stm http://news.bbc.co.uk/2/hi/health/7354458.stm • Creation of body parts in the lab – success seen with: • Regrown bladder (picture) • Blood vessels • Heart valves Image from: http://news.nationalgeographic.com/news/2006/04/0404_060404_bladders.html

12. Specialized Cells and Tissues Its all about team work! Tissue: groups of cells that function together to perform specialized tasks.

13. Animal Tissues 4 types of specialized tissues: Epithelial Tissue: • Lines body cavities and outer surface of body • Protects structures • Forms glands that produce hormones, enzymes and sweat Connective Tissue: • Supports and protects structures • Forms blood • Stores fat • Fills empty space

14. Animal Tissues Muscle Tissue: • Allows for movement Nervous Tissue: • Responds to stimuli • Transmits and stores information

15. Plant Tissues 4 types of specialized tissues Epidermal Tissue: • Forms the protective outer covering • Allows the exchange of materials and gases into and out of the plant through guard cell stomata Vascular Tissue: • 2 types of vascular tissue • Xylem: moves substances from roots to the leaves • Phloem: transports sugars from leaves to other areas

16. Plant Tissues Ground Tissue: • In the stem: provides strength and support • In the roots: stores food and water • In the leaves: photosynthesis Meristematic Tissue: • Unspecialized tissue capable of dividing by mitosis • Found in several locations in the plant • Responsible for growing new parts of the plant

17. Plant Tissues