1. Hierarchy of Structures in Animals

2. The Hierarchy of Structure
Cells
Least complex
Tissues
Organs
Organ Systems
Most complex
Organism

3. Organ systems : groups of organs that work together to perform a single function in the organism
eg. Digestive system
A complex organism such as an animal is made up of various organ systems

4. Most Organs are composed of several different types of tissue
stomach

5. The Four Types of Animal Tissue
Epithelial
Connective
Muscle
Nerve
Remember: tissue is made up of multiple cells

6. Epithelial Tissue-structure
Thin sheets of tightly packed cells
Covers surfaces and lines internal organs

7. Epithelial Tissue-function
Protects from dehydration
Creates low-friction surfaces
Ex: skin, lining of digestive system

8. Connective Tissue-structure
Various cells and fibres held together by a matrix of solids and liquids

9. Connective Tissue-function
Provides support and insulation
Ex. Bone, tendons, blood, connection between skin and muscle

10. Muscle Tissue-structure
Bundles of long parallel cells
Contain specialized proteins that allows fibres to contract or shorten

11. Muscle Tissue-function
Allows movement of tissue and organs
Ex. Skeletal muscle (biceps, quads)
Cardiac muscle
Digestive muscles

12. Nerve Tissue-structure
Long, thin cells
Have fine branches at ends to conduct electrical impulses

13. Nerve Tissue-function
Used to sense environment and communicate with the rest of the body
Ex. Brain, spinal cord, optical nerves

14. Stem Cells and Cellular Differentiation

15. Multicellular organisms develop from a single cell, which is called a zygote.

16. The zygote divides continuously
to form an embryo

17. Cellular differentiation: occurs when the cells of the embryo divide and begin to differ in shape, size, contents and function.

18. What do we call plants’ stem cells?
Meristems or meristematic cells
Located at root tips, terminal and lateral buds of plants

19. Stem Cells
A Stem cell is a cell that can differentiate into many different types of specialized cells.

20. There are 2 types of stem cells in animals:
1) Embryonic Stem Cells:
taken from the embryonic stage
can differentiate into any type of cell.

21. 2) Tissue or Adult Stem Cells: found in certain specialized tissue
Can differentiate into ONLY certain types of cells.
Ex. Bone marrow tissue stem cells can differentiate into white or red blood cells, platelets and many other types of cells.

22. Stem Cell Applications
To study development
Aids our understanding of how normal development and abnormal development occurs.
May lead to therapies for diseases and birth defects
eg Cleft palate

23. Stem Cell Application To replace damaged cells and treat diseases
Treat burns
To replace blood in leukemia patients
Possible future application: replaced damaged tissues for Parkinson's disease, stroke, heart disease and diabetes.

24. Stem Cell Application To study disease
Stem cells, engineered to contain the diseased gene are used to model & understand the disease process

25. Stem Cell Application
Could provide a resource for testing new medical treatments
New medications could be tested for safety on specialized cells generated in large numbers from stem cell lines – reducing the need for animal testing.

26. What are the ethical issues around stem cell usage?
Stem cell research is controversial and involves moral and ethical dilemmas for many people
What are the ethical issues around stem cell usage?

27. Watch: The role of stem cells (12 mins)
Go to
Username: calctor
Password: calctor
Put in keyword: “Clone the role of stem cells”
Click and watch; make sure speakers are on

28. The End