hierarchy of structures in animals. the hierarchy of structure least complex most complex cells...
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Hierarchy of Structures in Animals
The Hierarchy of StructureLeast complex Most complexCellsTissuesOrgansOrgan SystemsOrganism
Organ systems : groups of organs that work together to perform a single function in the organismeg. Digestive system A complex organism such as an animal is made up of various organ systems
Most Organs are composed of several different types of tissuestomach
The Four Types of Animal TissueEpithelialConnectiveMuscleNerve Remember: tissue is made up of multiple cells
Epithelial Tissue-structureThin sheets of tightly packed cellsCovers surfaces and lines internal organs
Epithelial Tissue-functionProtects from dehydrationCreates low-friction surfaces
Ex: skin, lining of digestive system
Connective Tissue-structureVarious cells and fibres held together by a matrix of solids and liquids
Connective Tissue-functionProvides support and insulation Ex. Bone, tendons, blood, connection between skin and muscle
Muscle Tissue-structureBundles of long parallel cellsContain specialized proteins that allows fibres to contract or shorten
Muscle Tissue-functionAllows movement of tissue and organsEx. Skeletal muscle (biceps, quads)Cardiac muscleDigestive muscles
Nerve Tissue-structureLong, thin cellsHave fine branches at ends to conduct electrical impulses
Nerve Tissue-functionUsed to sense environment and communicate with the rest of the bodyEx. Brain, spinal cord, optical nerves
Stem Cells and Cellular Differentiation
Multicellular organisms develop from a single cell, which is called a zygote.
The zygote divides continuously to form an embryo
Cellular differentiation: occurs when the cells of the embryo divide and begin to differ in shape, size, contents and function.
What do we call plants stem cells?Meristems or meristematic cells
Located at root tips, terminal and lateral buds of plants
Stem CellsA Stem cell is a cell that can differentiate into many different types of specialized cells.
There are 2 types of stem cells in animals: 1) Embryonic Stem Cells: taken from the embryonic stagecan differentiate into any type of cell.
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.
Stem Cell ApplicationsTo study development Aids our understanding of how normal development and abnormal development occurs.
May lead to therapies for diseases and birth defectseg Cleft palate
Stem Cell ApplicationTo replace damaged cells and treat diseasesTreat burns To replace blood in leukemia patientsPossible future application: replaced damaged tissues for Parkinson's disease, stroke, heart disease and diabetes.
Stem Cell ApplicationTo study diseaseStem cells, engineered to contain the diseased gene are used to model & understand the disease process
Stem Cell ApplicationCould provide a resource for testing new medical treatmentsNew medications could be tested for safety on specialized cells generated in large numbers from stem cell lines reducing the need for animal testing.
Stem cell research is controversial and involves moral and ethical dilemmas for many peopleWhat are the ethical issues around stem cell usage?
Watch: The role of stem cells(12 mins)Go to http://www.learn360.com/Username: calctorPassword: calctorPut in keyword: Clone the role of stem cellsClick and watch; make sure speakers are on