Chapter 4. 4 major types of tissues Epithelial tissue- Covers surface of body, lines hollow organs...
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Transcript of Chapter 4. 4 major types of tissues Epithelial tissue- Covers surface of body, lines hollow organs...
Cell ConnectionsChapter 4
4 major types of tissuesEpithelial tissue- Covers surface of body,
lines hollow organs and body cavities. Ex: Skin and stomach tissue
Connective tissue- Holds organs in place, protects and supports body. Ex: Tendons and ligaments
Muscular tissue- Generates physical force and movements. Ex: Biceps, quadriceps
Nervous tissue- Helps control and coordinate body movement by detecting changes and responding with nerve impulses. Ex: Brain and spinal cord
To function in a coordinated way as part of a tissue, cells must have cell junctions.
Cell junction- points of contact between neighboring plasma membranes.
Imagine trying to build a house with nothing to hold the lumbar, roof, and walls together.
Plant cellsPlasmodesmata- Channels between adjacent
plant cells. They form a circulatory and communication system connecting the cells in plant tissues.
*Helps water and small molecules pass easily from cell to cell.
Animal cellsAdjacent cells in animal tissues also connect
by cell junctions; there are three types:
Tight junctionsAnchoring junctions
(desmosomes)Gap junctions
Tight junctionsBind cells very tightly togetherForms a leakproof sheetPrevents passage of materialsLines digestive tract, preventing contents from leaking into surrounding tissues.
Anchoring junctionsStrongly link cells together with cytoskeletal
fibersForms strong sheetsCommon in tissues that have to stretch, such
as skin and heart muscle.Helps keep skin cells from separating
Ex: Desmosomes
Gap junctionsChannels similar to plasmodesmata in plant
cellsAllows small molecules to flow between
neighboring cells.Important for chemical communication.