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Tissue renewal

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TISSUE RENEWAL, REGENERATION & REPAIR

TISSUE RENEWAL, REGENERATION & REPAIRJOMIN GEORGELECTURERFACULTY OF HEALTH INFORMATION MANAGEMENTEmail: [email protected] word healing, used in a pathological context, refers to the bodys replacement of destroyed tissue by living tissue.

[email protected] of healing

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Regeneration, the replacement of lost/ damaged tissue by tissues of similar in type.

OCCURS ONLY IN TISSUES WITH REGENERATIVE ACTIVITY.

[email protected] , gastrointestinal tract. Hematopoietic 4Repair

A process in which lost/ damaged tissue replaced by fibrous tissue or scar.

Eg. Healed myocardial [email protected]

Cell ProliferationAn increase in the number of cells as a result of cell growth and cell division. [email protected] of Normal Cell ProliferationIn adult tissues the size of cell populations is determined

The rates of cell proliferation.

differentiation, and death by apoptosis

[email protected] process by which a cell becomes specialized in order to perform a specific function, . Uncontrolled 7

[email protected] proliferation can be stimulated by physiologic and pathologic conditions.The proliferation of endometrial cells under estrogen stimulation during the menstrual cycle.The thyroid stimulating hormonemediated replication of cells of the thyroid that enlarges the gland duringpregnancy [email protected] PROLIFERATIVE ACTIVITYAccording to regenerative capacity of the cell, the tissue of the body can divide into 3 [email protected] dividing tissues

These Cells proliferate throughout life, replacing those that are destroyed. Stratified squamous epithelia of the skin, oral cavity, vagina, and cervix; the lining mucosa of all the excretory ducts of the glands of the body (e.g., salivary glands, pancreas, biliary tract); [email protected]

Quiescent tissuesNormally have a low level of replication; however, cells from these tissues can undergo rapid division in response to stimuli . Thus capable of reconstituting the tissue of origin.Eg:- are the parenchymal cells of liver, kidneys, and [email protected] Smooth muscle cells, chondrocytes, and osteocytes are quiescent in adult mammals but Proliferate occurs in response to injury.

partial [email protected] tissues

These are non-dividing cells. If lost, permanent cells cannot be replaced, because they dont have the capacity to proliferate. For example: adult neurons, striated muscle cells, and cells of the [email protected]

Cell [email protected]

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What you think if you can clone [email protected] cell divide ??

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The cell cycle, or cell-division cycle, is the series of events that take place in a cell leading to its division and duplication (replication) that produces two daughter [email protected] cells are characterized by their self-renewal properties and by their capacity to generatedifferentiated cell lineages21

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[email protected] THE CELL CYCLE/ LIFE CYCLE.Not [email protected] cycle into two period24Phases of the Cell CycleThe two main divisions of the cell cycle are interphase and mitosis.

[email protected] In eukaryotic cells, this process includes of four distinct phases. Mitosis phase (M), Gap 1 phase (G 1), Synthesis phase (S), and interphaseGap 2 phase (G 2)[email protected] this segment of the cell cycle, a cell doubles its cytoplasm and synthesizes DNA. It is estimated that a dividing cell spends about 90-95 percent of its time in this phase.

[email protected] phase: The period prior to the synthesis of DNA. In this phase, the cell increases in mass and organelle number in preparation for cell division. Animal cells in this phase are diploid, meaning that they have two sets of chromosomes.

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S phase: The period during which DNA is synthesized. The chromosome content is doubled in this [email protected] phase: The period after DNA synthesis . prior to the start of mitosis. The cell synthesizes additional proteins and continues to increase in size.

[email protected] resting phase where the cell has left the cycle and has stopped dividing.

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The cell cycle have checkpointsCheck [email protected]

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Small GrowthMetabolismPreparation for DNA SynthesisJust finished divisionReplication of DNA and CentrosomesMore growthProtein synthesisPreparation for [email protected]

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[email protected] of MitosisIn mitosis and cytokinesis, the contents of the dividing cell are equally distributed between two daughter cells. Mitosis has four phases:

Prophase Metaphase Anaphase Telophase.

[email protected] is the division of the cytoplasm in eukaryotic cells that produces distinct daughter cells. Cytokinesis occurs at the end of the cell cycle following mitosis or meiosis.In animal cell division, cytokinesis occurs when a contractile ring of microfilaments forms a cleavage furrow that pinches the cell membrane in half. In plant cells, a cell plate is constructed that divides the cell in two.38Prophase: In this stage, changes occur in both the cytoplasm and nucleus of the dividing cell. The chromatin condenses into discrete chromosomes. The chromosomes begin to migrate toward the cell center. The nuclear envelope breaks down and spindle fibers form at opposite poles of the cell.

[email protected] condense into chromosomesNucleolus disappersMicrotubule assembly begins39

Metaphase: In this stage, the nuclear membrane disappears completely. The spindle fully develops and the chromosomes align at the metaphase plate (a plane that is equally distant from the two poles).

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[email protected]: In this stage, paired chromosomes (sister chromatids) separate and begin moving to opposite ends (poles) of the cell. Spindle fibers not connected to chromatids lengthen and elongate the cell.

[email protected]: In this stage, the chromosomes are cordoned off into distinct new nuclei and the genetic content of the cell is divided equally into two parts. Cytokinesis begins prior to the end of mitosis and completes shortly after telophase. Cell wall for plants.Cleavage furrow forms

[email protected] by means of a rope.Begin to decondense into chromatinNuclear membarane form each other.

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IDENTIFY

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[email protected] ProliferationTissue typeCell cyclePMAT

[email protected] What are the phase mitosis ?What is the function of checkpoints in cell cycle?In which phase the chromosomes aligned as equator line?What are the different types of tissue classification [email protected]

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