Medical Biology Lecture 4 Mitosis (2023-2024)

University of Al-Ameed College of Medicine Medical Biology Lecture 4 MITOSIS A S S I S T. P RO F. D R . A H M E D Z U H A I R A LW A E L I 2023-2024 Introduction  Welcome to today's lecture on mitosis, a fundamental process in cell biology that underlies growth, development, and tissue repair....

University of Al-Ameed College of Medicine Medical Biology Lecture 4 MITOSIS A S S I S T. P RO F. D R . A H M E D Z U H A I R A LW A E L I 2023-2024 Introduction  Welcome to today's lecture on mitosis, a fundamental process in cell biology that underlies growth, development, and tissue repair.  Mitosis is a highly regulated and orchestrated mechanism, crucial for maintaining genomic stability and cellular integrity. Objectives of the Lecture  Upon complete the lecture, students will be able to:  Understand the Phases of Mitosis:   Describe the key events in each phase of mitosis, from prophase to cytokinesis. Recognize the dynamic changes in cellular components during mitosis.  Explore Mitosis in Health:   Understand the physiological roles of mitosis in growth, development, and tissue repair. Appreciate how mitosis contributes to the maintenance of normal cellular function.  Examine Diseases Related to Mitosis:   Investigate how dysregulation of mitosis contributes to cancer development. Explore genetic disorders resulting from errors in mitosis, such as aneuploidy-related conditions.  Consider Mitotic Abnormalities and Therapeutic Opportunities:   Examine current therapeutic strategies targeting mitosis in cancer treatment. Discuss potential future developments in drug development aimed at modulating mitotic processes. Overview of Mitosis  Definition: Mitosis is the process of cell division that results in two identical daughter cells from a single parent cell.  Phases of Mitosis: Prophase, Metaphase, Anaphase, Telophase (PMAT).  Cytokinesis: The division of the cytoplasm following mitosis. Phases of Mitosis - Prophase  Chromosome Condensation: Chromosomes become visible and compact during prophase.  Nuclear Envelope Breakdown: The nuclear envelope dissolves, allowing spindle fibers to interact with chromosomes.  Centrosome Movement: Centrosomes move to opposite poles of the cell. Phases of Mitosis - Metaphase  Chromosome Alignment: Chromosomes align at the cell's equator, known as the metaphase plate.  Spindle Fibers Attachment: Spindle fibers attach to the centromeres of chromosomes. Phases of Mitosis - Anaphase  Sister Chromatid Separation: Centromeres split, and sister chromatids move to opposite poles.  Chromosome Movement: Spindle fibers shorten, pulling chromatids towards the centrosomes. Phases of Mitosis - Telophase  Nuclear Envelope Reformation: Chromatids reach opposite poles, and nuclear envelopes begin to reform. Cytokinesis  Cytokinesis: Division of the cytoplasm, resulting in two separate daughter cells. Mitosis in Health  Growth and Development: Mitosis is essential for the growth of tissues during development and throughout life. Mitosis in Health  Tissue Repair: After injury or damage, mitosis allows for the replacement of damaged cells and tissue repair. Mitosis in Health  Maintenance of Cellular Function: Mitosis helps maintain the proper number of cells in tissues for optimal function. Cells number Cells function Mitosis health Diseases Related to Mitosis  Cancer:  Uncontrolled cell division is a hallmark of cancer.  Mutations affecting cell cycle checkpoints or regulatory proteins can lead to unbridled mitotic activity.  Examples: Breast cancer, colon cancer, leukemia. Diseases Related to Mitosis  Genetic Disorders:  Errors in mitosis can result in aneuploidy, where cells have an abnormal number of chromosomes.  Examples: Down Syndrome, Turner Syndrome. Mitosis and Cancer  Tumor Formation: Dysregulation of mitosis can lead to the formation of tumors.  Metastasis: Cancer cells often exhibit aberrant mitotic activity, contributing to their ability to spread to other tissues.  Targeted Therapies: Understanding mitotic pathways is crucial for developing targeted therapies against cancer. Mitotic Index and Cancer Diagnosis  Mitotic Index: A measure of the rate of mitosis in a tissue sample.  Cancer Diagnosis: Higher mitotic indices are often associated with more aggressive and rapidly dividing cancers.  Prognostic Indicator: Mitotic index is a prognostic indicator in cancer pathology. Mitosis and Genetic Disorders  Aneuploidy: Abnormal chromosome numbers due to errors in mitosis.  Down Syndrome: Trisomy 21, an example of a genetic disorder resulting from aneuploidy.  Importance of Proper Chromosome Segregation: Ensuring proper segregation is critical for preventing genetic disorders. Mitotic Abnormalities and Therapeutic Opportunities  Targeting Mitotic Pathways: Mitotic inhibitors are a class of anticancer drugs that target the mitotic process.  Mitosis as a Therapeutic Target: Opportunities for developing drugs that selectively inhibit mitosis in cancer cells. Conclusion  Mitosis is a fundamental process with vital roles in growth, development, and tissue maintenance.  Dysregulation of mitosis is associated with diseases, particularly cancer and certain genetic disorders.  Ongoing research into mitotic pathways offers potential therapeutic avenues for mitigating diseases related to mitotic abnormalities. Questions and Homework  What molecular events during mitosis can become dysregulated in cancer cells, leading to uncontrolled growth?  Can you provide examples of specific cancers and the mitotic abnormalities associated with their development?  How might dysregulated mitosis contribute to the formation of tumors in cancer?  In what ways can mitotic abnormalities impact the genomic stability of a cell? Questions and Homework  What are the key phases of mitosis, and how does each phase contribute to the accurate division of a cell?  Can you explain the role of cytokinesis in the completion of the cell division process?  How does mitosis contribute to tissue growth during development and throughout an individual's life?  In what ways does mitosis play a role in tissue repair after injury or damage?  Thank you for your attention. It's time for questions and discussion.