Anatomy-and-Physiology-unit-2.pppppppptx

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1. Cell Division Cell division is the process by which a parent cell divides into two daughter cells. Cell division usually occurs as part of a larger cell cycle in which the cell grows and replicates its chromosome before dividing. There are two types of cell division: Mitosis and Meiosis . Most of the time when people refer to “cell division,” they mean mitosis, the process of making new body cells. Meiosis is the type of cell division that creates egg and sperm cells. Mitosis is a fundamental process for life.

2. Mitosis Mitosis is a fundamental process for life. During mitosis, a cell duplicates all of its contents, including its chromosomes, and splits to form two identical daughter cells. Because this process is so critical, the steps of mitosis are carefully controlled by certain genes. When mitosis is not regulated correctly, health problems such as cancer can result.

3. https://byjus.com/biology/mitosis/

4. Interphase - is the portion of the cell cycle that is not accompanied by visible changes under the microscope, and includes the G1, S and G2 phases. During interphase, the cell grows (G1), replicates its DNA (S) and prepares for mitosis (G2). Prophase - stage of cell division, before metaphase, during which the chromosomes become visible as paired chromatids and the nuclear envelope disappears. The first prophase of meiosis includes the reduction division . Metaphase - in metaphase, the spindle has captured all the chromosomes and lined them up at the middle of the cell, ready to divide. At this stage, the two kinetochores of each chromosome should be attached to microtubules from opposite spindle poles .

5. Anaphase - in anaphase, the sister chromatids separate from each other and are pulled towards opposite ends of the cell. The protein “glue” that holds the sister chromatids together is broken down, allowing them to separate. Each is now its own chromosome. Telophase - in telophase, the cell is nearly done dividing, and it starts to re-establish its normal structures as cytokinesis takes place. The mitotic spindle is broken down into its building blocks. Two new nuclei form, one for each set of chromosomes. Nuclear membranes and nucleoli reappear.

6. Meiosis Meiosis is a type of cell division in sexually reproducing organisms that reduces the number of chromosomes in gametes (the sex cells, or egg and sperm). In humans, body (or somatic) cells are diploid, containing two sets of chromosomes (one from each parent ). Prophase- Meiosis I, the first meiotic division, begins with prophase I. During prophase I, the complex of DNA and protein known as chromatin condenses to form chromosomes. The pairs of replicated chromosomes are known as sister chromatids, and they remain joined at a central point called the centromere.

7. Metaphase 1- In metaphase I, the homologous pairs of chromosomes align on either side of the equatorial plate. Anaphase 1- in anaphase I, the spindle fibers contract and pull the homologous pairs, each with two chromatids, away from each other and toward each pole of the cell. Telophase 1- telophase I, the chromosomes are enclosed in nuclei. The cell now undergoes a process called cytokinesis that divides the cytoplasm of the original cell into two daughter cells. Each daughter cell is haploid and has only one set of chromosomes, or half the total number of chromosomes of the original cell.

8. Apoptosis   Apoptosis is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemical events lead to characteristic cell changes and death.

9. https://www.genome.gov/genetics-glossary/apoptosis Induction- Induction of apoptosis occurs when one or several cells of a living organism are infected with a virus, leading to cell death. Cell death in organisms is necessary for the normal development of cells and the cell cycle maturation. It is also important in maintaining the regular functions and activities of cells.

10. Early stage - is represented by changes to, and ultimate loss of, the mitochondrial membrane potential. Mitochrondrial membrane potential is detected by JC-1, a dye that selectively enters the mitochondria. Mid stage- In the intrinsic pathway BAX and BAK create a pore within the outer membrane of the mitochondria which leads to membrane depolarization and release of pro-apoptotic factors. The factors released form the signaling complex known as the apoptosome . Late stage- The late stage of apoptosis is characterized by DNA fragmentation ( karyorrhexis ), which starts upon completion of nuclear condensation ( pyknosis ). It is mediated by both caspase dependent and independent routes. In the late phase significant morphological and phenotypical changes also occur.

11. TISSUES DAMAGE A tissue is an aggregate of cells in an organism that have similar structure and function. Tissues that work in unison to carry out a specific set of functions form an organ. Examples of plant tissues are meristematic tissues and vascular tissues. The most common soft tissues injured are muscles, tendons, and ligaments. These injuries often occur during sports and exercise activities, but sometimes simple everyday activities can cause an injury. Sprains, strains, and contusions, as well as tendinitis and bursitis, are common soft-tissue injuries. Tissues of all types are vulnerable to injury and, inevitably, aging. In the former case, understanding how tissues respond to damage can guide strategies to aid repair. In the latter case, understanding the impact of aging can help in the search for ways to diminish its effects.

12. What is the cause of tissue damage? Many bacteria cause extensive tissue damage by the liberation of toxins into extracellular fluids. https://apexsofttissue.com.au/why-soft-tissue/

13. INFLAMMATION and REPAIR Inflammation is the standard, initial response of the body to injury. Whether biological, chemical, physical, or radiation burns, all injuries lead to the same sequence of physiological events. Inflammation limits the extent of injury, partially or fully eliminates the cause of injury, and initiates repair and regeneration of damaged tissue.

14. https://www.aboutkidshealth.ca/article?contentid=926&language=english TYPES OF INFLAMMATION Chronic inflammation is also referred to as slow, long-term inflammation lasting for prolonged periods of several months to years. Generally, the extent and effects of chronic inflammation vary with the cause of the injury and the ability of the body to repair and overcome the damage . Acute inflammation is an immediate, adaptive response with limited specificity caused by several noxious stimuli, such as infection and tissue damage (tissue necrosis). The response to sudden body damage, such as cutting your finger. To heal the cut, your body sends inflammatory cells to the injury. These cells start the healing process.

15. TISSUE REPAIR Tissue repair is defined as the restoration of tissue architecture and function following an injury. In toxicant-induced injury, tissue repair plays a primary role in determining whether the patient will recover from injury, or whether the injury will progress and lead to death .   Stages of Wound Healing Inflammatory Phase- Inflammation both controls bleeding and prevents infection. The fluid engorgement allows healing and repair cells to move to the site of the wound. During the inflammatory phase, damaged cells, pathogens, and bacteria are removed from the wound area .

16. Proliferative Phase - in the proliferation phase, the provisional wound matrix formed during homeostasis is replaced by granulation tissue, consisting of a large amount of fibroblasts, granulocytes, macrophages, blood vessels, in complex with collagen bundles, which partially recovers the structure and function of the wounded skin. Remodeling Phase - third phase of healing consists of remodeling, which begins two to three weeks after the onset of the lesion and can last for one year or more. The core aim of the remodeling stage is to achieve the maximum tensile strength through reorganization, degradation, and re-synthesis of the extracellular matrix .

17. https://www.mdpi.com/2075-1729/11/7/665