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Apoptosis There are two ways that a cell can die: necrosis and apoptosis. Necrosis occurs when a cell is damaged by an external force, such as poison,

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Presentation on theme: "Apoptosis There are two ways that a cell can die: necrosis and apoptosis. Necrosis occurs when a cell is damaged by an external force, such as poison,"— Presentation transcript:

1 Apoptosis There are two ways that a cell can die: necrosis and apoptosis. Necrosis occurs when a cell is damaged by an external force, such as poison, a bodily injury, an infection or getting cut off from the bloodsupply (which might occur during a heart attack or stroke). When cells die from necrosis, it's a rather messy affair. The death causes inflammation that can cause further distress or injury within the body.. cellblood

2 Apoptosis Programmed cell death (Apoptosis) is the process by which cells in plants and animals die through self – destruction rather than due to injury. Also referred to in animal cells as apoptosis, the process is typically a part of embryonic development of all animals and is thought to be responsible for the development of individual digits and the elimination of excess materials in various stages of animal development.

3 Apoptosis It is also an element of the immune system in animals, and the process by which excess or flawed( become cracked ) cells in the body are eliminated to maintain homeostasis and health.immune system Programmed cell death can also have a negative effect on the body of an animal or human being when triggered by viruses.

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5 Apoptosis Programmed cell death is thought to be an especially important part of animal growth and development in early life and the embryonic stage. Examples : 1- Evidence indicates that the early development of individual fingers and toes in a human fetus is due to the apoptosis of the cells that would exist between the digits but die off, leaving the remaining cells to form the individual fingers. 2- The reincorporation of a tadpole’s tail into its body as it becomes a frog is due to cell death, rather than the continued division and growth of those tail cells.

6 Apoptosis Unfortunately.. - programmed cell death can be hindered by certain viruses and other adverse physiological conditions. The spread of cancer throughout an animal’s body is typically due to apoptosis not properly occurring in the organism’s body. In ideal conditions, cancerous cells should be ordered to die by proteins in the body, preventing those cancerous cells from dividing and spreading.

7 Apoptosis The programmed cell death does not properly occur, however, in many cases of cancer, leading to the spread of potentially deadly cells throughout the body. The human immunodeficiency virus (HIV) similarly uses programmed cell death in a negative way by causing T helper cells that typically fight off viruses and other infections in the human body to begin self-destructing. This condition, referred to as acquired immunodeficiency syndrome (AIDS), effectively destroys the body’s immune system, which often leads to complications or death from other illnesses.HIV

8 Apoptosis Programmed cell death is an important process in development, immune defense, and cancer protection, but it must be regulated to prevent uncontrolled cell death. An inhibitor of apoptosis protein, or IAP, is a type of protein that is able to stop apoptosis

9 Apoptosis by inhibiting caspases : (proteins that are necessary for the initiation of apoptosis). ---NOTE : ( Caspases are the primary proteins involved in the initiation of apoptosis, so naturally, they are the primary targets of almost every inhibitor of apoptosis). They also regulate some transcription factors that are important for the synthesis of various proteins that lead to apoptosis. -It is believed that inhibitors of apoptosis may be related to tumor formation because one of the characteristics of many cancerous cells is the inability to undergo apoptosis.

10 Apoptosis There are also regulatory proteins that exist for the purpose of regulating inhibitors of apoptosis. The second mitochondria-derived activator of caspase, or SMACmitochondriacaspase

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