Related Experiment Video
Updated: Jul 7, 2026
12:17
Detection and Isolation of Apoptotic Bodies to High Purity
Published on: August 12, 2018
Morphological assessment of apoptosis
Francesca Doonan1, Thomas G Cotter
1Tumour Biology Laboratory, Biochemistry Department, Bioscience Research Institute, University College, Cork, Ireland.
Methods (San Diego, Calif.)
|March 4, 2008
Summary
Apoptosis is an orderly cell death process with distinct morphological features, unlike necrosis. However, distinguishing between them is becoming complex as variations and overlaps in cell death are increasingly recognized.
Area of Science:
- Cellular Biology
- Pathology
- Biochemistry
Background:
- Apoptosis, or programmed cell death, is crucial in development, tissue homeostasis, and disease.
- Apoptotic cells exhibit characteristic shrinkage and formation of apoptotic bodies, rapidly cleared by neighboring cells.
- Necrosis involves membrane rupture, swelling, and inflammation, lacking the controlled nature of apoptosis.
Purpose of the Study:
- To define and contrast apoptosis and necrosis based on their distinct morphological features.
- To highlight the limitations of morphological assessment in classifying cell death.
- To underscore the evolving understanding of cell death, recognizing a continuum between apoptosis and necrosis.
Main Methods:
- Morphological description using light and electron microscopy to identify and quantify apoptosis.
- Comparative analysis of cellular and nuclear changes in apoptotic versus necrotic cells.
- Review of emerging research on cell death variations and overlaps.
Main Results:
- Distinct morphological differences exist between apoptosis (shrinkage, blebbing, apoptotic bodies) and necrosis (swelling, membrane loss, inflammation).
- Morphological assessment remains a primary method for differentiating apoptosis and necrosis.
- The study acknowledges a spectrum of cell death, with features of both apoptosis and necrosis coexisting in some cells.
Conclusions:
- While morphological differences are foundational, they are insufficient for definitive classification in all cases.
- The field recognizes a continuum of cell death, challenging strict binary distinctions between apoptosis and necrosis.
- Careful consideration is needed when labeling cell death based solely on morphology due to emerging complexities.
Related Concept Videos
01:30Apoptosis
Apoptosis is a combination of two Greek words, 'apo' and 'ptosis,' meaning separation and falling off, respectively. Hippocrates used this word to describe gangrene, which was caused due to bandaging of fractured bones. Apoptosis was distinguished from necrosis in 1970 when John Kerr reported observations of morphological changes occurring during apoptosis. During one experiment, he observed that the disruption of blood supply to the liver tissue resulted in a size reduction of the tissue.
01:17Phagocytosis of Apoptotic Cells
Cells undergoing apoptosis form apoptotic bodies that must be removed immediately to prevent inflammation, autoimmune diseases, and necrosis. Phagocytosis is carried out by professional phagocytes such as macrophages or immature dendritic cells. Non-professional phagocytes such as epithelial cells and fibroblasts also take part in this process; however, they are not as effective as professional phagocytes.
Normal cells contain receptors that prevent them from being recognized by phagocytes.
Normal cells contain receptors that prevent them from being recognized by phagocytes.
01:22Cellular Injury V: Apoptosis and Autophagy
Cells respond to damage and stress through highly coordinated processes that decide whether they survive or undergo controlled self-destruction. Two major pathways involved in this regulation are apoptosis, a type of programmed cell death, and autophagy, a survival mechanism that helps cells adapt to adverse conditions.ApoptosisApoptosis removes aged or injured cells to maintain tissue balance. During this process, the cell shrinks, chromatin condenses and fragments, and membrane-bound...
01:30Overview of Cell Death
Cell death is an essential process where the body gets rid of old or damaged cells. Cell proliferation and death need to be balanced, as an imbalance between the two may lead to cancer or autoimmune diseases.
Cell death was observed in the early 19th century, but there was no experimental evidence to prove it. In 1842, Carl Vogt first discovered cell death in a metamorphic toad; however, it was not termed ‘cell death.’ Scientists discovered different cell death pathways only in the 20th century...
Cell death was observed in the early 19th century, but there was no experimental evidence to prove it. In 1842, Carl Vogt first discovered cell death in a metamorphic toad; however, it was not termed ‘cell death.’ Scientists discovered different cell death pathways only in the 20th century...
01:31The Intrinsic Apoptotic Pathway
Internal cellular stress, such as cellular injury or hypoxia, triggers intrinsic apoptosis. The B-cell lymphoma 2 (Bcl-2) family of proteins are the primary regulators of the intrinsic apoptotic pathway. For example, during DNA damage, checkpoint proteins, such as Ataxia Telangiectasia Mutated (ATM protein) and Checkpoints Factor-2 (Chk2) proteins, are activated. These proteins phosphorylate p53 which further activates pro-apoptotic proteins, such as Bax, Bak, PUMA, and Noxa, and inhibits...
01:17The Extrinsic Apoptotic Pathway
The extrinsic apoptotic pathway is initiated when extracellular death-inducing signals, such as specific cytokines, activate the death receptors expressed on the cell surface. The immune cells involved in this pathway are natural killer cells (NK cells) and cytotoxic T-lymphocytes. NK cells are critical in innate immune response, while cytotoxic T-lymphocytes are associated with adaptive immune response. These cells recognize specific receptors expressed on the altered cells and activate...