A schema is a mental construct consisting of a cluster or collection of related concepts (Bartlett, 1932). There are many different types of schemata, and they all have one thing in common: schemata are a method of organizing information that allows the brain to work more efficiently. When a schema is activated, the brain makes immediate assumptions about the person or object being observed.

Cellular injury occurs when a cell cannot maintain homeostasis or adapt to stressors such as hypoxia, toxins, or trauma. Depending on severity and duration, injury may be reversible, allowing recovery, or irreversible, leading to cell death.General Mechanisms of Cell InjuryAlthough causes vary, most cellular injuries arise from a few key mechanisms that disrupt essential functions and often amplify one another. Cell survival depends on the extent and balance of these disturbances.ATP depletion...

In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...

In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...

Necrosis is a form of irreversible cell death caused by severe injury such as ischemia, toxins, or trauma. Unlike programmed cell death, it is an uncontrolled, pathological process that typically provokes inflammation in surrounding tissues.Pathophysiologic ChangesNecrosis begins when cells sustain critical damage, leading to swelling of organelles, particularly mitochondria, and rapid ATP depletion. As energy levels decline, membrane ion pumps fail, leading to calcium influx and eventually,...

Cellular injury is any process that disrupts a cell’s ability to maintain homeostasis, leading to structural or functional changes. It is broadly classified based on etiology (cause) and mechanism of damage.Classification by EtiologyCellular injury may result from several causes. Hypoxic injury happens due to reduced oxygen delivery, most commonly from inadequate blood supply, such as arterial obstruction; for example, coronary artery thrombosis can cause myocardial infarction. Chemical injury...