Disease and Cellular Response: Cellular Adaptations, Injury, and Inflammation

Vocabulary practice flashcards covering cellular adaptations, mechanisms of cell injury and death, leukocyte functions, phases of inflammation, and fever mechanisms.

Homeostasis

The body's ability to maintain a dynamic steady-state of internal balance or equilibrium.

Hyperplasia

An increase in the number of cells in an organ or tissue resulting from cell replication.

Hypertrophy

An increase in the size of cells due to increased workload or a pathological condition, most common in cardiac and skeletal muscle tissue.

Atrophy

A reduction in cell size caused by disuse, decreased blood flow, malnutrition, or decreased workload.

Metaplasia

The replacement of one cell type with another cell type that can better endure stress, typically caused by chronic inflammation or irritation.

Dysplasia

Abnormal cell growth within a specific tissue resulting in cells of abnormal size, shape, or appearance; often precedes cancerous changes.

Free Radical Injury

Cellular injury caused by highly reactive chemical molecules containing an unpaired electron in their outer orbit that pull electrons from healthy cell molecules.

Hypoxic Cell Injury

Cellular injury resulting from oxygen deprivation, caused by a lack of $O_2$ or impaired blood flow to the tissue.

Reversible Cell Injury

Cellular injury that causes impaired cell function without cell death, allowing the cell to recover normal homeostasis if the cause is removed in time.

Apoptosis

Controlled, programmed cell death (implosion) in which cell membrane integrity is maintained, preventing intracellular contents from releasing into the extracellular space and avoiding inflammation.

Necrosis

Uncontrolled cell death (explosion) characterized by loss of cell membrane integrity, causing cell contents to leak into the extracellular space and trigger an inflammatory response.

Telomeres

The outermost tails of chromosome arms that shorten during each round of cell replication.

Replicative Senescence

The cessation of cell division and subsequent cell death that occurs when telomeres become too short to replicate.

Leukocytosis

A higher than normal level of white blood cells (frequently neutrophils) in the blood, serving as an indicator of infection or inflammation.

S.H.A.R.P.

The mnemonic for the five cardinal signs and symptoms of inflammation: Swelling, Heat, Altered function, Redness, and Pain.

Granulocytes

A group of white blood cells characterized by cytoplasmic granules, recalled by the mnemonic "Granpa B.E.N." (Basophils, Eosinophils, and Neutrophils).

Neutrophils

The most abundant granulocytes, making up approximately $60\%$ of white blood cells, which act as the first responders in acute bacterial infections.

Eosinophils

Granulocytic white blood cells that elevate primarily during allergic reactions and parasite infections.

Basophils

Granulocytic white blood cells that become elevated in response to allergic reactions.

Monocytes

Agranulocytic white blood cells circulating in the blood that migrate into damaged or infected tissues to become phagocytic macrophages.

T Memory Cells

T lymphocytes that reside in lymph nodes for years after an infection and rapidly clone upon re-encountering the same pathogen.

Helper T-Cells

A subset of T lymphocytes responsible for activating and regulating both T cells and B cells.

Killer T-Cells

Effector T cells that attack virus-infected cells and tumor cells, destroying antigens via phagocytosis.

Natural Killer (NK) Cells

Lymphoid cells with surface markers distinct from killer T cells that destroy abnormal cells, such as cancerous cells.

Suppressor T-Cells

T lymphocytes that downregulate the immune response back to normal levels after an infection and help prevent autoimmunity.

B Cells

Bone marrow-derived lymphocytes that mediate humoral immunity by synthesizing antibodies and assisting in T-cell activation.

Antigen

Short for "antibody generator," any substance or cell surface identifier that triggers the body to produce antibodies.

Antibodies (Immunoglobulins)

Specific protective proteins produced by B-cell lymphocytes that attach to complementary antigens to inhibit reproduction and tag them for destruction.

Chemotaxis

The process by which white blood cells navigate and migrate through tissue along a chemical concentration gradient toward the site of injury.

Exudate

An inflammatory fluid accumulation consisting of plasma, white blood cells, and chemical mediators at the site of tissue injury.

Vascular Phase of Acute Inflammation

The early stage of acute inflammation characterized by local vasodilation and increased capillary permeability, resulting in increased blood flow and fluid accumulation.

Cellular Phase of Acute Inflammation

The stage of acute inflammation where leukocytes (primarily neutrophils) emigrate through vessel walls, migrate via chemotaxis, and phagocytose microbes.

Acute-Phase Proteins

Proteins produced by the liver during systemic inflammation to provide protective immune functions, including fibrinogen, C-reactive protein, and serum amyloid A.

C-Reactive Protein (CRP)

An acute-phase liver protein whose elevated blood levels serve as a non-specific marker of systemic inflammation and a risk indicator for myocardial infarction.

Serum Amyloid A Protein (SAA)

An acute-phase protein synthesized by the liver during systemic inflammation that supplies cellular energy.

Bands

Immature white blood cells whose elevated presence in circulation indicates that the body has depleted its supply of mature adult neutrophils.

Systemic Inflammatory Response Syndrome (SIRS)

A severe systemic condition caused by massive cytokine release that leads to generalized vasodilation, increased capillary permeability, multi-organ failure, and circulatory shock.

Pyrogen

Any agent that induces a fever, including foreign microbes or endogenous chemical mediators like Interleukin-1.

Interleukin-1

An endogenous cytokine and pyrogen that directly acts on the hypothalamus to elevate the body's thermoregulatory set point.