cellular response in disease

atrophy

cell shrinks from reduced nutrients, altered innervation, reduced blood supply, or disuse

hypertophy

cell enlarges due to increased functional demand → cells get sent more resources

hyperplasia

number of cells increase, often alongside hypertrophy

• commonly seen in endocrine cells

metaplasia

one mature cell type is replaced by another

reversible

usually from chronic irritation

dysplasia

abnormal cell morphology from chronic stress or injury → often a precursor to cancer

cells change shape

what is necrosis?

premature cell death

caused by factors external to the cell

what is necrosis related to?

most commonly related to ischemia and oxygen deprivation

what is apoptosis?

programmed cell death

generally triggered by normal, healthy processes in the body

what is apoptosis related to?

most commonly related to the normal aging process

🍌biological triggers of inflammatory response

bacteria, viruses, fungi, parasites

🍌environmental triggers of inflammatory response

toxins, particulates, tissue injury

🍌mediators of the inflammatory response and function

macrophages/lymphocytes release cytokines → chemokines → chemotaxis

🍌classic vascular signs of inflammation. how?

redness, heat, swelling, pain

from INC capillary permeability and immune cell migration

🍌how is the inflammatory response resolved? what happens if it doesn’t?

resolves once the stressful stimulus is removed

if stressor/impaired lymphatic drainage persists → chronic inflammation, tissue damage, chronic disease

🍌what is innate immunity?

first line of defense

nonspecific: cytokines, chemokines, immune cells

🍌what is adaptive immunity?

targeted response

recognizes repeat exposure and mounts a stronger reaction → the basis for vaccines

🍌what happens when regulation fails?

autoimmune disorders

allergic reactions

🍌what happens in autoimmune disorders?

immune system loses tolerance for the body’s own cells

T- and B-cells attack self-tissue

🍌what happens in an allergic reaction?

hypersensitivity of immune cells to other harmleses exposures

🍌how does persistent stress lead to disease?

persistent stressor can push cells past the point of returning to homeostasis → chronic inflammation

chronic stress can drive progression: metaplasia → dysplasia → neoplasia

🍌can removing the stressor sometimes reverse the process?

yes! (ex: controlling GERD reflux)

effects are asymptomatic until significant damage has occurred → why screening matters

🍌biomarkers of disease

ESR (erythrocyte sedimentation rate): rises with inflammation, infection, and cancer

CRP (C-reactive protein): rises with bacterial infection, autoimmune disease, and CVD (cardiovascular disease)

🍌pharmacologic/surgical interventions vs. other treatments for disease

most pharmacologic/surgical interventions target the resulting disease, not the cellular adaptation itself

other treatments aim to reduce the intensity of the inflammatory or immune response directly