Pathology Flashcards
what are aspects of disease
ETIOLOGY_ cause of disease.
PATHOGENESIS_ mechanism of development of disease.
MORPHOLOGY_ structural alterations induced in cell and tissues (Gross and microscopic findings)
CLINICAL MANIFESTATIONS_ Signs and symptoms
PROGNOSIS- Expected outcome of disease
describe etiology types
There are two major classes of etiologic factors:
Genetic (e.g., Inherited mutations and disease-associated gene variants, or polymorphisms)
Acquired (e.G., Infectious, nutritional, chemical, physical).
describe pathogenesis
Pathogenesis refers to the sequence of events in the response of cells or tissues to the etiologic agent, from the initial stimulus to the ultimate expression of the disease.
Even when the initial cause is known (e.g., infection or mutation), it is many steps removed from the expression of the disease.
describe molecular and morphological changes
Morphologic changes refer to the structural alterations in cells or tissues that are either characteristic of a disease or diagnostic of an etiologic process.
More recently the limitations of morphology for diagnosing diseases have become increasingly evident, and the field of diagnostic pathology has expanded to encompass molecular, biologic and immunologic approaches for analyzing disease states.
describe clinical manifestation
The end results of genetic, biochemical, and structural changes in cells and tissues are functional abnormalities, which lead to the clinical manifestations (symptoms and signs) of disease, as well as its progress (clinical prognosis)
all forms of disease start with molecular or structural alterations in cells course and outcome).
define cell injury
sequence of events that occur if the limits of adaptive capability are exceeded or no adaptive response is possible
describe irreversible injury
Cell injury is reversible up to a certain point, but if the stimulus persists or is severe enough from the beginning, the cell suffers irreversible injury and ultimately cell death
describe cell death and its pathways
Cell death, the end result of progressive cell injury, is one of the most crucial events in the evolution of disease in any tissue or organ.
It results from diverse causes, including ischemia (reduced blood flow), infection, and toxins.
Cell death is also a normal and essential process in embryogenesis, the development of organs, and the maintenance of homeostasis.
There are two principal pathways of cell death, necrosis and apoptosis
describe autophagy
Nutrient deprivation triggers an adaptive cellular response called autophagy that may also culminate in cell death.
Calcium is often deposited at sites of cell death, resulting in pathologic calcification.
Finally, the normal process of aging itself is accompanied by characteristic morphologic and functional changes in cells.
what are the causes of cell injury
oxygen deprevation chemical and drugs physical agents infectious agents immunological reactions genetic abnormalities nutrient imbalances
define cellular adaptation
Adaptations are reversible changes in the
Size
Number
Phenotype
Metabolic activity
Functions of cells
in response to changes in their environment.
what is hypoxia
decreased level of oxygen in blood
causes of hypoxia
ischemia
hypoxemia due to lack of oxygen or lack of oxygen carrying capacity
what is ischemia
reduced blood flow
what is hypoxemia
hypoxia and ischemia
what are intracellular adaptations
Cellular adaptation is a cellular response to severe physiological stress or an excessive pathological stimulus.
what is atrophy
Reduced size of an organ or tissue resulting from a decrease in cell size and number.
examples of physiological atrophy are
Notochord and thyroglossal duct, undergo atrophy during fetal development.
The uterus decreases in size shortly after parturition
Menopause - physiologic atrophy
Endometrium
Vaginal epithelium
Breast
what are causes of pathological atrophy
starvation neuropathic atrophy (due to loss of innervation) senile atrophy (in old age)
what is the mechanism of atrophy
nutritional deficiency and disuse
activation of ubiquitin proteosomal pathway
autophagic vacuoles containing cell organelles formed, they fuse with lysosomes and organelles are digested
define hypertrophy
Increase in the size of the cells, which results in enlargement of organ without any changes in the number of cells.
physiological hypertrophy examples
kidney hypertrophy after one kidney removed
skeletal muscle hypertrophy in athletes
examples of pathological hypertrophy are
hypertrophic heart in uncontrolled hypertension
describe mechanism of cardiac hypertrophy
The mechanisms driving cardiac hypertrophy involve at least two types of signals:
mechanical triggers, such as stretch, and soluble mediators that stimulate cell growth, such as growth factors.
adrenergic hormones.
These stimuli turn on signal transduction pathways that lead to the induction of a number of genes
which in turn stimulate synthesis of many cellular proteins, including growth factors and structural proteins.
The result is the synthesis of more proteins and myofilaments per cell, which increases the force generated with each contraction, enabling the cell to meet increased work demands.
degenerative changes in heart because of hypertrophy
When this happens in the heart, several degenerative changes occur in the myocardial fibers, of which the most important are :
Fragmentation
loss of myofibrillar contractile elements.
ventricular dilation and ultimately cardiac failure.
There may be finite limits on the abilities of the vasculature to adequately supply the enlarged fibers
the mitochondria to supply ATP
or the biosynthetic machinery to provide sufficient contractile proteins or other cytoskeletal elements.
what are the degenerative changes because of hypertrophy
An adaptation to stress such as hypertrophy can progress to functionally significant cell injury if the stress is not relieved.
Whatever the cause of hypertrophy, a limit is reached beyond which the enlargement of muscle mass can no longer compensate for the increased burden.
define hyperplasia
Increase in the number of cells in an organ or tissue, usually resulting in increased mass of the organ or tissue
examples of physiological hyperplasia are
adult breast tissue during lactation
gravid uterus
regeneration of liver
examples of pathological hyperplasia are
multinodular goiter
endometrial hyperplasia
benign prostatic hyperplasia
what are the causes of pathological hyperplasia
Viral infections, papilloma viruses, cause skin warts and mucosal lesions composed of masses of hyperplastic epithelium
Growth factors produced by viral genes or by infected cells, stimulate cellular proliferation
