Cellular Adaptation Part 1 Flashcards
What is Cellular Stress
The cell’s reaction to any adverse environmental condition that perturbs
cellular homeostasis.
What is pathology?
Pathos (suffering) and Logos (study)
It is a discipline devoted to the study of diseases:
- Cause (the etiology) ,
- Mechanism (the Pathogenesis)
-The study of disease
-Bridges science and medicine
-underpins every aspect of patient care (diagnostic testing—–>genetic technologies)
-Preventing disease
Etiology of Cell Injury
Causes of disease e.g
-Hypoxia & ischemia
-Toxins
-Infections
-Abnormal immune reactions
-Genetic Abnormalities
-Nutritional Imbalances
-Physical Agents
Pathogenesis
Mechanisms of disease
Hypoxia and Ischemia
Hypoxia refers to oxygen
deficiency within tissues and organs
Ischemia means reduced
blood supply.
These are among the
most common causes of cell injury e.g lungs (asthma), brain (stroke), heart (blocked coronary arteries)
Toxins and Infections
-Toxin, any substance poisonous to an organism
- Infectious Agents: All types of infectious pathogens, such as viruses, bacteria, fungi, and parasites, can injure cells by diverse
mechanisms, including liberation of toxins and eliciting harmful
immune responses
Abnormal Immunological Reactions
Although the immune
system defends the body
against pathogenic
microbes, immune reactions can also result in cell and tissue injury.
Genetic Abnormalities
- Chromosomal
abnormalities (e.g.
Down Syndrome) - Gene Mutation (e.g.
Sickle cell Anaemia).
Nutritional Imbalances
- Starvation (Protein-
calorie insufficiency) - Mal-Nutrition (vitamin
deficiencies) - Obesity (excessive dietary
intake)
Physical Agents
Trauma, extremes of
temperature, radiation,
electric shock, and sudden
changes in atmospheric
pressure all have
damaging effects on cells
Initial Response to Stressful Stimulus
Geared towards helping the cell to defend against and recover from the insult
Atrophy
Reduced size
of an organ or tissue
caused by reduction in
the size and number of
cells
e.g
-Muscle Atrophy
- Senile (Brain) Atrophy
Hypertrophy
An enlargement of cells that results in increase in the size of the organ.
e.g
- changes to the uterus in pregnancy
Hyperplasia
An increase in the number of cells in an organ that stems from increased proliferation, either of differentiated cells or, in some instances, progenitor cells.
Hyperplasia can be physiologic or pathologic;
Physiologic Hyperplasia
Hyperplasia is stimulated by hormones or growth factors.
1) hormonal hyperplasia, (PHYSIOLOGICAL)
exemplified by the proliferation
of the glandular epithelium of the female breast at puberty and during pregnancy.
2) Compensatory hyperplasia
in which residual tissue grows after
removal or loss of part of an organ.
e.g skin repair, liver regeneration
Hormonal imbalances can lead to pathologic
hyperplasia
Benign prostatic hyperplasia is
common example of pathologic
hyperplasia induced by responses
to hormonal stimulation, in this case by androgens and estrogens
Metaplasia
-A change in
which one adult cell type
is replaced by another
adult cell type.
-In this type of cellular
adaptation, a cell type
sensitive to a particular
stress is replaced by
another cell type better
able to withstand the
adverse environment
Dysplasia
A term used to describe the presence of abnormal cells within a tissue or organ.
Dysplasia is not cancer, but it may sometimes become cancer.
e.g Barrett’s esophagus is a condition in which the
lining of your esophagus
changes.
The tissue that lines your
esophagus becomes more
like the tissue that lines
your intestine
