Trans 1- Cell adaptation Flashcards
the study (logos) of disease (pathos)
Pathology
Disease is due to cellular abnormalities:
o Altered ability to proliferate
o Dysfunction
o Disturbed homeostasis
Cells react to adverse stimuli by:
o Cellular adaptation § Hypertrophy § Hyperplasia § Atrophy § Metaplasia o Reversible injury o Irreversible injury and cell death o Apoptosis o Necrosis
Types of cellular adaptation
Hypertrophy
Hyperplasia
Atrophy
Metaplasia
response to hormonal or
endogenous influences
physiologic
response of the cell to injurious
stimuli which enable them to escape injury
pathologic
are continuously cycling
skin cells
are stable and will go to G1 if needed.
“Prometheus and his liver regeneration.”
Hepatocytes
are permanent cells and non-dividing. They cannot regenerate.
Heart muscles and Neurons
- Increase in the number of cells
* Encountered in cells which are capable of dividing
Hyperplasia
Hyperplasia is encountered where
epithelium
blood cells
connective tissues
In hyperplasia, these are PHYSIOLOGIC if normal stressor
o Breasts in pregnancy
o Menstrual endometrium
In hyperplasia, these are PATHOLOGIC if normal stressor
o ACTH from pituitary adenoma
o High estrogen
• Increase in the size of cells due to an increase in the
cellular contents
• Encountered in cells which are not capable of or have
limited capacity to divide
Hypertrophy
Hypertrophy is encountered where
in myocytes and skeletal muscles
In hypertrophy, these are PHYSIOLOGIC if normal stressor
Skeletal Muscles with Exercise
In hypertrophy, these are PATHOLOGIC if normal stressor
Hypertensive cardiomegaly
Histological Comparisons between Pregnancy and Normal Uterus
Pregnancy has bigger cells compared to the Normal Uterus
A normal heart weighs
250 g
- Decrease in the size of a previously normal cell
* Not hypoplasia, Cells under hypoplasia never developed to begin with.
Atrophy
In atrophy, these are PHYSIOLOGIC if normal stressor
non-pregnant uterus and
brain in senility
In atrophy, these are PATHOLOGIC if normal stressor
loss of stimulus (blood, innervation, endocrine, disuse, mechanical compression
Poliio virus affects
anterior motor neurons
Gyri become smaller, sulci become wider
Atrophy Normal Brain
More fat rather than beefy-looking
Skeletal Muscle Atrophy
Renal atrophy due to atherosclerosis or incidental cancer
renal atrophy
Change of Epithelium from one to another in an abnormal
location (Chronic cervicitis, Chronic bronchitis, Barrett Esophagus).
Gastro-esophageal junction demarcation is not clear.
Due to reflux.
Metaplasia
from squamous epithelium of normal esophagus to the glandular type along the gastroesophageal junction
Glandular metaplasia
• Not an adaptive response
• Limbo/grey area between normal and neoplastic tissue
• Alteration in the size, shape and organization of the
cellular components of a tissue
• Disorganized, haphazard cellular growth
• Like metaplasia, reflects persistence of injurious
influences and may regress
• Pre-neoplastic, step before cancer.
Dysplasia