Post on 12-Dec-2021
transcript
Cell Injury-I
cellular Adaptation
Dr.Ekbal iskandar
CELLULAR ADAPTATION:
The ability of cells to respond to various types of
stimuli and stress to escape injury
CELLULAR ADAPTATION:
The cell changes that occur are:
▪ Atrophy..reduction in size and cell number
▪Hypertrophy.. enlargement of individual cells
▪Hyperplasia..increase in cell number
▪Metaplasia..transformation from one type
of epithelium to another)
▪Dysplasia..disordered growth of cells
Cellular Changes
Then anaplasia/neoplasia
HYPERPLASIAIncrease in the number of cells.
Physiologic hyperplasia.. normal stressor.
Increase in the size of the breasts during pregnancy,
Increase in thickness of endometrium during menstrual cycle,
liver growth after partial resection.
Pathologic hyperplasia:proliferation of endometrium due to prolonged estrogen stimulus.
Only cells that can divide will undergo hyperplasia;
hyperplasia of the myocytes in the heart and neurons in the
brain does not occur.
1- FOLLICULAR HYPERPLASIA (LYMPH NODE)
2- SINUS HYPERPLASIA (LYMPH NODE)
The lymph node
The lymph node
Follicular hyperplasia (lymph node)
▪ Nodal architecture is preserved
▪ Follicles are increased in number
▪ Variable in size and shape
▪ Margins of the follicles are sharply defined
▪ Germinal centers are activated & Tingible body
macrophages (with nuclear debris)
Follicular hyperplasia (lymph node)
Germinal centers are activated & Tingible
body macrophages
Follicular hyperplasia
(lymph node)
Sinus hyperplasia (lymph node)
▪ Medulla: Sinus are dilated and prominent,, often
containing increased macrophages, lymphocytes
and plasma cells.
▪ Cortex: atrophic or hyperplastic follicles
Sinus hyperplasia (lymph node)
Sinus hyperplasia (lymph node)
HYPERTROPHYIncrease in the size of the cell.
Physiologic hypertrophy: normal stressor.
Enlargement of skeletal muscle with exercise.
Hypertrophy of uterine smooth muscle during pregnancy
Pathologic hypertrophy: chronic abnormal stressor.
Left ventricular hypertrophy due to long-standing increased
afterload such as HTN, stenotic valves
Hypertrophy of uterine smooth muscle during pregnancy
ATROPHY
▪ The shrinkage in cell size by /loss of cellular substance/
▪ Atrophied cells are smaller than normal but they are still
viable (not necessarily undergo apoptosis or necrosis)
Physiologic
Tissues present in embryo or in childhood (e.g., thymus)
PathologicDecreased workload
Loss of innervation
Decreased blood supply
Inadequate nutrition
Decreased hormonal stimulation
Aging
Fatty changes/fatty degeneration/ (lymph node)
▪ Benign mature adipocytes populate node
▪ Capsule is thinly attenuated with fine vascular
trabeculae dividing fat deposits
Fatty changes/ (lymph node)
METAPLASIANonneoplastic transformation (protective mechanism) in
which one mature/adult cell type (epithelial or mesenchymal)
is replaced by another mature cell type
Physiological Metaplasia:
Cervical ectopy
Pathological Metaplasia.
response to chronic chemical or physical stimuli:
Intestinal metaplasia (Barrett metaplasia)
Squamous metaplasia of the bronchi due to smoking →
ciliated pseudostratified columnar epithelium to
squamous epithelium
Endocervical squamous metaplasia
▪ The presence of islands of squamous cells above the
SCJ.
▪ It is a common physiological condition.. (Mostly due to
hormonal changes that occur during puberty).
▪ Transformation of columnar endocervical epithelium to
squamous ectocervical-like epithelium.
Squamous metaplasia
Squamous metaplasia. Uterine cervix
Squamous metaplasia. Respiratory mucosa
Barrett's esophagus, intestinal metaplasia
Barrett’s Esophagus
Intestinal Metaplasia of the Esophagus
THANK YOU