HI MY DEAR FRIENDS, I HOPE YOU ALL ARE DOING WELL.
SO TODAY, I AM GOING TO TAKE YOU THROUGH THE JOURNEY OF REVERSIBLE CELL INJURY & CELL ADAPTATION
"REVERSIBLE CELL INJURY":
"WHEN THE INJURED CELL REGAINS ITS
NORMAL FUNCTIONING BACK IS CALLED AS REVERSIBLE CELL INJURY"
*MILD NON-LETHAL INJURY*(LIKE ISCHEMIA, HYPOXIA, MECHANICAL, THERMAL, CHEMICAL INJURY)
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LEAD TO MILD ISCHEMIA(DECREASE IN BLOOD SUPPLY)
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CAUSES MILD HYPOXIA ( DECREASE IN OXYGEN SUPPLY)
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DUE TO MILD HYPOXIA, THERE OCCURS ANAEROBIC GLYCOLYSIS INSIDE THE CELL
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WHICH LEADS TO:
1) DECREASE IN ATP SYNTHESIS
2) INCREASE IN LACTIC ACID PRODUCTION
1) DECREASE IN ATP SYNTHESIS :
a) DECREASE IN ATP SYNTHESIS LEADS TO INACTIVATION OF Na-K ATPase PUMP.
b) THIS CAUSES INCREASE IN INTRACELLULAR Na+ ion CONCENTRATION.
c) INCREASE IN INTRACELLULAR Na+ ION CONCENTRATION CAUSES MORE AND MORE VOLUME OF ECF (EXTRACELLULAR FLUID) TO MOVE INSIDE THE CELL WHICH ULTIMATELY LEADS TO CELLULAR SWELLING.
2) INCREASE IN LACTIC ACID PRODUCTION :
a) INCREASE IN LACTIC ACID PRODUCTION CAUSES DECREASE IN pH.
b) DECREASE pH LEADS TO DNA CONDENSATION (PYKNOSIS).
****MORPHOLOGY:
1) ELECTRO-MICROSCOPIC CHANGES IN CELL:
* LOSS OF MICROVILLI,
*CYTOPLASMIC MEMBRANE BLEBS FORMATION,
*ORGANELLE SWELLING: a) ESPECIALLY MITOCHONDRIA & ROUGH ENDOPLASMIC RETICULUM.
b) SWELLING OF ROUGH ENDOPLASMIC RETICULLUM CAUSES DETACHMENT OF RIBOSOMES FROM IT. THIS LEADS TO A DECREASE IN PROTEIN SYNTHESIS, ULTIMATELY LEADING TO THE BREAKDOWN OF MORE AND MORE TRIGLYCERIDES INTO FREE FATTY ACIDS( CALLED AS FATTY CHANGE).
2) LIGHT MICROSCOPIC CHANGES:
* CELL SWELLING,
* CLOUDY APPEARANCE OF CELLS ( DUE TO FATTY CHANGE).
***CELL ADAPTATION:
"CELL ADAPTATION MEANS CHANGES MADE BY CELL WITHIN IT IN RESPONSE TO THE ADVERSE EFFECT/ INJURY."
# THERE ARE 4 - TYPES OF CELL ADAPTATION:
1)HYPERTROPHY,
2) HYPERPLASIA,
3) METAPLASIA,
4) ATROPHY.
| HYPERTROPHY | HYPERPLASIA |
| 1) IN HYPERTROPHY, THERE IS AN INCREASE IN CELL SIZE. |
1)IN HYPERPLASIA, THERE IS AN INCREASE IN CELL NUMBER. |
| 2)STIMULUS: INCREASE IN WORKLOAD. | 2)STIMULUS: INCREASE IN WORKLOAD. |
| 3) MECHANISM: INCREASE IN STRUCTURAL PROTEIN. | 3) MECHANISM: INCREASED CELL PROLIFERATION. |
| 4)GENERALLY OCCURS IN TISSUES THAT CANNOT DIVIDE | 4) GENERALLY OCCURS IN TISSUES THAT CAN DIVIDE |
| 5) EXAMPLES: | |
|
A) PHYSIOLOGICAL: 1)skeletal muscle: Athletes, bodybuilders. 2)cardiac muscle: Athletes 3) Uterus: Pregnancy 4) Breast: Puberty, Pregnancy, Lactation |
A) PHYSIOLOGICAL: 1) Breast: Puberty, Pregnancy. 2) Uterus: Pregnancy |
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B) PATHOLOGICAL: 1) CARDIAC MUSCLE IN HYPERTENSION |
B) PATHOLOGICAL: 1) ANDROGEN; BPH( BENIGN PROSTATE HYPERPLASIA. 2) ESTROGEN: ENDOMETRIAL HYPERPLASIA. |
*****IN PREGNANCY:
HYPERTROPHY>>>>>HYPERPLASIA
3) METAPLASIA:
" CHANGE IN PHENOTYPE OF ALREADY DIFFERENTIATED CELL IS CALLED AS METAPLASIA"
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***OCCURS DUE TO STEM CELL REPROGRAMMING***
TYPES:
1) EPITHELIAL METAPLASIA,
2) CONNECTIVE METAPLASIA.
1) EPITHELIAL METAPLASIA: IT IS FURTHER OF TWO TYPES:
A) SQUAMOUS CELL METAPLASIA
B) COLUMNAR CELL METAPLASIA
A) SQUAMOUS CELL METAPLASIA:
" ANY OTHER EPITHELIUM REPLACED BY SQUAMOUS CELL IS CALLED AS SQUAMOUS CELL METAPLASIA"
EXAMPLES:
1) RESPIRATORY SYSTEM: * SMOKING,
* VIT-A DEFICIENCY,
*CHRONIC BRONCHITIS.
2)BILE DUCT INFECTION,
3)PANCREATIC DUCT INFECTION,
4) URINARY BLADDER: STONES/ SCHISTOSOMIOSIS,
5) ENDO CERVIX: HPV INFECTION
B) COLUMNAR CELL METAPLASIA :
" ANY OTHER EPITHELIUM REPLACED BY COLUMNAR CELLS IS CALLED COLUMNAR CELL METAPLASIA"
EXAMPLE: BARRETTS ESOPHAGUS.
4) ATROPHY:
" DECREASE IN CELL SIZE OR NUMBER IS DEFINED AS ATROPHY"
EXAMPLES:
1) PHYSIOLOGICAL: *** LOSS OF ENDOCRINE STIMULUS IN MENOPAUSE DECREASES UTERINE SIZE.
2) PATHOLOGICAL: ****DECREASED WORK LOAD-MUSCLES INSIDE CASTS OVER FRACTURED LIMB.
***ISCHEMIC ATROPHY- SENILE ATROPHY OF THE BRAIN.
***PRESSURE ATROPHY: TUMORS COMPRESSING THE SURROUNDING ORGANS.
THANKS, A LOT MY DEAR FRIENDS, FOR SPENDING YOUR MOST PRECIOUS TIME AND READING MY ARTICLE. HOPE I COULD HELP YOU ALL WITH THE CONCEPT.
FOR ANY QUERY RELATED TO TOPIC U, CAN CONTACT ME
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