Cell Injury Flashcards
What is cell injury _
Cell injury is defined as functional and morphological effects of variety of stress’s on the cell from various etiological agents which result in changes in its internal and external environment
On what factors cellular response depends
① host that is type of cell nutrition it is reaching
@ factors pertaining to injurious agents
What are types of cels
Labile cells
Stable cells
Permanent cells
What are labile cells
Continuous regeneration from stem cells self renewal
Haematopoitic stem cells
Epithelial cells of surface
Duct epithelial- salivalyglands, pancreas, biliary tract - skin, Oral cavity vagina cervix
Mucous _ git, uterus, fallopian, ubladden
Stable cells
. Parenchyma - liver,. pancreas ,renal tubules
Mesenchymal cells - endothelium
regeneration in response to injury
Permanent cells
Non proliferative in postnatal life
Neutrons
Cardiomyocytes
What are the different stages of injury
Normalcells Pathological or physiological stress Cellular adaptation If stress persists Reversible cell injury Irreversible cell injury or cell death That is necrosis or apoptosis
What is the definition of adaptation
They are reversible
Structural and functional responses to physiological stress or pathological stress
During which a New altered steady state is achieved
Allowing the cell to survive and continue to function
What are different types of adaptations
Hypertrophy Hyperplasia Atrophy Metaplasia Displasia
Definition of hyperplasia l
Increase in No of cells Not size of cells resulting in enlargement of organ or tissue
May or may not be hypertrophy and hyperplasia occurs together
Occurs in labile cells and stable cells
What is the mechanism of hyperplasia
Increased production of growth factors and growth factor receptors
How neoplasia differs from hyperplasia
In neoplasia hyperplasia occurs without growth regulatory mechanism due to change in genetic composition of cells but in hyperplasia as long as stimulus present the effect will be there
What is physiological hyperplasia
Female breast during pubcity, pregnancy, lactation
Uterus in pregnancy
Endometrium after menstrual cycle
These all come under hormonal hyperplasia
What is physiological compensatory hyperplasia
Occurs in liver and bone marrow
liver after donation
Bm afterhaemorrageand blood donation -
Examples of pathological hyperplasia
Endometrial hyperplasia due to oestrogen excess
Ducal hyperplasia of the Brest
Benign prostatic hyperplasia in old age
Skin warts from human papilloma virus
Definition of hypertrophy
There is increase in size not in number see-in permanent cells May or may not be associated with plasia Uterus = both plasia + trophy Cardiomyo cites - only hypertrophy
What is mechanism of hypertrophy
Cellular swells more structural components and proteins
Physiological hypertrophy examples
Uterus in pregnancy
Examples of pathological hypertrophy
Cardiac muscle
Smooth muscle
Skeletal muscle
Compensatory hype-ropy
In what conditions cardiac hypertrophy occurs -
Systemic hypertension
Aortic valve stenosis
Aortic value insufficiency
Mitral value insufficiency
SAAM
In what conditions smooth muscle hypertrophy occurs
Cardiac aclasia
Pyloric stenosis
Intestinal strictures
Muscular arteries in hypertension
In what condition skeletal muscle hypertrophy occurs
Hylpertropied muscles in athletes and tabours
Compensation hypertrophy occurs in?
Liver after hepectotomy
Kidney after nephrectomy on one side nephrons increases
Morphological features of hypertrophy
Organ enlarged
DNA, RNA increase prote synthesis increases and er, and organelle increases myofibrils alto increase
Atrophy definition
Decrease in size and number of cells without or with shrinkage of the tissue
Atrophied cells are smaller in size but viable there is no guarantee they need to go necrosis or apoptosis
What is the mechanism of atrophy
Reduction in cell organelles chiefly mitochondria and myofilaments and er
Physiological atrophy is seen in
Lymphoid issue with age Thymus. In adult life Gonads after menopause Uterus aft parturition Brain with aging. Bony trabuculae in osteoporosis
Pathological atrophy seen in
Starvation atrophy general weakness,anemia, emaciation known as cache is in cancer patients
Ishemic atrophy kidney in renal atherosclerosis and brain brain in cerebral atherosclerosis
Neuropathic atrophy = poliomyelitis,motor neurone disease
Disuse atrophy wasting of immobilised hand
Endocrine = hypo pituitary secretions may cause atrophy of thyroid
Pressure= erosion of skull in meningioma and erosion of sternum in arch of aorta aneurysm
Idiopathic
What are morphology of atrophy
Cells smaller in size
Increase in autophagic vacuoles
Shrinkage in cell size due to cell organelles , mito amd myofilamemts
Defination of metaplasia
A reversible change in which one adult matured cell type is replaced by other adult cell type
It is reversible
Mechanism of metaplasia
Reprogramming of stem cells occurs not the change in already existing cellls
Types of metaplasia
Epithelial squamous and columnar
Mesenchymal _ osseous and cartilaginous
Epithelial metaplasia
Most common type
Replacement of one epithelium by stronger but less well specialised epithelium
Columnar epithelium → squamous epithelium
Bronchus.( pseudostratified columnar ciliated epithelium) in chronic smokers
Uterine endocervix( normally lined by simple columnar epithelium ) in prolapse of uterus
Gallbladder( normally lined simple columnar epithelium)
In cholelithiasis
In prostate(normally lined simple columnar epithelium) in chronic prostatitis
Vita A deficiency, squamous metaplasia in nose, bronchi
Lacrimal and salivary glands
Examples of metaplasia
Barett’s esophagus → change of normal squamous epithelium to columnar epithelium
Cervical erosion → change of normal squamous epithelium to columnar epithelium
Mesenchymal metaplasia
Less common
One adult type of mesenchymal tissue to another lie formation of cartilage, bones or adipose tissue
Osseus metaplasia
Monckebergs medial calorific sclerosis(in arterial
Wall in old age)
Myositis ossificans
Cartilage of larynx and bronchi in eldest ppl
In scar of chronic inflammation of prolonged duration
Cartilaginous metaplasia
In healing of fractures cartilaginous metaplasia may occur where there in undue mobility
Dysplasia definition
Disordered cellular development
Characterised by cellular cytologic changes
Explain cytological changes
No of layers increases
Disorderly arrangement
Loss of basal polarity Pleomorphism Increased n/c ratio Hyperchromatism Increased mitotic activity
Cell injury
Cell injury when cells are stressed so severely or persistently that they are no longer able to adapt or when cells are exposed to damaging genes
Types of cell injury
Necrosis
Apoptosis
What are the causes for cell injury
A) genetic causes B)aquired causes Hypoxia and ischaemia Physical agents Chemical agents Microbial agents Immunologic agents Nutritional derangement Aging Psychogenic diseases Iatrogenic factors Idiopathic diseases
What are 5 mechanisms of cell injury
ATP depletion Mitochondrial damage Loss of calcium homeostasis Defects in membrane permeability Free radical injury
Explain ATP depletion mechanism of cell injury os
ATP formation decreases
Na+ k+ pump decreases influx of cal and Na+ increases
Efflux of k+ increases
Er swelling, cellular swelling, loss of microvilli, Blebs formation :
. In
Anaerobic glycolysis occurs due to ishecemia lactic acid
Ph v
What are effects caused by atp depletion
Na and k+ pump stops working
Influx of calcium increases and effulx of k+increases
Er swelling ,cellular swelling loss of microvilli blebs
Anaerobic glycolysis glycogen decreases and lactic acid increases ph decreases
Clumping of nuclear chromatin
Detached ribosomes cause decrease protein synthesis
What happens when ishcemia occurs
Ischemia
Mitochondria reduces oxidative phosphorylation
Na k pump decreases sodium and water enters and k exists
Endoplasmic reticulum dilates ,the cell swells blebs appears
How anaerobic glycolysis affect the cell injury
Anaerobic glycolysis
Glycogen decreases
Lactic acid increases ph decreases
Interferes with enzymes and nuclear chromatin
Decreased atp
Rer loses ribosomes
Proteins
Synthesis falls
Structural proteins and enzymes depletion
Due to atp depletion
How the mitochondrial damage effects the cell injury
Mitochondrial damage
Mitochondrial permeability transition pore
Loss of mitochondrial membrane
Failure of normal oxidative phosphorylation
Atp decreases
Mitochondrial damage
Abnormal oxidative phosphorylation
Formation of ro
Deleterious effects
As the permeability of mitochondria increases c reactive protein blw outer and inner membranes
Mitochondrial damage c reactive protein come out and promote apoptosis
Calcium homeostasis
Normally Ca will be less intracellurlly what ever cal present is present on the er and mito
As the mitochondrial damage occurs and permeability increases the ca in the cells increases
Several enzymes like phospholipids
Atpase
Proteases
Endonucleases
Consequencesof membrane damage
Mitochondrial membrane damage
Plasma damage
Lysososomal membrane damage
Explain plasma membrane damage
Loss of osmotic balance.
Effluent of fluids and ions
Loss of cellular contents
Atp decreases
What is Fenton reaction
H202 +fe+2 =fe+3 +oH+oh-
Haber Weiss reaction
H202 +02= 20H-+ 02
