Cell injury: irreversible

Question 1

define cell injury

Answer 1

The basis of all diseases is injury to the smallest living unit of the body, cld cell.

Question 2

causes of cell injury

Answer 2

1. Hypoxia (deficiency of oxygen)
2. physical agent
3. biological agents
4. chemical agents + drugs
5. Endogenous toxins
6. Immunologic rx (hypersensitivity)
7. Nutritional imbalance
8. Genetic abnormalities

Question 3

in causes of cell injury: hypoxia is due to

Answer 3

(i) Ischaemia
(ii) Decrease of o2 carrying capacity of bld due to anemia, cardiac or respiratory failure and CO poisoning.

Question 4

in causes of cell injury: physical agent eg

Answer 4

• burns
• deep cold
• radiation
• mechanical trauma
• electric shock

Question 5

in causes of of cell injury: biological agents eg

Answer 5

viruses
bacterial toxins
fungi
parasites.

Question 6

in causes of cell injury: chemical agent and drugs eg

Answer 6

alkalis
acids
insecticides
alcohol
narcotic drugs
air pollutants

Question 7

in causes of cell injury: Endogenous toxins eg

Answer 7

uremia
jaundice
diabetic ketosis

Question 8

in causes of cell injury: Nutritional imbalance eg

Answer 8

protein calorie malnutrition
starvation
obesity
diabetes mellitus
deficiency of other substances and vitamins.

Question 9

what r the pathogenesis Of Cell Injury?
Hypoxic and ischemic injury to the cells occur through:

Answer 9

(A)- ATP depletion
(B)- over production of o2 – derived free radicals due to imbalance
b2iann free radicals generation + radical defense system.
(C)-Defect in membrane selective permeability
(D)- Increased intracellular ca+ and loss of ca+ homeostasis that result from damage of both cell membrane & mitochondrial membrane and ER.

Question 10

what does the increased intracellular Ca+ cause?

Answer 10

activation of degenerative cellular enzymes as:
protease
ATPase
phospholipase
endonuclease. (that cause damage & mutation of the nucleus)

Question 11

Irreversible Cell Injury…

Answer 11

Severe stimuli leads to necrosis & apoptosis

Question 12

Reversible Cell Injury…

Answer 12

Mild stress for short duration leads to biochemical change
or
mild form of morphologic change in the affected cells (hydropic swelling).

Question 13

what is the def of necrosis?

Answer 13

• is local death of cells
• while the individual is alive
• followed by morphological changes - in the surrounding living tissue.

Question 14

what r the causes of cell necrosis?

Answer 14

viruses
ischaemia
bacterial toxins
hypersensitivity
ionizing radiation.

Question 15

when does the Morphologic Change In Necrosis appear?

Answer 15

The changes don’t appear in the affected cells by light microscopy before 2-6 hours according to
the type of the affected tissue.

Question 16

what r the changes in cytoplasm that. take place in necrosis?

Answer 16

1. Swelling + granularity of cytoplasm.
2. Loss of cellular membrane.
3. Fusion of cells.

Question 17

what r the Nuclear changes that happen in necrosis?

Answer 17

I.Pyknosis eg n becomes shrunken condensed and deeply stained.
II.Karyorrhexis: rupture of nuclear membrane w/ fragmentation of n.
III. Karyolysis: n dissolves + disappears.

Question 18

what happens to the effected tissue in necrosis?

Answer 18

the affected tissue changes to homogeneous eosinophilic mass with nuclear debris

Question 19

What Is The Morphologic Pattern Of Necrotic Cell Mass?

Answer 19

1. Coagulative necrosis special types of necrosis.
2. Liquefactive necrosis.
3. Caseous necrosis.
4. Fat necrosis.
5. Gangrenous Necrosis.
6. Fibrinoid necrosis.
7. Zinker’s Necrosis .

Question 20

all available info on Coagulative necrosis:

Answer 20

It is caused by sudden ischaemia e.g. infarction of heart, kidney + spleen.

Grossly :
- It appears dry pale opaque.
- It is TRIANGULAR: due to the fan like distribution of the supplying bv.
- The infarct area is surrounded by narrow zone of inflammation and congestion.

Microscopically:
-The structural outline of the affected tissue is preserved
- but the cellular details are lost

Question 21

talk about Liquifactive Necrosis:

Answer 21

• The necrosed tissue undergoes rapid softening
  e.g.
  1)infarction of nervous tissue (brain)
  2) suppurative inflammation (Abscess)

 Grossly: the affected tissue appears as homogenous amorphous substance.

 Microscopically: it appears as homogenous eosinophilic structure.

Question 22

what is zat Caseous Necrosis

Answer 22

***it is characteristic of tuberculosis.

• The necrotic tissue undergoes slow partial liquefaction forming yellow cheesy material.

Microscopically:
. It shows amorphous granular eosinophilic material
. lacking the cell outlines.

Grossly
. the caseous material resembles clumpy cheese (caseous necrosis)

Question 23

what is the cause of necrosis in TB?

Answer 23

Is the hypersensitivity reaction caused by tuberculoprotein content of the cell wall of Mycobacterium.

Question 24

rant about fat necrosis?!

Answer 24

It is necrosis of adipose tissue including two types:
1.Traumatic: caused by trauma to adipose tissue
e.g. breast and subcutaneous tissue. 2. Enzymatic: which occurs in case
of acute haemorrhagic pancreatitis.

Question 25

Gangrenous Necrosis................

Answer 25

* Due to area of coaculative necrosis followed by putrefaction dry gangrene. OR * When the liquifactive action of the bacteria is more pronounced it is cld wet gangrene.

Question 26

not important but who is Fibrinoid Necrosis?

Answer 26

(A) Collagen diseases (eg. Rheumatic fever, Rheumatoid, Sclerodermia, Lupus erythematosus and Polyarteritis nodosa). (B) In the wall of bv in malignant hypertension

Question 27

also not important but what is Zenker’s Necrosis

Answer 27

Of the rectus abdominus muscle and diaphragm as a complication of : -Bacterial infection particularly typhoid fever. -The striated muscles lose its striation, swell and fuse together in homogeneous structureless mass.

Question 28

what r the Fates And Local Effects Of Necrosis :

Answer 28

1. A small area undergoes repair: forms inflammation 2. If the necrotic area is wide: granulation then gliosis 3. Old unabsorbed caseous: becomes heavily calcified (dystrophic calcification) 4-when the necrotic tissue is infected with putrefactive Organism-=Gangrene

Question 29

what r za General Effects Of Necrosis?

Answer 29

1. Release of enzymes from the breakdown tissue into the bld forms the basis of clinical tests for diagnosis e.g. detection of transamenase in myocardial infarction and liver necrosis in hepatitis. 2. Absorption of dead products into the circulation leads to leukocytosis and fever (Not diagnostic)

Question 30

define apoptosis?

Answer 30

It is programmed death of cells in living tissues.

Question 31

list how apoptosis differs from necrosis

Answer 31

 Occurs in both physiological and pathological conditions.  Starts by nuclear changes in the form of chromatin condensation and fragmentation followed by cytoplasmic budding and then phagocytosis of the extruded apoptotic bodies.  Plasma membrane are thought to remain intact during apoptosis until the last stage so does not initiate inflammatory reaction around it.

Question 32

MAJOR CRITERIA OF APOPTOSIS:

Answer 32

1- Morphological changes 2- Chromatin condensation 3- DNA fragmentation 4- Cell death

Question 33

what r Examples of physiologic and pathologic cases accompanied with apoptosis???

Answer 33

1. Programmed cell death during embryogenesis. 2. Hormone dependent cell involution in case of endometrial cell break down during menstrual cycle. 3. Cell death in tumours during regression induced by cytotoxic drugs or irradiation. 4.In some viral disease e.g. viral hepatitis in which apoptotic cells are known as councilman bodies.

Question 34

what is the stimuli/ etiology of necrosis?

Answer 34

Hypoxia and Toxins

Question 35

what is the stimuli/ etiology for apoptosis?

Answer 35

Physiologca an Pathological

Question 36

what is the Histologic Appearance of necrosis??

Answer 36

Cellular swelling/ burst Releasing their intracellular contents and nuclear changes (pyknosis, Karyohexsis & karyolysis)

Question 37

what is the histological appearance of apoptosis??

Answer 37

Single cell death cells shrink choramatin condensation apoptotic bodies which r engulfed by surrounding cells

Question 38

what happens to the cell size in necrosis??

Answer 38

enlarged

Question 39

what happens to the cell size in apoptosis??

Answer 39

Reduced (shrinkage)

Question 40

Plasma membrane in necrosis is _____ and in apoptosis_______

Answer 40

Disrupted Intact

Question 41

Adjacent inflammation in necrosis is _____ and in apoptosis_______

Answer 41

Present Absent