Cellular response to stress and noxious stimuli

Question 1

what are the properties of disease

Answer 1

• etiology (cause, risk factors)
• Pathogenesis
• Morphologic changes
• Clinical manifestations

Question 2

what are the changes in response to physiological states (adaptations)

Answer 2

Hypertrophy
Hyperplasia
Atrophy
Metaplasia

Question 3

what is the increase in the size of cells which

increases the size of the organ

Answer 3

hypertrophy

Question 4

what is an example of hypertrophy

Answer 4

fat gaining in adipose tissue (weight gain)

Question 5

what causes

a) Physiologic hypertrophy
b) Pathologic hypertrophy

Answer 5

a) hormones, growth factors

b) work overload e.g. exercise

Question 6

what are the mechanisms of hypertrophy

Answer 6

✓Increased production of cellular proteins
✓Switch of adult to fetal or neonatal forms
✓Re-expression of some shut down genes

Question 7

what is hyperplasia

Answer 7

increment in the number of cells in an organ or tissue in response to a stimulus

Question 8

true or false, hypertrophy and hyperplasia cannot occur at the same time

Answer 8

false they can

Question 9

what kind of cells does hyperplasia only take place

Answer 9

in a tissue with cells capable of dividing i.e. not in muscle or nerve cells

Question 10

what are the mechanisms of hyperplasia

Answer 10

✓Growth factor dependent proliferation of mature cells

✓Increased output of new cells from stem cells

Question 11

what is the opposite of hypertrophy

Answer 11

atrophy (reduction in size of an organ or tissue due to a decrement in cell size & number)

Question 12

where is physiological atrophy usually seen

Answer 12

in fetuses

Question 13

what are the types of pathological atrophy

Answer 13

Disuse atrophy
Denervation atrophy
Senile atrophy
Undernourishement
Loss of endocrine stimulus
Continuous pressure

Question 14

what are the mechanisms of atrophy

Answer 14

• Nutrient deficiency or disuse

* autophagy (self-eating)

Question 15

what are residual bodies

Answer 15

vesicles containing indigestible materials

Question 16

what is example of residual bodies

Answer 16

Lipofuscin granules in brown atrophy

Question 17

what is metaplasia

Answer 17

is a reversible change in which one differentiated cell type is replaced by another cell type which is better able to withstand the adverse environment

Question 18

what are examples of metaplasia

Answer 18

✓Columnar epithelium → stratified squamous epithelium
✓Stratified squamous → mucinous epithelium
✓Connective tissue metaplasia

Question 19

what are mechanisms of metaplasia

Answer 19

➢Reprogramming of stem cells
➢Reprogramming of mesenchymal cells in connective tissue
➢Cytokines, growth factors, extracellular matrix components causing gene expression and hence differentiation
➢Retinoic acid regulates progenitors derived from tissue stem cells

Question 20

when does injury develop

Answer 20

• limits of adaptive responses are exceeded
• cells exposed to ınjurious agents, stress
• cells are deprived of essential nutrients
• compromised by mutations

Question 21

what does reduction in oxidative phosporylation cause

Answer 21

→depleting energy stores (ATP)
→ ion pumps are affected then stop
→causing water influx
→ cells swell

Question 22

what is hypoxia

Answer 22

Having low oxygen levels in your tissues

Question 23

what can cause hypoxia

Answer 23

• Decreased blood flow (ischemia)
• Cardiorespiratory failure
• decreased oxygen carrying capacity of the blood

Question 24

what can cause cell injury and death

Answer 24

oxygen deprivation 
physical agents
chemical agents 
infectious agents 
immunologic response
genetic derangements 
nutritional imbalance

Question 25

what is the main change that occurs morphologically during reversible injury as seen on a light microscope

Answer 25

cellular swelling

Question 26

what is vacuolar degeneration

Answer 26

cells show small clear vacuoles within the cytoplasm

Question 27

what changes are seen on an electron microscope during reversible injury

Answer 27

▪Plasma membrane alterations; blebbing (protrusions of the cell membrane), blunting, loss of microvilli ▪Mitochondrial changes; swelling, small amorphous densities ▪Dilation of ER; detachement of polysomes, intracytoplasmic myelin figures ▪Nuclear alterations; disintegration of granular & fibrillary elements

Question 28

what is it called when cells are lethally injured

Answer 28

necrosis

Question 29

why do necrotic cells have a glassy homogenous appearance

Answer 29

because of loss of glycogen

Question 30

why do myelin figures appear during cell necrosis

Answer 30

due to enzymes digesting the organelles and dead cell is replaced by whorled phospholipid structures called myelin figures

Question 31

what forms in necrotic cells due to damaged membranes

Answer 31

calcium soaps causing calcification

Question 32

# define these three forms of changes in the nucleus a) Karyolysis b) Pyknosis c) Karyorhexis

Answer 32

a) basophilia of the chromatin fades & DNA is dissolved b) nucleus shrinks, basophilia increases, chromatin condenses into solid shrunken basophilic mass c) pyknotic (irreversible condensation of chromatin) nucleus undergoes fragmentation

Question 33

what are the types of necrosis

Answer 33

1. coagulative necrosis 2. liquefactive necrosis 3. gangrenous necrosis 4. caseous necrosis 5. fat necrosis 6. fibrinoid necrosis

Question 34

what is the localized area of coagulative necrosis called

Answer 34

infarct

Question 35

what happens to the architecture of dead tissues in coagulative necrosis

Answer 35

they are preserved

Question 36

how are necrotic tissues removed in coagulative necrosis

Answer 36

by leucocytes

Question 37

coagulative necrosis can affect everywhere except what organ

Answer 37

the brain

Question 38

what leads to coagulative necrosis

Answer 38

obstructed vessels leading to ischemia (restriction in blood supply to tissues)

Question 39

in coagulative necrosis how long does an anucleated cells persist

Answer 39

days or weeks

Question 40

what process is blocked during coagulative necrosis and hence what does it stain

Answer 40

proteinolysis (due to enzyme denaturing) , eosinophilic

Question 41

what does hypoxic death of cells within central nervous system often manifest as

Answer 41

liquefactive necrosis

Question 42

what forms during liquefactive necrosis and why

Answer 42

pus forms because of tissue digestion

Question 43

where does gangrenous necrosis usually occur

Answer 43

Seen usually in a limb which lost its blood supply

Question 44

what happens when bacteria superimpose and turn to a liquefactive necrosis

Answer 44

wet gangrene

Question 45

in which disease is caseous necrosis usually see

Answer 45

tuberculosis

Question 46

what necrosis is usually associated with trauma to the pancreas

Answer 46

fat necrosis

Question 47

how does fat saponification in fat necrosis occur

Answer 47

when fatty acid combines with calcium forming chalky deposits

Question 48

what happens during fibrinoid necrosis

Answer 48

antigen antibody complexes deposit in the arterial walls causing fibrin deposition

Question 49

what do does fibrinoid necrosis stain

Answer 49

bright eosinophilic

Question 50

what does response to injurious stimuli depend on

Answer 50

the nature of the injury its duration severity

Question 51

what causes hypoxia

Answer 51

Mechanical arterial obstruction

Question 52

what restores blood flow to ischemic tissue and promotes recovery but paradoxically may exacerbate the injury causing cell death

Answer 52

Ischemia-reperfusion

Question 53

what is a complement system

Answer 53

enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen's cell membrane

Question 54

what is toxic injury

Answer 54

conversion to toxic metabolites or direct toxicity

Question 55

what is apoptosis

Answer 55

a tightly regulated suicide program within the cell

Question 56

what are apoptotic bodies

Answer 56

fragments containing portions of nuclear & cytoplasmic material formed during apoptosis

Question 57

what enzyme is mainly responsible for apoptosis

Answer 57

caspases

Question 58

what are the mechanisms of apoptosis

Answer 58

1. intrinsic pathway | 2. extrinsic pathway

Question 59

in the intrinsic pathway, what does cytochrome bind to in the cytosol

Answer 59

apoptosis activating factor1 forming an apoptosome which then binds to caspase-9 triggering a cascade of caspases

Question 60

during intrinsic pathway what happens when the outer cell membrane becomes more permeable

Answer 60

release of death inducing pro-apoptotic molecules into the cytoplasm

Question 61

what activates caspase 10 in the extrinsic pathway

Answer 61

Cytoplasmic domain intracellular apoptotic signals. the caspase 10 then activates caspase 8

Question 62

what happens during execution phase

Answer 62

caspase system cleaves cytoplasmic DNAse inhibitor hence cleaving DNA and leading to dead cell removal

Question 63

give 5 morphological changes during apoptosis

Answer 63

cell shrinkage chromatin condensation Formation of cytoplasmic blebs & apoptotic bodies Phagocytosis of apoptotic cells by macrophages Plasma membranes remain intact

Question 64

which type of necrosis has no inflammation

Answer 64

apoptosis

Question 65

what is another name for the extrinsic pathway

Answer 65

death receptor-initiated pathway of apoptosis