Cell Adaptation and Response to Stress

Question 1

cell injury can be –?

Answer 1

reversible - goes back to normal cell

irreversible - ends up in apoptosis or necrosis

Question 2

hypertrophy

Answer 2

increase in size of cells. can increase organ size.

physiological: muscle in workout, uterus in pregnancy
pathological: heart wall thickness increases

Question 3

hyperplasia

Answer 3

increase in cell number
physiological: hormonal trigger - breast tissue growth
compensatory - residual tissue growth after removal/loss ie. liver regrows after surgery to resect part.

pathological = excessive hormone = endometrial hyperplasia.

stimulus abated then hyperplasia disappears.

Question 4

atrophy

Answer 4

decrease in cell size

causes = decrease work load, loss of innervation, aging, inadequate nutrition, diminished blood supply.
physiological & pathophysiological = same cell changes

Question 5

aplasia & hypoplasia

Answer 5

aplasia = no cell proliferation
hypoplasia = less cell proliferation

Question 6

metaplasia

Answer 6

one cell type replaced by a different cell type that handles stress a little better.

can be malignant transformation

Question 7

causes of cell injury

Answer 7

vascular: hypoxia (low O2) ischemia (no blood supply)

environment, infection, inflammation, inherited disorder, nutrional imbalance

Question 8

general principles of cell injury

Answer 8

1. depends on type of injury, duration and severity
2. consequences depend on type, status, adaptability of injured cell
3. injury results from functional and biochemical abnormalities.

Question 9

Mitochondrial damage

Answer 9

decrease ATP (pumps relying on ATPfail, anabolic respiration = decrease pH, decrease protein synthesis)

increase ROS : damage caused by rate of production and removal. production>removal = membrane damage, protein misfolding, DNA damage.

Question 10

entry of Ca2+

Answer 10

increase mt permeability = decrease ATPase to pump out ca2+ = decrease ATP. activate cellular enzymes = cell damage

Question 11

plasma membrane

Answer 11

loss of cellular components - less ATP, osmotic imbalance

Question 12

lysosomal membrane

Answer 12

leak enzymes - self-digestion

Question 13

mechanisms to protect DNA from damage

Answer 13

• DNA repair enzymes
• apoptosis
• immune surveillance

Question 14

necrosis

Answer 14

pathological process of cell death characterized by structured failure & injury to neighbouring cells *immune system activated

Never physiological

Question 15

apoptosis

Answer 15

programmed cell death characterized by organized dissassembly and safe-guarding neighbouring cells.

physiologial - removve webbing btw fingers & toes in utero
pathological - radiation = apoptosis of skin cells.

Question 16

morphology of necrosis

cytoplasmic changes & nuclear changes

Answer 16

cytoplasmic - enlarged cells , increase eosinophilia

nuclear - pyknosis (nuclear shrinkage & increase basophilia); karyorrhexis = fragmentation of shrunken nucleus; karyolysis = dissolution of chromatin.

Question 17

patterns of necrosis

Answer 17

coagulative; liquefactive; caseous; fat necrosis; fibrinoid necrosis; gangrenous necrosis

Question 18

coagulative necrosis

Answer 18

preserve outline of tissue

Question 19

liquefactive necrosis

Answer 19

loss of tissue structure & surrounded by inflammation

bacterial/fungal, usually in brain.

Question 20

caseous necrosis

Answer 20

collection of fragmented/lysed cells with amorphous granular pink appearance. tissue structure lost

Question 21

fat necrosis

Answer 21

destruction due to release of activated lipase.

Question 22

fibrinoid necrosis

Answer 22

deposition of immune complexes & fibrin produces pink amorphous fibrinoid.

Question 23

gangrenous necrosis

Answer 23

no pattern