Cell Injury

Question 1

what are some responses to cellular response to stress and injury

Answer 1

atrophy

hypertrophy

hyperplasia

metaplasia

Question 2

what is atrophy?

Answer 2

decrease in the size of cells due to loss of cell substance

either physiological or pathological

• decreased workload
• loss of innervation
• diminished blood supply
• inadequate nutrition
• loss of endocrine stimulation

Question 3

what is hypertrophy?

Answer 3

increase in the size of the cells resulting in an increase in the size of an organ

reflects increased production of cellular protein

occurs in cells incapable of division

physiological: skeletal muscle in exercise, uterus in pregnancy
pathological: left ventricular hypertrophy in hypertension

Question 4

what is hyperplasia?

Answer 4

increase in the number of cells - usually also the size of the organ

physiologically: breast during pregnancy, after a partial hepatectomy
pathologically: excessive hormonal/growth factor

controlled process but fertile soil for cancer

Question 5

columnar epithleium is better for what?

Answer 5

it is more adapt for acid, bile etc - contains goblet cells which produce mucous

Question 6

squamus cell epithelium is better adapt for

Answer 6

physical strenghth, like skin, doesn’t produce mucous

Question 7

what is the greatest factor of malnutrition in our country?

Answer 7

obesity

Question 8

cellular response depends on …?

Answer 8

on the injury

• type
• severity
• duration

Question 9

consequences of cellular injury depends on …?

Answer 9

The cell

• type
• state
• adaptability

Question 10

which cell systems are most vulnerable to injuries?

Answer 10

• mitochondria
• cell membrane- requires energy to maintain
• synthetic apparatus - proteins and enzymes
• cytoskeleton
• genetic apparatus (DNA)

Question 11

what mechanisms occur with cell injury?

Answer 11

• inhibition of aerobic respiration = ATP depletion
• generation of oxygen species (free radicals)
• defects in membrane permeability (ion depletion)
• disruption of calcium homeostasis (calcium influx)

Question 12

PET scan detects what?i

Answer 12

it shows the activity of cells

Question 13

describe what occurs when there is a decreased oxidative phosphorylation within the mitochondria?

Answer 13

• decreaed ATP
• increased anaerobic glycolysis
• reduced activity of sodium pump
• increased cytosolic free calcium - activates enzymes
  
  • ATPase- decreased ATP
  • phospholipase - decreased phospholipids
  • endonuclease - nuclear chromatin damage
  • protease- disruption of membrane and cytoskeletal proteins

Question 14

normal function of lysozomes?

Answer 14

degradation of proteins

Question 15

what ion, in high concentration, leads to necrosis?

Answer 15

calcium

Question 16

How are free radicals degraded?

Answer 16

• spontaneous decay
• inactivation by enzymes
• antioxidants

Question 17

how do free radicals cause cell injury?

Answer 17

• lipid peroxidation of membranes - react with membrane to produce highly reactive lipid peroxide
• oxidative modification of proteins
• react with DNA and cause mutation
• generally cells irreversibly damaged by free radicals are deleted by apoptosis (by gaurdian of the genome = P53)

Question 18

what are the morphological changes associated with reversible cell injury?

Answer 18

cellular swelling (liver swells up after a three day drinking binge)

ultrastructural changes: plasma membrane alteration, mitochondrial swelling, dilation of ER with retachment of ribosomes, nuclear alterations

Question 19

what is the definition of necrosis?

Answer 19

a live organism experiencing tissue death

so you couldn’t find necrosis on a dead person… becuase all of their tissue is dead

this is important b/c it generates an infection in the surrounding tissues

Question 20

what nuclear changes are associated with necrosis?

Answer 20

• nucleus becomes pale = karyolysis
• nucleus become small and dense= pyknosis
• fragment/breakdown of the nucleus = karyorrhexis

Question 21

what is coagulative necrosis?

Answer 21

preservation of the structural outlines, with necrosis

characteristic of hypoxic cell death except in the brain

Question 22

what is liquefactive necrosis?

Answer 22

transformation of solid tissue into a liquid mass

• complete digestion of the dead cells leads to a complete loss of the tissue

characteristic of bacterial and some fungal infection , and hypoxic cell death in the CNS and the brain due to very little connective tissue stroma

Question 23

what is fat necrosis?

Answer 23

necrosis due to lipases = common in breast

creates a hard mass and is a symptom of malignancy

Question 24

what is gangrenous necrosis?

Answer 24

not a distinctive pattern of cell death - but infective in nature

ischaemia with secondary bacterial infection

• wet gangrene
• gas gangrene
• dry gangrene

Question 25

what are some physiological reasons for apoptosis?

Answer 25

* thymus gland after infanthood * endometrial shedding with menstrual cycle * death of inflammatory cells after inflamation * deletion of autoreactive T cells in thymus

Question 26

what is the mechanism of apoptosis?

Answer 26

energy dependent using various genes to regulate plasma membrane remains intact, therefore inflammation is not induced involved in morphogenesis and control of organ size

Question 27

What are the controlling factors of apoptosis?

Answer 27

inhibitors = growth factrs, cell matrix, sex steroids etc inducers = growth factor withdrawal, loss of matrix attachment, glucocorticoids, some viruses, free radicals etc

Question 28

what internal signal leads to apoptosis?

Answer 28

mitochondrial damage

Question 29

what external signal leads to apoptosis?

Answer 29

surface suicide receptor ( FAS CD95) is stimulated

Question 30

dystrophic calcificaiton is what?

Answer 30

calcium level is normal in blood but the tissue is abnormal ex) in cardiology= calcification of coronary arteries, breast calcificaiton due to breast carcinoma