Chapter 2 - Cellular Injury and Adaptation

Question 1

Most common cause of cell injury

Answer 1

Hypoxia

Question 2

Major mechanisms leading to hypoxia

Answer 2

Ischemia, cardiopulmonary failure, and decreased oxygen-carrying capacity of the blood (e.g., anemia)

Question 3

Vitamin deficiencies: A

Answer 3

Night blindness, squa- mous metaplasia, immune deficiency

Question 4

Vitamin deficiencies: C

Answer 4

Scurvy

Question 5

Vitamin deficiencies: D

Answer 5

Rickets and osteomalacia

Question 6

Vitamin deficiencies: K

Answer 6

Bleeding diathesis

Question 7

Vitamin deficiencies: B12

Answer 7

megaloblastic anemia, neuropathy, and spinal cord degeneration),

Question 8

Vitamin deficiencies: folate (B9)

Answer 8

Megaloblastic anemia and neural tube defects

Question 9

Vitamin deficiencies: Niacin (B3)

Answer 9

Pellagra (diarrhea, dermatitis, and dementia)

Question 10

Critical intracellular targets that are susceptible to injury

Answer 10

DNA

Production of ATP via aerobic respiration

Cell membranes

Protein synthesis

Question 11

Damage to DNA, proteins, lipid membranes, and circulating lipids (LDL) can be caused by Oxygen-derived free radicals, which are:

Answer 11

Superoxide anion (O2 –)

Hydroxyl radical (OH•)

Hydrogen peroxide (H2O2).

Question 12

ATP depletion can cause … and increase …

Answer 12

Disruption of Na+/K+ or Ca++ pumps

Anaerobic glycolysis that leads to a decrease in cellular pH

Question 13

Influx of calcium can cause problems because calcium is a second messenger, which can activate a wide spectrum of enzymes, like…

Answer 13

Proteases (protein breakdown), ATPases (contributes to ATP depletion), phospholipases (cell membrane injury) and endonucleases (DNA damage)

Question 14

Mitochondrial dysfunction causes…

Answer 14

Decreased oxidative phosphorylation and ATP production

Formation of mitochondrial permeability transition (MPT) channels

Release of cytochrome c (a trigger for apoptosis).

Question 15

Protective factors against free radicals include:

Answer 15

• Antioxidants
Vitamins A, E, and C

• Superoxide dismutase
Superoxide → hydrogen peroxide

• Glutathione peroxidase
Hydroxyl ions or hydrogen peroxide → water

• Catalase
Hydrogen peroxide → oxygen and water

Question 16

Myocardial injury rises the levels of

Answer 16

Troponin

CPK-MB

Lactate dehydrogenase (LDH)

Question 17

Features of Reversible cell injury:

Answer 17

Decreased synthesis of ATP by oxidative phosphorylation.

Decreased function of Na+K+ATPase membrane pumps, which in turn causes influx of Na+ and water, efflux of K+, cellular swelling (hydropic swelling), and swelling of the endoplasmic reticulum

Switch to anaerobic glycolysis

Decreased protein synthesis leads to detachment of ribosomes from the rough endoplasmic reticulum

Plasma-membrane blebs and myelin figures

Question 18

Features of Irreversible cell injury:

Answer 18

Severe membrane damage with a massive influx of calcium and efflux of intracellular enzymes and proteins

Marked mitochondrial dysfunction

Rupture of the lysosomes → activation of acid hydrolases → autolysis

Question 19

Nuclear changes seen in Irreversible cell injury:

Answer 19

Pyknosis (degeneration and condensation of nuclear chromatin)

Karyorrhexis (nuclear fragmentation)

Karyolysis (dissolution of the nucleus)

Question 20

Morphologic types of necrosis: concept

Answer 20

Cell death in living tissue, often with an inflammatory response

Question 21

Most common form of necrosis, most often due to ischemic injury (infarct):

Answer 21

Coagulative necrosis

Question 22

Coagulative necrosis, is caused by…

Answer 22

Denaturing of proteins within the cytoplasm

Question 23

In coagulative necrosis, microscopic examination shows…

Answer 23

Loss of the nucleus but preservation of cellular shape

Question 24

Coagulative necrosis does not occur in the…

Answer 24

Brain

Question 25

Liquefaction necrosis is caused by...

Answer 25

Hydrolytic enzymes, leading to autolysis (release of proteolytic enzymes from injured cells) and heterolysis (release of proteolytic enzymes from inflammatory cells).

Question 26

Liquefaction necrosis occurs in...

Answer 26

Abscesses, brain infarcts, and pancreatic necrosis

Question 27

Caseous necrosis gross appearance is:

Answer 27

soft, friable and “cheese-like"

Question 28

Caseous necrosis is characteristic of...

Answer 28

Granulomatous diseases

Question 29

Fat necrosis is caused by...

Answer 29

action of lipases on adipocytes it's characteristic of acute pancreatitis

Question 30

Fat necrosis: gross examination

Answer 30

Chalky white appearance.

Question 31

Fibrinoid necrosis is a form of necrotic...

Answer 31

connective tissue that histologically resembles fibrin

Question 32

On microscopic examination fibrinoid necrosis has an...

Answer 32

Eosinophilic (pink) homogeneous appearance

Question 33

Fibrinoid necrosis is often due to...

Answer 33

Acute immunologic injury and vascular hypertensive damage

Question 34

Dry gangrene has ... for the microscopic pattern

Answer 34

Coagulative necrosis

Question 35

Wet gangrene has ... for the microscopic pattern

Answer 35

Liquefactive necrosis

Question 36

Apoptosis: concept

Answer 36

Programmed cell death without inflammatory response.

Question 37

Apoptosis: in morphologic appearance...

Answer 37

the cell shrinks in size and has dense eosinophilic cytoplasm

Question 38

Nuclear changes in apoptosis

Answer 38

Pyknosis and karyorrhexis

Question 39

Stimuli for apoptosis include

Answer 39

Cell injury and DNA damage, Lack of hormones, cytokines, or growth factors Receptor-ligand signals: Fas binding → Fas ligand; tumor necrosis factor (TNF) → TNF receptor 1 (TNFR1)

Question 40

Function of Protein bcl-2

Answer 40

Inhibiting apoptosis

Question 41

How does the Protein bcl-2 inhibit apoptosis?

Answer 41

Preventing release of Cytochrome C from mitochondria Binding pro-apoptotic protease activating factor (Apaf-1)

Question 42

Function of protein p53

Answer 42

Stimulates apoptosis

Question 43

How does the protein p53 stimulate apoptosis?

Answer 43

Arresting the cell cycle If DNA repair is impossible, p53 stimulates apoptosis.

Question 44

Protein p53 is elavated by...

Answer 44

DNA injury

Question 45

Execution of apoptosis is mediated by...

Answer 45

a cascade of caspases (cysteine aspartic acid proteases).

Question 46

Function of caspases in apoptosis

Answer 46

Digest nuclear and cytoskeletal proteins activate endonucleases

Question 47

Physiologic examples of apoptosis:

Answer 47

Embryogenesis Menstrual cycle Selective death of lymphocytes

Question 48

Pathologic examples of apoptosis:

Answer 48

Viral diseases (viral hepatitis [Councilman body]) Graft-versus-host disease Cystic fibrosis (duct obstruction and pancreatic atrophy).

Question 49

Atrophy: concept

Answer 49

Decrease in cell size and functional ability

Question 50

Causes of atrophy

Answer 50

Decreased workload/disuse (immobilization) Ischemia (atherosclerosis) Lack of hormonal or neural stimulation Malnutrition Aging

Question 51

Atrophy: Light microscopic examination shows...

Answer 51

Small shrunken cells with lipofuscin granules

Question 52

Atrophy: Electron microscopy shows...

Answer 52

Decreased intracellular components and autophagosomes.

Question 53

Hypertrophy: concept

Answer 53

Increase in cell size and functional ability due to increased synthesis of intracellular components

Question 54

Cell types that are unable to exhibit hyperplasia:

Answer 54

Nerve, cardiac, skeletal muscle cells

Question 55

Increased expression of growth-promoting genes (proto-oncogenes) is related to...

Answer 55

Hyperplasia

Question 56

Metaplasia: concept

Answer 56

Reversible change of one fully differentiated cell type to another

Question 57

Pathologic accumulation: Russell bodies

Answer 57

Intracytoplasmic accumulation of immunoglobulins in plasma cells

Question 58

Lipofuscin

Answer 58

Perinuclear yellow-brown pigment Due to indigestible material within lysosomes Common in the liver and heart

Question 59

Melanin is derived from...

Answer 59

Tyrosine found in melanocytes and substantia nigra

Question 60

Hemosiderin

Answer 60

Golden yellow-brown granular pigment found in areas of hemorrhage or bruises

Question 61

Examples of intracellular hyaline:

Answer 61

Renal proximal tubule protein reabsorption droplets Russell bodies Mallory's hyaline (alcoholic)

Question 62

Examples of extracellular hyaline:

Answer 62

Hyaline arteriolosclerosis Amyloid Hyaline membrane disease of the newborn

Question 63

Examples of Dystrophic calcification:

Answer 63

Fat necrosis (saponification) Psammoma bodies (laminated calcifications that occur in meningiomas and papillary carcinomas of the thyroid and ovary) Mönckeberg medial calcific sclerosis in arterial walls Atherosclerotic plaques.

Question 64

Dystrophic calcification is the precipitation of calcium phosphate in...

Answer 64

Dying or necrotic tissues

Question 65

Metastatic calcification is the precipitation of calcium phosphate in...

Answer 65

Normal tissue due to hypercalcemia

Question 66

Causes of hypercalcemia:

Answer 66

Hyperparathyroidism Renal failure Paraneoplastic syndrome vitamin D intoxication Milk-alkali syndrome Sarcoidosis Paget disease Multiple myeloma