Chapter 1 ( Cell )

Question 1

How decrease in cell size occurs ?

Answer 1

1- ubiquitin proteasome degradation of intermediate filaments of cytoskeleton
2- autophagy of cellular components

Question 2

Causes of methemoglobinemia ?

Answer 2

Oxidant stress ex : sulfa and nitrate drugs

New borns

Question 3

How decreased ATP causes cellular dysfunction ?

Answer 3

1- Na-K pump leads in sodium and water build up
2- Ca pump leads in Ca build up
3- Aerobic glycolysis leads in lactic acids build up and low pH which denatures proteins and precipitates DNA

Question 4

Hall mark of reversible cellular injury ?

Answer 4

Cellular swelling resulting in
1- loss of microvilli
2- membrane blebbing
3- dissociation of ribosomes from RER and decreased protein synthesis

Question 5

Hall mark of irreversible cellular injury ?

Answer 5

Membrane damage :
1- Plasma membrane damage : cytosolic enzymes leaking to serum and Ca leaks into cells
2- Mitochondrial membrane damage : loss pf ETC and Cytochrome C leaking to cytosol which activates apoptosis
3- Lysosomal membrane damage : hydrolytic enzyme leaks to cytosol which is activated by high Ca

Question 6

Steps of loss of nucleus during cell death ?

Answer 6

1- Pyknosis : nuclear condensation
2- Karyorrhexis : fragmentation
3- Karyolysis : dissolution

Question 7

Appearance of caseous necrosis ?

Answer 7

Cottage cheese like appearance

Question 8

Examples of pathological disorders that show Sammoma bodies ?

Answer 8

1- Papillary carcinoma of the thyroid
2- Meningiomas
3- Papillary serous carcinoma of the ovary

Question 9

Examples for apoptosis ?

Answer 9

1- endometrial shedding during menstrual cycle
2- removal of cells during embryogenesis
3- CD8+ T cell mediated killing of virally infected cells

Question 10

Pathways of activating Caspases ?

Answer 10

1- intrinsic mitochondrial pathway :
Cellular damage , DNA damage , decreased hormonal stimulation —> ATM activation —> P53 activation —> Bcl-2 inactivation —> BAC activation —> pores in the mitochondria —> leakage of cytochrome C —> form complex with APAF-1 —> activation of cspase cascade ( caspase 9 )
2- Extrinsic pathway : FAS ligand binds FAS death receptor ( CD95 ) activating caspases
TNF binds TNF receptor activating caspases ( caspase 8 )
3- Cytotoxix CD8 T cell mediated pathway : CD8 T cells secret perforins —> creates pores in cell membrane —> Granzymes enter cells trough the pores —> activate caspases

Question 11

Examples for pathologic generation of free radicles ?

Answer 11

1- Ionizing radiation : water hydrolyzed to hydroxyl free radicle
2- Inflammation : NADPH oxidase generates syperoxide ions
3- Metals : generates hydroxyl free iron ( Fenton reaction )
4- drugs and chemicals : metabolized by P450 system of liver generating free radicles

Question 12

How free radicles cause cellular injury ?

Answer 12

Peroxidation of lipids

Oxidation of DNA and proteins

Question 13

Mechanisms of free radicals elimination ?

Answer 13

1- Antioxidants as Vit A,C,E
2- Enzymes as
Superoxide dismutase ( superoxide O2’ )
Glutathione peroxidase ( different free radicles )
Catalase (H2O2)
3- Metal carrier proteins as transferrin and ceruloplasmin

Question 14

CCL4 ?

Answer 14

Organic solvent used in dry cleaning industry
Converted to CCl3 free radicle by P450 system of liver which cases cell injury and impaired protein synthesis
Decreases apolipoproteins leads to fatty liver

Question 15

Features of Amyloid ?

Answer 15

Beta-pleated sheet configuration

Congo red staining and apple green birefringence when viewed microscopically under polarized light

Question 16

Primary amyloidosis ?

Answer 16

Systemic deposition of AL amyloid which is derived from immunoglobulin light chain
With plasma cell dyscrasias as MM

Question 17

Secondary amyloidosis ?

Answer 17

Systemic deposition of AA amyloid which is derived from Serum Amyloid Associated protein (SAA)

Question 18

SAA ?

Answer 18

Acute phase reactant that is increased in chronic inflammatory state , malignancy and familial mediterranean fever

Question 19

FMF mechanism ? Presentation ?

Answer 19

Autosomal recessive
Dysfunction of neutrophils
Presents by : episodes of fever and acute serosal inflammation ( can mimic appendicitis , arthritis , MI )
High SAA during attacks deposits as AA amyloid in tissues

Question 20

Clinical findings of systemic amyloidosis ?

Answer 20

1- Nephrotic syndrome
2- Restrictive cardiomyopathy or arrhythmia
3- Tongue enlargement , malabsorption , hepatosplenomegaly

Question 21

Amyloid in serum cardiac amyloidosis ? Presentation ?

Answer 21

Non mutated serum transthyretin

Usually Asymptomatic

Question 22

Amyloid in familia amyloid cardiomyopathy ? Presentation ?

Answer 22

Mutated serum transthyretin

Restrictive cardiomyopathy

Question 23

Amyloid in NIDDM ?

Answer 23

Amylin in islets of pancreas

Question 24

Amyloid in Alzheimer disease ?

Answer 24

A Beta amyloid derived from Beta-amyloid precursor protein ( Beta-APP ), gene of which present on chromosome 21

Question 25

Amyloid in dialysis associated amyloidosis ?

Answer 25

Beta2-microglobulin deposits in joints

Question 26

Amyloid in medullary carcinoma of the thyroid ?

Answer 26

Calcitonin