Pathology - General

Question 1

Define Hypoxia

Answer 1

low O2 delivery to tissues

Question 2

What are the three causes of hypoxia? Examples?

Answer 2

Ischemia, Hypoxemia, Decreased O2 carrying capacity
Ischemia: decreased blood flow; low arterial flow, venous blockage, systemic shock
Hypoxemia: low partial pressure of O2; high altitude, hypoventilation, diffusion defect, V/Q mismatch
Decreased O2 capacity: anemia, methemoglobinemia, CO poisoning

Question 3

Coagulative necrosis

Answer 3

tissue remains firm and keeps its shape
ischemic infarction
wedge shaped area of necrosis
pale or red (red if re-perfusion injury)

Question 4

Liquefactive Necrosis

Answer 4

enzymatic lysis of cells

Brain infarction, abscess, pancreatitis

Question 5

Gangrenous Necrosis

Answer 5

resembles mumified tissue
characteristic of lower limb ischemia
if infection is superimposed on dead tissue -> wet gangrene

Question 6

Caseous Necrosis

Answer 6

‘cottage-cheese’

TB or fungal

Question 7

Fat necrosis

Answer 7

deposits of calcium
trauma to fat (breast tissue) and pancreatitis mediated damage
process of calcium deposition is called saponification

Question 8

Fibrinoid necrosis

Answer 8

necrotic damage to the blood vessel wall
bright pink stain
characteristic of malignant hypertension and vascultitis

Question 9

Apoptosis enzymes

Answer 9

Caspases

Question 10

Intrinsic apoptosis pathway

Answer 10

cellular damage lead to inactivation of bcl2, which normally stabilizes the mitochondrial membrane
destabilized mitochondrial membrane leaks cytochrome c which activates caspases

Question 11

Extrinsic / receptor-ligand apoptosis pathway

Answer 11

FAS ligand binds FASr (CD95) on the target cell, which activates caspases
ex. negative selection of tcells in the thymus

Question 12

Cytotoxic CD8 apoptosis pathway

Answer 12

perforins secreted by the CD8 cell create pores in the membrane; granzyme comes in through the pores and activate caspases

Question 13

Name the antioxidant enzymes

Answer 13

superoxide dismutase: O2- to H2O2
Gluthathione peroxidase: 2GSH + radical = GSSH + H2O
Catalase: H2O2 to O2 and H2O

Question 14

primary amyloid

Answer 14

AL amyloid from immunoglobulin light chain

asso: plasma cell dyscrasias, like MM

Question 15

secondary amyloid

Answer 15

AA amyloid, from serum associated amyloid

chronic inflammation states

Question 16

Function of CD14

Answer 16

recognizes LPS from gram negative bacteria (a PAMP)

Question 17

Four attractants of neutrophils

Answer 17

LTB4, IL8, C5a, bacterial products

Question 18

Steps of neutrophil arrival and function

Answer 18

Margination, Rolling, Adhesion, Transmigration and Chemotaxis, Phagocytosis, Destruction, Resolution

Question 19

CD4 cell activation

Answer 19

extracellular antigen phagocytosed and presented on MHCII

2nd signal: B7 on the APC binds CD28 on the CD4 cell

Question 20

Th1 products

Answer 20

secrete IFN-gamma, which activates macrophages; and IL2 which activates CD8 cells

Question 21

Th2 products

Answer 21

secretes IL4/IL13, which helps Bcells class switch to IgE; and IL5,which helps Bcells class switch to IgA and eosinophil chemotaxis

Question 22

CD8 cell activation

Answer 22

intracellular antigen is presented on MHCI

2nd signal is IL2 from CD4 Th1 cells

Question 23

B cell activation

Answer 23

CD40 on B cells binds CD40L on helper t cells

Question 24

Defining cell of a granuloma

Answer 24

epithelioid histiocyte

macrophage with lots of pink cytoplasm

Question 25

Granuloma formation

Answer 25

macrophages secrete IL12 -> Th cells to Th1 type

Th1 cells secrete IFN-gamma, which converts macrophages to epithelioid histiocytes