Week 6 Tissue Injury- Nelson

Question 1

Hypertrophy

Answer 1

increased SIZE of cell leads to increase in size of organ or tissue

Results from increased production of cellular proteins

increased demand or stimulation

Ex: Thickness of left ventricle, uterus after pregnancy

Question 2

Hyperplasia

Answer 2

increased NUMBER of cells leads to increase in organ or tissue

occurs if the cells of the organ can divide

increased demand or stimulation

Question 3

Atrophy

Answer 3

decreased nutrients and decreased stimulation

Decrease in cell SIZE and NUMBER resulting in reduced size of tissue or organ

Common causes:
Decreased workload
loss of innervation
diminished blood supply
inadequate nutrition
loss of endocrine stimulation
pressure

Question 4

Metaplasia

Answer 4

chronic irritation
adaptive response in which one differentiated type of cell is replaced by another cell type

Reprogramming of stem cells in normal tissue OR reprogramming of undifferentiated mesechymal cells

External stimuli

Ex: normal columnar epithelium changed to squamous metaplasia in lungs (loosing cilia) in smokers

Question 5

Necrosis

Answer 5

loss of membrane integrity
Microscopic changes:
nucleus fades away, shrinks, cell content leaked out

specific proteins and enzymes can be detected in blood as diagnostic test

Question 6

Apoptosis

Answer 6

Characterized by induction of REGULATED enzymatic suicide program that active intrinsic enzyme to degrade cells own DNA and nuclear/ cytoplasmic proteins

Causes:
DNA damage
accumulation of misfolded proteins
viral infection

Question 7

Coagulative necrosis

Answer 7

architecture of dead tissue is preserved (infarct)

Question 8

Liquefactive necrosis

Answer 8

digestion of the dead tissue results in liquid viscous mass, typically seen in focal bacteria or fungal infections. Lots of pus filled with neutrophils

Question 9

Gangenous necrosis

Answer 9

clinical term, not specific. usually applied to necrosis of a limb undergoing coagulative ischemic necrosis

Question 10

caseous necrosis

Answer 10

cheese-like necrosis associated with necrotizing granulomas

Question 11

fat necrosis

Answer 11

focal areas of fat destruction

Question 12

Fibrinoid necrosis

Answer 12

necrosis seen in immune reactions involving vessels

Question 13

Describe mechanism of cell injury due to depletion of ATP

Answer 13

ATP is required for all synthetic degradative processes in the cell

caused by reduced blood supply of oxygen and nutrients, mito changes or exposure to certain toxins

Question 14

Describe mechanism of cell injury due to mitochondrial damage

Answer 14

mito supply ATP to the cell through oxidative phosphorylation

damage caused by oxygen deprivation, oxygen free radials, increased cytosolic Ca+

results in defect in mito membrane, failure of ETC, depletion of ATP, formation of reactive oxygen species
escape of mitochondrial membrane proteins (cytochrome C)

Question 15

Describe mechanism of cell injury due to influx of calcium and loss of calcium homeostasis

Answer 15

this may cause

mito membrane defect, no ATP generation, activation of lytic enzymes, induce apoptosis

Question 16

Describe mechanism of cell injury due to oxygen derived free radials

Answer 16

Caused when production of ROS increases, scavenging systems are ineffective, or oxidative stress

may cause wide variety of conditions and diseases (chemical and radiation injury, ischemia reperfusion, cancer, aging, degenerative diseases

Question 17

Mechanism of cell injury due to defects of membrane permeability

Answer 17

can occur due to ROS, decreased phospholipid synthesis (or increased breakdown), cytoskeleton abnormalities

Results in
mito membrane damage (decreased ATP)
Plasma membrane damage loss of osmotic balance, and cellular components,
release of lytic enzymes if lysosomal membranes compromised

Question 18

When does injury become irreversible?

Answer 18

mitochondrial dysfunciton (depletion of ATP) and profound distrubance in membrane function (rupture of lysosomal and plasma membranes)

Question 19

Define autophagy

Answer 19

a survival mechanism during nutrient deprivation can cannibalize itself and recycle the digested contents

Question 20

What are the four main pathways of abnormal intracellular accumulations?

Answer 20

-abnormal metabolism
(fatty change in liver associated with alcohol abuse)
defect in protein folding/transport
(excess cholesteral causing atherosclerotic vascular disease)
lack of enzyme
(glycogen storage diseases)
ingestion of indigestible materials
(Exogenous pigments like a tatoo)

Question 21

Dystrophic calcifications

Answer 21

occurs in areas of necrosis

NORMAL serum calcium levels

Question 22

Metastatic calcification

Answer 22

due to herpcalcemia secondary to disordered calcium metabolism
ELEVATED serum calcium levels
found in normal tissues

Question 23

Cellular aging

Answer 23

result of progressive decline in cellular function and viability casued by genetic abnormalities and the accumulation of cellular and molecular damage due to effects of exposure to exogenous influences

Question 24

Biochemical markers:

AST

Answer 24

found in liver, heart, skeletal muscle, brain and kidneys

Question 25

Biochemical markers

ALT

Answer 25

liver

Question 26

Biochemical markers

ALP

Answer 26

bile duct damage

Question 27

Biochemical markers

Troponin 1

Answer 27

cardiac muscle