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Chapter 1
Cell Pathology
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
Outline of Cell Pathology
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Structure & function of normal cell
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Integration & coordination of cell function;
response to injury
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Reversible; Irreversible
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Rudolf Virchow
(1821–1902)
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Introduced concept of cellular
pathology
Considered father of modern
cellular pathology
1821- 1902, Berlin, pathologist and
statesman, one of the most
prominent physicians of the 19th
century. He pioneered the modern
concept of pathological processes by
his application of the cell theory to
explain the effects of disease in the
organs and tissues of the body.
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Structure & Function of a Cell
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Basic unit of life
Nucleus
Cytoplasm
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Mitochondria
Ribosome
Endoplasmic reticulum
Golgi apparatus
Lysosome
Cytoskeleton
Plasma membrane
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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The Nucleus
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Essential component of most
living cells
Contains DNA, RNA, nuclear
proteins
Major components seen by
electron microscope:
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Nuclear membrane
Chromatin (during mitosis
becomes chromosomes)
Nucleolus
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Gene Expression
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Plasma Membrane
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Forms outer surface of cell
Composed of proteins, lipids, carbohydrates
Bilayer surface
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Internal
External
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Equilibrium of Cell
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Steady state maintained
between cell & its
surrounding
Equilibrium = homeostasis
External stimuli can alter
homeostasis
Imbalance in homeostasis
can cause:
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Cell injury
Cell death
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Steady State (Homeostasis)
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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INTRODUCTION
WHEN AN
INJURY
OCCURS IT
MUST GO
THROUGH 3
STAGES OF
HEALING
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Courtesy of Tracie Yarber
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
Stage 1: Acute Inflammatory
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Increase blood flow to the area that brings
cells and chemicals to begin the healing
process.
 Phagocytes- Eat up dead cells.
 Leukocytes- Infection fighting white blood
cells.
 Platelets-Carry blood clotting materials.
THIS STAGE LASTS FOR ABOUT 2 DAYS
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Courtesy of Tracie Yarber
Stage 2: Repair
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The injured area has
been filled with the
blood, cells, and
chemicals needed to
rebuild the injury
 Fibroblasts begin
building fibers across
the injury and form
the scar. THIS
PROCESS LASTS
FROM 6 WEEKS TO
3 MONTHS.
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Courtesy of Tracie Yarber
Stage 3: Remodeling
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Builds tissue strength in the tendons, ligaments
and muscles to withstand stress applied to the
body.
THIS STAGE TAKES UP TO A YEAR OR MORE.
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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CONCLUSION
Soft tissue healing requires the tissue to go through 3
stages:
Acute Inflammatory
Repair
Remodeling
The injury should be healed completely after about a
years time.
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Cell Injury
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Reversible cell injury
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Cellular swelling
Irreversible cell injury
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Cell death
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Reversible Cell Injury
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Cellular Swelling
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Normal microvilli
Swollen microvilli
Invagination of cell
membrane
Swollen
mitochondria,
dilated RER
Loss of intracellular
contact
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Cell Membrane Permeability Changes
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Regulates flow of
sodium (Na) &
potassium (K) across
membrane
Na+/K+ ATPase pump
requires energy
produced by
mitochondria
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Nuclear Changes in
Irreversible Cell Injury
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Pyknosis:
condensation
Karyorrhexis:
fragmentation
Karyolysis:
dissolution of
nuclear structure as
result of enzymatic
digestion
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Causes of Cell Injury
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Hypoxia is a condition in which
the body or a region of the body
is deprived of adequate oxygen
supply
Anoxia means a total depletion
in the level of oxygen, an
extreme form of hypoxia or "low
oxygen".
Microbes
Inflammation
Immune reactions
Genetic & metabolic disorders
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Major Causes of Hypoxia/Anoxia
Hydrogen peroxide link
Superoxide, is a compound
that contains the superoxide
anion with the chemical
formula O2−.
Hydroxyl radical Free radical
and aging. The human body is
in constant battle to keep from
aging. Research suggests that
free radical damage to cells
leads to the pathological
changes associated with
aging.
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Reperfusion Injury
During anoxia, radicals will build up.
After a heart attack, if the blood flow
is reestablished, then the spreading
of these radicals will actually
increase the cellular death.
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Reperfusion Injury
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Reperfusion injury is the tissue damage
caused when blood supply returns to the
tissue after a period of ischemia or lack of
oxygen. The absence of oxygen and nutrients
from blood during the ischemic period creates
a condition in which the restoration of
circulation results in inflammation and
oxidative damage through the induction of
oxidative stress rather than restoration of
normal function.
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Toxic Cell Injury
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Direct toxin: heavy metals (i.e., mercury)
disrupt S-S bonds
Indirect toxin: carbon tetrachloride
metabolized in liver to form carbon trichloride,
which is more toxic
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Microbial Pathogens
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Bacteria: produce toxins
Viruses: “kill cells from within”
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Direct
Indirect
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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Viral Cell Injury
Lytic cycle- Makes new viruses
Lysogenic cycle – hides inside
the DNA
Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc.
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