Introduction to Pathology By Gandi Li Department of Pathology West China Medical School.
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Transcript of Introduction to Pathology By Gandi Li Department of Pathology West China Medical School.
Introduction to Pathology
By Gandi Li
Department of Pathology
West China Medical School
Where there is love of medicine, there is love of humankind.
-- Hippocrates
(460-377 BC)
The most common diseases in developing countries
Infectious diseases (viral hepatitis, tuberculosis, bacterial pneumonia, bacterial diarrheas, AIDS, et al)
Atherosclerosis and hypertension
Cancer
Emphysema and chronic bronchitis
What happens in Nepal?
Disease could reasonably be defined as internal problems that cause pain and/or interfere with a person's ability to work, play, and/or love others. Pathology is the scientific study of disease. Now more and more people know many diseases are lifestyle-related.Pathology is a bridge between medicine and basic sciences for medical students.Pathology is also one of the most important methods to diagnose disease in clinical practice.
Pathology involves
Etiology (causes of diseases,Why?)
Pathogenesis (mechanisms, How?)
Pathological changes (lesions, What?) Morphological changes (anatomical pathology) Functional changes (pathophysiology)
Clinical manifestations (signs and symptoms)
Sequelae (healing, complications, death)
Branchs of pathologyGeneral pathology cell injury tissue repair hemodynamic disord
ers inflammation tumor
Systemic pathology the blood vessels and
the heart the respiratory system the digestive system the urinary system the male and female
genital system the nervous system the endocrine system
GOAL of PATHOLOGY GOAL of PATHOLOGY for MEDICAL STUDENTSfor MEDICAL STUDENTS
Be able to understand and analyze the relationship between pathologic changes and clinical manifestations.Be able to take a clinical history and order tests logically.Be able to develop a correct diagnosis.Be able to communicate with professionals and patients.Does become a physician or a pathologist?
Physician or surgeon mostly.
What does a PATHOLOGIST do?
SURGICAL PATHOLOGY Interpret biopsies (e.g., skin, breast, gastroi
ntestinal tract)Evaluate surgical resection specimens (e.
g., colectomy, nephrectomy, mastectomy)Frozen sections (intra-operational rapid dia
gnosis)
What does a PATHOLOGIST do?
CYTOPATHOLOGY (e.g., Pap smears, FNA - Fine Needle Aspiration)CLINICAL PATHOLOGY Hematology (Peripheral blood smear, bone marrow,
coagulation disorders). Chemistry (Blood, urine, cerebrospinal fluid, effusions). Microbiology. Blood bank.
AUTOPSY PATHOLOGY Final diagnosis, forensic pathology--criminal
investigation
How to study pathology?
Background:
Basic medical sciences (anatomy, histology, physiology, biochemistry, immunology, microbiology, parasitology,et al)
Medical terms (e.g. hyperplasia, et al)
Clinical knowledge (physical examination, laboratory tests, X-ray, CT, et al)
How to study pathology?
The key for studying pathology:
Characteristic
morphologic lesions (lesions)
Clinical manifestations
PathogenesisEtiology
FunctionalChanges(Pathophysiology)
How to study pathology?
Approach to good result:Lectures and textbooksLaboratory practice: gross specimen and glass slidesClinicopathologic conference (CPC)Autopsy demonstration (real or video)Recommend internet web sites: http://www-medlib.med.utah.edu/webPath/webpath.html
Observation of gross specimen:a hypertrophic heart (left) and a normal heart (right)
Gross observation of a nutmeg liver and mircoscopic changes
Cancer cells in ascites of a patient with gastric carcinoma
Summary of introduction
The terms disease pathology general patholog
y lesion pathologist surgical pathology
The roles of pathology in medical education and clinical practice
How to study pathology Uebung machts Master. (Practice trains master) Arbeit machts Spass! (Work brings happy!)
A famous painting about autopsy by Rhunbrant in 18 century
“As is our pathology, so is our medicine”
“Ask not what disease the patient has, but rather what patient the disease has.”
Sir William Osler (Canadian Physician)
Cell Injury, Adaptation and Death
Overview of cell injury
Causes of cell injury
Mechanisms of cell injury
Cellular adaptation to injury
Reversible and irreversible cell injury
Programmed cell death---- apoptosis
Cellular aging
Overview of cell injury
Homeostasis requires functional cooperation in widely distributed cells.
Normal cells homeostasis
Adaptativecells
Reversibleinjured cells
Cell death
necrosisapoptosisatrophy,
hypertrophyhyperplasiametapllasia
LethalReversible
Lethal
Reversible
Reversible
intracellular accumulations, degenerationA summary of the relationship between normal cells,
adaptative cells, reversible injured cells and cell death
The relationship between cellular function, cell death andthe morphologic changes of cell injury.
Causes of cell injury
Ischemia/hypoxia (e.g. heart attack)Chemical agents (toxins, acid, drugs) Active oxygen species: free radicals, oxidants, electrop
hiles
Infectious agents (bacterial, virus, parasite)Immunologic reactions (hypersensitivity)Genetic defects (Down’s syndrome)Nutritional imbalances (protein insufficiency)Physical agents (trauma, temperature)Aging
Mechanisms of cell injury
ATP depletion
Oxygen deprivation or generation of reactive oxygen species
Loss of calcium homeostasis
Defects in plasma membrane permeability
Mitochondria damage
Mechanism
of ischemic and hypoxic
injury
Cell mechanisms of injury
Free radicals/ reactive chemicals
Normalmetabolisms
O 2
OH•
H2O2
NO
SOD/CatalaseGlutathiole peroxidase/GSSG
Vitamin E, C
Detoxification
Cell membraneMitochondriaEndo. Retic.DNA
Neutralization of free radicals
SOD
2O2 + 2H+ H2O 2 + O2 catalase
2H2O2 2H2O + O2
glutathione peroxidase
2OH• + 2GSH GSSH + 2H2O glutathione reductase
SummaryAny stimuli and stresses can result in cell injuries.The injurious consequences depend on not only the type of injury, its duration, its severity, and also the type, status, adaptability and genetic makeup of the injured cell. Cell injury can be divided into reversible and irreversible.The loss of cell function is far before the cell death, but the morphological visible changes appear far behind the cell death.
Cellular adaptation to injury
Concept of Adaptation: When cells encounter physiologic stresses or
pathologic stimuli from outside and inside of body, they can alter themselves to achieve a new steady state and preserve viability.All kinds of adaptation may be considered as disorders of growth and/or differentiationCellular adaptation can be considered as a state between the normal, unstressed cell and injured, overstressed cell.
Atrophy
Definition: (briefly, decrease in cell size) Shrinkage in the size of the parenchymal cells b
y loss of cell substances in a well developed organ or tissue is known as atrophy. Or:acquired shrinkage of cells, tissues or organs.Simple atrophy (loss of cell size only)Numerous atrophy (loss of cell size and number through apoptosis)Differentiation: aplasia, hypoplasia
Testis:Right: Atrophied Left: Normal
There are kidneys and ureters of a one-year-old boy. The right Kidney is hypoplastic and the left one with a three-ureters abnormality.
Atrophy
The reasons of atrophy: Decreased workload disuse atrophy Loss of innervation neuropathic atrophy Diminished blood supply ischemic atrophy
press atrophy Absence of nutrition undernourished
atrophy Loss of hormone stimuli endocrine atrophy Aging senile atrophy
Brain atrophy in an old patient with arteriosclerosis. Note thewidened sulci and narrow convolutions.
Brain atrophy in a patient with Alzheimer’s disease. The gyri are narrowed and the sulci widened toward to frontal pole.
Hydrocephalus (left) and nephrohydrosis (right)Note the dilated ventricles and thinner grey and whine matter. The renal calyces and renal pelvis are dilated too.
There are some skeletal muscle fibers. The number of cells is the same as before the atrophy occurred, but the size of some fibers is reduced. In this case, innervation of the small fibers in the center was lost. This is a trichrome stain.
Atrophy
The atrophied cells, tissue and organ have Reduction of physiologic functions Decreased synthesis Increased catabolism—increased protein degradat
ion through
Lysosomes digest the senescent organelles (autolysis)
If the number of cells decrease, there is apoptosis (cell suicide), or programmed cell death
Hypertrophy
Definition: (briefly: increase in cell size)
an increase in the size of parenchymal cells and consequently an increase in the size of the organ.
No increase of cellnumber in a purified
hypertrophy!
Hypertrophy
Compensatory hypertrophy Mechanical stimuli---skeletal muscle of a sportsma
n Increased workload---left ventricle hypertrophy of s
ystemic hypertension Decompensation---heart failure
Endocrine hypertrophy Hormonal stimuli---pregnant uterus
---Cushing’s syndrome
Hypertrophy of left ventricle (centripetal hypertrophy) in a patient with essential hypertension. Note the marked thickened wall of ventricle.
a. Hypertrophy of the left ventricleb. Normal myocardial fibersc. Hypertrophic myocardial fibers
A pregnant uterus (right) and normal uterus (left)
Physiologic hypertrophy of the uterus during pregnancy.Left: gross appearance of a normal uterus and a gravid uterus.Middle: small spindle-shaped uterine smooth muscle cells fromA normal uterus. Right: large, plump hypertrophied smooth muscle cells froma gravid uterus.
Cushing’s syndrome resulted from adenoma of adrenal cortex
Hypertrophy
Hypertrophic cells and organ with Increased function Increased synthesis of structural protein Induced by two types of signals
Mechanical triggers----stretchTrophic triggers----activation of alpha-adrenergi
c receptors
Differentiate fromhyperplasia, pseudohypertrophy
Hyperplasia
Definition: (briefly, increase in cell number)An increase in the number of parenchymal cells in an organ or tissue.Hyperplasia can occur with hypertrophy in various tissue except muscles.Hyperplasia can be divided into Physiologic hyperplasia
Hormonal: breast glandular epithelium at pregnancy Pathologic hyperplasia
Compensatory: liver after partial resection
Hyperplasia of endometrium in an adult woman with menorrhagia
Examples of hyperplasia:
Red bone marrow of blood donor
Examples of hyperplasia:
Hyperadrenalism
Examples of hyperplasia:
Goiter (absence of iodine)
Hyperplasia of prostatic gland
Note the prostate isnodular enlarged
Hyperplasia
Hyperplasia is induced by stimulation of hormonal or growth factors, cytokines and chemokines through the signal transduction pathway
Hyperplasia can turn off when the organ restores or the stimulus stops
Continuous pathologic hyperplasia constitutes a fertile soil for cancerous proliferation
MetaplasiaDefinition: (briefly: change in cell type)A reversible change in which one adult cell type is replaced by another adult cell type.This replacement is through hyperplasia of “stem cell” or “undifferentiated cell”, so metaplasia is actually an abnormal hyperplasia.The significances of metaplasia are To be able to withstand the stress better To be able to transform into a cancerous proliferati
on
Squamous metaplasia in bronchus in a heavy smoker
Squamous metaplasia of laryngeal respiratory epithelium in a heavy smoker
Columnar to squamous metaplasia: Barrett metaplasia inlower part of esophagus
Intestinal metaplasiain a patient with chronic atrophic gastritisNote the gobletcells
This is dysplasia. The normal squamous epithelium at the left transforms to a disorderly growth pattern at the right. This is farther down the road toward neoplasia.
Summary of adaptation
Enlargement of an organ can result from Hypertrophy Hyperplasia Hypertrophy with hyperplasia Pseudohypertrophy (actual atrophy) Edema Tumor Congestion Inflammation
Summary of adaptation
Shrinkage of an organ can result from Atrophy Aplasia and hypoplasia
Hyperplasia persists only for so long as the stimulus is applied. When it is removed, the hyperplastic tissue tends to revert to its normal size.Hyperplasia must be distinguished from dysplasia and neoplastic proliferation.
Summary of adaptation
Metaplasia is an abnormal hyperplasia.It can become a malignant neoplasm.
All kind of adaptation can be considered as abnormal growth and/or differentiationAdaptation is the result of long time persisted, but mild stimuliMost adaptations are reversible when the stimulus is removed
Metaplasia
Normal cells
Dysplasia Malignant tumor
Simpleatrophy
Numerousatrophy
Hypertrophy Hyperplasia
adaptation
Sum
mary of abnorm
al grow
th
Learn words
Greek derivation:
dys- bad, abnormal
hyper- above, excessive
hypo- below, deficient
meta- beyond, between
-plasia a forming
-trophe nourishment
Requirements
The overview of cell injuries
The main mechanisms of cell injury Ischemia/hypoxia free radicals
Concepts and recognition of lesions Adaptation Atrophy Hypertrophy Hyperplasia Metaplasia
Give samples of various forms of adaptation and understand their significances
Thank you for your attention!