HISTOLOGY:

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HISTOLOGY THE MICROSCOPIC STUDY OF BIOLOGICAL
MATERIAL PATHOLOGY THE STUDY OF DISEASE and
THE MORPHOLOGIC CHANGES THAT OCCUR IN
INJURY, DEATH, REPAIR, ADAPTATION
ACCUMULATIONS, ATROPHY, HYPERTROPHY,
HYPERPLASIA, METAPLASIA INFLAMMATION NEOPLAS
IA
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HISTOLOGY THE MICROSCOPIC STUDY OF BIOLOGICAL
MATERIAL
Derivatives of the three germ layers Endoderm,
Mesoderm, Ectoderm ---Epithelium ---Connective
Tissue ---Neural
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EPITHELIUM comprised of cells that cover the
exterior surface of the body, and line both the
internal closed cavities of the body, and
those body tubes that communicate with the
exterior --alimentary, respiratory,
genitourinary Can be impervious (epidermis or
bladder) , secretory (stomach), absorptive
(intestines), be a transport system(trachea),
or receive sensory stimuli (taste buds of the
tongue)
Epithelium is attached to its underlying
connective tissue by basement membrane
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SQUAMOUS AND TRANSITIONAL EPITHELIUM
Human skin
Mouse skin
BLADDER
Mouse skin
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GLANDULAR EPITHELIUM
Small intestine with villi Mucin stain showing
goblet cells
Colon with NO villi Mucin stain showing goblet
cells
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Epithelial cells (continued--mouse tissues)
Kidney glomerulus/tubules
Liver
Pancreas
Lung
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CONNECTIVE TISSUES ---CELLS -fibroblasts -adip
ose cells -undifferentiated mesenchymal
cells -cells of the hematopoietic
system ---EXTRACELLULAR MATRIX -EXTRACELLULAR
FIBERS -collagen fibers -reticular
fibers -elastic fibers -GROUND SUBSTANCE
-proteoglycans -hyaluronic acids - TISSUE
FLUID
Trichrome stain for collagen
Silver stain for supporting reticulin fibers
MUSCLE, CARTILAGE AND BONE
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TYPES OF MUSCLE Cardiac, Smooth, Skeletal
Cardiac striations central nuclei Skeletal
striations eccentric nuclei Smooth
central nuclei
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Non-epithelial tissues (continued)
Bone/cartilage
Spleen
Brain-hippocampus and ventricle
Cerebellum
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HISTOCHEMISTRY IMMUNOHISTOCHEMISTRY IN SITU
HYBRIDIZATION
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USE OF HISTOCHEMISTRY TO DETECT DIFFERENCES IN
BONE AND CARTILAGE FORMATION
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USE OF HISTOCHEMISTRY TO DETECT DIFFERENCES
DETECTED ON ROUTINE HE STAINS
HE
TRAP stain for osteoclasts
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Use of AlcianBlue/PAS to detect differences in
Mucin content within Brunners glands of duodenum
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USE OF HISTOCHEMISTRY TO DETECT INFECTIOUS
ORGANISMS
Silver stain (GMS) to detect presence of fungal
hyphae in tissue x200
Grams stain to detect bacteria in tissue (oil
immersion x1000)
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MORE EXAMPLES OF HISTOCHEMISTRY
Fontana-Masson for melanocytes
Luxol Fast Blue for myelin
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Cracked tissue artefact
Folded artefact
Knife mark folded arterfact
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HISTOLOGY THE MICROSCOPIC STUDY OF BIOLOGICAL
MATERIAL PATHOLOGY THE STUDY OF DISEASE and
THE MORPHOLOGIC CHANGES THAT OCCUR IN
INJURY, DEATH, REPAIR, ADAPTATION
ACCUMULATIONS, ATROPHY, HYPERTROPHY,
HYPERPLASIA, METAPLASIA INFLAMMATION NEOPLAS
IA
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CELL INJURY reversible or irreversible if
prolonged Due to oxygen deprivation--ischemic (
no blood flow) , mechanical trauma (burns),
chemical agents (acetaminophen) , infectious
agents, immunologic reactions, genetic defects,
nutritional imbalances etc.
INTRACELLULAR ACCUMULATIONS fatty change of
liver cells in alcoholism or obesity, glycogen
deposits in diabetes, accumulation of pigments
like iron after hemorrhage
METAPLASIA (one cell type is replaced by another
cell type cigarette smoking induced change of
bronchial epithlelial cells to squamous,
Barretts esophagitis--where the squamous
epithelium of the esophagus is replaced by
columnar epithelium)
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CELL DEATH necrosis (occurs from the
progressive degradative action of enzymes on
the lethally injured cells) apoptosis
-programmed destruction of cells during
embryogenesis -hormone dependent involution in
the adult - cell deletion in proliferating cell
populations, immune cells, tumors, etc.
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HYPERPLASIA An increase in the number of cells
in an organ or tissue, which may then have an
increased volume. Physiologic hyperplasia
Proliferation of mammary glandular epithelium at
pregnancy, compensatory hyperplasia of the liver
after partial hepatectomy
HYPERTROPHY An increase in size of cells and
thus an increase in the size of the organ eg
physiologic hypertrophy of uterus during
pregnancy, hypertrophy of the cardiac muscle in
hypertension or valvular disease, hypertrophy of
skeletal muscles due to heavy exercise
ATROPHY a shrinkage in the size of the cells due
to -a decreased work load ( when a limb is
immobilized in a plaster cast) -loss of
innervation -diminished blood supply -loss of
endocrine stimulation -aging
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INFLAMMATION AND REPAIR Is a protective response,
where the goal is to rid the body of the initial
cause of injury and the consequences ACUTE
relatively short duration. There is an alteration
of blood vesels such that there is an exudation
of fluid and plasma proteins, with an emigration
of leukocytes, predominantly neutrophils, into
the focus of injury. CHRONIC is of longer
duration and is associated with the accumulation
of lymphocytes and macrophages and allowing the
repair process to occur, using angiogenesis and/
or fibrosis.
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Hematopoietic cells
Erythroid Megakaryocytes
Leukocytes
Red blood cells (rbcs)
Lymphoid
platelets
CD41
Monocytes
B cells T cells NK cells
Mac-1
Myeloid
B220
CD3
Plasma cells
dendritic cells macrophages
F480
Granulocytes
Gr-1
Neutrophils Eosinophils Basophils (polymorphonuc
lear PMNs)
mast cells
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NEOPLASIA new abnormal growth A neoplasm
is a abnormal purposeless mass of tissue, the
growth of which exceeds and is uncoordinated with
that of normal tissues, and which persists in the
same excessive manner after cessation fo the
stimuli which evoked the change Tumor
swelling. Benign tumor -- no infiltration into
surrounding tissue. Malignant tumor
cancer Cancer is the common term for all
malignant tumors. Cancer derives from the Latin
term crab presumably because it adheres to any
part that it seizes in an obstinate manner like
the crab
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Robbins and Kumar textbook of Pathology
description of the process of malignant
progression and metastasis
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Benign tumors fibroadenomas, polyps of the
colon, lipomas CARCINOMAS -Malignant tumors of
epithelial cells -well differentiated,
moderately differentiated, poorly
differentiated -squamous carcinomas -
adeno-carcinomas alveolar papillary tubular
(anaplastic, undifferentiated, large cell, small
cell) (hepatocellular carcinoma,
cholangiocarcinoma)
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SARCOMAS Malignant tumors of supporting
tissue -chondrosarcomas--cartilage -osteosarcoma
s--bone -hemagiosarcomas--blood vessel -gliomas
(astrocytoma, glioblastoma) -lymphomas -melanom
as -rhabdomyosarcomas -leiomyosarcomas -fibrosa
rcomas -seminoma, teratoma, etc.
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Teratoma has multiple tissue types
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IMMUNOHISTOCHEMISTRY is an important adjunct to
histopathologic evaluation
Epithelium Keratins --pan-keratin and
antibodies to keratins of different molecular
weights Supporting connective tissues
--Vimentin--fibroblasts, blood vessels --vWF,
CD31 (PECAM)-- endothelial cells of blood
vessels Hematopoeitic tissues CD45, B220, CD3,
F480, Mac-1, Gr-1, CD41 Muscle desmin, smooth
muscle actin Neural GFAP, NeuN, F480/Mac-1, MBP,
NSE, S100 Hormones specific antibodies--insulin,
casein, etc. Germ cells alpha-feto protein
(teratomas) Proliferation markers-Ki-67