Intro His to Path

8/9/2019 Intro His to Path

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Introduction to 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

NEOPLASIA


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HISTOLOGY:


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

BLADDER

Human skin Mouse skin

Mouse skin


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GLANDULAR EPITHELIUM

Small intestine with villi

Mucin stain showing goblet cellsColon with NO villi

Mucin stain showing goblet cells


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Epithelial cells (continued--mouse tissues)

LiverKidney glomerulus/tubules

PancreasLung


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CONNECTIVE TISSUES:

---CELLS:

-fibroblasts-adipose 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

MUSCLE, CARTILAGE AND BONE

Trichrome stain for collagen

Silver stain for supporting reticulin fibers


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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 H&E STAINS

H&E

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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Silver stain (GMS) to detect

presence of fungal hyphae in

tissue x200

Grams stain to detect bacteria in

tissue (oil immersion x1000)

USE OF HISTOCHEMISTRY TO DETECT INFECTIOUS ORGANISMS


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Luxol Fast Blue for myelinFontana-Masson for melanocytes

MORE EXAMPLES OF HISTOCHEMISTRY


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Folded artefact Cracked tissue artefact

Knife mark + folded arterfact


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HISTOLOGY:


PATHOLOGY: THE STUDY OF DISEASE and THE MORPHOLOGIC CHANGES THAT OCCUR IN

INJURY, DEATH,

REPAIR, ADAPTATION:ACCUMULATIONS, ATROPHY, HYPERTROPHY,

HYPERPLASIA, METAPLASIA

INFLAMMATION

NEOPLASIA


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METAPLASIA: (one cell type is replaced by another cell type: cigarette smoking inducedchange of bronchial epithlelial cells to squamous, Barretts esophagitis--where the squamous

epithelium of the esophagus is replaced by columnar epithelium)

CELL INJURY: reversible or

irreversible if prolonged

Due to: oxygen deprivation--ischemic ( noblood flow) , mechanical trauma (burns),

chemical agents (acetaminophen) , infectious

agents, immunologic reactions, genetic

defects, nutritional imbalances etc.

INTRACELLULAR ACCUMULATIONS: fatty change ofliver cells in alcoholism or obesity, glycogen deposits in diabetes,

accumulation of pigments like iron after hemorrhage


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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 thenhave 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 inhypertension 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 andthe 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 ofinjury.

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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Red blood cells

(rbcs)

Hematopoietic cells

Erythroid Megakaryocytes

Leukocytes

platelets

mast cells

Granulocytes

Neutrophils Eosinophils Basophils(polymorphonuclear PMNs)

Myeloid

Monocytes

dendritic cells macrophages

B cells T cells NK cells

Plasma cells

Myelo-monocytic Lymphoid

Gr-1

F480

Mac-1

CD41

CD3

B220


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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 likethe crab


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Robbins and

Kumar textbook

of Pathology

description of

the process of

malignantprogression and

metastasis


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Benign tumors: fibroadenomas, polyps of the colon, lipomas

CARCINOMAS:

-Malignant tumors ofepithelial 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

-osteosarcomas--bone

-hemagiosarcomas--blood vessel

-gliomas (astrocytoma, glioblastoma)

-lymphomas

-melanomas

-rhabdomyosarcomas

-leiomyosarcomas

-fibrosarcomas

-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

Intro His to Path

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