Introduction to pathology在线视频

Hello everyone

Welcome to the world of pathology

So what is pathology

To understand that question

we must first understand the pathological states

Prior to this

we have learned Anatomy Histology and Embryology Physiology and Cellular Biology etc

They are sciences of the body under normal circumstances

Pathology deals with the functional and morphological changes under the pathological states

So what is the pathological states

Let's take some examples to understand this question

First let's take liver as an example

A normal liver weighs about 1400 grams

it is divided into left and right lobes

it has capsule the surface is very smooth, very soft

In pathological states

it becomes smaller and lighter

its texture turns firm its surface become granulated

It loses its luster even though with capsule

cross section shows many island-like lesions

It is the typical morphological changes of portal cirrhosis

Besides that

the liver might look smaller, lighter, firmer

meantime it would change in color

turns light-greenish

This is a type of cirrhosis due to the blockage of the bile ducts called cholestatic cirrhosis

In some cases

the liver becomes larger

take this for example

this liver enlarges significantly

there is a huge mass in the middle and left lobe of the liver

This lump looks gray white in color

with bleeding and necrosis

despite its clear border there are many surrounding irregular satellite lesions

This is the morphological change of hepatocellular carcinoma

Under the microscope, histologically

what changes will happen to the hepatocytes

First let's review what we've learned about liver in Histology

The liver is composed of the hepatic lobules

The central vein is in the center of hepatic lobules

the peri-lobular region is called portal region

The hepatocytes line up to form hepatic cords

The space between hepatic cords is called hepatocyte sinus

This is normal histology of liver tissue

So in pathological states

the liver can become highly swollen

hepatocytes are significantly enlarged

with clearing and granulation of the cytoplasm

the nuclei are in the center of the hepatocytes

Due to the severe swelling of hepatocytes

the hepatic cords become widened

leading to narrowing even disappearing of the hepatic sinuses

Now we cannot see the hepatic sinuses

These are typical cellular changes of acute viral hepatitis under the microscope

In other cases

there're many vacuoles within the hepatocytes

These irregular vacuoles are lipids

This is the histological and cytological change in the case of fatty degeneration of the liver

In some cases

there will be fibrous connective tissue in the liver

Proliferation of fibrous tissue destroys the original architecture of the liver

forming many island-like structures

These island-like structures are called pseudo-lobules

Because the pseudo-lobules are completely different from the normal hepatic lobules

Inside the pseudo-lobules you might find a hepatic central vein, or you might not

The portal region might even appear in a pseudo-lobule

That is

the fibrous connective tissue proliferates, intersperses, separates the normal liver tissue

making the liver firmer

So this is the histological change of portal cirrhosis under the microscope

Sometimes

hepatic cords disappear

hepatocytes pile up to form nests

Hepatocytes form adenoid structures or rose-like structures

nuclei enlarge nuclear-plasma ratio imbalance

the pathologic mitotic figures appear

with swelling and neovasculization in the mesenchymal

This is the histological change of hepatocellular carcinoma

Through the examples above

we might understand

the major task for the study of pathology or the pathological states

For example

it suggests that the viral hepatitis is caused by viruses

Hepatocellular carcinoma is a tumor

Hepatic cirrhosis is caused by fibrous connective tissue proliferation

which destroys the normal architecture of normal liver

forming many pseudo-lobules

To conclude our examples illustrated that

the so-called pathology is a study that deal with the etiology and pathogenesis of diseases

Besides the cause of diseases

it also studies the mechanism of diseases

What causes this disease and how does it happen

How it affects the morphological structure of organs and what microscopic change will be present

Because of the structural changes

there will also be alterations in histological, cytological functional and metabolic aspects

For example

cirrhotic patients might have ascites

What's the cause of that

Why there is hypoalbuminemia

Liver dysfunction might interfere with the synthetic functions, leading to hypoalbuminemia

Hence

the study which reveals the law of disease transformation from the occurrence to the development and eventually the result

to clarify the essence of diseases

is called pathology

To conclude

The task of pathology is to study the pathogenesis of diseases

the pathological changes microscopically and morphologically, lesions

the law of disease transformations, result

and finally to make an accurate pathological diagnosis

So that's it for our class

Thank you all