Necrosis在线视频

Hello everyone today we are going to learn

the knowledge about necrosis

What is necrosis

The death of a local histiocyte

in a living tissue

is called necrosis

What must be remembered here is

this necrosis must be in living tissue

called necrosis

In necrotic tissue

metabolism will stop

Function will be lost and

another characteristic change which causes

inflammation in the surrounding tissue

It is a kind of irreversible injury

that is to say after removing the damaging factors

This necrosis

It is impossible to go back to normal

then necrosis is manifested in which

aspects of tissue cell

We know that tissue cells have nuclear cytoplasm

And the Interstitial components

between the surrounding cells then

when necrosis occurs the most important

and characteristic change

Is reflected in

nucleus

Then there is threes very important changes

in the nucleus and the first one called

pyknotic

That is to say this cell

Its nuclear

become smaller

smaller

chromatin condensation Basophilic enhancement

The nucleus is dehydrated called pyknosis

The second type is called karyorrhexis

That is the chromatin of nucleus

Will collapse into some

small fragments

At the same time the nuclear membrane of the nucleus is also ruptured

There is another one that is also common

called karyolysis

the nuclear gradually faded and disappeared

caused by

the degradation of DNA

in chromatin

In the end possibly leaving the outline of the nucleus

There are three kinds of nuclear changes

which are characteristic of necrosis changes

Let's look at this it is liver cell necrosis

In endoscopic n represents necrosis

This is the cords of the liver cells

The local part of hepatic lobule

Let's take a look when the necrosis occurred

We magnify it locally

First

The image we can see and the arrow points to

this nucleus compared with the normal liver nucleus

significantly smaller in size darker in color

Basophilic enhancement

In the second picture we see a nucleus

As

karyorrhexis

That is the nucleus breaks into small fragments

The third picture we see in here

The nucleus gradually disappeared or just left

An inconspicuous outline This is called

karyolysis

Then in addition to the nucleus

the cytoplasm will also change accordingly

For example cytoplasmic staining red showing fine particles

The tension of the cell membrane causes

some inflammation in the surrounding tissue

Why is the cytoplasm red

Darken because Basophilic ribosome

of Intracellular cytoplasm

Will be reduced or lost when necrosis occurs

In this way its binding capacity to acid dye Eosin is increased

Therefore the staining of cytoplasm was obviously deepened

redden

substrate of mesenchyme between mesenchymal cells

and cells may disintegrate

collagen fibers will swell and liquefy

Or the whole fiber structure disappeared Finally

This kind of mesenchyme and what I said before

necrosis cells will be fused into

a granular unstructured

red-colored mass

Let's look at normal cardiomyocytes

When it occurs

we think it is

a kind of coagulation necrosis

Then we'll introduce coagulation necrosis

The nucleus of a cardiomyocyte

can be seen to dissolve

blurred

And its cytoplasm is significantly redder

than normal cardiomyocytes

Then

Between the dissolved and necrotic cardiomyocytes

There is a lot of inflammatory cell infiltration

between the new cells of coagulation necrosis

We think there are three kinds of necrosis

If the

Protein coagulation

has a major advantage

protein coagulation

Tissue cells lack of water present a gray dry solidified change

we think it is

A Kind of coagulation necrosis

It's more likely to occur in parenchyma heart and kidney or skin

The second is liquefaction necrosis

In organization such as brain tissue pancreatic tissue

When necrosis occurs

Including tissue abscesses

Tissue abscesses to be learned in the future

In the necrotic tissue

dissolved by the decomposition of enzymes

Is in a dominant position

this enzyme dissolves the tissue

Which becomes liquid and forms some cavity

This is called liquefaction necrosis

Unlike them

There are some special types of necrosis such as

caseous necrosis

Fat necrosis

Fibrinoid necrosis and gangrene

Next let's go into details one by one

coagulation necrosis means

hard

Off-white yellow-white

solidification of change

Generally wedge-shaped

There is a very obvious line with the surrounding health tissue

it is a red bleeding band

Let's take a look it is generally

Coagulative necrosis of kidney

There is a triangle under the capsule of the kidney

Or wedge

Such a yellow and white lesion

Pointed toward the renal bottom toward the tunicle

At the same time it has a boundary with the surrounding normal renal tissue

Very clear

It is obvious in fresh specimens

That Pink or red congestion bleeding bands

It is a coagulated necrosis of the spleen as well as kidney

Pointed toward the porta lienis bottom toward the tunicle

a yellow wedge

Or a white solidified necrotic foci

Under the microscope

when necrosis occurs

nucleus

The cytoplasm and the surrounding mesenchyme will change

it is a kind of

change that protein coagulation is in a dominant position

So the outline of its tissue is visible

For example when kidney coagulation necrosis occurs

We can see this side is the normal kidney tissue

This side is Necrotic kidney tissue

Then

boundary is very clear

In addition we can barely recognize

glomeruli and tubules in necrotic areas

It was fixed

This is a coagulation necrosis

corresponding to it

Liquefaction necrosis

It usually occurs in some special parts such as

brain tissue

brain tissue contains more lipids and more water

And so when it occurs dissolved by the decomposition of enzymes

is in a dominant position It's also called encephalomalacia

Then the second category is

For example the pancreatic tissue is special

because it has more protease So

When pancreatic necrosis occurs enzyme release

and dissolve surrounding tissues to form liquefaction necrosis

then the third category abscess

is a kind of inflammation acute pyogenic inflammation

that a lot of neutrophil exudation during infection

Neutrophils release large amounts of hydrolases

dissolve the surrounding tissue and liquefy it

it is a kind of inflammation change

Let's take a look at the brain tissue this is coronal section

We can see it is near the capsula interna

That a lesion near like Screen mesh

limited

The corruption liquefied in there has flowed out

Then leave a kind of structure like Screen mesh

it is same that a bright loose area

in the brain tissue under the microscope

The dead brain cells and the nerve cells were liquefied

Which may be absorbed or eventually form a scar

Let's compare with coagulation necrosis

On the left side coagulation necrosis happened in kidney

Liquefaction necrosis is on the right. What's the difference

When Coagulation necrosis occurs

The outline of the tissue vaguely can be recognized

all the tubules of the bulbar can be seen

When it occurred we can see Local organizations liquefied

structure was unclear at the same time a large number of neutrophils were infiltrated

This is a change in kidney cyst

and the special kind of necrosis

Let's look at caseous necrosis

It is more likely to occur in tuberculosis infections

This is caseous necrosis of a kidney

The whole kidney is completely replaced by necrotic material

Then The necrotic material is yellow

Very delicate and moist

those material like cheese called caseous necrosis

Well Under the microscope

This caseous necrosis of its organizational structure is complete Destroyed

can not see the original structure

Which is a vague piece

A complete necrosis

C represents the site of caseous necrosis

Then in the central part of the tubercle

You can see something like this

caseous necrosis then there are some special changes around it

For example this Langerhans cells indicated by the black arrow

And the inner epithelial cells indicated by the thin arrow above the line

then I will introduce those in detail

There is also a large number of special types of necrosis called fat necrosis

For example acute pancreatitis

when we talk about Pancreatitis we know that pancreas has more enzymes

When it gets inflamed pancreatic enzymes flooding out

Break down all kinds of fat in cells

Glycerin and fatty acids especially the fatty acid which

combined with calcium ions in the surrounding tissue

And then form some calcium soaps those are

some opaque gray-white spots

We can see some of the spots on the mesentery which

structure were changed Under the microscope

The dead cells have vaguely outline

sometimes we can see can blue ingredients

called fat necrosis

You can see some Fat capsules

big fat capsule which fused by

the dissolved cell

and nucleus dissolved

sometimes we can see some calcium soaps

Then there is a form of fat necrosis

called traumatic fat necrosis

For example the breast was hit

In this way when the lipid droplets flooded out

Macrophages will come to devour these lipid droplets

to form special structures This is rare

Under the microscope

then another kind of necrosis is

called fibrinoid necrosis

It is a necrosis of small blood vessels in fibrous connective tissue

Which can be seen in some allergic diseases rheumatic disease

systemic lupus erythematosus glomerular nephritis and so on

Under the microscope

Mostly some unclear granular unstructured deposited

eosinophilic pieces Which looks like cellulose

So called fibrinoid necrosis

Then this one

We're looking at that patient who has malignant hypertension

With a fibrinous necrosis in a small artery

They also have a more important category is called gangrene

a Special type of necrosis gangrene

gangrene which means necrotic tissue

with a spoilage infection

It must be with a spoilage infection

and the gangrene tissue

with black color or dark green color even has a foul smelling

So What role does the spoilage bacteria play

They decompose dead tissue

produce hydrogen sulfide which

Will combine with ion decomposed in hemoglobin

then form iron sulfide

the color of iron sulfide is black so is gangrenous tissue

Gangrene is usually common in the limbs

And internal organs that communicate with the outside world

We divided into three categories

dry gangrene moist gangrene gas gangrene

Dry gangrene occurs in the limbs especially lower limbs

And the outside Where the evaporation of the body surface is more often in lower limbs

For example central arteriosclerosis thromboangiitis obliterans

or the frostbite of

extremities

when body got a gangrene This gangrenous limb was dry and dehydrated

The surface evaporation of epidermis was more often

Then black color

Since formation of iron sulfide boundary between it and

the surrounding normal tissue is very clear

Then Dry gangrene is usually caused by

blocking and Ischemia of artery which supplying this part of the tissue

The venous reflux is fine it means

For example lower limbs

Let's take a look

Artery cut off vein return .so this part of the limb

It must be ischemia simultaneously

evaporation of body surface is more often so it must be ischemia and dry

So when necrosis occurs this part of the limb will be small dry black and hard

We will use these four words to describe it

smaller

dry

blackened

Harden

The boundaries are very clear

moist gangrene unlike it always occurs on

Viscera connected to the body surface such as

The uterus the lungs the intestines the appendix etc

Of course moist gangrene can also occur in lower limbs

at this time it must be accompanied by obstruction of venous reflux

Which means the blood will be silted in the lower limbs

In that's situation may get spoilage infection

moist gangrene

So moist gangrene of the organ

without shortage of water it will be obviously swelling and

Moist When putrefactive bacteria decompose it which will be a black green color

and produce a stench the boundary with the normal tissue is not clear

The pathogenesis of moist gangrene is arterial blockage

and the veins blocked with congestion and edema

This is moist gangrene in the small intestine.as we saw

The boundary between normal intestine and gangrene intestine is not clear

With Black Green color

we can see the artery is very

Stiffness there are thrombosis inside or some other embolus happened

then

More Swelling

More humid

softer texture

Gas gangrene is rare usually common in war

Some muscle gunfire injury can cause gas gangrene

it will happen in deep

Open wounds and with the infection of Achalme's bacillus

It may occur in deep tissue muscle that large amounts of gas are produced

When you crush it you will hear a crepitant rale

The swelling of the dead tissue produces gas

So that present a honeycomb-like appearance

And organization will have a brick-red change

Let's look at the ending of the necrosis

A better ending if a small Necrotic foci occurs

our body are going to release all kinds of hydrolases to dissolve it

Finally absorbed

original structure and function will be restored

So if large necrotic foci occurs

There's no way to eliminate it

At this time the body will separate and discharge it

for example erosion

Erosion is superficial defect on body surface

or mucous membrane

defect

The necrotic material will be removed from the defect

The deeper one is called an ulcer

For example gastric ulcer

duodenal ulcer

Necrotic foci will escape from the ulcer

then more deep tissue

The deep tissue rather than the mucosal surface will be

separated and discharged through some natural pipes

As the bronchial duct or urinary tract

This pipes will drain this necrotic mass

then larger

There's no way to separate and discharge it

Without any natural channels on the surface

At this time the larger necrotic foci will have a organization

To replace discharging

look at this picture

This part This is myocardium

We can see that cardiomyocyte in the following cardiomyocyte

When necrosis occurs in part of cardiomyocyte

We see that the nucleus are dissolved and

Disappeared

a while later new granulation tissue grows into the necrotic tissue

There are a lot of fibroblasts appeared

between some newborn capillaries

It is organization that dead tissue

Is replaced by granulation tissue

Then body

There's such a way to repair this necrosis called encasement calcification

That means if

The foci is too large to rule it out

We can change it by

wrapping it around and isolating it

with a lot of fibrous tissue forms around it

Well in necrotic foci

There is no way discharge its necrotic tissue so

In the late stages there are often some calcium salt inside it

Deposition is related to what we talk about former in denaturation

Deposition of calcium salt also known as calcification

those are the outcomes of necrotic

course is over today thank you