INTRODUCTION TO PATHOLOGY ( cell adaptation and 4 aspects of disease.)

Summary

This video script from Shine Tech's YouTube channel offers an introduction to pathology, defining it as the scientific study of disease. It outlines the four evolutionary steps of a disease: etiology, pathogenesis, morphologic changes, and functional derangement or clinical significance. The script also delves into cell adaptation, detailing its types—hypertrophy, atrophy, hyperplasia, and metaplasia—exploring their causes and implications in both physiological and pathological contexts. The aim is to provide a foundational understanding of how diseases evolve and how cells adapt or respond to various stimuli.

Takeaways

• 🔬 Pathology is the scientific study of disease, focusing on its causes, mechanisms, and effects on the body.
• 🧬 Disease is defined as an abnormal variation in the structure or function of the body's parts.
• 📈 The evolution of a disease typically involves four steps: etiology, pathogenesis, morphologic changes, and functional derangement or clinical significance.
• 🧐 Etiology refers to the cause or causes of a disease, including primary causes and idiopathic cases where the cause is unknown.
• 🛠 Pathogenesis is the process by which the disease's cause operates to produce pathological and clinical manifestations.
• 🔍 Morphologic changes are structural alterations in cells or tissues that occur as a result of pathogenesis.
• 🔬 Morphologic changes can be gross, visible to the naked eye, or microscopic, requiring a microscope to observe.
• 🏥 Clinical significance pertains to how morphologic changes in organs affect their function and lead to the signs and symptoms of a disease.
• 💊 Cell adaptation is a response to stress, where cells may undergo reversible changes in number, size, phenotype, or function.
• 🌱 There are four types of cell adaptation: hypertrophy (increase in cell size), atrophy (reduction in cell size), hyperplasia (increase in cell number), and metaplasia (change in cell type).
• 🚫 Cell injury can lead to reversible or irreversible changes, with irreversible injury ultimately resulting in cell death through necrosis or apoptosis.

Q & A

What is pathology?

Pathology is the scientific study of disease, focusing on the causes, mechanisms, and effects of diseases on the body's structure and function.

What are the four evolutionary steps of a disease?

The four evolutionary steps of a disease are etiology (the cause), pathogenesis (the mechanisms through which the cause operates), morphologic changes (structural alterations in cells or tissues), and functional derangement or clinical significance (the clinical features or symptoms of the disease).

What is the difference between primary etiology and idiopathic disease?

Primary etiology refers to diseases where the cause is known, while idiopathic diseases are those where the cause remains unknown.

What is the term used to describe the period from exposure to a disease-causing agent to the first manifestation of signs and symptoms?

This period is known as the incubation period or latent stage.

How are morphologic changes categorized in the context of disease?

Morphologic changes can be categorized as gross morphologic changes, which are visible to the naked eye, and microscopic morphologic changes, which require a microscope to observe.

What is cell adaptation and why is it important?

Cell adaptation refers to reversible changes in the number, size, phenotype, metabolic activity, or function of cells in response to changes in their environment. It is important because it represents the cell's initial response to stress, which can prevent cell injury or death if successful.

What are the four types of cell adaptation mentioned in the script?

The four types of cell adaptation are hypertrophy (increase in cell size), atrophy (reduction in cell size), hyperplasia (increase in the number of cells), and metaplasia (a change in cell type).

What causes atrophy in cells?

Atrophy can be caused by decreased workload or disuse, denervation, diminished blood supply, inadequate nutrition, loss of endocrine stimulation, and aging.

How does hypertrophy differ from hyperplasia?

Hypertrophy involves an increase in the size of cells, often without the formation of new cells, resulting in an increase in the size of the organ. Hyperplasia, on the other hand, involves an increase in the number of cells, often due to increased cell proliferation.

What is metaplasia and how does it occur?

Metaplasia is a type of cellular adaptation where one adult cell type is replaced by another adult cell type, usually in response to a particular stress. It occurs through the reprogramming of stem cells to differentiate along a new pathway, rather than a phenotypic change of already differentiated cells.

Can you provide an example of physiological hyperplasia?

An example of physiological hyperplasia is the proliferation of glandular epithelium in the female breast during puberty and pregnancy, which is stimulated by hormones.

Outlines

00:00

🔬 Introduction to Pathology and Disease Evolution

The video begins with an introduction to pathology, defined as the scientific study of disease. It explains that a disease is an abnormal variation in the body's structure or function. The script outlines the four evolutionary steps of a disease: etiology (the cause), pathogenesis (mechanisms of disease), morphologic changes (structural alterations in cells or tissues), and functional derangement or clinical significance (the clinical manifestations or symptoms). The video promises to explore these steps in detail, starting with etiology and moving through to the causes of cell injury.

05:00

🧬 Etiology and Pathogenesis in Disease Development

This paragraph delves deeper into the concept of etiology, which refers to the causes and contributing factors of a disease, and distinguishes between primary etiology and idiopathic cases. It then transitions to pathogenesis, which describes the processes through which the disease's cause leads to pathological and clinical manifestations. The discussion includes the concepts of the incubation period and the latent stage, emphasizing the progression from etiology to pathogenesis and the resulting morphologic changes in cells and tissues.

10:04

📚 Morphologic Changes and Clinical Significance

The script continues by detailing morphologic changes, which are structural alterations following pathogenesis and can be either gross or microscopic. It explains that these changes impact the organ's function and lead to clinical features, which are the signs and symptoms of a disease. The paragraph also touches on the causes, prognosis, and the importance of understanding the morphological changes in determining the clinical significance of a disease.

15:06

🛠 Cell Adaptation Mechanisms in Response to Stress

The focus shifts to cell adaptation, which is the cell's response to stress through reversible changes in number, size, phenotype, metabolic activity, or function. The video outlines four types of cell adaptation: hypertrophy, atrophy, hyperplasia, and metaplasia. It emphasizes that adaptation is the cell's initial response to stress, which can either be successful or lead to reversible or irreversible injury, ultimately resulting in cell death.

20:06

🏗️ Types of Cellular Adaptation: Hypertrophy and Atrophy

This section discusses two types of cellular adaptation: hypertrophy, an increase in cell size leading to organ enlargement, and atrophy, a reduction in cell size due to loss of substance. It explains the causes of atrophy, such as decreased workload, denervation, diminished blood supply, inadequate nutrition, loss of endocrine stimulation, and aging. Hypertrophy is presented as the opposite, occurring when cells have a limited capacity to divide and can be either physiological, as seen in athletes, or pathological, as in cardiac enlargement due to hypertension.

25:06

🌱 Hyperplasia and Metaplasia: Cellular Adaptation Responses

The video script describes hyperplasia as an increase in the number of cells within an organ due to proliferation, which can be physiological, such as in the female breast during puberty and pregnancy, or pathological, such as endometrial hyperplasia. It also introduces metaplasia, a change where one adult cell type is replaced by another in response to stress, and explains that this adaptation arises from the reprogramming of stem cells rather than a change in already differentiated cells.

🔄 Metaplasia: Adaptation Through Cell Type Replacement

The final paragraph focuses on metaplasia as a type of cellular adaptation where a sensitive cell type is replaced by another that can better withstand adverse conditions. It distinguishes between connective tissue metaplasia, seen in muscle tissue with calcium accumulation, and epithelial metaplasia, which occurs in habitual smokers where normal columnar epithelial cells are replaced by stratified squamous epithelium to adapt to the stress of smoke inhalation.

Keywords

💡Pathology

Pathology is defined as the scientific study of disease. It is the central theme of the video, which aims to explore the nature and progression of diseases. In the script, pathology is discussed in the context of understanding the structural or functional abnormalities in the body that constitute a disease.

💡Disease

A disease, as mentioned in the script, is an abnormal variation in the structure or function of any part of the body. It is a key concept in the video that helps to establish what pathology studies, with examples including various causes such as trauma, toxins, infections, and genetic abnormalities.

💡Etiology

Etiology refers to the cause or causes and modifying factors responsible for the initiation and progression of a disease. It is a fundamental aspect of pathology discussed in the video, where understanding the primary cause (primary etiology) or unknown cause (idiopathic) of a disease is crucial.

💡Pathogenesis

Pathogenesis is the mechanism through which the cause of a disease operates to produce pathological and clinical manifestations. The video explains that this term encompasses the processes that occur from the introduction of a disease-causing agent into the body to the appearance of signs and symptoms.

💡Morphologic Changes

Morphologic changes are structural alterations in cells or tissues that occur following pathogenesis. The video distinguishes between gross and microscopic morphologic changes, which are observable with the naked eye and require a microscope, respectively. These changes are a direct result of the disease process.

💡Functional Derangement

Functional derangement, as discussed in the video, refers to the impact of morphologic changes on the normal function of an organ, leading to clinical features such as signs and symptoms of a disease. It is the final step in the evolution of a disease, linking structural changes to observable clinical outcomes.

💡Cell Adaptation

Cell adaptation is a response of cells to changes in their environment, which can be reversible or lead to cell injury or death. The video focuses on this concept, explaining that cells may adapt through various mechanisms such as hypertrophy, atrophy, hyperplasia, and metaplasia in response to stress or changes in their environment.

💡Hypertrophy

Hypertrophy is defined as an increase in the size of cells, resulting in an increase in the size of an organ. The video provides examples of both physiological hypertrophy, such as in the skeletal muscles of bodybuilders, and pathological hypertrophy, such as in the heart due to hypertension.

💡Atrophy

Atrophy, as explained in the video, is the shrinkage in the size of cells due to the loss of cell substance, leading to reduced function. Causes of atrophy include decreased workload, denervation, diminished blood supply, inadequate nutrition, loss of endocrine stimulation, and aging.

💡Hyperplasia

Hyperplasia refers to an increase in the number of cells in an organ, stemming from increased proliferation. The video distinguishes between physiological hyperplasia, such as in the female breast during puberty and pregnancy, and pathological hyperplasia, such as endometrial hyperplasia which can lead to abnormal uterine bleeding.

💡Metaplasia

Metaplasia is a type of cellular adaptation where one adult cell type is replaced by another adult cell type, often in response to a particular stress. The video describes how metaplasia can occur due to reprogramming of stem cells to differentiate along a new pathway, such as in habitual cigarette smokers where the normal respiratory epithelium is replaced by stratified squamous epithelium.

Highlights

Pathology is defined as the scientific study of disease.

A disease is an abnormal variation in the structure or function of the body.

Diseases evolve through four steps: etiology, pathogenesis, morphologic change, and functional derangement or clinical significance.

Etiology refers to the cause or causes of a disease, with known causes termed primary etiology and unknown causes termed idiopathic.

Pathogenesis involves the mechanisms through which the cause of a disease operates to produce pathological and clinical manifestations.

Morphologic changes are structural alterations in cells or tissues following pathogenesis.

Morphologic changes can be gross or microscopic, observable with the naked eye or requiring a microscope.

Functional derangement or clinical significance refers to the impact of morphological changes on the normal function of an organ and the resulting clinical features.

Causes of disease can include trauma, toxins, infections, immunological abnormalities, and genetic abnormalities.

Cell adaptation is a reversible change in response to environmental changes, including hypertrophy, atrophy, hyperplasia, and metaplasia.

Hypertrophy is an increase in cell size, resulting in an increase in the size of the organ, and can be physiological or pathological.

Atrophy is the shrinkage of cells due to the loss of cell substance, leading to reduced function but not cell death.

Hyperplasia is an increase in the number of cells in an organ, which can be physiological, such as hormonal hyperplasia, or pathological.

Metaplasia involves a change in one adult cell type being replaced by another adult cell type to withstand adverse environments.

Connective tissue metaplasia can occur in mesenchymal cells, leading to bone formation in soft tissues due to calcium accumulation.

Epithelial metaplasia is observed in habitual smokers, where normal columnar epithelial cells are replaced by stratified squamous epithelium to adapt to smoke exposure.

The video concludes with a summary of the steps in the evolution of disease and the types of cell adaptation.

Transcripts

hello there welcome to shine Tech's

YouTube channel in this video we're

going to look at introduction to

pathology so in this video we're going

to Define what pathology is then from

there we're going to look at the steps

in the evolution of disease and then

from there we're also going to look at

cell injury cell death

adaptation and cell adaptation then from

there we're going to finally look at the

causes of the of cell injury so to begin

with let's define what pathology is so

pathology is simply the study a

scientific study of disease scientific

study

of of disease so in pathology we study

diseases so what is a disease a disease

is simply an abnormal variation in

structure or function of any part of the

body so if you there is an abnormal

variation in the function or structure

of any part of the body that is called a

disease and a disease will take four

evolutionary steps so these are the

steps the evolutional steps in a disease

so the first step is iology and then

from there the disease will is going to

progress to

pathogenesis after pathogenesis we have

morphologic change and then from there

we have a functional dment or clinical

significance so these are the

evolutional steps

in in a of a disease okay so I'm going

to look at these steps one by one in

detail so these are the four aspects of

the disease Okay so

let's start by looking at etiology so

the term iology simply refers to the

cause or the

causes and mod and modifying factors

which are responsible for the initiation

and progression of a disease so when you

look at this term iology what should

come into your mind is the cause of a

disease so iology is simply the cause of

a disease and if the cause of that

disease is known that is referred to as

primary iology and if it is not known

then we say it is idop idop idiophatic

okay so that is about theology then from

the cause of the disease we move on to

what we call pathogenesis okay so

pathogenesis is simply the

mechanisms through which the cause

operates to produce to produce

pathological and clinical

manifestation okay so the mechanisms the

processes through which the cause okay

through which the iology operates to

produce pathological and clinical

manifestation is what we call

pathogenesis of a disease so and this

pathogenesis could take place in Latin

stage or incubation period which is the

period from exposure to the first

manifestation of signs and symptoms that

is Inc incubation period and the latent

stages from exposure to

B to subclinical to subclinical Onset

that is what we call lent stage okay

then from there the from pathogenesis we

are going to progress

to what we call morphologic changes okay

so I've looked at etiology I've looked

at pathogenesis which is the mechanisms

through which now the cause operates to

produce what we call to produce clinical

features or clinical manifestations

which are the signs and symptoms now

those mechanisms are what we call

pathogenesis so so after

penesis we're going to proceed to

morphologic changes so morphologic

changes these are structure

alterations in cells or tissues so it

can be in

cells or in tissues that occurs

following pathogenesis okay so we have

the cause then that cause causes what we

call theology will progress to progress

to pathogenesis where the mechanisms

takes place

now those mechanisms are going to cause

alterations in the cells or tissues okay

now those alterations that are which

occurs following pathogenesis are what

we call morphologic changes and these

morphologic changes they can be gross

morphologic changes or microscopic

morphologic changes so those morphologic

changes which we are able to see with

our naked eyes are what we call G

morphologic changes and those ones which

require the a of a microscope to for us

to see the changes which has occurred in

cells or tissues then those are called

microscopic changes so from morphologic

changes we move on now to the last uh

evolutional step of a disease which is

functional derangement and clinical

significance so here now we have um the

morphological changes in the organ will

now influence the normal function of the

organ okay the morphologic changes in

the organ influence the normal function

of the organ and determines the clinical

features so from the morphological

changes we have alterations in the cells

and tissues now those alterations will

bring about what we call clinical

features which are the

and symptoms of a disease okay and then

from there clinical features also have a

cause and prognosis of the disease okay

so those were the four uh aspects of a

disease or we can call them the steps in

the evolution of disease which are the

uh

iology

uh we have iology and then we have our

pathogenesis morphologic changes which

are of two type gross morphology

morphologic change and we also have

microscopic morphologic change and then

from there the last one is the

functional derangement or clinical

significance which are the signs in

symptoms now the disease has developed

okay then uh let's also look at um uh

the next part which is cell injury cell

death and adaptation but before we look

at this let's summarize the last part

where we say uh we talk we have talked

about the evolution or steps of a

disease which are the

iology first one is iology so iology or

the cause of the disease a disease can

be caused by a lot of things and one of

them is uh

trauma okay trauma can cause can be a

cause of a disease and then have toxin

toxin

which are which can come from chemicals

or from microbes then from there we have

infections we have immunological

abnomalities those are some of the

environmental causes of disease and then

from there we have genetic abnormalities

all those are going to lead to what we

call iology and from iology we're going

to progress

to pathogenesis which involves the

mechanism of the disease what happens

after that that cause has been

introduced in the body What mechanisms

takes place is what we call

pathogenesis then after pathogenesis

pathogenesis which are the mechanisms

are going to cause um alteration they

going to cause changes in the tissues

and cells okay so those changes are what

we call morphological changes or

morphologic abnormalities then these

morphological changes are now going to

lead to what we call clinical manifest

vations which are the signs and symptoms

so in a nutshell that is all about the

steps in the evolution of disease or we

can call them them the four aspects of

the disease so let's now move on to cell

injury cell death and adaptation but

mainly we're going to focus on Cell

adaptation in this

video okay so we have a normal cell in

the body okay so that normal cell if um

subjected to a stress that cell is going

to adapt to that uh situation to that

environment okay there is a stress which

is stressing the cell then that cell

first of all it will adapt to that

situation okay let's say there is a

chemical which has been ingested or a

drug okay so the cell will try to adapt

to the environment and then from there

if it fails to adapt then it is going to

have a reversible injury okay so if that

uh stimulus is injurious then uh the

cell will be reversibly injured meaning

this injury can be uh this cell can be

reversed to the normal situation the

normal way or the normal the cell can

revers to its normal

uh functions then from there if um the

injury is severe then the cell is going

to uh be irreversibly injured okay so if

it is irreversibly injured that cell

can't be revered to its normal way or it

normal function then eventually that

cell is going to die okay so that will

lead to cell death so a cell can die in

in two ways which is by necrosis or by

apoptosis okay yeah so but in this video

our main focus is cell

adaptation of which if a cell is

stressed the first thing will be to

adapt to that situation okay and then

cell adaptation is of four types we have

hypertrophy atrophy hyper plasure and

meta pleasure so these are the four

types of cell

adaptation okay so what is cell

adaptation so cell adaptation these are

reversible changes in the number okay so

it can be in the number size

phenotype metabolic activity or function

of cells in response to changes in their

environment okay so a cell will try to

adapt in several ways either by Chang in

the number in the size the phenotype or

metabolic activities or even a function

okay so the changes in the function size

number and phenotype U of cells in

response to changes in their environment

is referred to as cellular adaptation

and as I have already said it is of four

types cell will try to adapt via

hypertrophy atrophy hyper pleasure and

meta pleasure so now let's now look at

what really are these types of

adaptation are like hypertrophy what is

hypertrophy what happens and what are

some of the changes the cells undergo in

hypertrophy atrophy hyper plasure and

meta plure so let's now start by looking

at atrophy first as a type of adaptation

so under atropy trophy the cell will try

to uh shrink uh this is

simply shrinkage in the cell in the size

of cells by the loss of cell substance

first of

all this trophy is simply simply means

growth and this a means uh reduced okay

reduced so atrophy simply reduced in the

growth of cell substance okay so the

cell this is simply shrinkage in the

size of cells by the loss of cell

substance that is atrophy or in other

words you can just say reduced in the

size of the cell is atrophy then from

there atrophic

cells may just have diminished function

but they are not dead Okay atrophic

cells are not not de they may just have

diminished reduced functions okay but

they are not de but now what are the

causes of atrophy reduced in the cell

substance reduction in the cell

substance what might cause that okay so

some of the

causes uh here we have decreased

workload or disuse okay so if the cell

is not used it is going to reduce in

size it is going to be at

okay

reduced or decreased workload like for

example if um if the heart overworks

what will happen is that the myocardial

tissue is going to increase that is

hypertrophy so it is going to increase

but in some other parts if the cells are

not used then they are going to undergo

they're going to be atrophied they're

going to reduce in size then from there

the other cause is

denervation denervation okay loss of

innovation to the cell can cause atrophy

then we also have diminished blood

supply we know that blood supplies

nutrients and oxygen to tissues now if

that Supply is reduced automatically the

cell is going to be atrophied then the

other thing is inadequate nutrition

inadequate nutrition you do not have

adequate nutrients for the cell to

increase in size so the cell will be

atrophied then loss of endocrine

stimulation okay that cell is no longer

stimulated then it is going to atropy

then aging which is s now atrophy in old

age mostly cells will undergo or be

atrophied so those are some of the

causes of atrophy then from there we

have what we call hypertrophy

okay so hypertrophy hyper that is

increased then trophy we say it is

growth so increased in the growth okay

so hypertrophy is an

increase okay an increase in the what in

the size of cells resulting in an

increase in the size of the organ so we

have an increase in cell size meaning

hypertrophy simply

the opposite of atrophy in atrophy we

had reduction in cell grow and then here

we have an

increased uh growth in the cell okay

then there are no new cells which are

formed in pure hypertrophy in pure

hypertrophy we do not have new cells

which are formed okay just larger cell

containing okay larger just larger cells

okay the cells will just increase in

size then they are going to contain

increased amount of structural proteins

and organel okay so the organel are

going to increase in size and then the

structure proteins are also going to

increase okay so hypertrophy occurs when

cells have a limited capacity to divide

okay most organs which have

limited capacity of cells to divide

that's where mostly hypertrophy takes

place okay so hypertrophy can be

physiological or pathological so under

physiological uh hypertrophy we have um

like for example skeletal muscle tissue

in body builders okay so skeletal muscle

in body builders we becomes hyper

hypertrophied like they increase in the

in size as we are able to view few

muscles of a body builder so that is an

example of a physiological it's a normal

normal thing it's not an abnormal so

when you talk about physiological

meaning it's a normal uh thing okay so

skto muscle tissue in body builders is

simply an example of physiological

hypertrophy now pathological hypertrophy

here we talking about abnormalities

something which is not normal so we can

see phys logical hypertrophy in cardiac

enlargement in hypertension or iotic

valve diseases okay so in um

cardiac

hypertension we have an

increased uh blood pressure okay so the

heart is overworking so due to

overworking the mardum is going to

increase in size it is going to become

hypertrophy okay th is going to increase

in size and then in iotic valve disease

there is um stenosis of of the valve

there from

the uh left ventricle to the Iota we

have what we call the iotic valve there

so if this valve is not functioning

properly okay then the heart you have to

pump blood with

um High pressure so that that blood can

flow in that valve in that defected

valve so to do so it is has

to to increase its muscle tissue okay it

stried muscle tissue has to increase in

size so so that it overcomes this

obstacle which is on the way which which

is called iotic Val disease itic valves

tenoc okay the valves have become

rigid so they are not functioning

properly so the heart has to pump blood

with strength so that will cause the

cells of the heart to be

hypertrophied okay to increase in size

to overcome that obstacle that

derangement which has occurred there so

we can see pathological hypertrophy in

Artic valve diseases and also in cardiac

enlargement in

hypertension okay so that's all about

hypertrophy now let's move on to what we

call hyper pleasure so hyper also we are

talking about the increase then pleasure

is simply number so here we're talking

about the increase in the number of

cells so an increase in the number of

cells in an

organ okay in an organ that stems from

from increased proliferation so this

this increase should come from

proliferation okay where we have cells

which are dividing and then the number

of cells increases that is what we call

hyperplasia and it can also be

physiological or pathological so

physiological hyperplasia here we are

talking about

proliferation okay normal proliferation

of cells like for example pration of

glandular Epi of the female breast at

puberty and during pregnancy we normally

see breast being enlarged that is an

example of

physiological hyperplasia the increase

in number of granular cells in the

breast of a female that is an example of

physiologic go hyperplasia and that is

called hormonal hyperplasia why because

it is stimulated by hormones okay there

are hormones which are responsible for

stimulation of these cells to undergo

what we call hyperplasia that is

hormonal hyperplasia and then we also

have uh another example where we have

res residual tissue growth after removal

or loss of part of an organ a good

example here is the liver so if the

liver is damaged or you cut the piece of

the liver is going to to grow back it is

going to grow and uh uh and be be go

back to its normal it normal structure

so that is what we call compensatory

hyperplasia so hyperplasia is of two

type have hormonal hyperplasia and

composor Hyper pressure and

physiological hyper pressure then from

there hyper pressure can also be

pathologic okay can also be pathologic

and examples of pathologic hyper plasure

here we talking about endometrial

hyperplasia okay endometrial hyperplasia

which is the lining of the uterus which

we call the

endometrium increases in uh the number

of cells there increases after the

mation period there in females the

endometrium is going to increase the

cells there are going to increase and

that is what we call endometrial

hyperplasia but now if this thing is uh

abnormal

if we have abnormal production of

ovarian estrogen and separation of

progesteron what will happen is that the

number of cells in the endometrial is

going to increase it's going to be

excessive why because we have excessive

stimulation of release of estrogen and

that is going to cause what we call

endometrial hyperplasia and then we are

going to see

bleeding okay we going to see vinal

bleeding that is now what we call indom

material hyper plas and it can lead to

cancer okay then from there apart from

indom Material pleasure this

pathological hyperplasia can also be

seen in benign Pro prostatic hyperplasia

in males this is caused by androgens

over production of androgens is going to

cause benign Pro

protic hyper plure so these are the

examples of pathologic hyper plure then

from hyper plasure we have what we call

metaplasia as a type of cellular

adaptation okay so metaplasia met

pleasure is simply a change in which one

adult cell type okay it can be epia or

methos cells okay so we have a change in

one adult cell

type is replaced by another adult cell

type okay so we have uh cell type which

is being replaced by an another type of

another adult cell type here okay so now

this type of cellular

adaptation in this type of cell

adaptation a cell type which is

sensitive to a particular stress okay so

a cell type which is sensitive to a

particular stress is going to be

replaced by another cell type which is

better able to

withstand adverse environment so we have

a stress okay a stress which is being

applied on a sensitive cell type so that

sensitive cell type is going to be

replaced by another cell type which will

be able to with stand okay that adverse

uh environment then that is what we call

Meta

pleasure okay so it

arises okay it arises by

reprogramming of stem cells to

differentiate along a new pathway rather

than a phenotypic change of already

differentiated cells so here we have

reprogramming of stem cells are being

reprogrammed to produce a new

pathway okay new types of cells

reprogramming of these stem cells to

produce new types of

cells not from uh not from

already differentiated cells okay but

from the stem

cells the stem cells are going to uh to

differentiate to replace the already

differentiated cells that's how this uh

mechanism of metapure takes place then

we have it is of two types we have what

we call connective tissue metap pleasure

have connective tissue metap pleasure

which occurs in mesos cells where we

have have uh bone occasionally formed in

soft tissues due to accumulation of

calcium this is mainly seen in muscle

tissue where if we have accumulation of

calcium then we are going to see uh bone

formation in that tissue in those selfy

tissues due to accumulation of calcium

then the other type is Epal metaplasia

so we have connective tissue metaplasia

and EP eal metapure so Epal

metapure this one occurs in habitual

cigarette smokers those who are

frequently smoke okay where the normal

cated colum epia cells of the tracha and

broni are often replaced by stratified

squ ethereum so have a sensitive tissue

type which is

cated Colum

Epal cell which is being replaced by

another Epal cell type which is

stratified squ Mass eperium this is done

to adapt to the current situation or to

the environment in uh where now we have

smoke okay okay in cigarette smokers we

have a stress okay as in form of smoke

so this sensitive serated colia is going

now to be repaced the stem cells are

going to form new cells which are

stratified SOS eperium to replace the

cated col etherum and that is

a that is what we call ethereal meta

pleasure so thank you very much for

watching don't forget to like And

subscribe and leave your comment in the

comment section see you in the next

video where we're going to talk about

cell injury and uh cell cell

death