Done By : raghda al-droubi & mariam ababneh

Cellular Adaptations

الو بتكون steady state بتكون homeostasis في الوضع الطبيعي بتكون Cell ال*

.Noxious stimuli و ما في Supplies available

Noxious او Injurious او وجود demands الي هوه اما نقصان في ال Stress اذا صار عنا*

بتدخل الخلية في مرحلة جديدة اسمها Genetic abnormality او stimuli

.adaptation

The adaptation is Reversible *

بزوال المسبب بترجع الخلية لل Homeostasisاالصلية.

في البداية بتكون Reversibleو اذا زاد injury اد عن حده بندخل في الاذا ز Stress ال*

عن حده اكثر من هيك بصيرirreversibleثم تموت الخلية.

1- Hypertrophy troph (growthنمو) increase in the size not in the number.

2- Hyperplasia

3- Atrophy

4- Metaplasia

Hypertrophy

Increase in cell size, no change in number of cells

زيادة البروتينات انتاجا و يزداد الحجم و ليس العدد على مستوى الخلية بسبب زيادة عدد و حجم العضيات داخل الخلية او

structural componentsنوعية

. معا بسبب زيادة حجم و عدد الخاليا مثال فيكون العضو نمو اما

*Mechanism: increase in (size + number) of organelles

*May be physiologic or pathologic

*Pathologic: The cause is abnormal

*Physiologic: No abnormal cause

**”Hypertrophy” of anything =increase in its size

*Cellular hypertrophy : increase in the size of the cell not in the number.

*Organ hypertrophy : increase in the size of the organ by increasing in the size of the cell or in

the number of the cell in the organ.

The adaptation is either

PHYSIOLOGICAL (مسبب غير مرضي) OR PATHOLOGICAL (مسبب مرضي)

Physiologic hypertrophy, an example:

• Skeletal muscle hypertrophy in weight lifters (because of

mechanical stretch)

• Increased workload (physiologic stress)

• Skeletal muscle cells respond to this by

increasing their size not number because they

have limited capacity to divide

Myocyte الي همه Skeletal muscle fiber ةما عندهم قدر

Regeneration على ال

ضغط عن طريق زيادة العدد بل زيادة الحجمبالتالي ما بستجيبوا لل

What is this organ? uterus

What did happen to it? Physiological hypertrophy

What is the difference between the lower two images?

Left pic is smooth muscle in normal condition, right pic

smooth muscle in pregnancy

What is the name of this condition?

Did the condition in this example occur alone or with

another condition?

Is this condition physiologic or pathologic? Physiologic

• What is the cause? Hormonal effect (estrogen and

progesterone)

Smooth muscle cells are able to regenerate.

hypertrophy and hyperplasia بصيرله smooth muscle cell in pregnancy ال

زداد حجم و عدد الخاليا ي*

.

Glandular epithelial cells in the breast in pregnancy and puberty قياًسا على ذلك في ال

hypertrophy and hyperplasia بصيرلها

Pathologic hypertrophy, an example:

*Cardiac myocytes in hypertension

*Increased workload, but the cause

here is pathological (not a physiologic stress)

*Limited capacity to divide, so it respond by

hypertrophy.

*in systemic hypertension the cardiac muscle

pump the blood against resistance

*pathological hypertrophy ألنه المسبب مرضي والي

هوه مرض ارتفاع الضغط الشرياني .

Some mechanisms in hypertrophy

• Mechanical triggers (e.g., stretch) -- exercise physiologic - heart pathologic. Major

physiologic hypertrophy.

• Trophic triggers has larger rule in pathologic hypertrophy (e.g., growth factors-

hormones) -- in myometrium in the uterus.

• Increased proteins, e.g., contractile proteins (myofilaments: actin and myosin) -- in the

skeletal and cardiac muscle .

• Switch in protein types synthesized:

- Example: Alpha form of myosin heavy chain is replaced by beta form…slower and more

energetically economical contractions

- من البروتينات و نصنعنوقف صناعة نوع Expression for protein ممكن نغير ال

Gene بروتينات ما كانت تتصنع يعني نتحكم على ال

Hyperplasia (plasia: number)

=increase in number of cells that are capable to divide

*May be physiologic or pathologic

*May occur concurrently with hypertrophy…in this case the stimulus is usually the same

myometrium بنفس الوقت مثل في ال Hypertrophy تحدث مع ال Hyperplasia ممكن ال

و في هذه الحالة بكون المسبب واحد puberty & pregnancy في حالتي الbreast و في ال

. hormonal)نفسه( بالعادة

Physiologic hyperplasia, examples:

*Glandular epithelium of the female breast at:

-Puberty Hormonal stimulation

-Pregnancy

.ادت الى زيادة العدد و الحجم للخاليا physiologic process هو عبارة عن

*Compensatory hyperplasia of the liver: After resection of a part of the liver, the remaining cells

start to divide as early as 12 hours after

…triggered by growth factors from:

-Uninjured hepatocytes الخاليا نفسها تإثر على بعضها او من خالل

-Non-parenchymal (mesenchymal/stromal) cells

…eventually: normal weight is restored and the hyperplasia is turned off by growth inhibitors

Pathologic hyperplasia (abnormal condition)

Mostly due to increase in hormones or growth factors, but the increase here is abnormal

and not physiologic

Examples:

*A disease called “Endometrial hyperplasia”:

-It causes abnormal menstrual bleeding (menorrhagia)

-Due to imbalance between estrogen and progesterone

*Blood vessels and fibroblasts in wound healing:

-Growth factors from leukocytes (WBCs) and connective tissue cells

ال لتحفيز prefoliation بسبب ال inflammation

Endometrial hyperplasia >>

بسبب عدم االتزان بين االستروجين و البروجسترون . uterus مرض يحدث في ال

• Menstrual cycle has 2 phases :

1- proliferative phase > increase in Estrogen

ستروجين لحتى تفرز اال ovary و بتؤثر على ال pituitary في هذه المرحلة بتطلع هرمونات من ال

2- ovulation

3- secretory phase > increase in Progesterone

In normal condition Estrogen do hyperplasia in the endometrial cell , *Progesterone control

Estrogen effect .

In case of imbalance between (estrogen and progesterone) then we will have Endometrial

hyperplasia .

Pathologic hyperplasia, another example

سببه افراز GF & HORMONEsبشكل غير طبيعي

• Skin warts: الثآليل

-Etiology: Human papilloma virus (HPV)

-Mechanism: Epithelial hyperplasia due to growth factors

…the GFs are encoded either by viral genes or host cell genes induced by the virus

ال GF اما تفرز مباشرة من الفايروس او يتحفز انتاجها

. Host cell by the virus من ال

يعمل Host cell لجين في ال activationمن خالل عمل

Patho hyperplasia حتى تسببGF افراز ل

Hyperplasia in the Epidermis بصير عنا

Atrophy

ما في عنا nutrient/supply بالتالي

عينة عشان نقلل نزيد تحطيم بروتينات مو metabolismو نقلل ال تقشف و نقلل صناعة البروتيناتبدنا نعمل

المصانع الي عنا.

= Shrinkage ( decrease in cell size)

*Atrophy of anything = decrease in its size

*organ trophy على مستوى العضو

*Mechanisms:

- decrease in metabolic activity

- decrease in synthesis (due to decreased metabolism) and increase in degradation of proteins,

so the substance of the cell is generally decreased

Atrophy, some of its causes

• Decreased workload…e.g., immobilization of a limb after fracture ) fracture or storke

consider pathologic condition )النه الخلية بتبطل تشتغل بسبب حدوث الكسور

• Loss of innervation (pathologic) للعضلة atrophy التغذية العصبية للعضالت اذا راحت بصير

• Diminished blood supply (ischemia)

الجسم بقل , لذلك كبار السن عندهم الواصل ألعضاء بالسن تصلب الشرايين بزيد ف بشكل عام الدم حالة التقدم في

atrophy صارله ألنهالدماغ اقل حجماً من الشباب

• Inadequate nutrition مثل المجاعات

• Loss of endocrine stimulation, e.g., menopause (this example is physiologic)

vaginal ,endometrial and endocervical atrophy عند المرأة بصيرsexual organs في الAtrophy بصير

• Aging…called “Senile atrophy” (pathologic) >>> senile مرتبط ب كبر السن

Atrophy, more about its mechanisms (نوقف الزيادة و نزيد التحطيم)

• Degradation of proteins is mainly by: ubiquitin-proteasome pathway

-Ubiquitin is a small peptide

-Ubiquitin binds to the cellular protein and targets it for degradation in proteasomes

-Ubiquitin ligase(enzyme) attaches ubiquitin to the protein that will be degraded

**This pathway is also responsible for the accelerated proteolysis seen in cancer cachexia ( الُهزال

بحيث بصير مريض السرطان جلد و عظم ....العضالت و البروتين في الجسم تحطمت(

• Autophagy: البلعمة الذاتية

- = Self-eating

- Common in atrophy

- Cell components are isolated in autophagic vacuoles

Metaplasia خر(الخلية ل نوع ا تحول نوع)ب

• Definition: One adult cell type is replaced by another adult cell type in response to stress

• Metaplasia occurs in epithelial or mesenchymal cell types…mesenchymal type is

generally pathological

• Epithelial metaplasia can be pathological or physiological ; ex >> from squamous to

columnar

• Mesenchymal metaplasia is pathological ; ex >> في العضلة الي bone بتكون شوية

تعرضت لجرح ) بمعنى اخر بصير تكلُّس او تعظُّم في العضلة (

The new type is better in withstanding the new environment

The stem cells are reprogrammed…not trans-differentiation of already differentiated cells

• What is the cause of this normal abnormal

condition? Smoking

• Is it epithelial or mesenchymal

metaplasia? epithelial

• Mention 2 disadvantages of the

condition in this example >

1- we lose Cilia.

2- Cancerogens.

In normal condition the type of cells in trachea are ( pseudostratified ciliated columnar

epithelium ) which transfer to ( squamous ) to bear the new chemical environment .

3 more examples of metaplasia

• Columnar-type metaplasia in the lower esophagus due to gastroesophageal reflux

disease (GERD)… What is the name of this condition?

• Squamous metaplasia of respiratory epithelium in vitamin A deficiency

…Vitamin A has a role in cell differentiation

• Bone formation in foci of injury (a mesenchymal metaplasia(