التكيفات الخلوية

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Questions and Answers

ما هي الأمثلة على الخلايا من نوع labile؟

خلايا العضلات الهيكلية

خلايا عصبية

الخلايا الكبدية

خلايا الجلد (correct)

ما هي نتيجة إصابة منطقة النخر بالبكتيريا?

زيادة كمية الأنسجة المصابة

إنتاج الغازات كمنتج ثانوي (correct)

تسريع عملية الشفاء

تشكل الأنسجة السليمة

أي من الخلايا تعتبر خلايا مستقرة؟

الخلايا الكبدية (correct)

الخلايا الدهنية

الخلايا السطحية

الخلايا المناعية

أي من الخيارات التالية لا يعد من الخلايا labile؟

الخلايا الكبدية Signup and view all the answers

أي من الخيارات التالية تشير إلى القدرة على إصلاح الأنسجة المصابة?

إصلاح الأنسجة المصابة Signup and view all the answers

ما هو المنتج الثانوي الناتج عن البكتيريا في منطقة النخر?

الغازات Signup and view all the answers

ما هو نوع الخلايا التي تتجدد بسرعة وتوجد في أماكن مثل الجلد وتجاويف الفم؟

خلايا labile Signup and view all the answers

كيف يؤثر النخر على الأنسجة المجاورة?

تأثير سلبي بسبب infection Signup and view all the answers

أي مما يلي يُعتبر مؤشراً على القدرة التجديدية للخلايا؟

سرعة التعافي Signup and view all the answers

ما الذي يجب اعتباره عند إصلاح الأنسجة المصابة?

قدرة الأنسجة على التجدد Signup and view all the answers

ما العلاقة بين الجذور الحرة وعملية الشيخوخة؟

تتورط في عملية الشيخوخة الطبيعية. Signup and view all the answers

أي من الحالات التالية ترتبط بتورط الجذور الحرة؟

السكري. Signup and view all the answers

ما هو السبب الرئيسي لحدوث النخر في الأنسجة؟

إصابة في خلوية ال رجعة فيها Signup and view all the answers

ما هي الحالة المرضية التي لا ترتبط بها الجذور الحرة وفقًا للمحتوى؟

التهاب المعدة. Signup and view all the answers

ما هي العوامل التي تؤثر على نوع النخر الذي ت·تعرض له الأنسجة؟

نوع الأنسجة المتضررة Signup and view all the answers

ما الذي يحدث للخلايا عندما تتعرض لفترات نقص الأكسجة؟

يفشل الاستقلاب الهوائي للخلايا. Signup and view all the answers

كيف تؤثر الجذور الحرة على الصحة العامة؟

تساهم في تطور عدد من الأمراض. Signup and view all the answers

ما هو التأثير الرئيسي لنقص الأكسجة على إنتاج الطاقة في الخلايا؟

انخفاض كبير في إنتاج ATP. Signup and view all the answers

أي من الخيارات التالية يعد وصفًا صحيحًا للنخر?

فقدان الوظيفة الخلوية بسبب الإصابة Signup and view all the answers

أي من التالي يعتبر دورًا سلبيًا للجذور الحرة؟

تسهم في الشيخوخة الطبيعية. Signup and view all the answers

ما هي النتيجة المشتركة للتعرض للنخر في الأنسجة؟

ضعف في الأداء الوظيفي Signup and view all the answers

ماذا يُشير الانتفاخ الذي تعاني منه الخلايا خلال نقص الأكسجة؟

فشل العمليات التي تعتمد على الأكسجين. Signup and view all the answers

في أي حالة يتم النخر بشكل شائع؟

نتيجة نقص في الأكسجين أو الإصابة Signup and view all the answers

أي من الخيارات التالية يُعبر عن تأثير نقص الأكسجة على الخلايا؟

فشل في الحصول على الطاقة اللازمة. Signup and view all the answers

ما الذي يحدث لعمليات الخلايا خلال نقص الأكسجة؟

تتوقف العمليات التي تعتمد على الأكسجين. Signup and view all the answers

ما هي الخلايا التي تتميز بالقدرة على الاستمرار في الانقسام طوال الحياة؟

الخلايا القابلة للتجديد Signup and view all the answers

أي من الخيارات التالية يشير إلى الخلايا التي توقفت عن الانقسام ولكن يمكن أن تعود لتجديدها؟

الخلايا المستقرة Signup and view all the answers

ما الخيارات الصحيحة بشأن تجديد الخلايا؟

يحدث التجديد في الخلايا القابلة للتجديد والخلايا المستقرة Signup and view all the answers

أي من الخيارات التالية تعكس عدم وجود دليل على الإصابة؟

دليل ضئيل أو معدوم على الإصابة Signup and view all the answers

ما هو التعريف الدقيق للخلايا المستقرة؟

الخلايا التي توقفت عن الانقسام مع إمكانية الرجوع Signup and view all the answers

Study Notes

Cellular Adaptations

Cells adapt to changing environmental factors to survive. These adaptations can involve changes in cell size, number, or type.

Atrophy

Atrophy is a decrease in cell or tissue size.
Reduced oxygen consumption and metabolism, while sometimes improving cell efficiency.
Usually reversible, except for atrophy due to nerve loss.
Causes include prolonged bed rest, disuse of tissues, malnutrition, and decreased blood supply.

Hypertrophy

Hypertrophy is an increase in cell size and tissue mass.
Occurs when a cell or tissue is subjected to an increased workload.
Cannot increase the number of cells to adapt.
Can be a normal physiological response (like muscle growth with exercise) or pathological (like heart hypertrophy with prolonged high blood pressure).
Can also be a compensatory mechanism (e.g., remaining kidneys enlarge to compensate for removal of a kidney).

Hyperplasia

Hyperplasia is an increase in the number of cells in an organ or tissue.
Only possible in cells capable of division (not muscles or nerve cells).
Can be normal (like breast or uterine growth during pregnancy) or abnormal (like gingival hyperplasia—excessive gum tissue growth).
Can be a compensatory mechanism (e.g., remaining liver cells increase in number to maintain liver function after a portion of the liver is surgically removed).

Metaplasia

Metaplasia is the transformation of one cell type to another type, potentially better suited for existing conditions.
Usually occurs in response to chronic irritation or inflammation.
Example: In chronic smokers, the columnar ciliated epithelium lining the airways gradually transforms into stratified squamous epithelium. While stratified squamous epithelium is better at handling continuous irritation, it lacks the necessary cilia for optimal function.

Dysplasia

Dysplasia is abnormal cell growth, resulting in tissues composed of cells with varying shapes and sizes.
Typically arises from chronic irritation and inflammation.
Potentially a significant precursor to cancer in certain tissues, especially the cervix and respiratory tract.

Cellular Injury

Cellular injury can occur in various ways, often related to the severity and duration of exposure to damaging agents or substances.
Injury can be reversible (cells recover), or irreversible (leading to cell death).

Free Radical Injury

Free radicals are highly reactive chemical species with one or more unpaired electrons in their outer shell.
Examples include superoxide, hydroxyl radicals, and hydrogen peroxide.
Generated as byproducts of normal cellular metabolism, but also formed by external sources.
Body has protective enzymes capable of neutralizing them, such as catalase and glutathione peroxidase.
Excessive free radicals can cause significant cellular damage via mechanisms like lipid peroxidation, protein damage, and DNA mutations.
External sources include cigarette smoke, organic solvents, pollutants, radiation, and pesticides.
Implicated in aging and various diseases, such as diabetes, cancer, atherosclerosis, Alzheimer's disease, and rheumatoid arthritis.

Ischemia/Hypoxia Injury

Ischemia is oxygen deprivation in cells and tissues, often stemming from reduced blood supply.
During ischemia, cellular aerobic metabolism fails leading to a dramatic decrease in ATP production.
Affected cells swell due to failure of energy-dependent processes (e.g., ion pumps reliant on ATP).
pH of the extracellular environment decreases, and anaerobic metabolism byproducts (like lactic acid) accumulate.
Imbalance of ionic concentrations within the cell can lead to calcium accumulation, and its surplus activates enzymes that break down vital cellular components.
Injury can be reversible if oxygen is restored rapidly, or irreversible leading to cell death.
Brain tissue is highly susceptible to oxygen deprivation, and irreversible cell death can happen within minutes.

Cellular Accumulations

In the instance of cellular injury, cells might gather various substances, including fats, proteins, glycogen, calcium, uric acid, and pigments (like melanin).
These accumulations are generally reversible but can signal greater cell damage.
Accumulation can lead to tissue or organ enlargement (e.g., fatty liver).

Cell Death

Cell death comprises two main types: programmed cell death (apoptosis) and necrosis.

Apoptosis (Programmed Cell Death)

A natural part of aging, involving regulated cell dismantling and removal.
May eliminate damaged or genetically abnormal cells.
Viruses (like Epstein-Barr virus) can induce apoptosis, killing both host cells and the virus.
Involves activation of specific suicidal genes in response to chemical signals, resulting in cell fragmentation and subsequent engulfment by other cells.
Disruption of natural apoptosis can contribute to cancer development.

Necrosis

Uncontrolled enzymatic digestion of the cell and its components.
Results from irreversible cellular damage.
Tissues subjected to necrosis can vary in response; commonly recognized types include gangrene (extensive tissue death).
Gangrene can be dry (shriveled, blackened surrounding skin) or wet (warm, moist, and oozing material). Gas gangrene occurs if bacteria produce gases as a byproduct.

Tissue Repair

Tissue repair involves two main methods: regeneration (repair with the same tissue) and replacement by scar tissue (repair with connective tissue).
The method depends on the type of cells damaged.
Some cells are fully or partially capable of regeneration, while others, such as nerve cells, only regenerate with scar tissue.

Regeneration

Tissues are repaired with identical replacement tissue.
There is typically a complete restoration of function, with minimal or no evidence of injury remaining.
Possible in labile cells (constantly dividing throughout life) or stable cells (stop dividing but can re-enter division under certain conditions).

Scar Tissue Repair (Replacement by Connective Tissue)

Function for the tissue is lessens or is entirely lost, with the formation of a scar.
Typically involves connective tissue (like collagen).
Scar tissue develops as a result of the repair process.
The process is important for healing following initial injury, but complete restoration of pre-injury strength and function aren't always achieved.

Wound Healing Stages

Inflammation phase: blood clot formation to stop bleeding; inflammatory cells arrive to clear debris.
Proliferation phase: collagen formation by fibroblasts, epithelial cell proliferation to close the wound, and new blood vessel formation.
Remodeling phase: collagen remodeling and strengthening of the scar. Keloids (abnormal) scars result from excessive collagen formation with reduced breakdown.

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يتناول هذا الاختبار التكيفات الخلوية المختلفة مثل الضمور والنمو والفرط. يشرح كيف تستجيب الخلايا لتغيرات العوامل البيئية من خلال التكيفات في الحجم والعدد والنوع. تعرف على الآليات الأساسية وراء هذه العمليات واستجابتها للضغوط المختلفة.