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- Dr . AbdElrahman Els3edyاكثر شرح مقارب للكلية وبيعرفك المهم وتركز على اي ومواضيع الاسئلة
- Dr . Elseidyملف شرح دكتور عبد الرحمن الصعيدي
- Dr. Khaled 2026Homeostasis
- Homeostasis+ Body fluidsالـ homoeostasis لحد سلايد 29
- Quiz 1 Homeostasisحل كويز د الصعيدي
📌 Physiology – Normal Body Function
- Studying normal function is essential to understand disease.
- Any deviation (increase or decrease) from normal = disease (Dis-ease).
🖇 Anatomy – Levels of Organization
- Systems → Organs → Tissues → Cells.
- Cell = Structural Unit of the human body.
🖇 Physiology – Internal Environment
- Intracellular Fluid (ICF): Inside the cell.
- Extracellular Fluid (ECF): Outside the cell = Internal Environment.
- ECF contains ions, gases, nutrients → supports cell function.
📌 Homeostasis
- Stability of ECF is vital for optimal cell and body function.
- Homeo = internal environment, Stasis = stability.
- Disruption → disease → requires correction.
- Failure to restore balance → serious complications or death.
🚨 Clinical Importance – Why Constancy Matters
- Enzymes work within narrow temperature and pH ranges.
- Small changes affect enzyme activity → disrupt body function.
🖇 Physiology – Set Point & Normal Range
- Set Point: Ideal value (e.g., Temp 37°C, BP 120/80).
- Normal Range: Acceptable fluctuation around set point.
- Deviation requires Correction or Compensation.
📌 Control Systems
- All systems help maintain stability.
- Two main leaders:
- Nervous System: Fast, short-term response.
- Endocrine System: Slow, long-term hormonal response.
🟠 Feedback Loop – Mechanism of Action
1. Stimulus (change/disturbance).
2. Receptor (detects change).
3. Afferent Pathway (signal to control center).
4. Control Center (analyzes, decides response).
5. Efferent Pathway (sends orders).
6. Effector Organ (executes correction).
🟣 Feedback Mechanisms
🔹 Negative Feedback:
- Response opposes the stimulus.
- Most common and essential for homeostasis.
- Examples:
- Temperature regulation.
- Blood glucose control (Insulin).
🔹 Positive Feedback:
- Response amplifies the stimulus.
- Rare, potentially dangerous if unchecked.
- Useful in specific cases:
- Blood clotting.
- Childbirth (Oxytocin → uterine contractions → more Oxytocin).
🚨 Forward Control
- Anticipatory mechanism: body predicts and prepares for changes.
- Mentioned briefly; main focus remains on feedback systems.