Physiology Lecture: Homeostasis

Introduction

• Topic: Homeostasis
• Definition: How the body maintains a constant internal environment.

Distinctions

• Homeostasis vs Hemostasis
  • Homeostasis: Stability of the internal environment.
  • Hemostasis: Blood control, such as coagulation.
  • Hematology: Study of blood.

Key Concepts

• Definition of Homeostasis:

  • Maintenance of nearly constant conditions in the body's internal environment, mainly in the extracellular fluid (ECF).
  • Example: Hydrogen ion concentration regulation, maintaining pH between 7.35 and 7.45.

• Disease and Homeostasis:

  • Disease: Ruptured homeostasis, referred to in pathology.
  • Physiology: Study of normal body functions; pathophysiology studies the disruption.

Body Systems Involved

1. Nutrient Intake & Oxygen Supply

   • Gastrointestinal Tract (GI): For food intake.
   • Respiratory System: For oxygen intake.
   • Circulatory System (CBS): Distributes nutrients and oxygen throughout the body.

2. Waste Removal & Communication

   • Liver & Kidneys: Remove waste products.
   • Nervous System (Fast): Uses neurons for immediate communication.
   • Hormonal System (Slow): Uses hormones for slower, sustained communication.

Detailed System Functions

• Circulatory/Cardiovascular System:

  • Heart pumps blood through arteries to capillaries.
  • Blood exchanges nutrients, oxygen, waste products, and CO2 with cells.
  • Plasma mixes with interstitial fluid.

• Lungs:

  • Remove CO2 through exhalation.
  • Supply O2 through inhalation.
  • CO2 is a major metabolic product.

• GI Tract & Liver:

  • Food digestion and nutrient absorption.
  • Liver acts as a lab to store, convert, or excrete absorbed substances.

• Kidneys:

  • Filter plasma, regulate pH, have endocrine functions, and excrete waste as urine.

Communication Systems

• Nervous System:

  • Neurons relay messages quickly.
  • Example: Reflex action to pull away from hot objects.

• Hormonal System:

  • Endocrine glands like the thyroid release hormones.
  • Thyroid hormone regulates body temperature and metabolism.
  • Hyperthyroidism: Excess hormone, feeling hot, weight loss.
  • Hypothyroidism: Deficient hormone, feeling cold, weight gain.

Conclusion

• Interactive Question:
  • "Does the extracellular fluid have more, less, or the same sodium ions as the intracellular fluid?"
• Engagement:
  • Follow up on social media for answers.

Closing Remarks

• Encourage viewers to subscribe and join on social platforms.
• Support on Patreon acknowledged.
• Sign-off with encouragement to stay safe, happy, and diligent in studies.