Makindo Medical Notes

Related Subjects: |Basic Chemistry for Medicine |Basic Physics for Medicine

Basic Physics for Medicine

Understanding basic physics is essential for medical professionals as it provides a foundation for comprehending various physiological processes, medical imaging, and treatment technologies. This guide covers fundamental concepts of physics relevant to medicine.

Mechanics

• Newton's Laws of Motion:
  • First Law (Inertia): An object will remain at rest or in uniform motion unless acted upon by an external force.
  • Second Law (Force): Force equals mass times acceleration (F = ma).
  • Third Law (Action and Reaction): For every action, there is an equal and opposite reaction.
• Biomechanics:
  • Study of the mechanical aspects of living organisms.
  • Applications: Understanding the mechanics of muscles, bones, and joints, and designing prosthetics and orthotics.

Fluid Mechanics

• Blood Flow:
  • Haemodynamics: Study of blood flow in the cardiovascular system.
  • Poiseuille's Law: Describes the flow of blood through a vessel (Flow rate = ΔPπr⁴ / 8ηL, where ΔP is the pressure difference, r is the radius, η is the viscosity, and L is the length of the vessel).
• Respiratory Flow:
  • Airflow dynamics in the respiratory system.
  • Ventilation: The process of moving air into and out of the lungs.

Thermodynamics

• Laws of Thermodynamics:
  • First Law: Energy cannot be created or destroyed, only transferred or transformed (conservation of energy).
  • Second Law: Entropy of an isolated system always increases; heat flows from hot to cold.
  • Third Law: As temperature approaches absolute zero, the entropy of a system approaches a constant minimum.
• Body Temperature Regulation:
  • Homeostasis: Maintenance of stable internal conditions, including temperature.
  • Mechanisms: Sweating, shivering, vasodilation, and vasoconstriction.

Electricity and Magnetism

• Electrocardiography (ECG):
  • Measures the electrical activity of the heart.
  • Applications: Diagnosing cardiac conditions and monitoring heart function.
• Medical Imaging:
  • Magnetic Resonance Imaging (MRI): Uses strong magnetic fields and radio waves to generate detailed images of organs and tissues.
  • X-rays: Use electromagnetic radiation to create images of bones and other structures.

Optics

• Vision:
  • Study of light and its interactions with the eye.
  • Refractive Errors: Conditions like myopia (nearsightedness), hyperopia (farsightedness), and astigmatism caused by imperfections in the eye's focusing ability.
• Medical Instruments:
  • Endoscopes: Use optical fibers to visualize internal organs and structures.
  • Microscopes: Magnify small structures for detailed examination.

Radiation Physics

• Types of Radiation:
  • Ionizing Radiation: High-energy radiation that can remove tightly bound electrons from atoms, creating ions (e.g., X-rays, gamma rays).
  • Non-ionizing Radiation: Lower-energy radiation that does not ionize atoms (e.g., ultraviolet light, microwaves).
• Radiation Therapy:
  • Uses high-energy radiation to kill or damage cancer cells.
  • Applications: Treatment of various cancers by targeting tumours.
• Radiation Safety:
  • Principles: Time, distance, and shielding to minimize exposure.
  • Monitoring: Use of dosimeters to track exposure levels.

Summary

Basic physics principles are fundamental to understanding many aspects of medicine, from biomechanics and fluid dynamics to thermodynamics, electricity, magnetism, optics, and radiation. These concepts are crucial for diagnosing and treating patients, designing medical equipment, and ensuring radiation safety. Mastery of these principles is essential for medical professionals to provide effective care and innovate in medical technologies.