Cell Physiology Basics YouTube Lecture Handout

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GENERAL PHYSIOLOGY

  1. Functional organization of cells.
  2. Milieu Interieur
  3. Cell Physiology.
  4. Transport through cell membrane.
  5. Membrane Potential
Illustration: GENERAL PHYSIOLOGY
Illustration: GENERAL PHYSIOLOGY

Milieu Interieur

  • Claude Bernard a French Physiologist coined the term Milieu interieur in 1949.
  • Milieu Interieur also called internal environment of body and is formed by extracellular fluid.

A Simple Cell

Illustration: A Simple Cell

Cells are capable of living, growing, and performing their special functions so long as the constancy of internal environment is maintained

Illustration: A Simple Cell

Important Factors to be Kept Constant

  • pH
  • Temperature
  • Nutrients, hormones, oxygen (supply)
  • Electrolytes
  • Water
  • Removal of metabolic waste products
Illustration: Important Factors to be Kept Constant

HOMEOSTASIS

  • The term was introduced by W. B. Cannon an American scientist in 1932
  • Definition: is maintenance of chemical & physical conditions of internal environment (extracellular fluid) constant for optimal functions of the cells

Homeostatic Control Systems

  • It includes various mechanisms involving almost all systems of body.
  • The mode of operation of various systems is through ‘feedback’ mechanism.
Illustration: Homeostatic Control Systems

Feedback Mechanisms

Feedback mechanisms include

  • Variable
  • Sensor
  • Integrator
  • Effector
Illustration: Feedback Mechanisms

Feedback mechanisms operate by

  • Negative feedback
  • Positive feedback

Negative Feedback Mechanisms

Most of the control systems act by it

  • It maintains stability of various factors
  • If a factor changes, the control system tries to push the factor in opposite direction so as to bring it back to normal
  • Regulation of Bp. , temp. , etc.
Illustration: Negative Feedback Mechanisms
Illustration: Negative Feedback Mechanisms

Positive Feedback Mechanisms

  • These mechanisms most of the time do not favour stability
  • The disturbance is increased further which can be fatal at times
  • Thus a vicious cycle sets
Illustration: Positive Feedback Mechanisms

At times it is helpful also eg.

  • Generation of action potential
  • During child birth
  • Clot formation
Illustration: Positive Feedback Mechanisms
Illustration: Positive Feedback Mechanisms

Two Big Systems Are Involved

  • Nervous system: via nerve impulses
  • Rapid but,
  • Short
  • Endocrinal: via production of hormones
  • Slow but,
  • Prolonged

Cell Physiology

  • Cell (L-store room) described by Robert Hooke
  • He had fabricated microscope in the middle of seventeenth century
  • He observed them in a piece of cork
  • Smallest structural and functional unit

Diameter is .