Cell Physiology Basics YouTube Lecture Handout
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GENERAL PHYSIOLOGY
- Functional organization of cells.
- Milieu Interieur
- Cell Physiology.
- Transport through cell membrane.
- Membrane Potential
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
Cells are capable of living, growing, and performing their special functions so long as the constancy of internal environment is maintained
Important Factors to be Kept Constant
- pH
- Temperature
- Nutrients, hormones, oxygen (supply)
- Electrolytes
- Water
- Removal of metabolic waste products
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.
Feedback Mechanisms
Feedback mechanisms include
- Variable
- Sensor
- Integrator
- Effector
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.
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
At times it is helpful also eg.
- Generation of action potential
- During child birth
- Clot formation
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 .