Homeometric regulation of the heart

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Characteristics[edit | edit source]

  • the ability to change the force of contraction of the cardiac muscle even with a constant length of cardiomyocytes

Means of homeometric control[edit | edit source]

Sympathetic[edit | edit source]

Parasympathetic[edit | edit source]

Potassium cations[edit | edit source]

  • At elevated extracellular concentrations, there is a slow depolarization of the resting membrane potential (values closer to zero) and a concomitant inactivation of some sodium channels (thus preventing the action potential), [1], net effect is:

Calcium cations[edit | edit source]

  • opposite effect to potassium cations
  • increased concentration gradually leads to spastic contraction (calcium cations initiate contraction)
  • at reduced concentration - flaccidity

Bowditch (Treppe) effect[edit | edit source]

Temperature[edit | edit source]

  • heat increases the permeability of the membrane to ions
  • frequency
  • Increased temperature significantly increases frequency
  • reduced temperature significantly decreases frequency
  • in near-death hypothermia (15-20 °C) frequency only a few beats per minute
  • frequency only a few beats per minute
  • force of contraction
  • temporarily strengthened when the temperature rises, then the metabolic system is exhausted and the contraction is weakened

Links[edit | edit source]

Related articles[edit | edit source]

References[edit | edit source]

Used literature[edit | edit source]

  • GUYTON, Arthur C. – HALL, John E. Textbook of Medical Physiology. 11. edition. Elsevier, 2006. ISBN 978-0-7216-0240-0.