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To excite a heart: a bird's view.

Publication ,  Journal Article
Sommer, JR; Bossen, E; Dalen, H; Dolber, P; High, T; Jewett, P; Johnson, EA; Junker, J; Leonard, S; Nassar, R
Published in: Acta Physiol Scand Suppl
1991

Ultrastructural investigations of avian cardiac muscle, including ratite hearts, have provided great insights into the mechanisms as to how excitation leads to contraction in the heart. The geometry of the conduction fibers of ratite hearts confirms earlier observations on birds showing that the geometry of the conduction system and its component cells is adapted to hearts of different sizes and rates of contraction so as to maintain a differential in conduction velocities between the conduction system and the working fibers. The study of the ratite conduction fibers bears out the idea of an inverse relationship between the size of the gap junctions and the input resistance of cardiac cells. The anomalous extended junctional SR typical of all avian hearts, proscribes the notion of direct contact transduction into calcium release for contraction of an excitatory signal propagating at the cell surface. Couplings appear well suited to maintain direct, if transitory, connections to the extracellular space in addition to harboring channels for intracellular calcium release.

Duke Scholars

Published In

Acta Physiol Scand Suppl

ISSN

0302-2994

Publication Date

1991

Volume

599

Start / End Page

5 / 21

Location

England

Related Subject Headings

  • Sarcoplasmic Reticulum
  • Physiology
  • Myocardium
  • Myocardial Contraction
  • Microtubules
  • Microscopy, Electron
  • Heart Conduction System
  • Calcium Channels
  • Calcium
  • Birds
 

Citation

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Sommer, J. R., Bossen, E., Dalen, H., Dolber, P., High, T., Jewett, P., … Nassar, R. (1991). To excite a heart: a bird's view. Acta Physiol Scand Suppl, 599, 5–21.
Sommer, J. R., E. Bossen, H. Dalen, P. Dolber, T. High, P. Jewett, E. A. Johnson, J. Junker, S. Leonard, and R. Nassar. “To excite a heart: a bird's view.Acta Physiol Scand Suppl 599 (1991): 5–21.
Sommer JR, Bossen E, Dalen H, Dolber P, High T, Jewett P, et al. To excite a heart: a bird's view. Acta Physiol Scand Suppl. 1991;599:5–21.
Sommer, J. R., et al. “To excite a heart: a bird's view.Acta Physiol Scand Suppl, vol. 599, 1991, pp. 5–21.
Sommer JR, Bossen E, Dalen H, Dolber P, High T, Jewett P, Johnson EA, Junker J, Leonard S, Nassar R. To excite a heart: a bird's view. Acta Physiol Scand Suppl. 1991;599:5–21.

Published In

Acta Physiol Scand Suppl

ISSN

0302-2994

Publication Date

1991

Volume

599

Start / End Page

5 / 21

Location

England

Related Subject Headings

  • Sarcoplasmic Reticulum
  • Physiology
  • Myocardium
  • Myocardial Contraction
  • Microtubules
  • Microscopy, Electron
  • Heart Conduction System
  • Calcium Channels
  • Calcium
  • Birds