Thin collagenous septa in cardiac muscle

Paul C. Dolber, Madison S. Spach

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

Light and electron microscopy were used to study the structure and distribution of thin collagenous septa (sheets) in dog and rabbit cardiac muscle to determine whether they, like thick collagenous septa, could affect electrical impulse propagation. Generally, thin septa (0.2–0.5 μm) ensheathed myocytes or groups of myocytes for short distances and thicker septa partially or completely ensheathed groups of myocytes for long distances (up to several mm); together, thin, and thick septa divided the myocardial mass into myocyte cords (funicles) of 10–30 μm diameter. Septal architecture varied not only between regions and within regions at different ages but also within single bundles, precluding the assumption that the architecture found in one bundle can be applied to another. Electron microscopy demonstrated that thick septa consisted of many tightly packed collagen fibrils, often with distinct layers running at different angles; thin septa consisting largely of circumferential collagen fibrils. Thin septa in dog ventricular papillary muscle generally contained few and widely spaced collagen fibrils, whereas thin septa in dog atrial Bachmann's bundle contained tightly packed collagen fibrils. In either site, thin septa were rarely breached by nexuses and thus marked sites where lateral intercellular electrical coupling was unlikely. Serial 7 μm cross sections of dog Bachmann's bundle stained by a modification of the picrosirius red technique showed that thin septa sometimes persisted uninterrupted over several myocyte lengths. The results provide evidence that thin septa comprimised of tightly packed collagen fibrils may significantly modify impulse propagation transverse to the longitudinal axis of the myocytes.

Original languageEnglish (US)
Pages (from-to)45-55
Number of pages11
JournalAnatomical Record
Volume218
Issue number1
DOIs
StatePublished - 1987
Externally publishedYes

Fingerprint

collagen
myocardium
myocytes
Muscle Cells
Myocardium
muscle
Collagen
Dogs
electron microscopy
dogs
Electron Microscopy
Papillary Muscles
microscopy
Running
cross section
light microscopy
rabbits
dog
Rabbits
Light

ASJC Scopus subject areas

  • Biotechnology
  • Anatomy
  • Ecology, Evolution, Behavior and Systematics
  • Histology

Cite this

Thin collagenous septa in cardiac muscle. / Dolber, Paul C.; Spach, Madison S.

In: Anatomical Record, Vol. 218, No. 1, 1987, p. 45-55.

Research output: Contribution to journalArticle

Dolber, PC & Spach, MS 1987, 'Thin collagenous septa in cardiac muscle', Anatomical Record, vol. 218, no. 1, pp. 45-55. https://doi.org/10.1002/ar.1092180109
Dolber, Paul C. ; Spach, Madison S. / Thin collagenous septa in cardiac muscle. In: Anatomical Record. 1987 ; Vol. 218, No. 1. pp. 45-55.
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