Ultrastructural morphometry of the myocardium of Thunnus alalunga

The common ventricle in the heart of the Thunnus alalunga was studied. The ventricular myocardium consists of an outer compact layer and a thick inner spongy layer. The compact layer has slightly larger cells (4-6 microns diameter) than the spongy layer (2.5-5 microns diameter). Ultrastructurally th...

Full description

Saved in:
Bibliographic Details
Published in:Cell and tissue research 1983-01, Vol.233 (2), p.427-438
Main Authors: Breisch, E.A, White, F, Jones, H.M, Laurs, R.M
Format: Article
Language:English
Subjects:
Animals
Biological and medical sciences
Blood Pressure
Fishes - anatomy & histology
Fundamental and applied biological sciences. Psychology
Heart
Heart - physiology
Heart Rate
Marine
Microscopy, Electron
Mitochondria, Heart - ultrastructure
Myocardium - ultrastructure
Myofibrils - ultrastructure
Thunnus alalunga
Tuna - anatomy & histology
Tuna - physiology
Vertebrates: cardiovascular system
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The common ventricle in the heart of the Thunnus alalunga was studied. The ventricular myocardium consists of an outer compact layer and a thick inner spongy layer. The compact layer has slightly larger cells (4-6 microns diameter) than the spongy layer (2.5-5 microns diameter). Ultrastructurally the myocardium displays normal arrangements of myofibrils and mitochondria. The sarcoplasmic reticulum is poorly developed. The intercalated discs are simple with the fascia adherens being the most frequent junctional type observed; occasionally a desmosome was seen. Nexus type junctions are present but are unassociated with the intercalated discs. There are no t-tubules evident but the plasmalemma exhibits numerous caveolae which rarely form couplings with the sarcoplasmic reticulum. A morphometric analysis of the volume percent of mitochondria and myofibrils showed that the myocardial cells in the spongy layer of the heart have a significantly greater volume percentage of mitochondria than the compact layer. No significant differences were found between myocardial regions when the volume percentages of myofibrils were compared. The physiological studies revealed that the albacore tuna has heart rates (120 bpm) and ventricular blood pressures (100 mmHg) that are among the highest reported for fish.
ISSN:0302-766X
1432-0878
DOI:10.1007/BF00238308