PRINCIPAL INSPIRATORY MUSCLE OF UROMASTIX HARDWICKII

  • Muhammad Abdul Azeem Department of Physiology, Faculty of Medicine, Umm Alqura University, Makkah, Saudi Arabia
  • Saima Gul Department of Physiology, University of Karachi, Pakistan
  • Sadaf Ahmed Department of Physiology, University of Karachi, Pakistan
  • Waheeb Dakheelullah Al-Harbi Department of Physiology, Faculty of Medicine, Umm Alqura University, Makkah, Saudi Arabia
  • Nabeeh Ibrahim Ali Rakkah Department of Physiology, Faculty of Medicine, Umm Alqura University, Makkah, Saudi Arabia
Keywords: Diaphragm, Uromastix, Ribcage elevator muscle, reptile, Inspiratory muscle

Abstract

Variations in the musculoskeletal system exist in different classes of animal. The chest muscles are specifically modified due to modifications in axial skeleton in each vertebrate class. In addition, diaphragm is one of the main respiratory muscle in mammals which is absent in reptiles, specifically lizards, having different modes of respiration, e.g., buccal, axial and hepatic piston. Additionally, they do not breathe well during locomotion. Since, sternum and chest cage both are properly developed in these animals, therefore, they must be having an alternate chest muscle involved in the act of inspiration. The purpose of this study was to identify the principal inspiratory muscle in the chest of the reptile Uromastix. Repeated dissections, visual observations and electrical stimulation of the exposed but intact chest muscle (pectoralis/supracoracoideus) of Uromastix have demonstrated three major parts in it. Being, superior (S), middle (M) and inferior (I), identified on the basis of their colour, position and response to electrical stimulation. Accordingly, the locomotor action of these parts S, M and I are forceful, mild and feeble adduction of fore limb, respectively. While, its inferior part (I) additionally showed further sub-divisions into 3 portions, Is, Im and Ii. On electrical stimulation, one of them, i.e., Ii portion of the chest muscle of Uromastix demonstrated rib-cage elevation and thus named, ‘Rib Cage Elevator’, helping inspiration. It is concluded that chest muscle of Uromastix play dual role, in locomotion as well as respiration.

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Published
2010-06-30
How to Cite
1.
Azeem M, Gul S, Ahmed S, Al-Harbi W, Ali Rakkah N. PRINCIPAL INSPIRATORY MUSCLE OF UROMASTIX HARDWICKII. PJP [Internet]. 30Jun.2010 [cited 8Mar.2021];6(1):42-6. Available from: http://pjp.pps.org.pk/index.php/PJP/article/view/746