Muscle fiber-type distribution pattern in the human cricopharyngeus muscle.
ABSTRACT Our previous studies described that the human cricopharyngeus (CP) is composed of two neuromuscular compartments (NMCs), horizontal and oblique. The present study was designed to explore the differences in muscle fiber-type distribution between the NMCs within the human CP and to examine the oxidative capacity of the muscle fibers. Seven adult human CP muscles obtained from autopsies were stained for myofibrillar ATPase, reduced nicotinamide adenine dinucleotide tetrazolium reductase (NADH-TR), and succinic dehydrogenase (SDH) to analyze enzyme-histochemical fiber-type characteristics. Notable findings obtained from this study are as follows: (1) Different NMCs within the human CP contained different percentages of muscle fiber types. The horizontal CP (CPh) contained more slow-twitch fibers than the oblique CP (CPo). (2) Each of the NMCs was dividable histochemically into two layers or subcompartments: a slow fiber-type inner layer and a relatively fast fiber outer layer. (3) As a whole, type I fibers had higher levels of NADH-TR and SDH than type II fibers. However, in both type I and II muscle fiber types, different patterns of oxidative enzyme activity were seen. Histochemically defined fiber layers of the CP are not seen in other mammals, suggesting that CP function is more specialized in humans.
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ABSTRACT: The upper esophageal sphincter (UES) forms a barrier between the pharynx and the esophagus. When closed, the barrier function serves to prevent reflux and aerophagia; when open, swallowing, belching and vomiting are possible. The closing muscles include caudal parts of the inferior pharyngeal sphincter and cranial parts of the upper esophagus musculature. Sphincter opening is achieved by muscles that insert from the outside to connect to the larynx and pharynx in the sphincter region. The closing muscles are innervated by branches of the glossopharyngeal and vagal nerves, and central control is probably mediated by several reflexes. This article presents an overview of the current understanding of the complex UES anatomy.HNO 05/2014; 62(5):385-94. · 0.54 Impact Factor
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ABSTRACT: Distribution pattern of fibre types was studied in the muscles of the soft palate (palatinus, levator veli palatini and tensor veli palatini muscles) in the dog. The fibrillar classification was based on using histochemistry and immunohistochemistry methods: myofibrillar adenosine thriphosphatase (mATPase) to different pH of pre-incubation; nicotine adenine dinucleotide (reduced) tetrazolium reductase (NADH-TR) and finally, application of specific monoclonal antibodies against myosin heavy chain isoforms I, IIa and IIx. In the palatinus and levator veli palatini muscles, pure type I fibres and the hybrid type IIax and IIc were shown, with a checkerboard distribution in the first and a clear predominance of hybrid fibre types (about 98% of the total population) in levator veli palatini muscle. On the other hand, in the tensor veli palatini muscle, type IIx and IIm fibres were identified (fast-twitch fibres related to fast-moving muscles and the powerful jaw muscles of carnivores). The tensor veli palatini muscle had a different distribution and fibrillar composition with predominantly type IIm fibres in its central zone, whilst the peripheral zone was primarily type I and IIx fibres.Anantomia Histologia Embryologia 03/2013; · 0.88 Impact Factor
Article: Upper esophageal sphincterGI Motility online. 05/2006;