This smooth muscle layer contains seromucous glands.

There is a smooth muscle layer below the epithelium arranged as two ribbons of muscle that spiral in opposite directions.

The smooth muscle layer is surrounded by irregular plates of hyaline cartilage which help maintain the patency of the airway.

Histologically, the ureter contains transitional epithelium and an additional smooth muscle layer in the more distal one-third to assist with peristalsis.

Postganglionic parasympathetic fibers will release acetylcholine next to the Reissessen muscle, a smooth muscle layer surrounding the bronchi.

After birth, oxytocin contracts the smooth muscle layer of band-like cells surrounding the alveoli to squeeze the newly-produced milk into the duct system.

Most patients feel maximum benefit over a period of 2 to 6 months when collagen deposition and wound healing are complete in the smooth muscle layer of the esophagus.

At light microscopy smooth muscle layers show fibrosis with vacuolar and other degenerative changes in smooth muscle fibres in the circular and longitudinal muscle layers.

The parasympathetic nerve supply comes from the parasympathetic preganglionic neurons in the sacral spinal cord and also terminates in the longitudinal and circular smooth muscle layers.

Proximal acini could be distinguished from peripheral and central acini by the cuboidal (as opposed to columnar) epithelial cells and by the presence of surrounding smooth muscle layers.

They are poorly-aligned defective endothelial cells with wide fenestrations, lacking a smooth muscle layer, or innervation with a wider lumen, and impaired functional receptors for angiotensin II.

This provides tighter control over the bloodflow through the glomerulus, since arterioles can be dilated and constricted more readily than venules, owing to arterioles' larger smooth muscle layer (tunica media).

Although, the structure of secondary and tertiary branches of mesenteric artery was similar, the smooth muscle layers of tertiary artery consisted of 12.4 0.4 smooth muscle cells in cross section (Fig.

The primary structural difference was that secondary arterial branches contain a greater number of smooth muscle cells within the tunica media and have 5 to 10 times thicker smooth muscle layer than that of veins.

Differences in smooth muscle layer thickness, however, do not always satisfactorily explain why in some instances, including stimulation of postganglionic nerve terminals, veins are more responsive than corresponding arteries [ 3 4 5 6 ] .

Conclusions The results of this study confirm previous studies that thicker and more tightly assembled smooth muscle layer, rather than the profile of the major contractile proteins, is the likely cause for a higher mechanical potential of the mesenteric artery compared to vein.

From the thicker smooth muscle layer of mesenteric artery we obtained a greater amount of total protein than from the thinner veins, but the fraction of the major motor proteins actin and myosin, as well as of thin filament-binding protein calponin, was indistinguishable.