(DCT) in contrast show a variety of shapes. The collagen fibers in this case, as in the previous micrograph, have a brighter red coloration than the cytoplasm of the smooth muscle cells, which provides further distinction between the two types of tissue. However, this is not always the case and the two may appear similarly stained.
Smooth muscle, small intestine, human, H&E, ×256. dense connective tissue (DCT) and the numerous circular profiles of the smooth muscle cell nuclei.
This micrograph shows at low magnification several bundles of cross-sectioned smooth muscle (SM). Again, note how the smooth muscle bundles are separated from one another by
Smooth muscle, small intestine, human, H&E, ×512; inset ×1,185.
At this higher magnification, the smooth muscle is again seen in cross section. As is typically the case, the distribution of the smooth muscle cell nuclei is not uniform, thus in some areas there appears to be a crowding of nuclei (lower box), whereas in other areas, there appears to be a paucity of nuclei (upper box). This is a reflection of the side-by-side orientation of the smooth muscle cells; thus, in this area, the cells are aligned in a manner that the nucleus has not been included in the thickness of the section. The inset is a higher magnification of this area and shows the cross-sectioned smooth muscle cells as circular profiles of varying size. Where the nuclei appear more numerous, the cells simply are aligned where the section has included the nucleus.
KEY CS, cross-sectioned bundles DCT, dense connective tissue DICT, dense irregular connective tissue LS, longitudinally sectioned bundles SM, smooth muscle SMC, smooth muscle cells
OVERVIEW OF THE NERVOUS SYSTEM / 352 COMPOSITION OF NERVE TISSUE / 353 THE NEURON / 353 Cell Body / 355 Dendrites and Axons / 357 Synapses / 358 Axonal Transport Systems / 363 SUPPORTING CELLS OF THE NERVOUS SYSTEM: THE NEUROGLIA / 363 Peripheral Neuroglia / 363 Schwann Cells and the Myelin Sheath / 364 Satellite Cells / 366 Central Neuroglia / 367 Impulse Conduction / 371 ORIGIN OF NERVE TISSUE CELLS / 373 ORGANIZATION OF THE PERIPHERAL NERVOUS SYSTEM / 375 Peripheral Nerves / 375 Connective Tissue Components of a Peripheral Nerve / 375 Afferent (Sensory) Receptors / 377 ORGANIZATION OF THE AUTONOMIC NERVOUS SYSTEM / 378 Sympathetic and Parasympathetic Divisions of the Autonomic Nervous System / 378 Enteric Division of the Autonomic Nervous System / 378 A Summarized View of Autonomic Distribution / 381 ORGANIZATION OF THE CENTRAL NERVOUS SYSTEM / 381 Cells of the Gray Matter / 382 Organization of the Spinal Cord / 382 Connective Tissue of the Central Nervous System / 383 Blood–Brain Barrier / 385 RESPONSE OF NEURONS TO INJURY / 386 Degeneration / 386 Regeneration / 387 Folder 12.1 Clinical Correlation: Parkinson’s Disease / 358 Folder 12.2 Clinical Correlation: Demyelinating Diseases / 366 Folder 12.3 Clinical Correlation: Gliosis: Scar formation in the CNS / 389