Cardiovascular System and Muscle
George W. Casarett in Radiation Histopathology: Volume II, 2019
Smooth muscle is closely related to ordinary connective tissue and is located chiefly in the internal organs, as described in previous chapters. Smooth muscle cells (fibers) are usually long and spindle-shaped, and sometimes branched. The nucleus is located in the middle or widest part of the cell. The cytoplasm contains fine myofibrils (filaments) running parallel and lengthwise through the cell, and the sarcoplasm is found between the fibrils. In smooth muscle bundles the cells are arranged with the thick middle part of the cell adjacent to the thin ends of neighboring cells, and the connective tissue fibers around muscle cells bind the muscle cells together. Between muscle bundles or layers there is loose collagenous and elastic connective tissue which contains a vascular network.
Fundamentals
Clare E. Milner in Functional Anatomy for Sport and Exercise, 2019
The other two types of muscles are involuntary, meaning that they are controlled by the autonomic nervous system and cannot be activated at will. Cardiac muscle is found in the walls of the heart and the great vessels. Smooth muscle is found in the walls of most blood vessels and hollow organs such as the intestine. Cardiac muscle forms the myocardium, the muscular wall of the heart. It is also found in the walls of the aorta, pulmonary vein and superior vena cava. Contractions of the cardiac muscle make the heart beat. Heart rate is controlled by the autonomic nervous system via specialized pacemaker cells. Cardiac muscle does not fatigue and contracts and relaxes continuously day and night for many years. Smooth muscle is found in the walls of most blood vessels, parts of the digestive tract, hair follicles and in the eye. This type of involuntary muscle can remain partially contracted for long periods of time. For example, smooth muscle controls the thickness of the lens of the eye by squeezing it, enabling the eye to focus at different distances.
Basic medicine: physiology
Roy Palmer, Diana Wetherill in Medicine for Lawyers, 2020
Muscle cells are also excitable by electrical, chemical or physical stimuli. Their contraction is activated by the action potential conveyed down the relevant nerve. There are three different types of muscle. Striated muscle makes up the mass of musculature that moves the skeleton and is under voluntary control; its cross-striations give a characteristic striped appearance under the microscope. Filaments of contractile proteins—actin and myosin—undergo shortening when the muscle is stimulated to contract. Smooth muscle lacks striations, and its contraction is involuntary. It is typically found in the wall of the gut where it undergoes spontaneous activity, but it is also under the control of the autonomic nervous system. Cardiac muscle is also striated; it is only found in the heart, where it contracts rhythmically without the need for external stimulation.
MiRNA: a potential target for gene diagnosis and treatment of atherosclerotic stroke
Published in International Journal of Neuroscience, 2021
Yi. Bao, Sijing. Li, Yayong. Ding, Xinyu. Du, Miao. Zhang, Wanjuan. Tang, Siqin. Zhou
In the aspect of vascular smooth muscle cells, K Knoepp et al. demonstrated that miRNA was involved in the differential gene regulation of vascular remodeling by inducing the formation of neointima through the femoral artery line bundle of C57BL/6 mice, which played a key role in the proliferation of vascular smooth muscle cells and provided a therapeutic target for in-stent restenosis after angioplasty [19]. Previous studies have found that miRNA-29, miRNA-143/145 and miRNA-221/222 are involved in the regulation of phenotypic transformation, proliferation and migration of vascular smooth muscle cells [20]. MiRNA-143/145 is expressed in many pathological and physiological processes and can control the smooth muscle cell phenotype. In the study of pluripotent mouse cardiac progenitor cells, miRNA-145 and miRNA-143 were found to be down-regulated in the injury or atherosclerotic vessels of smooth muscle cells with low proliferation and differentiation. KLF2 is a key regulator of endothelial gene expression patterns that induce atherosclerosis, and binding to the promoter induces a significant up-regulation of miRNA-143/145 clusters [21]. In addition, miRNA-145 and miRNA-143 synergistically target transcription factor networks, including kruppel-like factor 4, myocardin and Elk-1 (members of the ETS oncogene family), which promote the differentiation and proliferation of smooth muscle cells [22].
Rare giant primary intracranial angioleiomyoma in lateral ventricle: a case report and the literature review
Published in British Journal of Neurosurgery, 2020
Jiangwei Ding, Feng Wang, Yuan Li, Tao Sun
The typical form of ALM is rich and dilated thick-walled vascular lumen, mixed with spinous process cells, and collagen band inelastic protein. Mature smooth muscle bundles are located around or between blood vessels. Irregularly distributed smooth muscle cells have rod-shaped nuclei and eosinophilic cytoplasm, rarely mitosis, cytologic atypia, necrosis, or pleomorphism. Immunohistochemistry revealed that tumor smooth muscle cells expressed more myogenic antibodies such as SMA and Desmin, and vascular endothelial cells were positive for CD31 and CD34. CK, EMA, GFAP, claudin-1, PR, HMB45 and other epithelial and colloid antibodies were not expressed.25 Hachisuga et al.34 observed 526 cases of angioleiomyoma and found that 16 cases (3.0%) contained mature fat cells. Zhou et al.3 have reported a case with multiple fat foci in some areas of spinous cells. Zhou et al.26 found focal cluster cells in one tumor with negative HMB45, which were considered to be steatosis rather than angiomyolipoma. Pathologically, ALM should be differentiated from hemangioma meningioma and hemangiopericytoma.33,35,36
Giant Hepatic Hemangioma and Placental Chorangiosis: A Unique Case of Stillbirth?
Published in Fetal and Pediatric Pathology, 2019
Michele Paudice, Leonardo Alett Peñuela, Flaminia Torielli, Bruno Spina, Valentino Remorgida, Francesca Buffelli, Ezio Fulcheri, Cesare Arioni, Valerio Gaetano Vellone
A focal 6 cm in maximun diameter sub-glissonian hemorrhage was found within the right hepatic lobe (Fig. 1). This area was solitary and well-circumscribed by a fibrous capsule. Microscopically, it showed variable-sized vascular channels, covered by bland-looking endothelium (CD31+ and by immunohistochemistry (IHC), Fig. 2c). The vascular wall was composed of a thin layer of smooth muscle fibers, as demonstrated by the immunoreactivity of smooth muscle actin by IHC. Trabeculae of hepatocytes (Hep Par 1 positive) were entrapped within the vascular channels (Fig. 2). The flat lining endothelium showed diffuse and strong cytoplasmic immunoreactivity for WT1 (Fig. 3) and was negative for GLUT1 (erythrocytes were used as internal positive control) (Fig. 4). The negative expression of D2-40, Prox-1 and LYVE-1 excluded lymphatic differentiation.
Related Knowledge Centers
- Bladder
- Gastrointestinal Tract
- Lymphatic Vessel
- Muscle Contraction
- Sarcomere
- Striated Muscle Tissue
- Vascular Smooth Muscle
- Stomach
- Blood Vessel
- Uterus