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Overexpression of the mucin proteins, especially MUC1, is associated with many types of cancer. [ 5 ] [ 6 ] Although some mucins are membrane -bound due to the presence of a hydrophobic membrane-spanning domain that favors retention in the plasma membrane , most mucins are secreted as principal components of mucus by mucous membranes or are ...
The excessive mucus production seen in allergic asthma patients is due to goblet cell metaplasia, the differentiation of airway epithelial cells into mucin producing goblet cells. [17] These cells produce the thick mucins MUC5AC and MUC5B, which clog the airway, leading to the airflow obstruction characteristic of asthma. [17]
Pepsin is a protease that can digest and damage stomach cells. To prevent these disastrous effects, mucus and bicarbonate ions (HCO 3 −) are secreted by the foveolar cells. The mucus allows the acid at pH above 4 to penetrate lining, but below pH 4 (i.e. when acid is more concentrated) the acid cannot penetrate the mucus.
The chief and parietal cells produce and secrete mucus (F) to protect the lining of the stomach (C) against the harsh pH of stomach acid. The mucus is basic, while the stomach acid (A) is acidic. In the human digestive system, mucus is used as a lubricant for materials that must pass over membranes, e.g., food passing down the esophagus.
These findings may be significant for addressing the side effects suffered by cancer patient whose intestinal health is damaged by chemotherapy: approximately 40% of all cancer therapy patients experience gastrointestinal (GI) mucositis during their treatment, with the number jumping to 80% in patients receiving abdominal or pelvic irradiation ...
The mucosa is composed of one or more layers of epithelial cells that secrete mucus, and an underlying lamina propria of loose connective tissue. [1] The type of cells and type of mucus secreted vary from organ to organ and each can differ along a given tract. [2] [3]
The cells in the respiratory epithelium are of five main types: a) ciliated cells, b) goblet cells, c) brush cells, d) airway basal cells, and e) small granule cells (NDES) [6] Goblet cells become increasingly fewer further down the respiratory tree until they are absent in the terminal bronchioles; club cells take over their role to some extent here. [7]
Mucus forms a layer (or layers, in the case of the colon) that separates the bulk of the luminal contents from the intestinal epithelium. The mucus consists of a highly glycosylated hydrated gel formed by mucin molecules that are secreted by goblet cells. The mucus prevents large particles from contacting the epithelial cell layer while ...