chief cell

Examples of chief cell in the following topics:

• Gastric Phase

  • Histamine is a paracrine secretion from the enteroendocrine cells in the gastric glands.
  • Gastrin is a hormone produced by enteroendocrine G cells in the pyloric glands.
  • All three of these stimulate parietal cells to secrete hydrochloric acid and intrinsic factor.
  • The chief cells secrete pepsinogen in response to gastrin and especially Ach, and ACh also stimulates mucus secretion.
  • Below pH of two, stomach acid inhibits the parietal cells and G cells: a negative feedback loop that winds down the gastric phase as the need for pepsin and HCl declines.

• Digestive Properties of the Stomach

  • The hormone gastrin causes an increase in the secretion of HCl from the parietal cells and pepsinogen from the chief cells in the stomach.
  • Gastrin is released by G-cells in the stomach, via the base cells of the pyloric, cardiac, and fundic glands, in response to distension of the antrum, and digestive products (especially large quantities of incompletely digested proteins).
  • Parietal cells secrete hydrochloric acid and intrinsic factor

• Histology of the Large Intestine

  • The crypts and intestinal villi are covered by epithelium that contains two types of cells: goblet cells that secrete mucus and enterocytes that secrete water and electrolytes.
  • This is in contrast to the stomach, where the chief cells secrete pepsinogen.
  • In the intestine, the digestive enzymes are not secreted by the cells of the intestine.
  • During each mitosis, one of the two daughter cells remains in the crypt as a stem cell, while the other differentiates and migrates up the side of the crypt and eventually into the villus.
  • Goblet cells are among the cells produced in this fashion.

• Parathyroid Glands

  • Each parathyroid gland is covered by connective tissue and contains many secretory cells that are associated with a capillary network.
  • There are two major types of cells that make up parathyroid tissue: oxyphil cells and chief cells, the latter of which actually produce parathyroid hormone.
  • The function of oxyphil cells is unknown.
  • Parathyroid hormone (PTH), also known as parathormone, is released directly into the bloodstream, traveling to its target cells, which are often quite far away.
  • It then binds to a receptor (found either inside or on the surface of the target cells).

• Microscopic Anatomy of the Stomach

  • Different types of cells are at different locations down the pits.
  • The cells at the base of these pits are chief cells that are responsible for the production of pepsinogen, an inactive precursor of pepsin, which degrades proteins.
  • The secretion of pepsinogen prevents self-digestion of the stomach cells.
  • Further up the pits, parietal cells produce gastric acid and a vital substance, intrinsic factor.
  • Near the top of the pits, closest to the contents of the stomach, there are mucus-producing cells called goblet cells that help protect the stomach from self-digestion.

• Bone Tissue and the Effects of Aging

  • The osteoclasts are multi-nucleated cells that contain numerous mitochondria and lysosomes.
  • These cells are responsible for the resorption of bone and are generally present on the outer layer of bone, just beneath the periosteum.
  • The osteoclast then induces an infolding of its cell membrane and secretes collagenase and other enzymes important in the resorption process.
  • Low levels of calcium stimulate the release of parathyroid hormone (PTH) from chief cells of the parathyroid gland.

• Gross Anatomy of the Stomach

  • The stomach is divided into four sections, each of which has different cells and functions.
  • A mucous membrane lines the stomach that contains the glands (with chief cells) that secrete gastric juices.
  • The stomach is divided into four sections, each of which has different cells and functions .

• Comparing Plant and Animal Cells

  • Animal cells each have a centrosome and lysosomes, whereas plant cells do not.
  • Plant cells have a cell wall, chloroplasts and other specialized plastids, and a large central vacuole, whereas animal cells do not.
  • The cell wall is a rigid covering that protects the cell, provides structural support, and gives shape to the cell.
  • Fungal and protistan cells also have cell walls.
  • While the chief component of prokaryotic cell walls is peptidoglycan, the major organic molecule in the plant cell wall is cellulose , a polysaccharide comprised of glucose units.

• The Complement System

  • The complement system helps antibodies and phagocytic cells clear pathogens from an organism.
  • The serum complement system, which represents a chief component of innate immunity, not only participates in inflammation but also acts to enhance the adaptive immune response.
  • Specific activation of the complement via innate recognition proteins or secreted antibody releases cleavage products that interact with a wide range of cell surface receptors found on myeloid, lymphoid, and stromal cells.
  • This intricate interaction among complement activation products and cell surface receptors provides a basis for the regulation of both B and T cell responses.

• Cellular Differentiation

  • Three basic categories of cells make up the mammalian body: germ cells, somatic cells, and stem cells.
  • Pluripotent stem cells undergo further specialization into multipotent progenitor cells that then give rise to functional cells.
  • Hematopoietic stem cells (adult stem cells) from the bone marrow that give rise to red blood cells, white blood cells, and platelets
  • Mesenchymal stem cells (adult stem cells) from the bone marrow that give rise to stromal cells, fat cells, and types of bone cells;
  • Epithelial stem cells (progenitor cells) that give rise to the various types of skin cells