Examples of epithelial cells in the following topics:
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- Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands.
- Functions of epithelial cells include secretion, selective absorption, protection, transcellular transport, and detection of sensation.
- Exocrine and endocrine epithelial cells are highly vascular.
- Secretion is one major function of epithelial cells .
- Glands are formed from the invagination / infolding of epithelial cells and subsequent growth in the underlying connective tissue.
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- Cuboidal epithelial cells are cube-shaped with a single, central nucleus .
- Columnar epithelial cells are taller than they are wide: they resemble a stack of columns in an epithelial layer.
- The nuclei of columnar epithelial cells in the digestive tract appear to be lined up at the base of the cells .
- Columnar epithelial cells lining the respiratory tract appear to be stratified.
- Simple columnar epithelial cells absorb material from the digestive tract.
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- Epithelial tissue is composed of cells laid out in sheets with strong cell-to-cell attachments.
- The epithelial cells are nourished by substances diffusing from blood vessels in the underlying connective tissue.
- One side of the epithelial cell is oriented towards the surface of the tissue, body cavity, or external environment and the other surface is joined to a basement membrane.
- Epithelial tissues are identified by both the number of layers and the shape of the cells in the upper layers.
- Epithelial tissue is classified based on the number of cells, the shape of those cells, and the types of those cells.
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- Epithelial tissue is classified by cell shape and the number of cell layers.
- For example, simple squamous epithelial tissue describes a single layer of cells that are flat and scale-like in shape.
- Simple epithelial tissues are generally classified by the shape of their cells.
- These are simple columnar epithelial cells whose nuclei appear at different heights, giving the misleading (hence pseudo) impression that the epithelium is stratified when the cells are viewed in cross section.
- There are three principal classifications associated with epithelial cells.
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- Plasmodesmata are numerous channels that pass between cell walls of adjacent plant cells and connect their cytoplasm; thereby, enabling materials to be transported from cell to cell, and thus throughout the plant .
- These junctions are typically found in epithelial tissues that line internal organs and cavities and comprise most of the skin.
- For example, the tight junctions of the epithelial cells lining your urinary bladder prevent urine from leaking out into the extracellular space.
- Desmosomes act like spot welds between adjacent epithelial cells, connecting them .
- A plasmodesma is a channel between the cell walls of two adjacent plant cells.
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- How does a complex organism such as a human develop from a single cell—a fertilized egg—into the vast array of cell types such as nerve cells, muscle cells, and epithelial cells that characterize the adult?
- A multipotent stem cell has the potential to differentiate into different types of cells within a given cell lineage or small number of lineages, such as a red blood cell or white blood cell .
- One type of adult stem cell is the epithelial stem cell, which gives rise to the keratinocytes (cells that produce keratin, the primary protein in nails and hair) in the multiple layers of epithelial cells in the epidermis of skin.
- Adult bone marrow has three distinct types of stem cells: hematopoietic stem cells, which give rise to red blood cells, white blood cells, and platelets ; endothelial stem cells, which give rise to the endothelial cell types that line blood and lymph vessels; and mesenchymal stem cells, which give rise to the different types of muscle cells.
- The multipotent hematopoietic stem cells give rise to many different cell types, including the cells of the immune system and red blood cells.
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- A cell is the smallest unit of a living thing.
- A living thing, whether made of one cell (like bacteria) or many cells (like a human), is called an organism.
- For example, both animal and plant cells are classified as eukaryotic cells, whereas bacterial cells are classified as prokaryotic.
- For example, epithelial cells protect the surface of the body and cover the organs and body cavities within.
- Bone cells help to support and protect the body.
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- 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
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- Dendritic cells are immune cells that function to process antigens and present them to T cells.
- The function of epithelial dendritic cells is to capture microbial protein antigens and to transport the antigens to draining lymph nodes.
- Mature dendritic cells reside in the T cell zones of the lymph nodes, and in this location they display antigens to T cells.
- Dendritic cells are constantly in communication with other cells in the body.
- This communication can take the form of direct cell-to-cell contact based on the interaction of cell-surface proteins.
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- Most mucous membranes contain stratified squamous or simple columnar epithelial tissue.
- The epithelial tissue sheet lies directly over the layer of loose connective tissue called lamina propria.
- The submucosal glands are a companion to unicellular goblet cells, which also produce mucus, and are found lining the same tubes.