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Crypt (anatomy)
Crypts are anatomical structures that are narrow but deep invaginations into a larger structure. One common type of anatomical crypt is the Crypts of Lieberkühn. However, it is not the only type: some types of tonsils also have crypts. Because these crypts allow external access to the deep portions of the tonsils, these tonsils are more vulnerable to infection. References External links * - "Lymphoid Tissues and Organs: tonsil" Histology of crypt of tonsil at siumed.edu Anatomy {{Anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Invagination
Invagination is the process of a surface folding in on itself to form a cavity, pouch or tube. In developmental biology, invagination is a mechanism that takes place during gastrulation. This mechanism or cell movement happens mostly in the vegetal pole. Invagination consists of the folding of an area of the exterior sheet of cells towards the inside of the blastula. In each organism, the complexity will be different depending on the number of cells. Invagination can be referenced as one of the steps of the establishment of the body plan. The term, originally used in embryology, has been adopted in other disciplines as well. There is more than one type of movement for invagination. Two common types are axial and orthogonal. The difference between the production of the tube formed in the cytoskeleton and extracellular matrix. Axial can be formed at a single point along the axis of a surface. Orthogonal is linear and trough. Biology * Invagination is the morphogenetic processes by w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crypts Of Lieberkühn
In histology, an intestinal gland (also crypt of Lieberkühn and intestinal crypt) is a gland found in between villi in the intestinal epithelium lining of the small intestine and large intestine (or colon). The glands and intestinal villi are covered by epithelium, which contains multiple types of cells: enterocytes (absorbing water and electrolytes), goblet cells (secreting mucus), enteroendocrine cells (secreting hormones), cup cells, tuft cells, and at the base of the gland, Paneth cells (secreting anti-microbial peptides) and stem cells. Structure Intestinal glands are found in the epithelia of the small intestine, namely the duodenum, jejunum, and ileum, and in the large intestine (colon), where they are sometimes called ''colonic crypts''. Intestinal glands of the small intestine contain a base of replicating stem cells, Paneth cells of the innate immune system, and goblet cells, which produce mucus. In the colon, crypts do not have Paneth cells. Function The enterocyte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tonsils
The tonsils are a set of lymphoid organs facing into the aerodigestive tract, which is known as Waldeyer's tonsillar ring and consists of the adenoid tonsil, two tubal tonsils, two palatine tonsils, and the lingual tonsils. These organs play an important role in the immune system. When used unqualified, the term most commonly refers specifically to the palatine tonsils, which are two lymphoid organs situated at either side of the back of the human throat. The palatine tonsils and the adenoid tonsil are organs consisting of lymphoepithelial tissue located near the oropharynx and nasopharynx (parts of the throat). Structure Humans are born with four types of tonsils: the pharyngeal tonsil, two tubal tonsils, two palatine tonsils and the lingual tonsils. Development The palatine tonsils tend to reach their largest size in puberty, and they gradually undergo atrophy thereafter. However, they are largest relative to the diameter of the throat in young children. In adults, each p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
