The endoplasmic reticulum (ER) is, in essence, the transportation system of the eukaryotic cell, and has many other important functions such as protein folding. It is a type of organelle made up of two subunits – rough endoplasmic reticulum (RER), and smooth endoplasmic reticulum (SER). The endoplasmic reticulum is found in most eukaryotic cells and forms an interconnected network of flattened, membrane-enclosed sacs known as cisternae, and tubular structures in the SER. The membranes of the ER are continuous with the outer nuclear membrane. The endoplasmic reticulum is not found in red blood cells, or spermatozoa.
The Golgi apparatus, also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic cells. Part of the endomembrane system in the cytoplasm, it packages proteins into membrane-bound vesicles inside the cell before the vesicles are sent to their destination. It resides at the intersection of the secretory, lysosomal, and endocytic pathways. It is of particular importance in processing proteins for secretion, containing a set of glycosylation enzymes that attach various sugar monomers to proteins as the proteins move through the apparatus.
A lymph node, or lymph gland, is a kidney-shaped organ of the lymphatic system and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphocytes that include B and T cells. Lymph nodes are important for the proper functioning of the immune system, acting as filters for foreign particles including cancer cells, but have no detoxification function.
SR and related terms may refer to:
Intramembranous ossification is one of the two essential processes during fetal development of the gnathostome skeletal system by which rudimentary bone tissue is created. Intramembranous ossification is also an essential process during the natural healing of bone fractures and the rudimentary formation of bones of the head.
The reticular formation is a set of interconnected nuclei that are located throughout the brainstem. It is not anatomically well defined, because it includes neurons located in different parts of the brain. The neurons of the reticular formation make up a complex set of networks in the core of the brainstem that extend from the upper part of the midbrain to the lower part of the medulla oblongata. The reticular formation includes ascending pathways to the cortex in the ascending reticular activating system (ARAS) and descending pathways to the spinal cord via the reticulospinal tracts.
The myeloblast is a unipotent stem cell which differentiates into the effectors of the granulocyte series. It is found in the bone marrow. Stimulation of myeloblasts by G-CSF and other cytokines triggers maturation, differentiation, proliferation and cell survival.
Reticular fibers, reticular fibres or reticulin is a type of fiber in connective tissue composed of type III collagen secreted by reticular cells. Reticular fibers crosslink to form a fine meshwork (reticulin). This network acts as a supporting mesh in soft tissues such as liver, bone marrow, and the tissues and organs of the lymphatic system.
Reticular connective tissue is a type of connective tissue with a network of reticular fibers, made of type III collagen. Reticular fibers are not unique to reticular connective tissue, but only in this type they are dominant.
The terms glycans and polysaccharides are defined by IUPAC as synonyms meaning "compounds consisting of a large number of monosaccharides linked glycosidically". However, in practice the term glycan may also be used to refer to the carbohydrate portion of a glycoconjugate, such as a glycoprotein, glycolipid, or a proteoglycan, even if the carbohydrate is only an oligosaccharide. Glycans usually consist solely of O-glycosidic linkages of monosaccharides. For example, cellulose is a glycan composed of β-1,4-linked D-glucose, and chitin is a glycan composed of β-1,4-linked N-acetyl-D-glucosamine. Glycans can be homo- or heteropolymers of monosaccharide residues, and can be linear or branched.
The rumen, also known as a paunch, is the largest stomach compartment in ruminants and the larger part of the reticulorumen, which is the first chamber in the alimentary canal of ruminant animals. The rumen's microbial favoring environment allows it to serve as the primary site for microbial fermentation of ingested feed. The smaller part of the reticulorumen is the reticulum, which is fully continuous with the rumen, but differs from it with regard to the texture of its lining.
The stellate reticulum is a group of cells located in the center of the enamel organ of a developing tooth. These cells are star-shaped and synthesize glycosaminoglycans. As glycosaminoglycans are produced, water is drawn in between the cells, stretching them apart. As they are moved further away from one another, the stellate reticular cells maintain contact with one another through desmosomes, resulting in their unique appearance. The stellate reticulum is lost after the first layer of enamel is laid down. This brings cells in the inner enamel epithelium closer to blood vessels at the periphery.
The red pulp of the spleen is composed of connective tissue known also as the cords of Billroth and many splenic sinusoids that are engorged with blood, giving it a red color. Its primary function is to filter the blood of antigens, microorganisms, and defective or worn-out red blood cells.
The stroma of the ovary is a unique type of connective tissue abundantly supplied with blood vessels, consisting for the most part of spindle-shaped stroma cells. These appear similar to fibroblasts. The stroma also contains ordinary connective tissue such as reticular fibers and collagen. Ovarian stroma differs from typical connective tissue in that it contains a high number of cells. The stoma cells are distributed in such a way that the tissue appears to be whorled. Stromal cells associated with maturing follicles may acquire endocrine function and secrete estrogens. The entire ovarian stroma is highly vascular.
Parvocellular can refer to:
The reticulum is the second chamber in the four-chamber alimentary canal of a ruminant animal. Anatomically it is the smaller portion of the reticulorumen along with the rumen. Together these two compartments make up 84% of the volume of the total stomach.
Stellate, meaning star-shaped, may refer to:
Reticulation is a net-like pattern, arrangement, or structure.
Reticular describes a set of connective tissue, fibers, etc., in network form such as with cross-link bonds.
Reticular theory is an obsolete scientific theory in neurobiology that stated that everything in the nervous system, such as brain, is a single continuous network. The concept was postulated by a German anatomist Joseph von Gerlach in 1871, and was most popularised by the Nobel laureate Italian physician Camillo Golgi.
