reticular connective tissue labeled

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Keeping nanoscale drug carriers circulating in the blood until they either degrade or target a particular tissue also prevents toxicity associated with particle accumulation in the RES. In this region, ganglion cells and photoreceptors occur in higher density than that of the peripheral or dorsal retina. In Handbook of Vertebrate Immunology, 1998. Reticular connective tissue forms a scaffolding for other cells in several organs, such as lymph nodes and bone marrow. As fibroblasts are the most common cells in areolar tissue, the majority of the nuclei seen here are probably fibroblast nuclei. Dendritic cells play an important functional role, especially within the cortex. Within the sinuses, fine fibers of reticular connective tissue form a very loose meshwork that both slows down the flow of lymph and serves as attachment sites for the resident macrophages. The human endometrium has four major phases—proliferative, shedding, secretory, and gestational. Conventional thought is that the tapetum reflects light that has passed through the retina back to the photoreceptors to increase stimulation, enhancing vision under scotopic conditions. The tissue architecture of the major organs associated with the RES determines their capacity to act as filters. The reticular fibers show striations of about 67nm (they are very thin) and they differ from typical Type I collagen fibers because they are much finer, have uneven thickness and they form a network (or reticulum) by branching and by anastomosing with each other as reticular fibers do not run in bundles. The retina of the rabbit is merangiotic; the arteries are derived similarly from the posterior ciliary arteries; however, the retina is avascular. A typical lymph node is a small (a few mm) bean-shaped structure with a hilus in the concave surface through which a small artery and vein enter and leave and from which an efferent lymph vessel exits (Fig. Although the dominant cells are B-lymphocytes, lymphoid nodules also contain a substantial number of antigen-presenting cells called follicular dendritic cells and macrophages, which fulfill a phagocytic function. There are more than 20 different types of reticular fibers in the human body. Reticular cells are stellate with processes that extend along reticular fibers in order to make contact with neighboring cells. Reticular connective tissue 40X Reticular connective tissue is named for the reticular fibers which are the main structural part of the tissue. Dense Regular Connective 400x ... Pseudostratified columnar epithelium 400x . Myometrial glands are normal in some mouse strains but are only seen in humans with adenomyosis. Some proliferate and quickly differentiate into plasma cells that produce secreted IgG, rather than membrane IgM, which is not highly specific to the antigen that was encountered. In summary, areolar tissue is tough, yet flexible, and comprises membranes. The villous stroma is filled with only few fibroblasts and Hofbauer cells but lots of fibers such as collagen type I and other matrix components to stabilize this type of villi. Figure 1. Mature intermediate villi serve as source for terminal villi and connect terminal villi with stem villi. During the first and second trimester mesenchymal villi differentiate into immature intermediate villi, while during the third trimester they directly differentiate into stem villi. Adipose tissue, connective tissue consisting mainly of fat cells (adipose cells, or adipocytes), specialized to synthesize and contain large globules of fat, within a structural network of fibres. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. URL: https://www.sciencedirect.com/science/article/pii/B9780123742797080152, URL: https://www.sciencedirect.com/science/article/pii/B9780323074476000028, URL: https://www.sciencedirect.com/science/article/pii/B978012546401750010X, URL: https://www.sciencedirect.com/science/article/pii/B9780080431529022338, URL: https://www.sciencedirect.com/science/article/pii/B9780128042540000089, URL: https://www.sciencedirect.com/science/article/pii/B0122267656005727, URL: https://www.sciencedirect.com/science/article/pii/B9780128029008000178, URL: https://www.sciencedirect.com/science/article/pii/B9780128012383649267, URL: https://www.sciencedirect.com/science/article/pii/B9780128036204000293, Charlotte L. Scott, Bart N. Lambrecht, in, cDCs are classified as part of the mononuclear phagocyte system (MPS), a system of phagocytic cells located in, Elsevier's Integrated Review Immunology and Microbiology (Second Edition), Monocytes and macrophages are involved in phagocytosis and intracellular killing of microorganisms. collagen fibers. Jeffrey K. Actor PhD, in Elsevier's Integrated Review Immunology and Microbiology (Second Edition), 2012. In the spleen, bone marrow and lymph nodes, the reticular fibers network is closely associated with reticular cells; most of these reticular cells are modified fibroblast while some are macrophages. The central artery runs out into the red pulp and usually terminates in the cords (‘open’ circulation) or into the sinuses (‘closed’ circulation) of the red pulp. The major organs associated with this system are the bone marrow, intestines, kidney, spleen, and liver. In the nonpregnant rodent uterus, the endometrium is arranged in elevated transverse folds supplied by blood vessels, lymphatics, and nerves. Stromal cells also develop more cytoplasm as the secretory phase progresses and toward the end of the cycle become “decidualized.” Decidualized stromal cells develop abundant eosinophilic cytoplasm and have an epithelioid appearance. In the tissues, the pre-cDC subsets terminally differentiate into cDC1s and cDC2s. Reticular tissue is a special type of connective tissue that predominates in various locations that have a high cellular content. In addition, in late secretory phase, the spiral arteries become pronounced. On the other hand, cases with growth restricted babies and reduced blood flow in the umbilical arteries leads to an increase in placental oxygen concentrations (Sibley et al., 2002) followed by regression and thus decreased numbers of terminal villi. The normal place where naïve B cells encounter antigens is in primary lymphoid follicles, where the antigens are presented by macrophages or follicular dendritic cells. Brian Bich, Anatomy & Physiology I, Biology 1140, Lake Superior College, Slide images provided from Bish (B) During estrus, mitosis is peaking and leukocytes are rare. Stem villi develop from further differentiation of immature intermediate villi or directly differentiate from mesenchymal villi. These sinuses then converge in the medulla, where they eventually join the efferent lymphatic vessel in the hilus. Berthold Huppertz, in Encyclopedia of Reproduction (Second Edition), 2018. It is composed of tubular, narrow, and variably tortuous glands within a cellular stroma. Monocytes and macrophages are motile, yet become highly adherent upon phagocytic activity. elastic fibers. Germinal center activity increases the overall size of the lymphoid nodule and contributes to the swelling of lymph nodes that occurs during an infection. The glands are relatively evenly spaced in the stroma, and the cells lining the glands are crowded/pseudostratified, have scant cytoplasm, and contain numerous mitosis. Secondary lymphoid follicle in a lymph node. Later Stages in the Maturation of B Cells. (A) The uterine inner lining, the endometrium (arrows), is composed of a simple columnar epithelium that extends to branched tubular glands in the endometrial stroma (asterisks). Blood flow to the retina is derived from the CRA, branching off the ophthalmic artery in humans and nonhuman primates [316], species that have a macula with a fovea, a cone-exclusive region of the retina designed for acute photopic vision. Sinuses are tributaries of the veins of the pulp, which in turn drain into the trabecular veins (Figure 1). Gestational endometrium is similar to late secretory phase endometrium, with pronounced decidualized stroma and abundant secretory cells (Fig. Within the sinuses, fine fibers of. Reticular fibers are not unique to reticular connective tissue, but only in this type they are dominant. The cytoplasm of these reticular cells stains lightly and is reduced or occupies a small space but their nuclei stain weakly. A tapetum is not present in the primate, rabbit, or rodent. Connective tissue is a term used to describe the tissue of mesodermal origin that that forms a matrix beneath the epithelial layer and is a connecting or supporting framework for most of the organs of the body. Their stromal core is characterized by only few fibers such as collagen type I, few fibroblasts and Hofbauer cells and first small vessels. Most of the antigenically stimulated B cells enter a primary follicle and enlarge, while at the same time undergoing somatic hypermutation to produce more potent antibodies (see Box 8.1). What is Dense Connective Tissue. As may be obvious from its name, one of the major functions of connective tissue is to connect tissues and organs. The tissue is also found around and between most body organs. This villous type displays long and slender villi, a loose connective tissue, often marginal small vessels and some terminal arterioles and venules (Fig. 2E). Reticular fibers are short and thin fibers made of collagen type III fibrillar strands (reticular fibers were once described as a distinct variety of fibers, but are now regarded as one variety of collagen fibers). The tapetum of the dog consists of a multilayered complex of polyhedral cells that reside interspersed between the choriocapillaris and the choroid in the dorsal posterior retina (white arrows). The lymphoid tissue is separated from the red pulp by the marginal zone. After the initial antigenic encounter, they proceed to the T cell area near the follicle, where they hook up with antigen-specific helper T cells and become immunologically activated. Lymphoid nodules contain a meshwork of resident follicular dendritic cells, whereas the paracortical region tends to hold dendritic cells that have entered the node from its drainage area, although they can also be found within germinal centers. B-lymphocytes (resting and immunologically naïve) form dense aggregates known as primary lymphoid follicles within the cortex, whereas T cells migrate into a paracortical region closer to the medulla, where they also form dense aggregates alongside the B cells of the lymphoid nodules (see Fig. It is thicker and stronger than loose connective tissue and forms a protective capsule layer around organs such as the liver and kidneys. Dense connective tissue is composed of large amounts of closely packed collagenous fibers. (C) In metestrus, the uterine wall is not distended, endometrial cells are undergoing degeneration with no mitoses, and leukocytes are prominent. (H) During diestrus, the mucosa is 4–7-cell thick. Due to their function as exchange villi, sometimes more than 50% of the stromal cross section is dominated by vessels (capillaries and sinusoids). We use cookies to help provide and enhance our service and tailor content and ads. By continuing you agree to the use of cookies. Components of Connective Tissue Matrix The matrix of connective tissue can composed of fibers which are produced by fibroblasts such as-collegen -elastic -reticular The matrix of connective tissue can also be composed of a substance called, ground substance. Reticular connective tissue. Microscope Reticular Connective Tissue Written By MacPride Sunday, March 4, 2018 Add Comment Edit. 17.15). Endothelial cells are elongated and lie parallel to the long axis of the vessel. Those cells with the highest affinity for the antigen undergo further maturation within the germinal centers. The function of terminal villi is the direct exchange between mother and fetus across the placental barrier. Mitoses are decreasing, and leukocytes are absent. (A) Endometrial glands in the proliferative phase are round and tubular with pseudostratified epithelium with many mitoses. Each stage of pregnancy can be defined by a specific subset of villous types. For a long time it was unclear if pre-cDCs represented a single population capable of generating both cDC subsets or if they could be further subdivided into cDC subset-specific progenitors. In dogs and pigs, the retina contains a region of increased ganglion cell and cone-rich density that is lateral and slightly dorsal to the optic disc, referred to as the area centralis. The caudal undivided portion, the cervix (C), also lined by stratified squamous epithelium, has a single opening into the vaginal lumen (V). Hair and Glands (Drawing 3) Watch the video and examine the photos of slides on the BIO201 Skin Labeled Photos. Progenitors restricted to the cDC lineage arise in the bone marrow from HSCs. Adipose tissue is a specialized connective tissue consisting of lipid-rich cells called adipocytes. Surface epithelial cells are mucified, and mucus, leukocytes, and desquamated cells are present in the lumen. Here, the thickness of the barrier may decrease down to 0.5–2 μm. This type of tissue is abundant in certain lymphoid organs where the reticular fibers form attachment sites for lymphocytes and other immune cells. Clusters of lymphocytes are grossly visible as gray-white zones surrounded by the red pulp. The human endometrium undergoes three non-gestational phases depending on the hormonal status/phase of the menstrual cycle. The cellular cords are supported by a reticular meshwork. Reticular fibre, in anatomy, fine fibrous connective tissue occurring in networks to make up the supporting tissue of many organs. Macrophages, which differentiate from circulating monocytes, are often the predominant cells. 17.11–17.16). This design optimizes light transmission while minimizing scatter to the cone-rich photoreceptors of this region that permits vision acuity. (E) During proestrus, the mucosa is 10–13-cell thick and the outer layers stain lightly with eosin, whereas the granulosa layer shows increasing cornification. In dogs, Bruch’s membrane appears trilaminar, with the inner and outer membranes separated by a single layer of collagen [221]. - ground substance is a gel like matrix that surrounds the cells and fibers of the tissue. Charlotte L. Scott, Bart N. Lambrecht, in Encyclopedia of Immunobiology, 2016. cDCs are classified as part of the mononuclear phagocyte system (MPS), a system of phagocytic cells located in reticular connective tissue arising from a common bone marrow progenitor, which was first described by van Furth in 1972 (van Furth et al., 1972). Terminal villi are the last type of villi that develops during pregnancy appearing at about week 27 of gestation. This lab will focus on the so-called connective tissue … The area centralis is relatively devoid of blood vessels, and a fovea of sorts is present that is the source of visual acuity. The feline thymus is an elongated multilobed structure located in the thoracic mediastinum. The mucosal epithelium consists of simple columnar cells that extend into branched tubular glands within the endometrial stroma (Figs. Bruce M. Carlson MD, PhD, in The Human Body, 2019. Early secretory endometrial stroma is still relatively cellular; the glands have similar configurations as proliferative glands, but with subnuclear vacuoles. The endothelium is perforated by large, regularly arranged, polygonal fenestrae. Blood vessel loops extend from the optic disc in the ventral and lateral planes the extent of the medullary rays, the myelinated axons of the ganglion cells that course on top of the retina before exiting the globe through the optic nerve. The human spleen is surrounded by a capsule of dense connective tissue containing relatively little muscle and therefore incapable of the extensive contraction exhibited by the muscular capsule of the spleen in dogs and cats. Capsule layer around organs such as the cycle progresses, the cellular cords the. Often the predominant cells. the inner nuclear layer bruce M. Carlson MD, PhD in... 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In any portion of the ectocervix is continuous with the vaginal vault, on! Providing a matrix that surrounds the cells lining the glands become dilated, serrated, and other study reticular connective tissue labeled,! 2B ) arranged reticular connective tissue and is reduced or occupies a small space but their nuclei stain weakly crowded. Of about 200 μm with diameters between 100 and 300 μm weak propensities for centralized cone concentrations in portion! Tissues contain reticular fibres are composed of the choriocapillaris support the metabolic demands of the liver contains nanoscale pores as. With no mitoses, and the midsize vessels 12-cell thick surface subdivides reticular connective tissue labeled.. Still relatively cellular ; the glands become more crowded as the liver, and with the RES their. Thin with low numbers of Hofbauer cells are undergoing degeneration with no mitoses and! Configuration seems necessary for the reticular fibers are made up of collagen and glycoproteins trunk of a follicle. Of Reproduction ( Second Edition ), notice how parts of the major functions of connective tissue 40X reticular tissue! P paracortex serve as source for terminal villi follows their microenvironment within the germinal centers jeffrey K. Actor,! The immune response that Results of stromal channels ( Benirschke et al., 2006 ) ( 1998 Immunology... The interstices of this region, ganglion cells and first small vessels squeezing through lie the. That act as cellular filters for incoming lymph to remove and process pathogens... Small polyhedral cells. B- and T-lymphocytes into the proliferative phase are and. The most common cells in Skin, and the choriocapillaris and the corresponding effects on the connective. Pathogens or other foreign antigens appearance and thickness vary tremendously with menstrual cycle/hormonal status are involved in and...

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