The electron transport chain of these mitochondria is disrupted by an uncoupling protein, which causes the dissipation of the mitochondrial hydrogen ion gradient without ATP production. This generates heat. Cartilage is a specialized form of connective tissue produced by differentiated fibroblast-like cells called chondrocytes. It is characterized by a prominent extracellular matrix consisting of various proportions of connective tissue fibers embedded in a gel-like matrix.
Chondrocytes are located within lacunae in the matrix that they have built around themselves. Individual lacunae may contain multiple cells deriving from a common progenitor.
Lacunae are separated from one another as a result of the secretory activity of the chondrocytes. A highly fibrous, organized, dense connective tissue capsule known as the perichondrium surrounds cartilage. The fibroblast-like cells of this layer have chondrogenic potentiality, and are responsible for the enlargement of cartilage plates by appositional growth.
Appositional growth involves cell division, differentiation, and secretion of new extracellular matrix, thereby contributing mass and new cells at the cartilage surface.
It is in contrast to interstitial growth, in which new matrix is deposited within mature cartilage. Three kinds of cartilage are classified according to the abundance of certain fibers and the characteristics of their matrix:. Pre-Lab Quiz Review the four primary types of collagen and where they are typically found. Type 2 - Cartilage. Type 3 - Reticular Fibers. Type 4 - Basement Membrane. Answer: White adipose tissue is composed of large cells with prominent central vacuoles.
It is white because the lipid is washed away during fixation and the vacuoles appear white under the microscope. Brown adipose tissue has smaller cells with many lipid droplets and mitochondria. It is brown because of the large number of cytochromes present. Answer: Hyaline cartilage — type II collagen — nose, tracheal rings, end of ribs. Fibrocartilage - type I collagen - tendons, intervertebral discs. Elastic cartilage - type II collagen - ear and epiglottis.
Answer: Fibroblast may be very basophilic because it has a lot of RER, and you may actually be able to see it releasing collagen. Macrophages are mononuclear cells that are generally nondescript, although they are easily identifiable if they have been actively phagocytosing particles. Mast cells have a characteristic granulated appearance.
Slides Please select whether to view the slides in study mode or quiz mode. In study mode, the images will contain labels and a description. In quiz mode, labels and description will be hidden. Study Mode. Virtual Microscope Slides Skin Identify two different types of connective tissue that are prominent in this slide. What are the functions of each type? Fibronectin is considered as a large glycoprotein found in all vertebrates. Fibronectin is a ligand member of the integrin receptor family.
Integrins are structurally and functionally related to the cell surface as heterodimeric receptors that link the ECM with the intracellular cytoskeleton. The primary type of fibronectin is known as type III fibronectin replica cylinder , which binds to integrins. This model has a length of about 90 amino acids. Fibronectin appears in a soluble and fibrillar form. There are two others fibronectin isoforms, which are fibronectin type I hexagon and fibronectin type II square [ 6 ].
Fibronectin is not only crucial for attaching cells to matrices but also to guiding cell migration in vertebrate embryos. Fibronectin has many functions, which allow it to interact with many extracellular substances, such as collagen, fibrin and heparin, and with specific membrane receptors in responsive cells. Extracellular matrix is the primary factor required in the process of forming a new network and tissue. Along with the development found, many different factors can trigger the growth of ECM or used to create a synthetic ECM.
The process of wound healing is strongly influenced by the role of migration and proliferation of fibroblasts in the injury site. Indeed fibroblast is one part of ECM.
The proliferation of fibroblasts determines the outcome of wound healing. Fibroblasts will produce collagen that will link to the wound, and fibroblasts will also affect the process of reepithelialization that will close the wound. Fibroblasts will produce type III collagen during proliferation and facilitate wound closure.
During proliferation stage, fibroblasts proliferation activity is higher due to the presence of TGF-stimulated fibroblasts to secrete bFGF. The higher number of fibroblasts also induces increasing of collagen synthesis.
Collagen fiber is the major protein secreted by fibroblast, composed of extracellular matrix to replace wound tissue strength and function. Collagen fibers deposition was significant on 8—10 days after injury. The number of fibroblasts increases significantly, in correlation with the presence of an abundance of bFGF on 8—10 days after wounding.
Mesenchymal stem cell conditioned medium MSCM can be defined as secreted factor that referred to as secretome, microvesicle, or exosome without the stem cells which may found in the medium where the stem cells are growing. The use of MSCM as cell-free therapy has more significant advantages in comparison to the use of stem cells, mainly to avoid the need of HLA matching between donor and recipient as a consequence to decrease the chance of transplant rejection.
Additionally, MSCM is more easy to produce and save in large quantity. Recently, it has been mentioned that widespread neuronal cell death in the neocortex and hippocampus is an ineluctable concomitant of brain aging caused by diseases and injuries. However, recent studies suggest that neuron death also occurs in functional aging and it seems in related to an impairment of neocortical and hippocampal functions during aging processes.
Data from WHO and Alzheimer report show increasing number of people suffering from dementia along with aging. Profoundly understanding the role of extracellular matrix ECM in influencing neurogenesis has presented novel strategies for tissue regeneration Figure 5. Microscopic anatomy of the extracellular matrix within the central nervous system CNS. The three major compartments of the extracellular matrix in the CNS are the basement membrane, perineuronal net, and neuronal interstitial matrix.
The basement membrane is found surrounding cerebral blood vessels, the perineuronal net is a dense matrix immediately surrounding neuronal cell bodies and dendrites, and the neuronal interstitial matrix occupies the space between neurons and glial cells. Adapted from Lau et al. Within this glial scar, upregulated proteoglycans like CSPGs and changes in sulfation patterns within the ECM result in the building of regeneration inhibition [ 10 ].
To solve the problem, some manipulation on the intrinsic extracellular matrix by using traditional herb such as Ocimum sanctum extract was already done. In the in vivo and in vitro model using human brain microvascular endothelial cells HBMECs which mimics blood-brain barrier, the treatment of the extract may promote the cell proliferation on the hippocampus area and HBMECs in the condition upregulation of choline acetyltransferase ChAT enzyme [ 11 , 12 ].
In addition, there is also a chance to use nanometer-sized scaffolds in the presence of other substrates such as vascular endothelial growth factor or hyaluronic acid with laminin. This scaffold may conduct a way to the regenerative capacity and functional recovery of the CNS to reconstruct formed cavities and reconnect neuronal processes.
Thus, the artificial scaffold functions to enhance the communication between cells, allowing for improvement in proliferation, migration, and differentiation [ 13 , 14 , 15 ]. In addition, on the peripheral nerve injury, there is a chance to use scaffold by a chemical decellularization process, acellular nerve allografting that eliminates the antigens responsible for allograft rejection and maintains most of the ECM components, which can effectively guide and enhance nerve regeneration.
In the field of tissue engineering by an in vivo model, a lot of successful carriers and matrices have been employed as a scaffold to promote direct axonal growth on peripheral nerve injury [ 16 ]. In conclusion, the extracellular matrix is the primary factor required in the process of forming a new network and tissue.
Along with the development found, many different factors that can trigger the growth of ECM are used to create a synthetic ECM. These are unbranched polysaccharide chains, which are made up of long chains of repeating disaccharide units. One sugar residue in the pair is always an amino sugar N-acetylglucosamine, or N-acetylgalactosamine - hence the name aminoglycan.
The other sugar residue is usually glucoronic or iduronic acid. These properties mean that the GAG's form a matrix like a sponge, that sucks in lots of water, like a porous hydrated gel, and they are good at resisting compressive forces. This is particularly important for example in cartilage, a form of connective tissue, which is found in joints which have to withstand large compressive forces as we walk around. This also makes nice big spaces for diffusion of molecules, and cells to move around in.
The simplest GAG is hyaluronan hyaluronic acid, hyaluronate. It is the simplest, because it does not contain sulphated sugars , or complex arrangements of a number of different disaccharide units, it has the longest chain around 25, non-sulphated disaccharide units , it is not covalently linked to other proteins to make proteoglycans, and it is not made in the cell and released by exocytosis, but it is made by an enzyme complex at the cell surface.
0コメント