Variations in the composition of the extracellular matrix, determines the properties of the connective tissue. For example, if the matrix is calcified, it can form bone or teeth. Specialised forms of extracellular matrix also makes up tendons , cartilage , and the cornea of the eye. General connective tissue is either loose, or dense, depending on the arrangement of the fibres.
The cells sit in a matrix made up of glycoproteins, fibrous proteins and glycosoaminoglycans , which have been secreted by the fibroblasts, and the major component of the matrix, is in fact, water. Cells are the predominant feature in tissues specialised for protection haemopoietic tissue, blood - white blood cells or metabolic maintenance adipocytes, blood - red blood cells.
This is an example of loose connective tissue from a lymph gland. It contains some cells called 'plasma cells', finer elastin fibres and thicker collagen fibres. These cells are especially abundant on the surfaces of the hands and feet. The second is a melanocyte , a cell that produces the pigment melanin. Melanin gives hair and skin its color, and also helps protect the living cells of the epidermis from ultraviolet UV radiation damage.
As the name suggests, the stratum spinosum is spiny in appearance due to the protruding cell processes that join the cells via a structure called a desmosome. The desmosomes interlock with each other and strengthen the bond between the cells. Unstained epidermis samples do not exhibit this characteristic appearance.
The stratum spinosum is composed of eight to 10 layers of keratinocytes, formed as a result of cell division in the stratum basale. Interspersed among the keratinocytes of this layer is a type of dendritic cell called the Langerhans cell , which functions as a macrophage by engulfing bacteria, foreign particles, and damaged cells that occur in this layer.
The keratinocytes in the stratum spinosum begin the synthesis of keratin and release a water-repelling glycolipid that helps prevent water loss from the body, making the skin relatively waterproof.
As new keratinocytes are produced atop the stratum basale, the keratinocytes of the stratum spinosum are pushed into the stratum granulosum. The stratum granulosum has a grainy appearance due to further changes to the keratinocytes as they are pushed from the stratum spinosum.
The cells three to five layers deep become flatter, their cell membranes thicken, and they generate large amounts of the proteins keratin, which is fibrous, and keratohyalin , which accumulates as lamellar granules within the cells see Figure 5. These two proteins make up the bulk of the keratinocyte mass in the stratum granulosum and give the layer its grainy appearance. The nuclei and other cell organelles disintegrate as the cells die, leaving behind the keratin, keratohyalin, and cell membranes that will form the stratum lucidum, the stratum corneum, and the accessory structures of hair and nails.
The stratum lucidum is a smooth, seemingly translucent layer of the epidermis located just above the stratum granulosum and below the stratum corneum. This thin layer of cells is found only in the thick skin of the palms, soles, and digits. The keratinocytes that compose the stratum lucidum are dead and flattened see Figure 5.
These cells are densely packed with eleiden , a clear protein rich in lipids, derived from keratohyalin, which gives these cells their transparent i. The stratum corneum is the most superficial layer of the epidermis and is the layer exposed to the outside environment see Figure 5. The increased keratinization also called cornification of the cells in this layer gives it its name.
There are usually 15 to 30 layers of cells in the stratum corneum. And the thick reticular layer is made of dense connective tissue with irregular bundles of collagen fibers dense irregular connective tissue. The reticular layer contains hair follicles, sweat glands, Pacinian corpuscles, which sense pressure, lymph vessels and smooth muscle. To read about the skin in more detail, check out this link.
Which connective tissue composes the dermis of the skin? Saikat R. Feb 15, Explanation: Our skin has two principal layers : epidermis and dermis. Collagen fibers provide structure and tensile strength, with strands of collagen extending into both the papillary layer and the hypodermis. In addition, collagen binds water to keep the skin hydrated. Collagen injections and Retin-A creams help restore skin turgor by either introducing collagen externally or stimulating blood flow and repair of the dermis, respectively.
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