Tissue definition anatomy

Histology Definition Histology is the study of the microscopic anatomy ( microanatomy) of cells and tissues. Every cell of tissue type is unique, based on the many functions an organism carries out. Histology uses advanced imaging techniques to analyze and identify the tissues and structures present. Both light microscopy and specialized systems such as electron microscopy are used to visualize the tiny structures present in specially prepared tissue samples. The histology of different tissues can be used to identify unknown tissues, provide clues to the function of tissue or cells, or even identify disease in the cells of an organism. Basic Procedures in Histology Most scientists use the procedures developed by histology during the course of their studies. While histology is an enormously broad field, each researcher typically understands the basic histology of the organism they are working on. A botanist might not understand the human kidney, but plant tissues would be relatively familiar. The practices of histology have extended to nearly every field in science because of how useful they are in preparing and visualizing tissues. Starting with simple observations using light microscopy, histology has evolved hundreds of different techniques and procedures for staining and observing cells. The most basic form, a simple stain, is achieved by allowing a specialized staining material to wash over cells on a slide. The stains are formulated so that they only stick to certain ...

Epithelial Tissue Definition Epithelial tissues are thin tissues that cover all the exposed surfaces of the body. They form the external skin, the inner lining of the mouth, digestive tract, secretory glands, the lining of hollow parts of every organ such as the heart, lungs, eyes, ears, the urogenital tract, as well as the ventricular system of the brain and central canals of the spinal cord. The cells making up epithelia are often closely bound to one another through specialized structures called tight junctions. They are also free from blood vessels and nerves and are supported by a connective tissue called the basement membrane. They have polarity with a distinct basal domain facing the basement membrane and the other apical surface facing the lumen of an organ or the external environment. Functions of Epithelial Tissue Epithelial tissue has a number of functions, which include protection against abrasion, radiation damage, chemical stress and invasion by pathogens. A single organ can have different types of epithelial tissue based on the substances to which different surfaces are exposed. Protective tissue tends to be thicker, made of multiple layers of cells and often has inclusions such as keratin to provide mechanical strength and resistance. The skin of most mammals contains layers of thick keratinized dead epithelial cells protecting them against water loss and other stresses. Similarly, the esophagus is also exposed to a wide range of different textures, pH leve...

Learning Objectives Describe the characteristics of muscle tissue and how these dictate muscle function. By the end of this section, you will be able to: • Identify the three types of muscle tissue • Compare and contrast the functions of each muscle tissue type Muscle tissue is characterized by properties that allow movement. Muscle cells are excitable; they respond to a stimulus. They are contractile, meaning they can shorten and generate a pulling force. When attached between two movable objects, such as two bones, contraction of the muscles cause the bones to move. Some muscle movement is voluntary, which means it is under conscious control. For example, a person decides to open a book and read a chapter on anatomy. Other movements are involuntary, meaning they are not under conscious control, such as the contraction of your pupil in bright light. Muscle tissue is classified into three types according to structure and function: skeletal, cardiac, and smooth ( Table 4.2 Muscle type Structural elements Function Location Skeletal Long cylindrical fiber, striated, many peripherally located nuclei Voluntary movement, produces heat, protects organs Attached to bones and around entry & exit sites of body (e.g., mouth, anus) Cardiac Short, branched, striated, single central nucleus Contracts to pump blood Heart Smooth Short, spindle-shaped, no evident striation, single nucleus in each fiber Involuntary movement, moves food, involuntary control of respiration, moves secretions, ...

Provides Protection This fat acts as armor that protects muscles, bones, organs, and more delicate tissues. Think of subcutaneous tissue as the protective gear that athletes such as football and ice hockey players wear. It's the body's natural padding that cushions and protects your bones and muscles if you fall or take a hit. With aging, the volume of facial fat decreases, and there is less supportive tissue to support the skin's normal elasticity. The facial skin begins to droop and sag; the bones and muscles of the face also lose volume. Some people may choose to receive chemical cosmetic fillers to "plump up" the skin in these areas. • Driskell RR, Jahoda CA, Chuong CM, Watt FM, Horsley V. Exp Dermatol. 2014;23(9):629–631. doi:10.1111/exd.12450 • Lopez-Ojeda W, Pandey A, Alhajj M, et al. • Agarwal S, Krishnamurthy K. • Derraik JG, Rademaker M, Cutfield WS, et al. PLoS One. 2014;9(1):e86637. doi:10.1371/journal.pone.0086637 • Alexander CM, Kasza I, Yen CL, et al. J Lipid Res. 2015;56(11):2061–2069. doi:10.1194/jlr.R062893 • Ahn AC, Kaptchuk TJ. J Anat. 2011;219(4):515–524. doi:10.1111/j.1469-7580.2011.01407.x • Kim H, Park H, Lee SJ. Sci Rep. 2017;7(1):9613. doi:10.1038/s41598-017-10110-w • Mateos MV, San Miguel JF. Ther Adv Hematol. 2012;3(2):117–124. doi:10.1177/2040620711432020 • Caso G, McNurlan MA, Mileva I, Zemlyak A, Mynarcik DC, Gelato MC. Metabolism. 2013;62(3):337–340. doi:10.1016/j.metabol.2012.08.007 • Zhang S, Duan E. Cell Transplant. 2018;27(5):729–738. do...