Define tissue

Muscle Tissue Definition Muscle tissue is a specialized tissue found in animals which functions by contracting, thereby applying forces to different parts of the body. Muscle tissue consists of fibers of muscle cells connected together in sheets and fibers. Together these sheets and fibers and known as muscles, and control the movements of an organisms as well as many other contractile functions. There are three different types of muscle found in animals, depending on their use. While these muscles differ slightly, they function in a similar way. Function of Muscle Tissue Muscle tissue functions as a single unit, and is often connected to the same nerve bundles. A nerve impulse traveling from the brain or another outside signal tells the muscle to contract. The nerve impulse is transferred almost instantaneously to all the nerve cells in the muscle tissue, and the entire muscle contracts. At the cellular level, each muscle cell has a complex of proteins containing actin and myosin. These proteins slide past one another when the signal to contract is received. The filaments are connected to the ends of the cells, and as they slide past one another, the cell contracts in length. A single cell can contract up to 70% in length, which shortens the entire muscle when contraction happens. Muscle tissue can be used to move bones, compress chambers, or squeeze various organs. These different types of muscle tissue are discussed below. Types of Muscle Tissue Skeletal Muscle Tissue S...

Learning Objectives Identify the main tissue types and discuss their roles in the human body. By the end of this section, you will be able to: • Identify the four primary tissue types and discuss the structure and function of each • Describe the embryonic origin of tissue • Identify the various types of tissue membranes and the unique qualities of each The term tissue is used to describe a group of cells that are similar in structure and perform a specific function. Histology is the the field of study that involves the microscopic examination of tissue appearance, organization, and function. Tissues are organized into four broad categories based on structural and functional similarities. These categories are epithelial, connective, muscle, and nervous. The primary tissue types work together to contribute to the overall health and maintenance of the human body. Thus, any disruption in the structure of a tissue can lead to injury or disease. The Four Primary Tissue Types Epithelial tissue refers to groups of cells that cover the exterior surfaces of the body, line internal cavities and passageways, and form certain glands. Connective tissue, as its name implies, binds the cells and organs of the body together. Muscle tissue contracts forcefully when excited, providing movement. Nervous tissue is also excitable, allowing for the generation and propagation of electrochemical signals in the form of nerve impulses that communicate between different regions of the body ( An under...

Overview Cytology involves examining cells from bodily tissues or fluids under a microscope to determine a diagnosis. Image used with permission from the U.S. Centers for Disease Control. What is cytology? Cytology (also known as cytopathology) involves examining cells from bodily tissues or fluids to determine a diagnosis. A certain kind of physician, called a Healthcare providers use cytology in many different areas of medicine, but cytology tests are most commonly used to screen for or diagnose cancer. What kinds of cytology are there? There are two main kinds, or branches, of cytology: exfoliative cytology and intervention cytology. Healthcare providers can use cytology tests for almost all areas of your body. Some common types of cytology tests include: • Gynecologic cytology. • Urinary cytology. • Breast cytology. • Thyroid cytology. • Lymph node cytology. • Respiratory cytology. • Eye cytology. • Ear cytology. What is exfoliative cytology? Exfoliative cytology is a branch of cytology in which the cells that a pathologist examines are either “shed” by your body naturally or are manually scraped or brushed (exfoliated) from the surface of your tissue. Examples of exfoliative cytology that involve manual tissue brushing or scraping include: • Gynecological samples: A • Gastrointestinal tract samples: Your healthcare provider can brush off cells from the lining of your gastrointestinal tract (your stomach and intestines) during an • Skin or mucus samples: Your healthcar...

tissue culture, a method of biological research in which fragments of Historical developments An early attempt at tissue culture was made in 1885 by German zoologist tissue culture and defined the concept. Thereafter, a number of experimenters succeeded in Culture environments Cells may be grown in a To initiate a culture, a tiny sample of the tissue is dispersed on or in the medium, and the flask, tube, or plate containing the culture is then incubated, usually at a temperature close to that of the tissue’s normal environment. Sterile conditions are maintained to prevent contamination with microorganisms. Cultures are sometimes started from single cells, resulting in the production of uniform biological populations called

tissue typing identification of tissue types for purposes of predicting acceptance or rejection of hla antigens (HLA); if the donor and recipient are not HLA identical, the allograft is rejected, sometimes within minutes. The HLA genes are located in the complex, a region on the short arm of chromosome 6, and are involved in cell-cell interaction, Each person inherits one chromosome 6 from the mother and one from the father; that is, each parent transmits to the child one allele for each kind of antigen (A, B, C, D, and DR). If the parents are different at both alleles of a locus, the statistical chance of one sibling being identical to another is one in four (25 per cent), the chance of being identical at one allele only (half-identical) is 50 per cent, and the chance of a total mismatch is 25 per cent. Techniques for Tissue Typing. Histocompatibility testing involves several basic methods of assay for HLA differences. The most widely used method uses the Serologic methods are used to detect serologically defined antigens on the surfaces of cells. In general, HLA-A, -B, and -C determinants are primarily measured by serologic techniques. A second method, involving lymphocyte reactivity in a mixed lymphocyte culture, for determining HLA-D or lymphocyte-defined antigens, is now only rarely used. Essentially, the serologic method is performed by incubating target lymphocytes (isolated from fresh peripheral blood) with antisera that recognize all known HLA antigens. The cells ...

Lipoma A lipoma is a fatty tumor located just below the skin. It isn't cancer and is usually harmless. A lipoma is a slow-growing, fatty lump that's most often situated between your skin and the underlying muscle layer. A lipoma, which feels doughy and usually isn't tender, moves readily with slight finger pressure. Lipomas are usually detected in middle age. Some people have more than one lipoma. Symptoms Lipomas can occur anywhere in the body. They are typically: • Situated just under the skin. They commonly occur in the neck, shoulders, back, abdomen, arms and thighs. • Soft and doughy to the touch. They also move easily with slight finger pressure. • Generally small. Lipomas are typically less than 2 inches (5 centimeters) in diameter, but they can grow. • Sometimes painful. Lipomas can be painful if they grow and press on nearby nerves or if they contain many blood vessels. When to see a doctor A lipoma is rarely a serious medical condition. But if you notice a lump or swelling anywhere on your body, have it checked by your doctor. Causes The cause of lipomas isn't fully understood. They tend to run in families, so genetic factors likely play a role in their development. Risk factors Several factors may increase your risk of developing a lipoma, including: • Being between 40 and 60 years old. Although lipomas can occur at any age, they're most common in this age group. • Genetics. Lipomas tend to run in families. • Goldstein BG, et al. Overview of benign lesions of th...

Synonyms: Epithelium Epithelium is one of only 4 types of The cells in this tissue are tightly packed within a thin ECM. Forming sheets that cover the internal and external body surfaces (surface epithelium) and secreting organs (glandular epithelium). Functions of epithelial tissue are secretion, protection, absorption, transportation and special sensory receptive. Think epithelial tissue is not so interesting? What until you read about all its specializations! This page will introduce you to the Key facts Cell shape classification Squamous, cuboidal, columnar Cell layer classification Simple, stratified, pseudostratified, transitional Main features Contiguous cells Polarity (apical, lateral and basal cell surfaces) Intercellular junctions Basement membrane (extracellular matrix) Supported by connective tissue (lamina propria) Avascular, innervated Specialisations Apical: microvilli, cilia, stereocilia, modified stereocilia (sensory receptors) Secreting: tubular, acinar and tubuloacinar glands Functions Secretion, absorption, transportation, protection, receptor function (sensation) + Show all Structure Epithelial cells are the building blocks of epithelial tissue. Like every other cell, they are surrounded by cellular membranes. Epithelial cell membranes have three regions (domains) different in structure and function; apical, lateral and basal. This feature is called membrane polarity. Polarity Synonyms: Cell membrane, Membrana cellularis Each membrane pole exhibits v...

1 An Introduction to the Human Body • Introduction • 1.1 Overview of Anatomy and Physiology • 1.2 Structural Organization of the Human Body • 1.3 Functions of Human Life • 1.4 Requirements for Human Life • 1.5 Homeostasis • 1.6 Anatomical Terminology • 1.7 Medical Imaging • Key Terms • Chapter Review • Interactive Link Questions • Review Questions • Critical Thinking Questions • 2 The Chemical Level of Organization • Introduction • 2.1 Elements and Atoms: The Building Blocks of Matter • 2.2 Chemical Bonds • 2.3 Chemical Reactions • 2.4 Inorganic Compounds Essential to Human Functioning • 2.5 Organic Compounds Essential to Human Functioning • Key Terms • Chapter Review • Interactive Link Questions • Review Questions • Critical Thinking Questions • 3 The Cellular Level of Organization • Introduction • 3.1 The Cell Membrane • 3.2 The Cytoplasm and Cellular Organelles • 3.3 The Nucleus and DNA Replication • 3.4 Protein Synthesis • 3.5 Cell Growth and Division • 3.6 Cellular Differentiation • Key Terms • Chapter Review • Interactive Link Questions • Review Questions • Critical Thinking Questions • 4 The Tissue Level of Organization • Introduction • 4.1 Types of Tissues • 4.2 Epithelial Tissue • 4.3 Connective Tissue Supports and Protects • 4.4 Muscle Tissue and Motion • 4.5 Nervous Tissue Mediates Perception and Response • 4.6 Tissue Injury and Aging • Key Terms • Chapter Review • Interactive Link Questions • Review Questions • Critical Thinking Questions • 5 The Integumentary ...