CONNECTIVE

Lymphocytes

A type of white blood cell that make antibodies to fight off infections

3 types of cartilage

hyaline, elastic, fibrocartilage

Interterritorial matrix of hyaline cartilage

lowest concentration of sulfated proteoglycans

lacunae (cartilage)

spaces in the cartilage occupied by chondrocytes

reticular connective tissue

-a specialized CT with Type III collagen - forms fine networks/mesh called reticulin. -Cells producing reticular fibers are called reticulocytes (modified fibroblasts). -They are found in stroma of soft hematopoietic and lymphoid organs. -Do not stain with H&E but stain with silver stain

Cartilage

-a strong, flexible and semi-rigid supporting tissue. -It can withstand compression forces, and yet it can bend. -It is made up of cells called chondroblasts and chondrocytes, (chondro - cartilage) and extracellular matrix, made up about 10% aggrecan, 75% water, and a mix of collagen fibres and other constituents.

isogenous groups of chondrocytes

- two chondrocytes found within one lacuna - characteristic of hyaline (only in this one)

mast cells

-CT cells that are oval with basophilic granules filling the cytoplasm -May obscure nucleus -Exhibit metachromasia (The ability to change the color of a stain and stain differently than other tissues) -Involved in immune response (innate immunity), tissue repair, and immediate hypersensitivity (allergic) reactions -Basophilic granules -Contain heparin, histamine, and leukocyte chemotactic factor, precursors of inflammatory prostaglandins and leukotrienes

elastic cartilage

-Cartilage containing elastic fibers -Covered with perichondrium -Provides flexible, elastic support -External ear and epiglottis

adipocytes

-Found in many organs -Store lipid as neutral fats or triglycerides. -Used for energy storage, insulation, cushioning of organs -Empty-looking cells with thin margins; nucleus pressed against cell membrane; "signet ring" appearance (think college ring or engagement ring) -Brown fat (infants, hibernating animals) produces heat

plasma cells

-Immune cell that produces antibodies -Derived from a B lymphocyte -Spherical offset nucleus with clumps of heterochromatin -Basophilic cytoplasm with abundant RER (red arrow) and golgi (black arrows)

white adipose tissue

-Large adipocytes with a single large lipid droplet (unilocular) -Cells appear empty with a ring of cytoplasm and peripheral nucleus -Other organelles are located near the nucleus or throughout the ring of cytoplasm -Abundant smooth ER (used for lipid catabolism) -Abundant vasculature (microvasculature)

brown adipose tissue

-Multilocular, nucleus more centrally located, found adjacent to blood capillaries. -2-5% of newborn body weight - concentrated mainly in the neck, back and shoulders. -Decreases in concentration during childhood.

ground substance of connective tissue

-Typically transparent watery to solid extracellular substances in which the cells and fibers are suspended -COMPOSED OF: Glycosaminoglycans (mucopolysaccharides), polysaccharides composed of disaccharide subunits of hexosamine (commonly glucosamine) and uronic acid, Glycoproteins - carbohydrate covalently linked to a protein. and Proteoglycans - core glycoprotein bound to GAGs.

Perichondrium

-a sheath of dense irregular connective tissue that surrounds elastic and most hyaline cartilage (not articular cartilage). There are NO blood vessels! -hyaline and elastic only

elastic fibers

- composed of elastin and makes broad, often wavy, fibers -Commonly found interspersed with collagen fibers or smooth muscle -Branched and fuse with other elastic fibers to form a network within tissues that stretch and bend

Dense Irregular Connective Tissue (DICT)

-a type of tissue contains a dense woven network of collagen (and some elastic) fibers in a viscous matrix. -It is found in joint capsules, in the connective tissue that envelops muscles (muscle fascia), found in the deeper layers of skin (dermis); capsules around organs. -Densely packed, seemingly randomly arranged, collagen fibers -Fewer cells and less ground substance

loose adipose connective tissue

-any tissue in which adipocytes are predominate. -Adipocytes occur individually or in small clumps in many other connective tissues but a tissue predominantly composed of adipocytes. -These are specialized for storage of triglycerides, regulate metabolism (endocrine function of adipocytes important in energy homeostasis), thermal insulation, cushioning of organs. -15-20% of body weight in men and slightly more than that in women.

Dense Regular Connective Tissue (DRCT)

-consists of same components as DICT but the collagen fibers are arranged parallel to each other. -Increased resistance to stress in one direction ad thus are found in tendons and ligaments. -Fibroblasts may be inactive fibrocytes - also known as tendinocytes. -May be difficult to distinguish as they don't stain much darker than the surrounding collagen.

Fibrocartilage

-contains large bundles of collagen fibers. -Pubic symphysis, menisci, and intervertebral discs are major places we see this type. - Features: Chondrocytes are arranged axially or in a row - key for identification, NO perichondrium - blends with adjacent connective tissue, Found in pubic symphysis, menisci in knees, intervertebral discs, and tendinous attachments to bone

collagen fibers

-family of proteins that form extracellular fibers or sheets that have great tensile strength -Produced by fibroblasts and some other cell type -Typically arranged in a parallel bundle and joined together forming a lattice -*Collagen therefore yields both strength AND flexibility*

reticular fibers

-form structural framework for many organs, particularly soft organs of the immune system. -They also attach capillaries to surrounding tissue resulting in their increased concentration in lymphatic organs -Made of type III Collagen

hyaline cartilage

-most common type of cartilage. -It is homogenous, translucent, glassy appearance because of presence of fine collagen fibers. -It usually is covered by perichondrium. -It looks slightly basophilic overall in H&E sections. -Articular cartilage, trachea, fetal skeleton are major places we see this type.

loose (areolar) connective tissue

-refers to amount of collagen that is present, appears as though the tissue is "empty". -It is found beneath all epithelia, between muscles, passageways for nerves and blood vessels. -It contains cells, fibers, and ground substances in relatively even amounts. -most common cell is fibroblast -most common fiber is collagen

Macrophages

Found within the lymph nodes, they are phagocytes that destroy bacteria, cancer cells, and other foreign matter in the lymphatic stream.

lipid droplets

found in liver cell and fat cells

elastic connective tissue

a branching, densely packed elastic fibers. IT is able to stretch and recoil. It is found in walls of large arteries, trachea, vocal cords.

Chondrocytes in lacunae

cartilage

Chondroblasts

cartilage forming cells, produce matrix and surround themselves until they become trapped in little cavities

connective tissue fibers

collagen, elastic, reticular

different kinds of connective tissue

connective tissue proper, supporting connective tissue, fluid connective tissue

connective tissue cell types

fibroblasts, macrophages, adipocytes, mast cells, lymphocytes

Fibroblasts

produce and maintain connective tissue by secreting ECM and important in healing as they can produce fibrous connective tissue "scars" in tissues that are non-mitotic and cannot replace themselves.

mesenchymal cells

stem cells that respond to injury or infection by dividing to produce new fibroblasts, macrophages, or other CT cells

dense irregular collagen fibers

yellow line