Connective Tissues

Collagen fibers

(1/3) - are very strong and resist pulling forces, but they are not stiff, which promotes tissue flexibility. These fibers often occur in bundles lying parallel to one another - are found in most types of connective tissues, especially bone, cartilage, tendons, and ligaments.

Fibroblasts

(1/5) Type of Connective Tissue Cells are large, flat cells with branching processes. They are present in several connective tissues, and usually are the most numerous. - migrate through the connective tissue, secreting the fibers and ground substance of the extracellular matrix. -bind -collagen, elastin and reticular fibers

Elastic fibers

(2/3) - are smaller in diameter than collagen fibers, branch and join together to form a network within a tissue. - consists of molecules of a protein called elastin surrounded by a glycoprotein named fibrillin, which is essential to the stability of an elastic fiber - have the ability to return to their original shape after being stretched, a property called elasticity - are plentiful in skin, blood vessel walls, and lung tissue

Macrophages

(2/5) Type of Connective Tissue Cells develop from monocytes, a type of white blood cell. - have an irregular shape with short branching projections and are capable of engulfing bacteria and cellular debris by phagocytosis.

Reticular fibers

(3/3) consisting of collagen and a coating of glycoprotein, provide support in the walls of blood vessels and form branching networks around fat cells, nerve fibers, and skeletal and smooth muscle cells. Produced by fibroblasts, they are much thinner than collagen fibers. Like collagen fibers, reticular fibers provide support and strength and also form the stroma or supporting framework of many soft organs, such as the spleen and lymph nodes. These fibers also help form the basement membrane.

Plasma cells

(3/5) Type of Connective Tissue Cells are small cells that develop from a type of white blood cell called a B lymphocyte. - secrete antibodies, proteins that attack or neutralize foreign substances in the body. -are an important part of the body's immune response. - Chondrytes; osteocytes, blood cells

Masts cells

(4/5) Type of Connective Tissue Cells are abundant alongside the blood vessels that supply connective tissue. They produce histamine, a chemical that dilates small blood vessels as part of the inflammatory response, the body's reaction to injury or infection. - can also kill bacteria. -loose and dense

Adipoctes

(5/5) Type of Connective Tissue Cells also called fat cells or adipose cells, are connective tissue cells that store triglycerides (fats). They are found below the skin and around organs such as the heart and kidneys. - loose, cushy protection

Ground substance

- the component of a connective tissue between the cells and fibers, supports cells, binds them together, and provides a medium through which substances are exchanged between the blood and cells. -plays an active role in how tissues develop, migrate, proliferate, and change shape, and in how they carry out their metabolic functions - contains water and an assortment of large organic molecules, many of which are complex combinations of polysaccharides and proteins

Ground substance, fibers, cells

3 basic components

Collagen, reticular, elastic

3 types of fibers

Cells and extracellular matrix

Connective tissue consists of two basic elements.

Reticular connective tissue

Description: A network of interlacing reticular fibers and reticular cells. Location: Stroma (supporting framework) of liver, spleen, lymph nodes; red bone marrow, which gives rise to blood cells; part of the basement membrane; and around blood vessels and muscles. Function: Forms stroma of organs; binds together smooth muscle tissue cells; filters and removes worn-out blood cells in the spleen and microbes in lymph nodes.

Hyaline cartilage

Description: Consists of a bluish-white, shiny ground substance in the body (can stain pink or purple when prepared for microscopic examination) with fine collagen fibers and many chondrocytes; most abundant type of cartilage. Location: Ends of long bones, anterior ends of ribs, nose, parts of larynx, trachea, bronchi, bronchial tubes, and embryonic and fetal skeleton. Function: Provides smooth surfaces for movement at joints, as well as flexibility and support

Adipose tissue

Description: Consists of adipocytes, cells specialized to store triglycerides (fats) as a large centrally located droplet; nucleus and cytoplasm are peripherally located. Location: Subcutaneous layer deep to skin, around heart and kidneys, yellow bone marrow, and padding around joints and behind eyeball in eye socket. Function: Reduces heat loss through skin, serves as an energy reserve, supports, and protects.

Elastic cartillage

Description: Consists of chondrocytes located in a threadlike network of elastic fibers within the extracellular matrix. Location: Lid on top of larynx (epiglottis), part of external ear (auricle), and auditory (eustachian) tubes. Function: Gives support and maintains shape.

Fibrocartilage

Description: Consists of chondrocytes scattered among bundles of collagen fibers within the extracellular matrix. Location: Pubic symphysis (point where hip bones join anteriorly), intervertebral discs (discs between vertebrae), menisci (cartilage pads) of knee, and portions of tendons that insert into cartilage. Function: Support and joining structures together.

Areolar connective tissue

Description: Consists of fibers (collagen, elastic, and reticular) and several kinds of cells (fibroblasts, macrophages, plasma cells, adipocytes, and mast cells) embedded in a semifluid ground substance. Location: Subcutaneous layer deep to skin; superficial region of dermis of skin; connective tissue layer of mucous membranes; and around blood vessels, nerves, and body organs. Function: Strength, elasticity, and support.

Dense irregular connective tissue

Description: Consists predominantly of collagen fibers randomly arranged and a few fibroblasts. Location: Fasciae (tissue beneath skin and around muscles and other organs), deeper region of dermis of skin, periosteum of bone, perichondrium of cartilage, joint capsules, membrane capsules around various organs (kidneys, liver, testes, lymph nodes), pericardium of the heart, and heart valves. Function: Provides strength.

Elastic connective tissue

Description: Consists predominantly of elastic fibers; fibroblasts are present in spaces between fibers. Location: Lung tissue, walls of elastic arteries, trachea, bronchial tubes, true vocal cords, suspensory ligament of penis, and ligaments between vertebrae. Function: Allows stretching of various organs

Dense regular connective tissue

Description: Extracellular matrix looks shiny white; consists mainly of collagen fibers regularly arranged in bundles; fibroblasts present in rows between bundles. Location: Forms tendons (attach muscle to bone), most ligaments (attach bone to bone), and aponeuroses (sheetlike tendons that attach muscle to muscle or muscle to bone). Function: Provides strong attachment between various structures.

Bone Tissue

It supports soft tissues, protects delicate structures, and works with skeletal muscles to generate movement. Bone stores calcium and phosphorus; stores red bone marrow, which produces blood cells; and houses yellow bone marrow, a storage site for triglycerides.

Blood tissue

Liquid Connective Tissue - is a connective tissue with a liquid extracellular matrix called blood plasma, a pale yellow fluid that consists mostly of water with a wide variety of dissolved substances: nutrients, wastes, enzymes, hormones, respiratory gases, and ions. Suspended in the plasma are red blood cells, white blood cells, and platelets. Red blood cells transport oxygen to body cells and remove carbon dioxide from them. White blood cells are involved in phagocytosis, immunity, and allergic reactions. Platelets participate in blood clotting.

Connective Tissue Extracellular Matrix

consists of a fluid, gel, or solid ground substance plus protein fibers.

Fibers

in the extracellular matrix strengthen and support connective tissues. Three types of fibers are embedded in the extracellular matrix between the cells: collagen fibers, elastic fibers, and reticular fibers.

Classification of connective tissue

• Connective Tissue Proper - Loose, dense • Supporting Connective Tissue - Bone; cartilage • Fluid Connective Tissue (blood) I. Loose connective tissue A. Areolar connective tissue B. Adipose tissue C. Reticular connective tissue II. Dense connective tissue D. Dense regular connective tissue E. Dense irregular connective tissue F. Elastic connective tissue III. Cartilage G. Hyaline cartilage H. Fibrocartilage I. Elastic cartilage IV. Bone tissue V. Liquid connective tissue (blood tissue and lymph)

Functions of connective tissue

• Supporting and Protecting • Transporting material • Storing energy reserves • Defense