28 terms

Connective Tissue-Characteristics and Function

Human Anatomy 5 ed. Ch. 4
4 Classes of Connective Tissue
Connective Tissue Proper-fat tissue and fibrous ligaments, cartillage, bone tissue, and blood
All Connective Tissue Shares the Same Structural Plan
1.Relatively few cells, lots of extracellular matrix(the cells of connective tissues are separated by a large amount of extracellular matrix), 2. The extra cellular matrix is composed of ground substance and protein fibers. The differences between the physical properties and functions of each type of connective tissue are d/t differences in composition of E.M. 3.Embryonic Origin-all connective tissue originates from embryonic tissue called mesenchyme.
Three Types of Protein Fibers Found in Connective Tissue
Collagen fibers, reticular fibers, elastic fibers
Connective Tissue Proper
2 Subclasses-loose connective tissue and dense connective tissue
Loose Connective Tissue
Loose Areolar is the most widespread type, underlies almost all epithelial tissue in the body, surrounds almost all small nerves and blood vessels, including capillaries functions are support and binding of other tissues, holding body fluids, defending the body against infection, storing nutrients as fat
Function: Provide Support
Fibers provide support, 3 types of fibers in areolar tissue E.M. that give tissue supportive properties-collagen, reticular, and elastic
Collagen Fibers
Strongest and most abundant type of fiber, allow connective tissue to withstand tension, appear as bundles of thinner, striped threads called unit fibrils
Reticular Fibers
short fibers that cluster into delicate networks that cover and support all structures bordering connective tissue, allow more "give" than collagen fibers,
Elastic Fibers
Contain a rubber like protein called Elastin, which allows them to function like rubber bands, if pulled taut, the elastic fibers recoil, and allow the stretched tissue to spring back into shape, can be seen in:
A sigle cell that produces all of the fibers of areolar connective tissue, the most abundant cell type in connective tissue proper, make and secrete the protein subunits of fibers
Function: Hold Fluid
The ground substance in EM of Alveolar Tissue holds tissue (interstitial) fluid, soaks and holds fluid like a sponge
Function: Fight Infection
Aerolar connective tissue is the main battlefield in the body's war against infection, microorganisms, and parasites. Invading organisms penetrate epithelial tissue then enter alveolar tissue, where a variety of defense cells migrate to after leaving the capillaries
"Big Eaters" Oval cells whose surface is ruffled by psuedopods-engulf and devour a wide variety of foreign materials as well as dead cells
Plasma Cells
Egg shaped cells that secrete protein molecules called antibodies, which bind to foreign molecules and microorganisms, marking them for destruction
Mast Cells
Oval cells that lie near the small blood vessels and contain many large secretory granules. (Mast means stuffed full of granules) Contain many chemicals that mediate inflammation, especially in severe allergies--> Histamine, heparin, and proteases
Neutrophils, Lymphocytes, and Eosinophils
WBCs that leave the blood stream to fight infection
Adipose Tissue
White Adipose Tissue/White Fat Tissue, similar to areolar in structure and function, but with much greater nutrient storing function, crowded with fat cells grouped into large clusters called lobules, richly vascularized, found under skin in hypodermis, around kidneys and eyeballs, breasts and abdomen
Reticular Connective Tissue
Resembles Areolar Connective Tissue, but only fibers in its matrix are reticular fibers, can be found inbone marrow, spleen, and lymph nodes
Areolar Tissue
Gell like matrix with all 3 fiber types, wraps and cushions organs, plays important role in inflammation, holds tissue, fights disease, found: most widely distributed connective tissue, found under epithelia
Dense Connective Tissue
Contains more collagen than areolar tissue, can resist extremely strong pulling forces, 3 types-irregular, regular, and elastic
Dense Irregular Connective Tissue
Primarily irregularly arranged collagen fibers, some elastic fibers, major cell type is fibroblast, Function-able to withstand tension exterted in many directions, provides structural strength, found in Dermis, submucosa of GI Tract, fibrous capsules of organs and joints
Dense Regular Connective Tissue
Primarily parallel collagen fibers, a few elastic fibers, major cell type is fibroblast Function: Attaches muscle to bone or muscle, withstands great tensile stress when pulling force is applied in one direction, found in: Tendons, most ligaments, aponeuroses
Dense Elastic Connective Tissue
Contains a high proportion of elastic fibers, allows recoil of tissue following stretching, maintains pulsatile flow of blood through arteries, aids passive recoil of lungs, found in:nwalls of large arteriesm certain ligaments in vertebral column, within walls of bronchial tubes
Amorphous but firm matrix, collagen fibers form an imperceptible network, chondroblasts produce the matrix and when mature chondrocytes lie in lacuncae, Function: Supports and reinforces, has resilient cushioning proerties, resists compressive stress Found in: most of embryonic skeleton, covers ends of long bones in joint cavities, Forms costal cartilages of the ribs, nose, trachea, and larynx
Cartilage: Elastic
Similar to hyaline, but with more elastic fibers in matrix, maintains shape of structure while allowing great flexability, found in:Supports external ear, epiglottis
Matrix similar but less firm to hyaline, thick collagen fibers predominate Function: Tensile strength with ability to absorb shock, Location: Intervertebral discs, pubic symphisis, discs of knee joints
Bone (Ossesous Tissue)
Hard, Calcified matrix containing many collagen fibers, osteocytes lie in lacunae, very well vascularized Function: Bone supports and protects by enclosing, provides levers for mucsles, stores calcium and minerals and fat, marrow inside bones is site of blood cell formation, found in: Bones, durr
Red and white cells in a fluid matrix (plasma), function-transport of respiratory gases, nutrients, wastes, and other substances location: Contained within blood vessels