histology - · pdf fileof tissue structure and function is very important to the good massage...
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HistologyHistology is the study of tissues. As a massage therapist you might
be asking yourself, “Why is it important form me to understand thestructure and function of tissues?” You might think that the only tissuethat is important for you to know about is muscle tissue. While it isimportant to understand the structure and function of muscle tissue, thefact is, connective tissues and nervous tissue are more greatly impactedby massage work than is muscle tissue. Having a strong understandingof tissue structure and function is very important to the good massagetherapist. For example, if you are massaging a person with significantedema (swelling) what should be your concerns? Where is this fluidbuildup occurring and why? As you begin to learn about the structure oftissues, the functional aspects of these tissues will become much clearerand more apparent. One of the most important tissues, of which themassage therapist should have a strong knowledge, is the collagenousconnective tissue family. This is the principal building material of theskin, fascia, ligaments, tendons, joint capsules, and believe it or not,muscles. In this chapter, you will begin to establish a strong foundationknowledge of tissues, which you will continue to build upon throughoutthe course.
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S t r u c t u r e a n d F u n c t i o n o f t h e H u m a n B o d y f o r M a s s a g e T h e r a p i s t s
Introduction to TissuesFour principal tissues
Epitheliumepi = upon + thele = nipple
General structure and functionTightly packed cells functioning as covering and lining tissues
General distributionAlways found as a surface tissues
Connective tissue
General structure and functionFew cells with lots of extracellular material; many functions
General distributionWide distribution — bone, tendon, fat, blood, cartilage
Muscle
General structure and functionElongated cells specialized to shorten
General distributionThe skeletal muscles of the body and many body organs
Nervous tissue
General structure and functionWirelike cells specialized for conduction of electrical signals
General distributionBrain, spinal cord, and nerves
H i s t o l o g y
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Epithelial TissuesClassification and Function
Classification of epithelial tissuesCell shape
Squamous (Flat)squama = scale
Cuboidalcubus = a cube + eidos = shape
Columnar
Number of layersSimple
Stratified
Functions of epithelial tissuesExchange surfaces
Secretion
Absorption
Excretion
Protection
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S t r u c t u r e a n d F u n c t i o n o f t h e H u m a n B o d y f o r M a s s a g e T h e r a p i s t s
Epithelial TissuesStructure, Distribution, and Function
Simple Epithelial TissuesStructure
Thin lining and covering layers
Relationship to connective tissue blood vessels
Distribution
Functions
H i s t o l o g y
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Simple EpitheliaSimple squamous epithelium
This tissue consists of a single layer of flat cells having avery smooth appearance when viewed with the unaidedeye. It is primarily found in two major locationsthroughout the body. It forms the inner lining of thecardiovascular system, lining blood vessels, thechambers of the heart, and lymphatic vessels. Therefore,it is the tissue that the blood is always in contact with asit moves through the body. A second area it is commonlyfound is lining the cavities that house the heart, lungs,and abdominal organs. In addition, the outside of theseorgans is covered with this simple epithelium. These arethe two major areas of distribution for this tissue.Additionally, it is found in the walls of the smallest airspaces of the lungs, forming the walls of some smallurinary tubes within the kidney.
Simple cuboidal epitheliumThis tissue is a single layer of polygonal cubed cells. It isoften referred to as glandular epithelium because of itsprominent distribution in the lining of many glands ofthe body.
Simple columnar epitheliumThis tissue consists of a single layer of tall columnarshaped cells. In some locations within the body thesurface of the cells is covered with small hairlikeprocesses termed cilia. The major site of distribution ofthis tissue in the body is the inner lining surface of thedigestive tract from the beginning of the stomach to theanus. Throughout this location it has no cilia. It is foundas a cilia covered surface lining the bronchi of the lungsand the uterine tubes.
Pseudostratified columnar epitheliumThis is an interesting tissue that fooled anatomists untilthe resolution of microscopes had evolved considerably.It is a simple epithelium but, as its name suggests, itlooks stratified. All the cells attach to the basal lamina,but they do not all reach the surface. This gives the tissuethe appearance of having cells stacked in multiple layers.This is the tissue forming the inside lining of the upperrespiratory tract. In these areas the surface is coveredwith cilia.
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S t r u c t u r e a n d F u n c t i o n o f t h e H u m a n B o d y f o r M a s s a g e T h e r a p i s t s
Stratified Epithelial TissuesStructureThick lining and covering layers
Relationship to connective tissue blood vessels
Distribution
Functions
H i s t o l o g y
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Stratified squamous epitheliumThis tissue, comprised of many cell layers, is the thickestepithelial tissue in the body. The bottom layer of cellshave a cuboidal shape but as the cells progress towardsthe surface they become thin and flat. It is the many flatlayers of surface cells from which the tissue derives itsname. This thick protective layer of cells forms thecovering of the body called the epidermis. It can also befound lining the inside of the mouth and nose, lining theesophagus and anus, and covering the surface of the eye.
Stratified columnar epitheliumThis is not a very common tissue in the body. It is foundin a few isolated places and has no general area ofdistribution. For example, it can be found in certainregions of the larynx (voice box) and pharynx (throat) aswell as lining the large excretory ducts of some glands.
Transitional (stratified cuboidal) epitheliumStudy of this tissue by the early anatomists revealed thatthe structure of the tissue appeared to undergo changes.Sometimes the cells looked more cuboid andmultilayered, while other times the tissue appearedthinner. This resulted from the stretching or distension ofthe tissue at its site of distribution — the lining of theurinary system. Because of its distribution as a lining ofthe urinary system from the large urinary tubules of thekidney through the ureter, bladder, and urethra, thistissue is often referred to as urinary epithelium.
Stratified Epithelia
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S t r u c t u r e a n d F u n c t i o n o f t h e H u m a n B o d y f o r M a s s a g e T h e r a p i s t s
Overview of Connective TissuesFour basic types
General structureExtracellular material forms greater percentage of tissue than cells
FunctionsVaried functions usually related to the extracellular material
Connective tissue properSoft connective tissue
CartilageFirm to rubbery connective tissue
BoneHard connective tissue
BloodFluid connective tissue
H i s t o l o g y
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Connective Tissue ProperBuilding Blocks
Cells — first building blockFixed cellsFibrocyte [Fibroblasts] fibra = fiber + –cyto = cell
Cells that produce extracellular fibers
Adipose cellsadeps, adip = fat
Cells specialized to store lipid energy reserves
Wandering cellsBody defense and repair cells of the white blood cell lineage
Macrophage
Mast Cell
Lymphocyte
Plasma Cell
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S t r u c t u r e a n d F u n c t i o n o f t h e H u m a n B o d y f o r M a s s a g e T h e r a p i s t s
Connective Tissue ProperBuilding Blocks
Extracellular matrix — second basic building blockInterfibrillar substanceWater with various suspended molecules between the fibers
FibersCollagen fiberskolla = glue + genere = to bear, carry
String-like proteins
Great tensile strength
Importance in connective tissue
Relevance to massage therapy
Elastic fibers
String-like or sheetlike branched proteins
Stretchability
H i s t o l o g y
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Connective Tissue ProperFunction and Classification
General functions of connective tissue proper
Classification of connective tissue properNamed after the most prominent feature of the tissue and thearrangement of that feature in the tissue.
Collagenous fibersLoose mesh of collagen
Dense mesh of collagenDense irregular meshes
Dense regular bands
Elastic fibers
Adipose cells
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S t r u c t u r e a n d F u n c t i o n o f t h e H u m a n B o d y f o r M a s s a g e T h e r a p i s t s
Connective Tissue ProperStructure, Distribution, and Function
Collagenous connective tissuesLoose collagenous connective tissue
Structure
Distribution
Function
Dense irregular collagenous connective tissueStructure
Distribution
Function
Dense regular collagenous connective tissueStructure
Distribution
Function
H i s t o l o g y
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Elastic tissueStructure
Distribution
Function
Adipose tissueStructure
Distribution
Function
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S t r u c t u r e a n d F u n c t i o n o f t h e H u m a n B o d y f o r M a s s a g e T h e r a p i s t s
CartilageBuilding Blocks and Classification
IntroductionLacks internal blood supply
Important skeletal and joint tissue
Building blocksCellsChondrocyteschondros = cartilage + –cyto = cell
Extracellular matrixInterfibrillar substance
Proteoglycans
FibersCollagen
Elastic
ClassificationCollagen fibers
Few fibers = hyaline cartilage
Many fibers = fibrocartilage
Elastic fibers
Elastic fibers = elastic cartilage
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Anatomists designate three forms of cartilage, againbased on the type and distribution of fiber in the groundsubstance. The three forms are hyaline cartilage (fewercollagen fibers), fibrocartilage (many collagen fibers), andelastic cartilage (elastic fibers).
Hyaline Cartilagehyalos = glasslike + cartilago = gristle
Hyaline cartilage is the most common cartilage in thebody, and all other cartilages are a modification of thiscartilage type. It consists of thin meshworks of collagenin a rubbery substrate. Hyaline cartilage forms themajority of the embryonic skeleton and after birth itpersists as the skeleton of the external nose, anterior endsof the ribs, in the walls of the upper respiratorypassageways, and as growth plates in the long bones.
Elastic cartilageElastic cartilage does not occur in many placesthroughout the body. As its name implies, it differs fromhyaline cartilage because as a result of the thickmeshworks of elastic fibers present in its matrix. Thishighly elastic tissue forms ths skeleton of the epiglottis(the flap-like door that covers the respiratorypassageways when you swallow) and the skeleton of theexternal ear.
FibrocartilageFibrocartilage receives its name from the large number ofthick collagen fibers that are densely distributed in therubbery matrix. The fibers are so densely packed in thetissue that there is little evidence of the surroundingmatrix. Fibrocartilage forms the strong intervertebraldiscs that separate the vertebrae. They also form articulardiscs, such as the menisci of the knee joint. These strongcartilages function as effective shock absorbers betweenbones.
Types of Cartilage