Presentation on theme: "Epithelial Tissue Histology: the study of tissues. Tissues:"— Presentation transcript:
1Epithelial Tissue Histology: the study of tissues. Tissues: Simply groups of similar cells that work together performing the same taskGreatest form of teamwork in the body
2Where are epithelial tissues found? With few exceptions, organs are composed of four basic tissue types:– Epithelial Tissue– Connective Tissue– Muscular Tissue– Nervous Tissue
3Why Study Histology?Knowing the difference between normal and abnormal tissue is the first step in diagnosis and treatment of patients.
4Skin, our largest and heaviest organ Epithelial TissueMuscular TissueNervous TissueConnective Tissuemade of all four tissue types
5Epithelial Tissue Makes up 3% of your body weight Cells don’t move They don’t send messagesTheir cells are all touching one anotherOf all tissues, they are the most widely varied in structure and function
6Locations of Epithelial Tissues Covers the bodyFound on the inside of hollow organs and the outside of all organsFound above a connective tissue layerLines the cavities, tubes, ducts, and blood vessels inside the body
7Epithelial AnatomyApical surface – upper surface that is free or exposed to the “exterior”Basal surface – attached surface (below)Microvilli – small fingerlike extensions that increase the surface area allowing for more work to be done
8Functions of Epithelial Tissue Protects from physical & chemical injuryProtects against microbial infectionContains nerve endings which respond to stimuliFilters, secretes & reabsorbs materialsSecretes fluids to lubricate joints
9Three Basic ShapesSquamous – like scales, or pancakes (“being squashed like a pancake”)Cuboidal – looks like cubesColumnar – longer and look like columns
10Cell OrganizationSimple – single layer of cells; typically found where absorption and filtration occursimple squamoussimple cuboidalsimple columnarStratified – layers of cells; common in areas where protection is needed like the skinstratified squamous
11Two Types of Stratified Columnar CiliatedUnciliatedciliaNo cilia
12Squamous Epithelium Simple Squamous Stratified Squamous Forms solid, single layer of cellslines blood vessels, body cavities and covers organsStratified SquamousForms epidermis and is mostly for protectionFound in areas of high friction
13Cuboidal Epithelium Simple Cuboidal Roughly cube shaped Line ducts in kidneys where absorption and secretion activities take place.Very, very rare to have stratified cuboidal
14Columnar Epithelium Simple columnar– one cell thick rectangular shaped (long and narrow)Lines digestive tract where absorption & secretion occurs.White spots are goblet cells which secrete mucousNo stratified columnar
15Confusing Epithelial Tissue Transitional Epithelium – Numerous layers of cells of varying and often irregular shapeShape of cells depends upon the amount of stretching (ex: bladder)
16Confusing Epithelial Tissue Continued… “Pseudostratified Columnar Epithelium”Tall rectangular cells, with multiple irregular rows of nuclei. Nuclei are positioned at differing levelsCells narrow in the area without the nucleusLocated in the trachea; secrete & move mucousGoblet cells secret mucous to aid cilia in moving substances across the cells’ surface
17Epithelial Tissue in Review… Epithelial tissues can be found in three types of membranes: Cutaneous, Serous, and mucous membranes.
18Mucosa MembranesMucus-secreting membranes line tubes; moistens and protects from enzymes and acid (i.e., stomach, trachea, mouth, and vagina)Membranes are involved in absorption and secretion.
19Serous MembranesSerous membranes line body cavities that do not open directly to the outsideThey cover the organs located in those cavities.Fluid lubricates the membrane and reduces friction and abrasion when organs move against each other.
20Cutaneous Membranes Cutaneous membranes cover the surface of the body. Consists of stratified squamous epitheliumCutaneous membranes are thick, relatively waterproof, and dry.Function = protection