Tissue Types. Key Terms Differentiation = produces specialized cells during embryonic development...
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Transcript of Tissue Types. Key Terms Differentiation = produces specialized cells during embryonic development...
Tissue Types
Key Terms
• Differentiation = produces specialized cells during embryonic development
• Tissues = groups of cells which are similar in structure and which perform common or related functions
• Histology = the study of tissues
Four Basic Kinds of Tissues
• Epithelial Tissue
• Connective Tissue
• Muscle Tissue
• Nervous Tissue
Epithelial Tissue• Locations:
– Covers the body– Lines organs, body cavities, and ducts– Forms glands
• Functions:– Protection from injury and microbial invasion– Regulates permeability– Secretes fluids to lubricate structures
Characteristics:
• Avascular (no blood vessels)
• Cells may show polarity (apical & basal surface, they are chemically and structurally different from one another)
• A basement membrane attaches epithelia to underlying connective tissues
• High rate of cell division (allows repair by sloughing off dead or injured cells, important because epithelium is exposed to physical stress)
Epithelial Tissue
The Polarity of Epithelial Cells
• Number of cell layers pg 113– Simple (single layer)– Stratified (several layers)– Pseudostratified (nuclei are at different levels & not
all cells reach the apical surface)
• Shape of cells (draw, location, function)– Squamous (thin, flat, irregular cells) pg 115– Cuboidal (cube shaped cells) pg 116– Columnar, ciliated and nonciliated (tall & slender
cells) pg 116, 117– Transitional (change shape from flat to cuboidal and
back) pg 119
Classification of Epithelia
Squamous Epithelia
Cuboidal Epithelia
Cuboidal Epithelia Cont.
Special Cuboidal Epithelia:Transitional Epithelia
cells can stretch
Columnar Epithelia
Columnar Epithelia
Columnar Epithelia
Many epithelia contain gland cells that produce secretions
Exocrine glands:– Produce secretions such as mucus and/or watery
solution through ducts onto the epithelial surface
Endocrine glands:– Ductless, release secretions directly into bloodstream
Glandular epithelia
Exocrine vs. Endocrine
Glands
Examples of Exocrine Glands
Time to Review
Simple squamous epithelium (lining of body cavities)
Simple cuboidal epithelium (lining of glands and ducts)
Simple columnar epithelium (lining of stomach, intestines)
Stratified squamous epithelium (skin)
Simple columnar epithelium (lining of digestive tract)
Simple cuboidal epithelium (lining of ducts in kidneys)
Simple squamous epithelium (lining of the heart)
Pseudostratified columnar epithelium (lining of nasal cavity)
Transitional epithelium (urinary bladder)
Stratified squamous epithelium (lining of mouth)
Type of Tissue Function Location
Pseudostratified columnar
removing dust and particles from airways, has cilia
lines the respiratory passageways
Simple Columnar Absorptionlines the uterus and most organs of the digestive tract
Simple Cuboidal Secretion and Absorptionglands, kidney tubules, ovaries
Simple Squamous Diffusion and Filtrationlungs, walls of capillaries and vessels
Stratified Squamous Protects underlying cellsskin(keratinized) and the throat, vagina, mouth (soft)
Stratified Cuboidal Protectionlines ducts of the mammary glands, sweat glands, pancreas
Stratified Columnar Protection, secretionmale urethra and vas deferens, parts of the pharynx
Transitional (unstretched)
Specialized to become distended
urinary tract