Exercise #6 Classification of Tissues - Epithelial Tissue

Human Anatomy & Physiology Laboratory Manual Thirteenth Edition Chapter 6 Classification of Tissues Copyright © 2019, 2017, 2015 Pearson Education, Inc. All Rights Reserved Figure 6.1 Levels of structural organization Copyright © 2019, 2017, 2015 Pearson Education, Inc. All Rights Reserved What is a tissue? n n n n A group of similar cells that usually have a common embryonic origin in an embryo and function together to carry out specialized activities The study of tissues is called histology. There are 4 basic types of tissues in the human body and they are categorized according to their structure and function Histology is very important for the study of pathology (diseases) since many diseases are first diagnosed at the tissue level. The 4 Tissue Types Epithelial, Connective, Muscular, Nervous Microscopy of Human Tissue n To be viewed under a microscope, tissue must be: q q q q Fixation: The tissue is immersed in a preserved with solvent to maintain its existing structure Embedding: Water is removed with alcohol, impregnated with paraffin wax Sectioning: The tissue is cut into slices thin enough to transmit light or electrons Staining: The tissue is immersed in dyes that stain different structures which also enhance contrast, although artifacts (distortions) detract from what the sample looks like in living tissues n Light microscopy uses colored dyes n Electron microscopy uses heavy metal coatings © 2016 Pearson Education, Inc. Four Types of Tissue • Tissues • Are collections of similar cells and cell products that perform specific, limited functions • Four types of tissue 1. 2. 3. 4. © 2015 Pearson Education, Inc. Epithelial tissue Connective tissue Muscle tissue Neural tissue Figure 4.1 Overview of four basic tissue types: epithelial, connective, muscle, and nervous tissues. Nervous tissue: Internal communication • Brain • Spinal cord • Nerves Muscle tissue: Contracts to cause movement • Muscles attached to bones (skeletal) • Muscles of heart (cardiac) • Muscles of walls of hollow organs (smooth) Epithelial tissue: Forms boundaries between different environments, protects, secretes, absorbs, filters • Lining of digestive tract organs and other hollow organs • Skin surface (epidermis) Connective tissue: Supports, protects, binds other tissues together • Bones • Tendons • Fat and other soft padding tissue © 2016 Pearson Education, Inc. EPITHELIAL TISSUE Epithelial Tissue • Epithelia • Layers of cells covering internal or external surfaces • Glands • Structures that produce secretions © 2015 Pearson Education, Inc. Epithelial Tissue • Characteristics of Epithelia • Cellularity (cell junctions) • Polarity (apical and basal surfaces) • Microvilli increase absorption or secretion • Cilia (ciliated epithelium) move fluid • Attachment (basement membrane or basal lamina) • Avascularity but innervated • Regeneration © 2015 Pearson Education, Inc. Surfaces of Epithelial Cells and the Basement Membrane Copyright © 2017 John Wiley & Sons, Inc. All rights reserved. Figure 4-1 The Polarity of Epithelial Cells. Cilia Microvilli Apical surface Golgi apparatus Nucleus Mitochondria Basement membrane Basolateral surfaces © 2015 Pearson Education, Inc. Epithelial Tissue • Functions of Epithelial Tissue 1. 2. 3. 4. Provide Physical Protection Control Permeability Provide Sensation Produce Specialized Secretions (glandular epithelium) © 2015 Pearson Education, Inc. Classification of Epithelial Tissue Covering and lining epithelia are classified according to two structural criteria: the shape of the cells and how many layers thick they are Copyright © 2017 John Wiley & Sons, Inc. All rights reserved. Figure 6.2a Classification of epithelia Arrangement or relative number of layer: Copyright © 2019, 2017, 2015 Pearson Education, Inc. All Rights Reserved Figure 6.2b Classification of epithelia Based on Cell shape Copyright © 2019, 2017, 2015 Pearson Education, Inc. All Rights Reserved Classification of Epithelia • Singular = Epithelium; Plural = Epithelia • Classes of epithelia 1. Based on cell shape • Squamous epithelia — thin and flat • Cuboidal epithelia — square shaped • Columnar epithelia — tall, slender rectangles 2. Based on number of cell layers • Simple epithelium — single layer of cells • Stratified epithelium — several layers of cells © 2015 Pearson Education, Inc. Classification of Epithelia • Squamous Epithelia • Simple squamous epithelium • Absorption and diffusion • Mesothelium • Lines body cavities • Endothelium • Lines heart and blood vessels © 2015 Pearson Education, Inc. Figure 6.3a Epithelial tissues Copyright © 2019, 2017, 2015 Pearson Education, Inc. All Rights Reserved Figure 4-3a Squamous Epithelia. Simple Squamous Epithelium LOCATIONS: Mesothelia lining pleural, pericardial, and peritoneal cavities; endothelia lining heart and blood vessels; portions of kidney tubules (thin sections of nephron loops); inner lining of cornea; alveoli of lungs FUNCTIONS: Reduces friction; controls vessel permeability; performs absorption and secretion Cytoplasm Nucleus Connective tissue a Lining of peritoneal cavity © 2015 Pearson Education, Inc. LM × 238 Nuclei Simple squamous cells © 2012 Pearson Education, Inc. Nuclei Basement membrane Simple cuboidal epithelium Renal corpuscles © 2012 Pearson Education, Inc. Simple squamous epithelium Simple squamous epithelium Nucleus © 2012 Pearson Education, Inc. Simple squamous epithelium © 2012 Pearson Education, Inc. Nucleus Classification of Epithelia • Cuboidal Epithelia • Simple cuboidal epithelium • Secretion and absorption • Stratified cuboidal epithelia • Sweat ducts and mammary ducts © 2015 Pearson Education, Inc. Figure 6.3b Epithelial tissues Copyright © 2019, 2017, 2015 Pearson Education, Inc. All Rights Reserved Figure 6.3b Simple Cuboidal Epithelium Simple Cuboidal Epithelium LOCATIONS: Glands; ducts; portions of kidney tubules; thyroid gland Connective tissue FUNCTIONS: Limited protection, secretion, absorption Nucleus Cuboidal cells Basement membrane a Kidney tubule © 2015 Pearson Education, Inc. LM × 650 Simple cuboidal epithelium Nuclei © 2012 Pearson Education, Inc. Simple cuboidal epithelium Nuclei Basement membrane © 2012 Pearson Education, Inc. Simple cuboidal epithelium Basement membrane © 2012 Pearson Education, Inc. Nuclei Figure 6.3f Epithelial tissues Copyright © 2019, 2017, 2015 Pearson Education, Inc. All Rights Reserved Figure 6.3f Simple Cuboidal Epithelium Stratified Cuboidal Epithelium LOCATIONS: Lining of some ducts (rare) FUNCTIONS: Protection, secretion, absorption Lumen of duct Stratified cuboidal cells Basement membrane Nucleus Connective tissue b © 2015 Pearson Education, Inc. Sweat gland duct LM × 500 Classification of Epithelia • Columnar Epithelia • Simple columnar epithelium • Absorption and secretion • Pseudostratified columnar epithelium • Cilia movement • Stratified columnar epithelium • Protection © 2015 Pearson Education, Inc. Figure 6.3c Simple Columnar Epithelial Copyright © 2019, 2017, 2015 Pearson Education, Inc. All Rights Reserved Figure 6.3c Simple Columnar Epithelial Simple Columnar Epithelium LOCATIONS: Lining of stomach, intestine, gallbladder, uterine tubes, and collecting ducts of kidneys Microvilli Cytoplasm FUNCTIONS: Protection, secretion, absorption Nucleus a © 2015 Pearson Education, Inc. Intestinal lining Basement membrane Loose connective tissue LM × 350 Simple columnar epithelium Basement membrane © 2012 Pearson Education, Inc. Basement membrane Nuclei © 2012 Pearson Education, Inc. Simple columnar epithelium Simple columnar epithelium Microvilli Goblet cell Nuclei Basement membrane © 2012 Pearson Education, Inc. Nuclei Goblet cell Simple columnar epithelium Basement membrane © 2012 Pearson Education, Inc. Figure 6.3d Epithelial tissues Copyright © 2019, 2017, 2015 Pearson Education, Inc. All Rights Reserved Pseudostratified columnar epithelium © 2012 Pearson Education, Inc. Goblet cell Pseudostratified columnar epithelium © 2012 Pearson Education, Inc. Nuclei Cilia Basement membrane Cilia Goblet cells Nuclei Basement membrane © 2012 Pearson Education, Inc. Pseudostratified columnar epithelium Goblet cell Cilia Pseudostratified columnar epithelium Nuclei Basement membrane © 2012 Pearson Education, Inc. Figure 6.3g Epithelial tissues Copyright © 2019, 2017, 2015 Pearson Education, Inc. All Rights Reserved Figure 6.3g Epithelial tissues Stratified Columnar Epithelium LOCATIONS: Small areas of the pharynx, epiglottis, anus, mammary glands, salivary gland ducts, and urethra Loose connective tissue Deeper cells FUNCTION: Protection Lumen Superficial columnar cells Lumen Cytoplasm Nuclei c © 2015 Pearson Education, Inc. Salivary gland duct Basement membrane LM × 175 Classification of Epithelia • Squamous Epithelia • Stratified squamous, Keratinized epithelium • Protects against abrasion and irritation • Keratin protein adds strength and water resistance • Stratified squamous, nonkeratinized epithelium © 2015 Pearson Education, Inc. Figure 6.3e Epithelial tissues Copyright © 2019, 2017, 2015 Pearson Education, Inc. All Rights Reserved Figure 4-3b Squamous Epithelia. Stratified Squamous Epithelium LOCATIONS: Surface of skin; lining of mouth, throat, esophagus, rectum, anus, and vagina FUNCTIONS: Provides physical protection against abrasion, pathogens, and chemical attack Squamous superficial cells b © 2015 Pearson Education, Inc. Surface of tongue Stem cells Basement membrane Connective tissue LM × 310 Stratified squamous epithelium © 2012 Pearson Education, Inc. Basement membrane Stratified squamous epithelium Nuclei Basement membrane © 2012 Pearson Education, Inc. Stratified squamous epithelium Nuclei Basement membrane © 2012 Pearson Education, Inc. Stratified squamous epithelium Nuclei Basement membrane © 2012 Pearson Education, Inc. Stratified squamous epithelium Nuclei © 2012 Pearson Education, Inc. Basement membrane Stratified squamous epithelium Nuclei Basement membrane © 2012 Pearson Education, Inc. Nuclei Basement membrane © 2012 Pearson Education, Inc. Stratified squamous epithelium, keratinized Basement membrane © 2012 Pearson Education, Inc. Dermal papilla Stratified squamous epithelium, keratinized Classification of Epithelia • Transitional Epithelium • Tolerates repeated cycles of stretching and recoiling and returns to its previous shape without damage • Appearance changes as stretching occurs • Situated in regions of the urinary system (e.g., ureters, urinary bladder, Upper part of urethra) © 2015 Pearson Education, Inc. Figure 6.3h Epithelial tissues Copyright © 2019, 2017, 2015 Pearson Education, Inc. All Rights Reserved Figure 4-4c Cuboidal and Transitional Epithelia. Transitional Epithelium LOCATIONS: Urinary bladder; renal pelvis; ureters FUNCTIONS: Permits expansion and recoil after stretching Epithelium (relaxed) Basement membrane Empty bladder Connective tissue and smooth muscle layers LM × 400 Epithelium (stretched) Full bladder c © 2015 Pearson Education, Inc. Urinary bladder Basement membrane Connective tissue and smooth muscle layers LM × 400 Nuclei Umbrella cells Transitional epithelium Basement membrane © 2012 Pearson Education, Inc. Transitional epithelium Umbrella cells Basement membrane © 2012 Pearson Education, Inc. Nuclei Transitional epithelium Umbrella cell Nuclei Basement membrane © 2012 Pearson Education, Inc.