Y1S1_MHSBLEC_1_EPITHELIAL TISSUE.docx.pdf

(MICRO LEC) – (MICROSCOPIC HUMAN STRUCTURAL BIOLOGY 1A) (EPITHELIAL TISSUE & Dr. Sarah Dalisay) (Y1S1_Week 1_August/2024) DIMAYACYAC - SALAMANCA - SALAS - SAMSON - SANCHEZ - SANTIAGO - SAROCA - SICAT - TABBILOS...

(MICRO LEC) – (MICROSCOPIC HUMAN STRUCTURAL BIOLOGY 1A) (EPITHELIAL TISSUE & Dr. Sarah Dalisay) (Y1S1_Week 1_August/2024) DIMAYACYAC - SALAMANCA - SALAS - SAMSON - SANCHEZ - SANTIAGO - SAROCA - SICAT - TABBILOS - TALOSIG - TAWASIL - TEOPENGCO - ULANG - UMALI - VENDIVIL 667 ○ Cardiac OUTLINE Tissues ○ Smooth Fundamental/Basic Types of Tissues ○ Epithelial Nervous Tissue ○ Connective ○ Muscular ○ Nervous Interpretation of stimulus Epithelial Tissue ○ Nerve cell / neuron ○ Characteristics ○ Functions ○ Classification EXAMPLE - ORGAN SKIN Naming (EPITHELIAL TISSUE) Covering/Surface Epithelium Simple Stratified Transitional Pseudostratified Glandular Epithelium Surfaces Specializations ○ Microvilli ○ Cilia ○ Stereocilia Goblet Cells Intercellular Junctions ○ Tight Junction ○ Adhering Junction ○ Gap Junction Must Know in Epithelium Metaplasia Glandular Epithelium Classification ○ Number of cells ○ Manner of secretions ○ Fate of secretions ○ Type of secretions ○ Morphology Simple Compound REFERENCES Epithelial Tissue PPT by Dr. Dalisay TISSUES MAIN CHARACTERISTICS OF THE FOUR BASIC TYPES Histology - study of tissues OF TISSUE Tissues - group of cells with similar functions and morphology FUNDAMENTAL / BASIC TYPES OF TISSUES Epithelial Tissue External or internal covering / lining of body Gland Connective Tissue Supporting / binding tissue Muscular Tissue Contraction / movement ○ Skeletal PAGE 1 OF 16  MICRO LEC – EPITHELIAL TISSUE EPITHELIAL TISSUE Naming of Epithelium Characteristics First Name - number of cell layer/s Second Name - shape Formed by epithelial cells Third Name - optional; if with special feature Cells are closely adherent to each other Cells are extremely cohesive Covering / Surface Epithelium Avascular Tissues Provided with a basement membrane or basal lamina Based on NUMBER of cell layer/s - 4 Subtypes: ○ Simple ○ Stratified BASEMENT MEMBRANE ○ Pseudostratified ○ Transitional NUMBER OF CELL LAYERS Maybe derived from the three germ layers: ○ Ectoderm - epidermis of skin; epithelium of cornea ○ Mesoderm - lining epithelium of kidney, male & reproductive tracts ○ Endoderm - lining epithelium of SHAPE OF THE CELL gastrointestinal tracts Functions Protection Absorption Secretion Excretion Filtration Lubrication Sensory Receptors Remember! All molecules or substances that Enter or Exit the body must Pass through the EPITHELIAL LAYER Epithelial Layers can modify and change this passage - influencing normal homeostatic mechanisms Classification Covering/ Surface Epithelium - membranous layer that covers the EXTERNAL / INTERNAL surfaces of the body. Squamous Glandular Epithelium - glands Cuboidal Columnar PAGE 2 OF 16 IM  MICRO LEC – EPITHELIAL TISSUE SIMPLE EPITHELIUM ENDOTHELIUM OF BLOOD VESSELS Lined by single layer of cells ○ According to cell Shape SIMPLE CUBOIDAL Simple Squamous Simple Cuboidal Simple Columnar SIMPLE SQUAMOUS Well - adapted for exchange and filtration purposes They provide little protection against mechanical abrasion PARIETAL LAYER OF BOWMAN’S CAPSULE Simple cuboidal - single layer of cuboidal cells - tubules of kidneys Simple squamous - single layer of flat cells ENDOTHELIUM of blood vessels MESOTHELIUM of body cavities Parietal layer of Bowman’s capsule Alveoli Corneal endothelium PAGE 3 OF 16 IM  MICRO LEC – EPITHELIAL TISSUE Lines small ducts and tubules that may have Absorptive surfaces such as in the small intestine excretory, secretory, or absorptive functions Secretory surfaces such as that of the stomach SIMPLE COLUMNAR STRATIFIED EPITHELIUM Lined by several layers of cells Well adapted for protective / barrier purposes STRATIFIED SQUAMOUS Simple columnar - single layer of tall, columnar cells - lining epithelium of intestines PAGE 4 OF 16 IM  MICRO LEC – EPITHELIAL TISSUE Stratified squamous ○ Maturation from cuboidal basal layer to TRANSITIONAL EPITHELIUM flattened surface layer Cornified / Keratinized Epidermis Non-Cornified / Non-Keratinized ○ Lines wet cavities ○ Esophagus, vaginal, larynx, anal canal STRATIFIED CUBOIDAL Stratified cuboidal - excretory ducts of salivary and sweat glands STRATIFIED COLUMNAR Stratified columnar - conjunctiva lining the eyelids Modification of Stratified epithelium Contains cells that are flattened and cells that are cuboidal Uroepithelium Lining epithelium of excretory passages of urinary system PAGE 5 OF 16 IM  MICRO LEC – EPITHELIAL TISSUE PSEUDOSTRATIFIED EPITHELIUM SURFACES - APICAL AND BASAL Stratified Epithelium Transitional Epithelium or Urothelium Modification of simple epithelium All cells are in contact with the basal lamina but not all of them reach the apical surface Pseudostratified Epithelium Cell shapes are variable False stratification Cilia are never present on TRUE stratified epithelia COMMON TYPES OF COVERING EPITHELIA Tightly packed, microscopic projections of the apical surface of intestinal absorptive cells; give the apical portion of the cell a striated / brush border appearance; INCREASE the cell’s surface area. Cilia Actively MOTILE processes that propel substances along their surfaces Respiratory epithelium PAGE 6 OF 16 IM  MICRO LEC – EPITHELIAL TISSUE CILIA CELL MEMBRANE MODIFICATIONS GOBLET CELLS Stereocilia Long microvilli in the epididymis and vas deferens of the male reproductive trace NON-MOTILE STEREOCILIA Modified columnar epithelial cells Synthesize and secrete mucus Scattered amongst many simple epithelial linings Respiratory and GI tract PAGE 7 OF 16 IM  MICRO LEC – EPITHELIAL TISSUE Adhering Junction INTERCELLULAR JUNCTIONS Zonula Adherens Desmosomes ○ link adjacent cells Hemidesmosome ○ link epithelial cells to Basement membrane ADHERING JUNCTION INTERCELLULAR JUNCTIONS Tight Junction ○ Occluding Junction or Zonula Occludens Adhering Junctions ○ Adhesion belt (Zonula Adherens) ○ Desmosomes (Macula Adherens) ANCHORING JUNCTIONS ○ Hemidesmosomes Gap Junctions Tight Junction forms a collar around each cell immediately beneath the apical surface, blocking passage of luminal contents between cells and also lateral movement of plasma membrane proteins and lipids in the plane of the membrane between the apical and the basolateral plasma membrane TIGHT JUNCTION Gap Junctions Contains connexons important in the control of growth, development, cell recognition and differentiation. provide the means of electrical coupling of visceral and cardiac muscle cells, permitting synchronous contraction PAGE 8 OF 16 IM  MICRO LEC – EPITHELIAL TISSUE ○ Shape GAP JUNCTIONS Third Name ○ optional; if with special future ILEUM FUNDAMENTAL TYPE: ○ EPITHELIAL SUBTYPE: ○ SIMPLE SPECIFIC SUBTYPE: ○ SIMPLE COLUMNAR LINING EPITHELIUM ○ Simple columnar epithelium WITH GOBLET CELLS INTERCELLULAR JUNCTIONS Specific Type? ○ simple columnar ○ lining epithelium: ○ Simple Columnar w/ goblet cells MUST KNOW IN EPITHELIUM Classification - subtype ○ Simple ○ Stratified ○ Pseudostratified ○ Transitional Specific Subtype ○ Simple Simple squamous, Simple cuboidal, Simple columnar ○ Stratified Stratified squamous, Stratified columnar, Stratified cuboidal ○ Pseudostratified Pseudostratified squamous, Pseudostratified columnar ○ Transitional Transitional Naming of Epithelium First Name ○ Number of cell layer/s Second Name PAGE 9 OF 16 IM  MICRO LEC – EPITHELIAL TISSUE KIDNEY PCT vs DCT FUNDAMENTAL TYPE: PROXIMAL CONVOLUTED TUBULE (PCT) ○ EPITHELIAL SUBTYPE: FUNDAMENTAL TYPE: ○ SIMPLE ○ EPITHELIAL SPECIFIC SUBTYPE: SUBTYPE: ○ SIMPLE SQUAMOUS ○ SIMPLE LINING EPITHELIUM SPECIFIC SUBTYPE: ○ Simple squamous epithelium ○ SIMPLE CUBOIDAL LINING EPITHELIUM ○ Simple cuboidal epithelium WITH BRUSH BORDERS DISTAL CONVOLUTED TUBULE (PCT) FUNDAMENTAL TYPE: ○ EPITHELIAL SUBTYPE: ○ SIMPLE SPECIFIC SUBTYPE: ○ SIMPLE CUBOIDAL LINING EPITHELIUM ○ Simple cuboidal epithelium WITH FEW OR SCANTY BRUSH BORDERS PAGE 10 OF 16 IM  MICRO LEC – EPITHELIAL TISSUE THYROID FOLLICLE EPIDERMIS - SKIN FUNDAMENTAL TYPE: FUNDAMENTAL TYPE: ○ EPITHELIAL ○ EPITHELIAL SUBTYPE: SUBTYPE: ○ SIMPLE ○ STRATIFIED SPECIFIC SUBTYPE: SPECIFIC SUBTYPE: ○ SIMPLE CUBOIDAL ○ STRATIFIED SQUAMOUS LINING EPITHELIUM LINING EPITHELIUM ○ Simple cuboidal epithelium ○ Stratified squamous keratinized (dry) epithelium URINARY BLADDER FUNDAMENTAL TYPE: ○ EPITHELIAL SUBTYPE: ○ TRANSITIONAL or UROEPITHELIUM PAGE 11 OF 16 IM  MICRO LEC – EPITHELIAL TISSUE Metaplasia TRACHEA FUNDAMENTAL TYPE: Transformation of one tissue to another type ○ EPITHELIAL A stratified squamous epithelium may replace other SUBTYPE: epithelial types in areas of chronic irritation ○ PSEUDOSTRATIFIED SPECIFIC SUBTYPE: Malignant and Benign Growths ○ PSEUDOSTRATIFIED COLUMNAR LINING EPITHELIUM Carcinoma - a malignant neoplasm, an abnormal or ○ Pseudostratified Columnar Ciliated Epithelium with Goblet Cells uncontrolled growth made up of epithelial cells; ARISE FROM SURFACE EPITHELIA Stratified squamous is most likely to undergo malignant change producing SQUAMOUS CELL CARCINOMA Glandular Epithelium Derived from epithelium EXOCRINE ○ connection with the surface epithelium ENDOCRINE GLANDULAR EPITHELIUM A 40 y/o man has a history of smoking. He complains of mucus accumulation and constant cough. A biopsy reveals that the epithelial lining of the tracheal lumen is stratified squamous epithelium. Which of the following terms describes the process of change to another epithelial type? a. Hypoplasia b. Neoplasia c. Metaplasia d. Hyperplasia PAGE 12 OF 16 IM  MICRO LEC – EPITHELIAL TISSUE I. Classification EXOCRINE AND ENDOCRINE GLAND According to: ○ Number of cells ○ Manner of secretions ○ Fate of secretions ○ Type of secretions ○ Morphology According to the Number of Cells UNICELLULAR CELL (GOBLET CELL) Unicellular gland - single secreting cell Goblet Cell Apocrine gland ○ partial destruction ○ Mammary glands Holocrine gland MULTICELLULAR CELL ○ total destruction ○ Sebaceous glands Merocrine gland ○ no destruction ○ Pancreas ○ Sweat glands ○ Salivary glands Serous gland Mucous gland Mixed gland Cytogenic gland Multicellular gland - duct, secretory unit ○ ovary, testes According to the Manner of Secretion Exocrine gland - with ducts ○ Brunner's gland ○ Salivary gland ○ Uterine gland Endocrine gland - ductless ○ Hormones ○ Islets of Langerhans PAGE 13 OF 16 IM  MICRO LEC – EPITHELIAL TISSUE TYPE OF SECRETION TYPE OF SECRETION (EXOCRINE GLANDS WITH MEROCRINE SECRETION Serous Mucous Mixed PAGE 14 OF 16 IM  MICRO LEC – EPITHELIAL TISSUE According to Morphology Simple ○ Simple tubular The glands of the body may also undergo neoplastic Simple epithelium-lined tubules that changes open to the surface ADENOMA Entire tubule runs in a straight course ○ a benign epithelial growth with Example: intestinal glands glandular morphology ○ Simple coiled tubular Deeper portion of the tubule is coiled ADENOCARCINOMA or convoluted ○ malignant growth Example: sweat gland ○ ARISE FROM GLANDS ○ Simple branched tubular Deeper portion of the tubules divides into branches that are lined with secreting cells Open into a superficial portion which serves as a duct Example: uterine gland ○ Simple acinar (simple alveolar) Does not occur in man Simplest form of alveolar gland containing a single sac with a dilated lumen and connected with the surface by a constricted portion ○ Simple branched alveolar (simple branched acinar) Simple alveolar gland, made up of numerous sac-like structures or out pocketings Example: large sebaceous gland of eyelids Compound ○ Compound tubular The terminal portions of the smallest tubules are more or less coiled tubules, usually branching Examples: pure mucous gland or oral activity, cardiac glands of stomach, some Brunner’s glands, Bulbourethral glands, renal tubules ○ Compound alveolar Composed of sac-like structures that branch and divide into numerous dilated segments Example: some portions of mammary glands ○ Compound tubulo-acinar Consists of tubular structures that divide into branches with sac-like dilatations or outpocketings Examples: large salivary gland, pancreas, esophageal glands, glands of the respiratory passages, mammary glands PAGE 15 OF 16 IM MICRO LEC – EPITHELIAL TISSUE PAGE 16 OF 16 IM