Epithelial Tissue Flashcards
Six Basic Characteristics of Epithelium (CAPAIR)
Cellularity
Attachment
Polarity
Avascular
Innervation
Regeneration
Epithelial Polarity
Differences between Basal, Apical, and Lateral Domains?
Basal: rests on basal lamina, anchors cell to underlying CT
Apical: directed toward exterior surface/lumen of enclosed cavity/tube
Lateral: communicates with adjacent cells (cell junctions)
What are the chracteristics of Apical Specializations?
What are the four types?
Increase SA of tissue for absorption
Move substances along epithelia
May be external or lumenal
Cilia, Flagella, Microvilli, Stereocilia
What are Microvilli and their specialized function?
Cytoplasmic processes containing actin core
Absorption and increase SA
What are Stereocilia/Stereovilli?
Function?
Location?
Microvilli of unusual length (actin core provides rigidity)
Increase SA for absorption/secretion
Restricted to epididymis and sensory cells of inner ear (Hair Cells)
What are Cilia?
What are Motile Cilia?
Primary Cilia?
Nodal Cilia?
Hair-like extension containing an axoneme, microtubule based structure
Propel substances across tissue
Immotile; chemosensors, osmosensors, mechanosensors
Embryonic; role in L/R axis determination
What are Flagella?
Function and Location?
Modified, motile cilia
Forward movement for sperm
Simple Squamous Cells
Location?
Function?
Lining blood and lymph vessels (endothelium)
Lining serous membranes (mesothelium)
Lining alveoli, loop of Henle
Exchange, Barrier, Lubrication
Simple Cuboidal
What are the location and function?
Kidney tubules, terminal bronchioloes, covering ovary
Absorption, Barrier, Secretion
Simple Columnar Cells
Location and Function
Auditory tubes, Uterus, Oviducts, Stomach, SI/LI, Gallbladder
Absorption, Secretion
Ciliated Simple Columnar Epithelium is found in Oviduct
Pseudostratified Columnar Ciliated
Location and Function?
Nasal Cavity, Pharynx, Trachea, Bronchi
Absorption/Secretion, Debris & Particle movement
Urothelium (Transitional)
Location and Function
Urinary Bladder, Ureters, Urethra
Barrier, Distensible Property
Nonkeratinized Stratified Squamous
Location and Function
Unique to Apical Layer
Oral Cavity, Pharynx, Esophagus, Anus, Vagina, Urethra, Cornea
Barrier and Protection
Apical Layers retain Nuclei
Keratinized Stratified Squamous Cells
Epidermis of Skin (Apical Layer cells do not retain nuclei)
Barrier, Protection
Stratified Cuboidal
Location and Function
Sweat glands/ducts, Ovarian Follicles, Salivary Gland Ducts
Barrier & Passageway
Mucous Membrane
Epithelia Tissue secreting mucus
Lines body cavities and tubular organs (Gut & Respiratory)
Serous Membrane
Epithelia tissue lining specific internal cavities
Forms smooth, transparent, two-layered membrane
Mesothelium: simple squamous epithlium comprises part of serous membrane
Merocrine Gland
Secretion delivered in membrane-bound vesicles to apical surface and undergo exocytosis
Holocrine Gland
Secretion accumulates within cell –> apoptosis
Secretion and cell debris are released
Apocrine Gland
Release of apical portion of cell, surrounded by cytoplasm within plasma membrane
Unicellular Glands
Simplest in structure
Single, secretory cells distributed among non-secretory cells
Goblet Cell: Mucus-secreting cell found lining intestines and respiratory tract
Multicellular Glands
Composed of more than one cell
Classified by arrangement & shape of secretory cells and ductal elements
Various combinations of duct and secretory portion are found in body
Secretory Cells are what two?
Mucous (Lipid Based - Stain White/Clear)
Serous (Water Based - Stain Darker)
Simple Tubular
Simple Coiled Tubular
Simple Branched Tubular
Simple Acinar
Simple Branched Acinar
Compound Tubular
Compound Acinar
Compound Tubuloacinar
Secretory cells form straight tube
Coiled tubular secretory portion deep in tissue
Branched tubular gland with wide secretory portion
Single layer of secretory cells
Secretory portion opens directly into the lumen
Coiled secretory portion located deep in tissue
Alveolar shaped secretory units, pyramid shaped secretory cell
Tubular and acinar secretory units; will have demilunes
Occluding Junctions (Zona Occludens)
Impermeable, allows cells to function as barrier
Encircle cells near their most apical surface
Increased Junctions –> Decrease Permeability
Occludins and Claudins
Anchoring Junctions
Lateral adhesions linking cytoskeleton to adjacent cells
Zonula Adherens: interacts with network of actin filaments inside cell
Macula Adherens (Desmosomes): interacts with intermediate filaments
Cadherins
Gap Junctions
Fluid Filled channels connect apposed cells
Mediate communication
Connexins
Focal Adhesions
Anchor actin filaments to basement membrane
Integrins
Hemidesmosomes
Anchor Intermediate filaments to basement membrane
Integrins
