Lecture 12: Epithelial Tissue Flashcards
Regular Cell
- What are the properties of the apical surface?
- What are the properties of the basal surface?
- What are the properties of the lateral surface?
1. What are the properties of the apical surface?
Faces exterior surface/lumen and participates in molecular filtering
2. What are the properties of the basal surface?
Rests on basement membrane and anchors cell to underlying connetctive tissue
3. What are the properties of the lateral surface?
Communicates and attaches to adjacent cells while maintaining integrity
Tight/Occluding Junctions
- What are their properties?
- Where do you normally find them?
1. What are their properties?
They are impermeable and acts as a barrier
2. Where do you normally find them?
Normally at apical surface
Gap/Communication Junctions
- What are their properties?
- Where do you normally find them?
- What are their properties?*
- Mediate communication with adjacent cells
- Uses Connexin to create a pore for fluid and ions to pass through
- Where do you normally find them?*
Lateral Side of Cells
Anchoring Junctions
- What is the function?
- What types of anchoring junctions are there?
1. What is the function?
Link a cell to the cytoskeleton of adjacent cells
2. What types of anchoring junctions are there?
Adherins: Cadherins that interact with actin filaments on the apical surface
Desmosomes: Cadherins that interact with intermediate filaments on the lateral surface
Hemidesomosomes: Basal adhesions that interact with integrins and intermediate filaments that anchor to basal lamina
What is the basement membrane?
Extracellular material where basal surface of cell rests on
-Permits diffusion of nutrients
What are the three types of Apical Specializations?
- Microvilli
- Stereocilia
- Cilia
Microvilli
What is their function?
What makes up the core of each Microvillus?
Function: Specialized for Absorption
Composition: Actin core
Stereocilia
- What is its function?
- What is its composition?
- Where is it found?
Function: Absorption and Secretion
Composition: Acting core and longer than usual microvilli (has less movement)
Location: Epididymis and the Sensory Cells of the Inner Ear
Cilia
- What is its function?
- What is its composition?
- Where is it found?
Function: Propel substances across tissue (to remove debris) and plays role in embryonic L/R axis determination
Composition: Internal arrays of microtubules (axoneme)
Location: Respiratory Tract
What are the three types of Cilia and their functions?
Motile: Beat in a wave like fashion to move substances
Primary: Immobile, but function as chemo-/osmo-/mechano- sensors
Nodal: Embryonic, help determine left/right axis
Where might you find Simple Squamous Epithelium?
Lining the Blood and Lymph Vessels (Endothelium)
Lining of Serous Membranes (Mesothelium)
-reduce friction
Lining Alveoli, Loop of Henle, Ducts
Where might you find Simple Cuboidal Epithelium?
Kidney Tubules, Glands, and Associated Ducts.
Terminal Bronchioles
Covering of the Ovary
Where might you find Simple Columnar Epithelium?
Auditory Tubes
Uterus
Oviducts
Stomach
Small / Large Intestines
Gallbladder
Where might you find Pseudostratified Columnar Ciliated Epithelium?
Lining of the Nasal Cavity
Pharynx
Trachea
Bronchi
(Respiratory System except the Terminal Bronchioles)
Looks like many layers but it is just one
Where might you find Urothelium?
Urinary Bladder
Ureters
Urethra
Multiple layers but doesn’t follow 3 shape rule
What is the special function of the Urothelium?
It is distensible
Where might you find Nonkeratinized Stratified Squamous Epithelium?
Oral Cavity
Portions of the Pharynx
Esophagus
Anus
Vagina
Urethra
Cornea
Apical cells have nuclei!
What is special about the Apical Layer of Keratinized Stratified Squamous Epithelium?
The cells there do not have Nuclei
Where might you find Stratified Cuboidal Epithelium?
Sweat Glands and Ducts
Ovarian Follicles
Salivary Gland Ducts
Release Products and very similar looking to Stratified Columnar
What function does a Goblet Cell perform?
Secretes mucus into the GI tract.
Simple Columnar Cells
What kind of membranes are the Peritoneum, Pericardium, and Pleura?
Serous Membranes (Mesothelium)
What is the example given for a Unicellular Gland?
Goblet Cell
What is the method of secretion for a Merocrine Gland?
Secretory products are wrapped in membrane bound vesicles to the apical surface and released via exocytosis.
Example: Salivary Gland
What is the method of secretion for an Holocrine gland?
Secretory product builds up inside of a cell, causing apoptosis
Cell ruptures and releases product along with cell debris
Example: Sebaceous Gland
What is the method of secretion for an Apocrine gland?
Secretory product released with the apical portion of cell
- Secretory product is surrounded by cytoplasm within the plasma membrane
- Example: Mammary Glands*
What is the secretory portion of a multicellular gland called?
The Acinus
In Exocrine Glands
What sort of secretions are formed in the Parotid Gland?
Serous
What sort of secretions are formed in the Sublingual Gland?
Mucous
What kind of secretions are formed in the Submandibular Gland?
Both Serous and Mucous
