CH.5 Epithelial Tissue Flashcards
3 main structure/functions of the epithelium
- Avascular
- Covers ext surfaces and internal cavities
- Creates barrier btwn ext envorment and undelying connecitve tissue
WHat are the 3 principle characteristics of epithelial cells?
- Close to each other, bind via cell juctions
- Exhibit functional and morpholoical polarity
- Basal structure attache to basment membrane
one-cell layer, thick rests in basement membrane. (can very in shape)
SImple
2 or more cell layers (shape of cell on surface determines its classification
Stratfied
width of the cell is greater than its height
Squamous
width, depth, and height are approximately the same
Cuboidal
– the height of the cell exceeds the width
Collumnar
appears stratified. Simple epithelium with all cells resting on basement and not all extend to free epithelia surface.
Psudostrasifed
stratified and lines lower part of urinary tracts.
Transitional urothelum
Endothelium lines? (2)
- Blood
- Lymphatic vessles
Mesothelium lines? (2)
- Abdomen
- Pleural Cavities
Specialized Epithelial Functions
5 specialized functions of epithelium
- Secretion (stomach
- Absorbtion (intestine & kidney)
- Transport (bronchial tree)
- Mechanical Protection (epidermis)
- Receptor Function (taste buds)
Directed toward the exterior surface or lumen
Apical Domain
Communicates with adjacent epithelia
Lateral Domain
Anchors cell to the basal lamina
Basal Domain
Apical Domain Modifications
Actin Filamint core
Microvilli
Apical Domain Modifications
Long microvilli
Sterocilia
Apical Domain Modifications
Microtubule Bundle
Cilia
Function of microvilli (apical)
- Increase SA for absorbtion
- Intesin & Kidney
- Long cytoplasmic processes containing core of actin
?
Stereocilia (apical)
Features of Stereocillia
- Long microvillia
- Absorbtion in male reproductive
- Sensory hair cell inner ear
Cillia are____ they generate motion via ____
Motile, activity of dynein
Cillia are what 3 sensors?
nodal important in embryonic dev
- Chemosensors
- Osmosensors
- Mechanosensors
in all euk. cells
Primary Ciliary Dyskinesia are?
Family of hereditary disorders
an absence of dynein arms in cilia
Kartageners syndrom
malformation of the radial spokes and dynein arms
Young’s Syndrome
What is the most prominant symptom of PCD?
Chronic respirator disorders like
* Bronchitis
* Sinusitis
deffective cillia
Specialized for Cell-to-Cell Adhesion
Unique proteins called cell adhesion molecules (CAMs)
Lateral Domain
3 types of juntions in the lateral domain?
- Occluding
- Anchoring
- Communicating
- Known as the Zonula Occludens
- Created by localized sealing of the plasma membrane between two adjacent cells
- Restricts passage of substances btwn cells.
Occluding Junctions
Tight Junctions
- interact with the actin filaments inside the cell
- Provides lateral adhesion between epithelial cells
- E-cadherin catenin complex.
Zona Adherens
Anchoring Junctions
interact with intermediate filaments
Macula adherens (desmosome)
Anchoring Junctions
anchor actin filaments into the basement membrane
Focal Adhesions
Anchoring junctions, cell to ECM
Anchor intermediate filaments into the basement membrane
Hemidesmosomes
Anchoring Cell to ECM
Permit direct passage of signaling molecules from one cell to another; transmembrane channels
Communicating/ gap junctions
Epithelia, smooth/cardiac muscle, and nerves
have what junctions?
Gap Junctions
Coordinated activity, 2 half channels
Gap junctions allow for exchange of
Ions, reg molecules, metabolites etc btwn cells.
Proteins called ____ make up gap junctions
Each channel consists of12 subunits
connexin
- basment membrane
- Cell to ECM junctions occur here
Basal Domain
The basment membrane is ____ positive in LM
PAS positive (purple
Specialized structure located next to the basal domain of epithelial cells and the underlying connective tissue
Basmement membrane
- Collagens
- Laminin
- Entactin/nidoge
- Proteoglycans
are all components of the?
Basment membrane
Important sites of signal detection and transduction
Mechanosensitivity
Focal Adhesions
- Provide increased adhesion to the basal lamina
- Cornea, skin, oral cavity mucosa, esophagus
Hemidesmosomes
Cells that transport fluid have ____ which increase SA for more transport protiens and channels to be present
Inflodings
Oriention of mitochondria can result in ____ appearance
Happens in salivary gland ducts
Straiated appearence
Secretion gland? (2)
- Endocrine
- Exocrine
Singnaling gland (2)
- Paracrine
- Autrocrine
mucous or serous (protein rich water)
Secrete products directly onto a surface or through ducts/tubes connected to a surface, concentrating, removing waste, adding substances.
Exocrine gland
no ducts
Hormones into blood stream to reach specific receptor on surface of distant cell
Endocrine land
Secretory product is delivered in membrane-bound vesicles which fuse with the plasma membrane to release their contents by exocytosis
Merocrine
Secretion
Secretory product is released in the apical portion of the cell surrounded by a thin layer of cytoplasm
Apocrine
Secretion
Secretory product accumulates within the maturing cell which simultaneously undergoes destruction
Holocrine
Secretion
- Very limited signaling range
- Reach target cells by diffusion
Paracrine
- Broad signaling range
- Travel through bloodstream to distant targets
Autocrine