Flashcards in Ch. 4 - Epithelial Tissue Deck (73):
Four types of tissue
Connective tissue (CT) key characteristic
Muscle tissue key characteristic
Elongated cells specialized for contraction and movement
Nervous tissue key characteristic
Long, fine processes specialized to receive, generate, and transmit nerve impulses
Most organs can be divided into _______ and _______.
The cells responsible for the organs' specialized functions
The cells that have a supporting role in the organ
Always CT except in the brain and spinal cord
Epithelial tissue key characteristic
Cellular sheets that line the cavities of organs and cover the body surface
What are the three principal functions of epithelial tissue? Give an example of each.
1. Covering, lining, and protecting surfaces (epidermis)
2. Absorption (intestinal lining)
3. Secretion (parenchymal cells of glands)
Amorphous, nonvascular, nonliving material secreted by the cell made up of protein, collagen, lamanin, fibronectin, and others
Connects and anchors the cell to the CT below (lamina propria) and filters material
Light microscopy term
Is epithelium vascular or avascular?
How does epithelium obtain nutrients?
Absorption from the surrounding tissue via simple diffusion
Same as basement membrane, but a TEM term
Divided into basal lamina and reticular lamina
The CT beneath epithelial cells
Provides nutrients to the cells
Gives the cell a polarity
Cell polarity and two examples
Cells have different specializations and functions at different regions of the cell
I.e. apical specializations - microvilli
basal specializations - junctions
The basement membrane allows the cell to do what three things?
2. Provides movement
3. Signal transduction
Aka cell signaling
Transmission of molecular signals from a cell's exterior to its interior
What are the three types of cell junctions?
1. Adhesion junctions
2. Gap junctions
3. Tight junctions
Attaches cells to other cells and to membranes
Each cell manufactures connexins
Junctions that form a seal between two cells
I.e. zona occludens
Tight junction found at cell apex
Cells fuse at this point
Inhibits paracellular movement
Adhesion junctions found on the sides of cells
Involves interactions of integral proteins
Forms a band between the two cells
Aka desmosome or "spot" junctions
Interactions of proteins
Adhesion junctions that form spot junctions, as opposed to the band junction found in zona adherens
Movement of material through small spaces between cells
What happens when someone has Celiac's disease?
When people are hyper-allergic to gluten, their intestinal cells release zonulin, a protein that breaks down the tight junctions between the intestinal cells. Gluten passes through and causes a painful response.
Apical specialization of epithelium
Very small, nonmotile extensions of the surface membrane that increase the surface area of the cell
Important for absorption
Contain actin filaments
Dark band observed under the light microscope
Site of microvilli at the apex of the cell
Can't see individual microvilli
Structure on the apex of the cell that aid in movement of materials across the cell surface (usually of mucous)
Have 9+2 arrangement
Shorter and more numerous than flagella
Found mainly in respiratory cells
9 pairs of microtubules in a ring around a central pair
Found in cilia and flagella
Structure on the cell that aids in movement
Have 9+2 arrangement
Longer and less numerous that cilia
Only cells in humans with flagella are sperm cells
Motor protein that binds to ATP and causes movement via sliding filament
Found in the microtubules of cilia and flagella on side arms
What are the two main groups of epithelia?
1. Lining or Covering epithelia
2. Secretory epithelia and glands
Organized into one or more layers that cover the external surface or line the cavities of organs
Classified according to the number of cell layers and the cell morphology in the surface layer
One layer of cells
Two or more layers of cells
Stratified, squamous, or columnar (rare)
Name for the top layer of cells i.e. stratified squamous (skin)
Stratified squamous cells
Important for protection
I.e. skin cells are stratified squamous cells
The epidermis is made up of _______ cells.
keratinized stratified squamous
Protein that guards against loss of water (water proof)
Found in the epidermis, hair, nails
Non-keratinized stratified squamous epithelium
Protects against abrasion
Not water proof
Kept moist by mucous
I.e. vagina, esophagus
Aka uroepithelium or urothelium
Specialized epithelium that undergoes transition depending on what the organ is doing
I.e. bladder cells stretch when the bladder is full and contract ("dome shaped") when it is empty
Found in the bladder, ureters, and part of the urethra
Pseudostratified ciliated columnar epithelium
Cells unique to the respiratory tract
Nuclei are located at different planes because the cells are different heights
Looks like the cells are stratified but they are simple
All cells are anchored to the same basement membrane
Specialized cells or organs made up of epithelial cells that function mainly to produce and secrete various macromolecules
Membrane-bound vesicles that store products to be secreted by glands
Secretory cells that function as a gland
Usually simple cuboidal, simple columnar, and pseudostratified epithelia
I.e. goblet cells (exocrine), enterochromaffin cells (endocrine)
Cells that act as glands
Cells that acts as endocrine glands
Secrete the hormone serotonin
Multicellular glands can be either _______ or _______.
Clusters of cells that secrete hormones to the blood vessels
Release produce into a duct
Release from the apex of the cell
The apex ruptures and the cell dies via apoptosis
I.e. apocrine sweat glands (secrete into hair follicle)
Entire cell breaks and becomes secretory product
I.e. sebaceous glands (found in the skin)
The epidermis (keratinized stratified squamous epithelium) is a _______ population of cells.
Exocytosis of protein of glycoprotein from membrane-bound vesicles
Most common form
Only form where the cell doesn't die
The glands have ducts and are not branched
Glands with ducts with two or more branches
Can have branching ducts and can have multiple tubular, acinar, or tubuloacinar secretory portions
Glands can be classified as _______ glands or as _______ glands.
Secretory portions can be _______ or _______.
Tubular secretory portions cons be either _______ or _______.
short; long and coiled
Acinar secretory portions
Rounded and saclike
Can be single or branched
Where are simple tubular exocrine glands found?
Mucous glands of the colon
Intestinal glands or crypts
Specialized epithelial cells that can contract due to actin and myosin
Found on the outside of the cells of exocrine glands
When they contract, they squeeze the gland
I.e. mammary and salivary glands
Not facing the lumen
The central core of cilia and flagella
Has a 9+2 arrangement
Has side arms consisting of dynein that allow movement
Where can simple squamous epithelium be found?
Where can simple cuboidal epithelium be found?
Thyroid gland follicles
Where can simple columnar epithelium be found?
Where can pseudostratified ciliated columnar epithelium be found?
Where can transitional epithelium be found?
Most of the urethra
I.e. olfactory and gustatory cells
Merocrine secretion from genes to product
3. Rough endoplasmic reticulum (RER)
4. Golgi apparatus
5. Vesicles formed