Chapter 2 Flashcards
Different types of cells come together to form?
Tissues
What are the 4 major tissue types?
- Epitheleal
- Connective
- Muscle
- Nervous
What is histology?
The study of tissues
What tissue forms sheets of compact cells in single or multiple
layers
• Location:
• Outer layer of skin and mucous membranes
• Lining body cavities and hollow organs
• Lines blood vessels, ducts, organ systems (e.g. cardiac, digestive, respiratory,
urinary, reproductive systems)
• Forms glands
• Secretory portion of glands as well as ducts
Epithelial Tissues
Closely packed cells with little extracellular matrix • Arranged in sheets of single or multiple layers • Polarity • Specialized contacts/junctions • Supported by connective tissue • Avascular but innervated • Regeneration
Epithelial Tissues
Cells have 2 sides
• Apical surface – free side
• Some apical surfaces contain microvilli or cilia
• Basal surface – bottom side
• Lateral surface – attaches sides of cells to
adjacent cells
• Contains junction
Polarity of Epitheleal tissues
Supported by Connective Tissue
All epithelial sheets are attached to
underlying connective tissue via the
basement membrane
• Attached via hemidesmosomes
• Basement membrane has 2 parts:
• The basal lamina– thin layer of collagen fibers,
laminin, glycoproteins and proteoglycans
• Lies closer to and is secreted by epithelial tissue
• The reticular lamina – thin layer of collagen
fibers
• Lies closer to and is secreted by the connective tissue
Specialized Contact
Epithelial cells fit close together to form continuous sheets (with the exception of glandular tissue) • Form several types of junctions to hold the cells together • A. Tight junctions • B. Adherens junctions • C. Desmosomes • D. Hemidesmosomes • E. Gap junctions
Types of Epitheleal Juctions: Strands of transmembrane proteins that bind cells together to prevent passage of molecules between cells • Transmembrane protein - occludin • Found in stomach and bladder – prevent leakage
Tight Junctions
Types of Epithelial junctions:
• Tunnels that connect adjacent cells
• Composed of connexons
• intercellular channels
• Allows ions, small particles, metabolites to
pass from cell to cell
• Allows for communication and fast spreading
of nerve and muscle impulses for fast travel
between cells
• Nerves, cardiac muscle, uterine smooth
muscle
Gap Junctions
Dense layer of proteins on inside
of plasma membrane that attaches to both
membrane proteins and cytoskeleton
(actin)
Plaques
Transmembrane glycoproteins
that insert into plaque in cell membrane
and extend into cadherin from an adjacent
cell.
Cadherins
Types of epithelial Junctions: • Bind cells by using plaques and cadherins to form adhesive belts that completely encircle a cell • Plaques are attached to microfilaments (actin) • Aid in resisting separation during contractile activities • Intestines
Adherens Junctions
Types of Epithelial Junctions:
Similar to adherens, plaque attached to cadherin
• Plaques bind to intermediate
cytoskeletal filaments (keratin)
• Form spots, not bands
• Contributes to stability of cell and resists
tension
• Really strong (especially with movement
and mechanical stress)
• Epidermis, Cardiac muscle
Desmosome Junction
Types of epithelial junctions: • Uses integrins instead of cadherins • Integrins attach to laminin • Basement membrane • Do not attach cell to cell • Used to anchor the epithelium to the underlying connective tissue
Hemidesomosomes
Are epithelial cells avascular? Yes or No
Yes
Are epithelial tissues innervated? yes or no
Yes
Can epithelial cells regenerate? Yes or No
Yes
What transmembrane protein does
a desmosome have?
Cadherins
Which of the following is true?
a. The apical end of epithelial tissue is attached to the basement
membrane
b. Epithelial tissue is innervated
c. Epithelial tissue is vascularized
d. Epithelial tissue is always arranged in singular sheets
e. Epithelial tissue does not regenerate
b. Epithelial tissue is innervated
Where are epithelial simple squamous cells found?
Found as endothelium (lining blood vessels, lymphatic vessels, alveoli) and mesothelium (lining body cavites)
Where are epithelial simple cuboidal cells found?
Found lining ducts of glands, kidney
tubules
Where are epithelial simple columnar cells found?
Found lining uterine tubes, ventricles
of brain
Where are epithelial stratified squamous cells found?
Found in superficial layer of skin, inside
mouth, esophagus, vagina, anus
Where are epithelial stratified cuboidal cells found?
Very rare but found in ducts of sweat
glands
Where are epithelial stratified columnar cells found?
Very rare, lines large ducts of some glands and part of urethra
Where are epithelial transitional cells found?
Lines the urinary tract; bladder, ureters and urethra
Where are epithelial pseudostratified cells found?
Ciliated is found lining upper respiratory tract
A single layer of cube shaped cells would be called: a. Simple squamous b. Simple cuboidal c. Simple columnar d. Stratified squamous e. Stratified cuboidal
b. Simple cuboidal
Which of the following would most likely be found lining blood vessels? a. Stratified squamous epithelium b. Simple squamous epithelium c. Stratified cuboidal epithelium d. Simple cuboidal epithelium e. Pseudostratified epithelium
b. Simple squamous epithelium
Glandular Epithelium: What is a gland?
one or more cells that make and secrete/export a product (secretion)
What gland releases into the blood?
Endocrine