Unit 1 Topic 2 Flashcards
Features of Epithelium
-closely packed cells with little to no ECM
-Attached to a basement membrane
-Exhibit polarity
Functions of Epithelium
-Cover surfaces and line hollow structures
-Secrete, absorb, and protect
-Forms glands and ducts
-Forms a selective barrier
Features of Connective
-Underlies epithelium
-3 components: fibers, cells, and extracellular matrix
-All derived from mesenchyme
-Most diverse group
Functions of Connective
-Provide Support
-Medium for exchange
-Storage of nutrients, vitamins, etc.
-Defense and protection
Features of Muscle Tissue
-Utilize actin and myosin to produce contraction
-Typically classified based on striations, number of nuclei, and shape
Functions of Muscle Tissue
-contract to produce tension
-extensibility and elasticity
Features of Nervous Tissue
-Neurons among neuroglia
Functions of Nervous Tissue
-Receives, transmits, and integrates information through producing and propagating action potentials
Description of Microvilli
“finger-like” cytoplasmic extensions
-actin core in center
Core of Microvilli
actin core anchors into terminal web
Function of Microvilli
-Increase in surface area to increase exchange
-Not associated with active movement
Location of Microvilli
-located on almost all small intestine cells
-More densly found in small intestine, uterine glands, placenta, and kidneys
Description of Stereocilia
Finger-like cytoplasmic extensions with connecting bridges
Core of Stereocilia
actin core anchors into the terminal web via different proteins than microvilli
Function of Stereocilia
-Reabsorption or transduction of mechanical stimuli to graded potentials
-Not associated with active movement
Location of Sterocilia
Limited to PSCE found in epididymis/ductus deferens and ear
Core of Cilia
Microtubules in 9 pairs (axoneme) with dynein arms (molecular motor proteins) connected by radial spikes
Description of Cilia
-Motile cytoplasmic extensions
-“9 sets of 2 +2”
Function of Cilia
-Propel particles over the apical surface
-Active movement
Location of Cilia
limited to columnar epithelium
Description of Zona Occludens (Occluding or Tight Junctions)
-Most at apical surface
-Associate with actin
-Homotypic (same particles are seen on each side)
-Claudin and occluding fusion protein connections
Function of Zona Occludens
-Localized sealing, regulates permeability
-restricts integral proteins to specific areas, involved in cell signaling
Zona Adherens (adhering junction or adhesion belt)
-Associates with terminal web of actin
-Proteins include cadherins, nectins, catenin, and viniculin
-Homotypic
Function of Zona Adherens
forms a belt to increase mechanical stability through anchorage/adhesion
Description of Macula Adheres (desmosomes)
-associates with intermediate filaments
-homotypic
-desmoglein and democolin
Function of Macula Adheres
anchorage/adhesion through localized spot weld
Description of Gap (communicating junctions or nexus)
-no association with cytoskeleton
-homotypic
-connexins
Function of Gap
permits intracellular passage of small molecules to allow coordination/cooperation
Type IV Collagen
self-assembling meshwork making a physical barrier and attachment site for other proteins
Laminins
cross-shaped multi-adhesive proteins that self-assemble into a network under the membrane
Integrins
transmembrane proteins that bind laminins and fibronectins to anchor cells to the basal lamina
Organization of Basal Lamina
type 7 collagen loops reach around the reticular fibers (composed of type III collagen) and into the type IV collagen meshwork
Fibroblast
predominant cell type; fusiform structure with multiple projections with ovoid nucleus; manufactures collagen, elastic, and reticular fibers as well as ECM materials
Adipocytes
storage and release of energy reserves; nuclei pushed to the periphery due to large lipid droplet
Mast Cells
cytoplasm filled with secretory granules of histamine, heparin, serine, proteases, and eosinophil/neutrophil chemotactic factors and produce leukotrienes; primary mediators of local inflammatory process, allergic reactions, and anaphylactic shock
Macrophages
differentiate from monocytes once in CT; destroy pathogens and present antigens to lymphocytes; large cells with vacuolated cytoplasm; also called tissue histiocytes
Plasma Cells
differentiate from B cells; produce antibodies from RER/Gogli; eccentric nucleus with potentially visible eragatoplasm
Eosinophils
migrate to the site of infection/allergic inflammation in response to factors released by mast cells/neutrophils; release histaminase to moderate effects of mast cells; crimson/red granules with a bilobed nucleus
Neutrophils
migrate to damaged and infected tissues; cells with multiple lobes and acidophilic granules
Lymphocytes
adaptive immune cells with only the nucleus available
Reticular Lamina
synthesized by the connective tissue cells; reticular fibers (type III collagen) and elastic fibers; anchors basal lamina to underly connective tissue
Exocrine Glands
-secrete at the apical surface and deliver to the surface of lumen via ducts
-Merocrine
-Apocrine
-Holocrine
Merocrine
-secretory vesicles empty on the surface of the cell; no loss of membrane or organelle structure
-salivary glands, exocrine and endocrine of pancreas, endocrine glands, sweat glands, and goblet cell
Apocrine
secretory product is accumulated in the apical portion of cell and part of the cell pinches off
-Mammary gland
Holocrine
cell accumulates secretory product then the entire cell is shed and disintegrates
-sebaceous glands
What are the 3 components of connective tissue?
Fibers, elastic, and reticular
Type I Collagen Fibers
-Forms: fibrils, large banded fiber
-Tissue/Distribution: bone, skin, tendons, ligaments, cornea, internal organs (~90% of body collagen)
-Synthesizing Cells: fibroblast, osteoblast
Type II Collagen Fibers
-Forms: fibril, small banded fiber
-Tissue/Distribution: interal organs
-Synthesizing Cells: fibroblast, reticular cell, smooth muscle cell, hepatocyte
Type IX Fibers
-Forms: fibril-associated
-Tissue/Distribution: cartilage (lateral association with type II)
-Synthesizing Cell: Chonroblasts
Type X Fibers
-Forms: network
-Tissue/Distribution: forming bone (hypertrophic zone of growth plate)
-Synthesizing Cell: Chondrocyte
Where is type I collagen located?
bone, skin, tendons, ligaments, cornea, interal organs
Where is type II collagen located?
cartilage (hyaline and elastic)
Where is type III collagen located?
internal organs (reticular fibers in lymph nodes, spleen, liver, blood vessels, skin)
Where is Type X collagen located?
cartilage (hyaline and elastic)
Fibroblast
predominant cell type; fusiform structure with multiple projections with ovoid nucleus; manufacture collagen, elastic, and reticular fibers as well as ECM materials
Adipocytes
storage and release of energy reserves; nuclei pushed to periphery due to large lipid droplet
Mast Cells
cytoplasm filled with secretory granules of histamine, heparin, serine, proteases, and eosinophil/neutrophil chemotactic factors and produce leukotrienes; primary mediators of loacal inflammatory process, allergic reactions, and anaphaylactic shock
Macrophages
differentiate from monocytes once in connective tissues; destroy pathogens and present antigens to lymphocytes; large cells with vacuolated cytoplasm; also called tissue histiocytes
Plasma cells
differentiate from B cells; produce antibodies from RER/Golgi; eccentric nucleus with potentially visible ergastoplasm
