unit 2 Flashcards
what are the four tissue types?
muscle, nerve, epithelium, connective tissue
what are the two types of connective tissue proper?
loose and dense
what are the three types of loose connective tissue?
areolar, adipose, reticular
what are the three types of dense connective tissue?
regular, irregular, elastic
what does connective tissue vary in?
structure, function, and content of cells and ECM
what are stromal cells?
class of connective tissue cells that build the infrastructure of any organ
what are the types of stromal cells?
resident and transient
what produces the contents of the extracellular matrix (ECM)?
stromal cells
what are the contents of the ECM?
protein fibers and ground substance
what kinds of protein fibers are found in ECM?
collagen, reticular, and elastic
what is ground substance?
amorphous mixture of proteins and carbohydrates with variable amounts of salts and H2O
holds everything
appears kind of transparent on slides
what are the types of resident cells?
fibroblast/fibrocyte
adipocyte
CT specific cells (chondrocyte, osteocyte, etc)
macrophage
mast cell
what are the types of transient cells?
plasma cell
lymphocyte
basophil
eosinophil
neutrophil
what cells have a hematopoietic origin?
macrophage, mast cell, transient cells
fibroblast
principle cell type of most CT
active, increased ECM protein synthesis
abundant, branched basophilic cytoplasm
what do fibroblasts look like?
large, prominent, oval, pale staining nucleus
fibrocyte
inactive, decreased ECM protein synthesis
what do fibrocytes look like?
smaller, darker, elongated nucleus
white adipose
contain a single lipid droplet per cell, function to insulate, protect, provide energy, hormone production
what does white adipose look like?
large polyhedral or spherical cells
flattened, peripheral nucleus
brown adipose
abundant in newborns, limited in adults
contain multiple lipid droplets per cell
generate heat
what does brown adipose look like?
smaller polygonal cells
what do macrophages do?
phagocytosis of bacteria/debris
what do mast cells do?
responses to allergens that bind IgE, secrete heparin, histamine, inflammatory mediators
what do plasma cells do?
produce antibodies
what do lymphocytes (B and T cells) do?
involved in innate and acquired immunity
what do basophil do?
secrete heparin, histamin, inflammatory mediators
what do eosinophil do?
anti-microbial
what do neutrophil do?
phagocytosis of bacteria/debris
collagen fibers
strong, flexible, high tensile strength
make up 25% of all protein in the human body
how many types of collagen fibers are there?
29, via configuration of 42 types of alpha chains
what are collagen fibers composed of?
subunits called collagen fibrils that are made up of collagen molecules
how are fibrillar collagen aligned?
monomers associate head to tail in overlapping, staggered rows
forms long fibrils
how are sheet collagen aligned?
monomers associate head to head and tail to tail
form a meshwork
how many types of collagen are there?
4
what are reticular fibers composed of?
type III collagen fibrils (3 alpha 1 chains)
reticular fibers
thinner than collagen
branched, forming a meshwork-like configuration
how are reticular fibers visible?
stain with PAS and silver salts
what are elastic fibers composed of?
an elastin core, elastin protein and fibrillar glycoprotein
elastic fibers
thinner and interwoven compared to collagen
branched and stretch to limit tearing
what kinds of carbohydrates are contained in ground substance?
glycosaminoglycans (GAGs), proteoglycans (PG), multi adhesive glycoproteins (MAPs)
glycosaminoglycans (GAGs)
most abundant heteropolysaccharide in ground substance
most negatively charged
most are post-translationally linked/bound to core proteins forming proteoglycans
proteoglycans
GAGs covalently bound to core proteins which facilitate ECM and cell-ECM organization
multi adhesive glycoproteins (MAPs)
small group of proteins facilitate ECM stabilization via binding sites for a variety of ECM proteins
loose CT
has fewer protein fibers and more ground substance
dense CT
has more protein fibers and less ground substance
(found in tendons and ligaments)
loose areolar CT
an abundance of ground substance, plus a few thin protein fibers
adipose loose CT
reticular loose CT
reticular fibers are the most predominant
regular dense CT
high density, parallel fibers
irregular dense CT
multidirectional fibers
elastin dense CT
significant embedded elastin
elastic fiber
collagen fiber
mast cell
large cells with dark staining cytoplasmic granules
lymphocyte
small cells with a high nucleus:cytoplasm ratio
macrophage
small and irregular nuclei
papillary layer left, reticular layer right
what is the origin of connective tissue?
mesenchyme
what are collagen molecules made of?
polypeptide triple helix alpha chains
collagen type I principle tissue distribution
loose and dense ordinary connective tissue
collagen fibers
collagen type I cells of origin
fibroblasts and reticular cells
smooth muscle cells
collagen type III principle tissue distribution
loose connective tissue
reticular fibers
papillary layer of dermis
collagen type III cells of origin
fibroblasts and reticular cells
collagen type IV principle tissue distribution
basement membranes
collagen type IV cells of origin
epithelial and endothelial cells
