Connective Tissue Flashcards
How is connective tissue classified ?
based on the types of cells and the mature of the ECM
Where is connective tissue found ?
usually found under the epithelial tissues as a supporting tissue
What are the primary functions of connective tissue ?
has a space filling role and a supportive role in bone, cartilage, and dense connective tissue
What are the two parts of the ECM
fibers and ground substances
What are the fibers in the ECM
collagen, reticular or elastic
What can the ground substance be made of in the ECM ?
glycoproteins (fibronectin, laminin), glycosaminoglcyans (chondroitin sulfate, keratane sulfate, dermatan sulfate, heparan sulfate, and hyaluronic acid) and proteoglycans
What type of stain stains collagen fibers pink-red
eosin
What are collagen fibrils made of ?
tropocollagen aranged with a gap between then and a lag between the rows which forms a periodic banding of the fibril
What is tropocollagen composed of
3 glycoprotein alpha chains in a left handed triple helix
What are the 4 types of collagens ?
type 1-bone, skin, tendon, ligaments
type 2- hyaline cartilage
type 3- reticular fibers
type 4- basement membrane
Reticular fibers
type III collagen fibrils, form a mesh like network, supporting structures for adipocytes, muscle cells, small blood vessels hemopoietic and lymphatic tissues
What does the staining of reticular fibers look like ?
eosin (red)
PAS (red)
silver salts (black) argyrophylic fibers
Elastic fibers
form a branching network
found in elastic cartilage, elastic arteries and elastic ligaments
produced by fibroblasts and smooth muscle cells
What are the two components of elastic fibers
elastin central core and fibrilin microfibrils around the core embedded into the elast
Lesion of the fibrillin gene results in what
marfans syndrome
staining of elastic fiers
eosin red
orcein brown
resourcin fuchsin-bluish grey
What forms reticular fibers
fibroblasts smooth muscle cells and scwann cells
what forms type 1 collagen
fibroblasts and osteoblasts
What are the symptoms of Mafans syndrome
chest deformity
long arms
arachnodactyly
aorta can rupture
What are the characteristics of Ehler-Danlos syndrome
mutations affecting collagen polypeptide chains, hyperflexibility of the joints, hyperextensibility of the skin, vascular and organ rupture in the most serious cases
osteogenesis imperfecta
genetic mutations of the genes that assemble type I collagen, fragile bones, severalforms according to the damaged genes. most severe form is type II which involves abnomrally small and fragile rib cage
What are the three morphologic classifications of connective tissue
embryonic connective tissue, connective tissue proper and specialized connective tissue
What are the two kinds of embryonic connective tissue
mesenchyme and mucous connective tissue
Specialized connective tissue is representative by
adipose tissue, blood, bone, cartilage, hemopoietic tissue and lymphatic tissue
connective tissue proper has two subtypes what are they ?
dense connective tisse and loose connective tissue
characteristics of embryonic connective tissue
few star or spindle shaped cells forming a network
gap junctions bind them together
extracellular space is filled with HUGE amts of viscious ground stubstance
mesenchyme embryonic connective tissue
primitive pluripotent connective tissue capable of turning into other tissue types
cellls: pluripotential mesemchymal cells
mucous connective tissue of embryonic ct
found in the umbilical cord
cells: fibroblasts and few mesenchymal cells
more space
Wharton’s Jelly
What are the general characteristics of dense connective tissue
few fibroblasts
little ground substance
large amount of collagen fiberss between them
What are the characteristics of dense REGULAR connective tissue ?
fibers are arranged in parallel array
present in tendons, aponeuroses, and ligaments
some ligaments contain large amount of elastic fibers instead of collagen: “elastic connective tissue”
What are the characteristics of dense IRREGULAR connective tissue
fibers arranged in bundles in every direction
present in submucosea of hollow organs
cells are fibroblasts
Characteristics of fibroblasts
star shaped cells with elogated disk like nucleus
synthesize fibers and ground substance
developed RER (basophilic cytoplasm
Characteristics of myofibroblasts
contain contractile elements
lack basal lamina
located in the loose connective tissue
involved in regulating the shape and emptying of the glands and wound contraction and closure
Characteristics of loose connective tisue
loosely arranged fibers
found beneth epithelial in the lamina propria mucosase
contains blood cells
can undergo significant swelling
What are the transient cell population in loose connective tissues
lymphocytes, plasma cells, neutrophils, eosinophils and basophils
white adipocytes
single fat drop filling the cytoplasm, ring shaped cytoplasm and flat peripheral nucleus
brown adipocytes
several fat droplets in cytoplasm, brown pigment characteristic for newborns (rapid energy release)
Macrophages
irregular shape, rounded nucleus, ingested material in cytoplasm, large golgi and RER, may for langhan cells by fusion
mast cells
large rounded with sperical nucleus basophil granules located next to small vessels resemble basophils tuloidin blue stains the granules metachromatically responsible for anaphylatic reactions
what is the function of heparan sulfate and heparain
blocks coagulation, responsible for basophila
what is action o histamine, SRS-A
vasodilation and edema
What are the function of eosinophil chemotactic factor and neutrophil chemotactic factor
cell attraction
mesenchymal cells
star or spindle shaped cells
pluripotent
located around vessels
lymphocytes
inteinsely staining, indented spherical nucleus, cytoplasm is thin and has a pale basophilic ring (T B and NK cells)
Where are NK cells found
bone marrow
Plasma cells
derived from B cells, antibody producing, heterachromatin in nucleus has the pattern of cartwheel or clock face
neutrophils
capable of migration, granules, nucleus is multilobed
eosinophils
named after the large eosinophilic granules in cytoplasm, typically bilobed
basophils
large basophilic granules in the cytoplasm, nucleus obscurred by the granules, closely related to mast cells of the connective tissue
