Connective Tissue Flashcards
connective tissue provides
structural and metabolic support for other tissues and organs
connective tissue carries
blood vessels
connective tissue functions in — repair
tissue
connective tissue mediates exchange of nutrients/metabolites/waste products between
tissue and circulation
primitive connective tissue derived from mesodermal mesenchyme contains (3)
stellate to spindle shaped cells, jelly like extracellular matrix and occasional fibers
mature connective tissue contains (20
cells
extracellular material
fibroblasts
pointed, elongate, spindle shaped cells
most abundant type of connective tissue cell
fibroblasts
fibroblasts are responsible for synthesizing and maintaining (2)
proteinaceous ground substance and connective tissue fibers (collagen, elastin, and reticular fibers)
myofibroblasts
fibroblasts with contractile ability
reticular cells
of lymph nodes and bone marrow
a type of fibroblast
reticular cells are morphologically similar to
primitive mesenchymal cells, look like branches fibroblasts
reticular cells synthesize
reticular fibers (made of reticulin)
reticular cells may also have —- function
phagocytic
reticular fibers are also synthesized by regular — in some tissues (in small numbers)
fibroblasts
adipocytes are responsible for
storage and metabolism of lipids
adipocytes are generally large, ballon shaped, clear spaces filled with —
lipid
ground substance
extracellular organic matrix
what fibers are embedded within the matrix? (3)
collagen
reticulin
elastin
how many types of collagen types are there? what are they based off of?
28
amino acid sequence
most collagen have a distinct 67-68 nm — pattern
banding
collagen is the principle fiber in the extracellular matrix, which provides
tensile strength
most abundant type of collagen
type 1
90% of collagen in the body
type 1 collagen
loose and dense connective tissue of skin, tendons, ligaments, bone and fibrocartilage
types of type 2 cartilage (2)
hyaline
elastic
what types of fibers are type 3 collagen?
reticulin fibers
reticulin fibers
thin, branching, net-like fibers
reticulin fibers are used for structural support in
organs
spleen, lymph nodes, bone
reticulin fibers are produced by (2)
reticular cells in the lymph nodes and bone marrow and fibroblasts everywhere else
reticulin fibers stain
argyrophilic
stains black with silver stain
basement membrane is composed of type - collagen
4
type 4 collagen doesn’t form
fibers, it forms a meshwork
type 5 collagen is fond in (3)
cornea
placenta
demo-epidermal junctions
what is the best known collagenopathy?
ehlers-danlos syndrome
ehlers-danlos syndrome effects type - collagen
5
ehlers-danlos syndrome is characterized by (3)
hyperextension of joints
skin fragility
poor wound healing
collagen is a
glycoprotein
collagen precursor proteins are produced by
fibroblasts
collagen is initially synthesized as
pro collagen, compose of three alpha polypeptide chains to form a triple helix
collagen synthesis
procollagen is then packed into secretory vesicles and secreted into the ECS
followed by extracellular enzymatic modification to form tropocollagen monomers
polymerization of tropocollagen into larger bundles results in final formation of collagen microfibrils
several microfibrils combine to form larger collagen fiber, several fibers make up a collagen bundle
pro collagen, tropocollagen, collagen, collagen microfibrils, collagen fiber, collagen bundle
elastin fibers are highly branched, their random coiling patterns allow for
stretching
elastic fibers are arranged in
fibers and sheets
elastic fibers are synthesized by fibroblasts as — precursor
tropoelastin
tropoelastin polymerizes to form
elastin
2 components of elastic fibers
elastin
fibrilin
elastin
protein core similar to collagen, surrounded by microfibrils of fibrilin
fibrilin
structural glycoprotein
how are elastin fibers stains?
T-blue
collagen: light gray/blue
elastin fibers: darker blue
marfans syndrome
autosomal dominant condition results in abnormal elastic fibers
marfans syndrome is characterized by
tall stature, long limbs, thin fingers
with marinas syndrome, you have an enlarged aorta with increased (2)
regurgitation
risk of developing a dissecting aneurysm
structural glycoproteins (2)
fibrillin
fibroxnectin
structural glycoproteins
large polypeptides with branched polysaccharide side chains
fibroxnectin is found within the
basement membrane
fibroxnectin aids in adhesion between cell membrane and ECM via adhesion molecules known as
integrins
non-filamentous glycoproteins (3)
laminin
entactin
tenascin
laminin, enacting, and tenascin are associated with
basement membrane and cell adhesion
ground substance
amorphous, transparent material with properties of semi-fluid gel
ground substance are long, unbranched polysaccharide chains of repeating
disaccharide units
disaccharide units of ground substance: one of the subunits is always
an amino sugar (either n-acetyl glucosamine or galactosamine)
glycosaminoglycan (GAG)=
mucopolysaccharide (MPS)
lysosomal storage diseases
non-functional or insufficient lysosomal enzymes
aka. mucopolysaccharidoses
most GAGs are
sulfonate
ex. chondroitin sulfate, herapan sulfate
most GAGs are covalent bound to protein molecules to form
proteoglycans (mucoproteins)
most common types of GAGs found in ECM (5)
hyaluronic acid chondroitin sulfate keratan sulfate dermatan suflate heparin sulfate
hyaluronic acid is found in most
connective tissue
chondroitin sulfate is found in (2)
cartilage and bone
keratan sulfate is found in (4)
cartilage
bone
cornea
intervertebral disk
dermatan suflate is found in (3)
dermis of the skin
blood vessels
heart valves
heparin sulfate is found in (3)
basement membrane
lung
liver
GAGs don’t compact well because they are
large, take up space
GAGs are – charged
negatively
due to sulfate and carboxyl side groups
because GAGs are negatively charged, they are
hydrophilic, attract water, form a gel like substance
ground substance is mostly made of (3)
GAGs (1’ hyaluronic acid)
proteoglycans
water
incompressibility of water provides — pressure of connective tissue
turgor
GAGs are reinforced with
fibrous protein
predominant GAG is loose connective tissue
hyaluronic acid (hyaluronate)
hyaluronic acid lacks
sulfated side groups
hyaluronic acid are several — sugars long
thousand, very long
hyaluronic acid does not form — themself, but it can bind with them
proteoglycans
ground substance is an impervious barrier to
microorganisms (hard to swim through and penetrate)
pathogenic bacteria produce — to destroy this barrier and facilitate their spread
hyaluroniase
loose (areolar) connective tissue
sparse fibers and abundant ground substance
viscous, gel-like consistency
loose connective tissue has a — function
supportive
loose connective tissue is located (2)
beneath epithelial and around neurons and blood vessels
dense connective tissue provides
structural support
abundant fibers, moderate number of cells, lesser ground substance
two types of dense connective tissue
regular
irregular
regular dense connective tissue
collagen fibers oriented parallel to each other
densely packed fibers and cells arranged in fascicles
(ex. ligaments, tendons, and aponeuroses)
irregular dense connective tissue
collagen fibers oriented randomly
moderate number of fibers and few cells
specialized connective tissue includes (7)
bone blood cartilage adipose tissue hematopoietic tissue lymphatic tissue mesenchymal CT (limited to embryo) mucus CT (limited to embryo)
adipose tissue contains adipocytes derived from
lipoblasts
primitive mesenchyme is adapted for storing
fat (1’ triglycerides)
why is fat energetically very active?
it has a rich blood supply
adipose tissue functions in (3)
energy storage
thermoregulation
shock absorber
white fat (unilocular) is distributed in
dermis and around intraperitoneal organs
percentages of white fat in men vs women
20% M
25% F
brown fat (multilocular) is highly
specialized
brown fat is present in (2)
infants
hibernating animals
brown fat is used in — to maintain body temperature
thermoregulation
brown fat is located in — in humans
adrenals
brown fat contains large numbers of — for heat
mitochondria