Lecture 8-9: Connective Tissue Flashcards
major categories of CT
embryonic
adult
special
embryonic CT
wharton’s jelly
found in umbilical cord and pulp of developing teeth
mostly matrix
adult CT
reticular
elastic
dense
loose
reticular CT
reticular fibers
like dense irregular CT but with reticular fibers
lymphatic tissue
elastic CT
elastic fibers
like dense irregular but with elastic fibers
walls of blood vessels
elastic fibers produced by smooth muscle not fibroblasts
dense CT
can be regular or irregular
white fibrous CT
dense regular CT
thick orderly bundles of collagen separated by rows of cells
elongated nuclei
tendons and ligaments
white fibrous CT organization
highly order bundles of collagen
bur can be wavy too — just all wavy at same time
dense irregular CT
thick bundles of collagen with no specific orientation
fascia, submucosa of GI tract, dermis
loose CT
areolar CT loose and random design cells>fibers Type I collagen and elastic fibers found beneath epithelial tissues, tunica adventitia
special CT
adipose
cartilage
bone
hematopoietic
adipose CT
giant white empty cells
150 micrometers in diameter
2 types: white or brown
white fat
found everywhere
unilocular
nucleus off to side of cell
why do most adipocytes appear to have no nucleus?
the cells is so large that the nucleus is often missed when slicing a specimen
single chambered cell
unilocular
divided into many small chambers or vesicles
multilocular
what does uni/multilocular refer to?
in white fat - single lipid droplet
brown - multiple lipid droplets
brown fat
found in only 2 places
multilocular
more cytoplasm than white
where is brown fat found?
between shldr blades of babies
hibernating animals
what gives brown fat it’s color?
abundant in mitochondria
capable of giving off energy as heat to keep the organism warm
CT matrix composition
scattered cells
protein fibers
ground substance
most common cell in CT matrix
fibrocytes and blasts
most common protein fiber in CT matrix
collagen
most common ground substance
GAGs and glycoproteins
collagen type I
general CT and bone
tensile strength
collagen type II
hyaline and elastic cartilage
tensile strength
collagen type III
parenchyma of organs, blood vessel walls
reticular framework but not long fibers
collagen type IV
basement membrane
meshwork and scaffolding
type I collagen fiber synthesis
synthesized as pre-propeptide secreted from fibroblast now = propeptide peptidase cleaves now = tropopeptide monomer monomers assembled now = collagen fibers several fibers = collagen
characteristic banding pattern of collagen
64nm banded pattern
monomers are in parallel staggered arrays, gaps between monomers = banding
what occurs before a pre-propeptide is secreted?
after translocation to the ER, the signal sequence is cleaved because it is no longer needed
what is peptidase responsible for in collagen synthesis
procollagen (propeptide) has non-helical terminal ends that prevent polymerization and must be cleaved before monomers can be assembled into a polymer
elastic fiber synthesis
synthesized as pre-propeptide secreted ----> propeptide extracellular enzymes convert now = tropoelastin monomer monomers assemble with aid =elastic fiber
extracellular enzymes in elastic fiber synthesis
secreted by fibroblasts
enzymes convert propeptides into tropoelastin monomers
what aids tropoelastin monomer assembly?
several types of fibrillins aid monomer assembly into sheets/fibers
fibrillin 1
provides force-bearing structural support
e fiber synthesis
fibrillin 2
regulates assembly of elastic fiber
what is the difference between tropocollagen and tropoelastin monomer assembly?
tropocollagen is spontaneous assembly
tropoelastin requires fibrillin helpers
GAGs
glycos–amino–glycans
characteristics of GAGs
large
negative charged
linear polymers
amorphous substance of CT
4 categories of GAGs
hyaluronic acid
heparin
chondroitin sulfate
keratan sulfate
only non-sulfate GAG
hyaluronic acid
hyaluronic acid
largest of GAGs
general CT
binds readily with water
hyaluronic acid binds readily with water……
allowing it to be a lubricant in synovial fluid
examples of hyaluronic acid locations
body of eye
synovial fluid
wharton’s jelly
heparan sulfate locations
BM, skin, liver, lung, BVs, mast cell granules
largest GAG
hyaluronic acid
dermatan sulfate locations
also called chondroitin sulfate
cartilage, bones, skin, BVs, heart valves, cornea
most abundant GAG? most abundant sulfated GAG?
hyaluronic acid
dermatan sulfate
keratan sulfate
2 types
type I — only found in cornea
type II — cartilage and nucleus pulp of spinal discs
GAG covalently linked to a protein
proteoglycan
all GAGs exist in proteoglycans except?
hyaluronic acid
proteoglycan aggregate description
long hyaluronic acid chain
core proteins perpendicular to it
cores attached to acid via linker protein
GAGs attached perpendicular to core proteins
proteoglycans are found perpendicular to …..
attached perpendicular to hyaluronic acid via linker protein
proteoglycans are stained with…..
conventional dyes because of sulfate groups
proteoglycans are polyanions…..
have multiple negative charges
attract water
hate each other
examples of glycoproteins
fibronectin
Chondronectin
laminin
glycoproteins
proteins with one or more heterosaccharide chains that contain a sugar
PAS+
fibronectin
major surface protein of fibroblasts
link cells, collagen and GAGs
chondronectin
derived from cartilage
adhesion between chondrocytes and collagen
laminin
found in basal laminae
attachment of epithelial cells to lamina propria
Noncollagenous glycoprotein
laminin
fibroblast/cyte shape
spindle shaped with central nucleus
resident cells in CT
fibroblasts/cytes
macrophages
mast cells
plasma cells
cells in CT that migrate from blood
macrophages
mast cells
plasma cells
macrophage shape
10-30 micrometers
oval-indented nucleus
irregular shape w/ blunt processes
macrophage mvt
amoeboid mvt
macrophage shape by type
wandering = oval shape
fixed = irregular
origination of macrophages
in bone marrow as monocytes
function of macrophages
part of the phagocytic system of helper cells
macrophages can fuse with…..
other macrophages to create large multinucleated phagocytic foreign body giant cells
macrophage locations
wandering in blood CT sinusoids of liver, spleen, lymph nodes, marrow alveoli of lungs CNS bone
macrophage in blood
wandering monocyte
macrophage in CT
histiocyte
macrophage in live sinusoid
Kupffer cells
macrophage in sinusoids of spleen, lymph nodes, and bone marrow
perialveolar macrophages
macrophage in alveoli of lungs
dust cells
macrophage in CNA
microglia
macrophages in bone
involved in bone reabsorption
osteoclasts
mast cell characteristics
irregular oval shape
small oval nucleus
stained with toluidine blue
contain membrane bound granules
when viewing mast cells…..
often unable to see the small nucleus due to membrane bound granules
mast cell granules contain
histamine
ECF-A
SRS-A
heparin
ECF-A
attracts eosinophils and neutrophils
recruiter factor
SRS-A
like histamine but with sustained effects
heparin
poor anticoagulant
probably involved in helping clear plasma lipids
functions of mast cells
involved in hypersensitive responses to allergens
membranes release leukotrienes
locations of mast cells
near small blood vessels
but absent from spleen
mucosal surfaces
CT
plasma cell characteristics
activated B lymphocytes
larger than lymphocytes
large pale nuclei with clock face
locations of plasma cells
rare in CT
serous membranes
lymphoid tissues
lamina propria of GI tract
explain the clock face plasma cells
refers to how the nucleus stains
heterochromatin near edges
euchromatin in center giving the pale center and dark edges
lymphocyte characteristics
6-8 micrometers
large heterochromatin nucleus
thin rim of cytoplasm
lymphocytes are numerous in the….
lamina propria of GI tract
