Connective Tissue Flashcards
what provides the supportive and connective famework (or stroma( for all tissues of the body
connective tissue
What is connective tissue formed by?
cells and ECM
Is connective tissue vascular or avascular?
Connective tissue is directly supplied by blood and lymphatic vesselsI
What is ECM made out of ?
mixture of collagens, noncollagenous glycoproteins, and proteoglycans surrounding connective tissue
What is the role of connective tissue in the body?
Mechanical role: supporting and tissue repair Defensive role: inflammation (first reaction of defense) and immune responses Metaboliclly: Energy storage (adipose tissue) Template for bone formation: cartilage
What produces CT and ECM?
fibroblast
What is chondroblast?
a type of fibroblast that produces cartiledge
What are the three major groups of connective Tissue?
Embryonic Adult Special
Describe Embryonic CT
hydrophilic mainly ECM Whartons Jelly
Describe Adult CT
Loose Dense (regular and irregular) *structural diversity: the proportion of cells to fibers and ECM varies from tissue to tissue) therefore LooseCT and Dense CT
Describe Special Connective Tissue
Adipose Tissue Bone Tissue Cartiledge Hematopoeitic Tissue (bone marrow, reticular)
What are the major components of CT?
Fibers:Collagen, Elastic, Reticular Fibers Cells: resident (fibroblast), immagrant cells ECM ground substance):collagen, non-collagenous proteins and proteoglycans(trap water)
Fibroblast make
connective tissue fibers and ECM
Reticular CT
provide delicate meshwork to allow passage of cells and fluid
Elastic CT
provides elasticity (ligaments of vertebral column and wall of aorta)
How is CT classified?
- proportion of cells, fibers, and ECM : dense or loose 2. Organization of fibers: regular or irregular
Embryonic CT
loose connective tissue covered by amnion the major component is hydrophilic ECM has alot of proteoglycans
What type of consistency does embryonic CT have?
jelly like…Whartons Jelly (mucoid CT)
Where is embryonic Connective Tissue Found?
Umbilical Cord Pulp of developing tooth
Loose CT
Has MORE CELLS than collagen fibers
What type of cells do fibroblast have ?
oval nucleur shape
Where is loose CT found?
mucosa and submucosa and surrounding blood vessels, nerves and muscles
Dense connective Tissues
MORE COLLAGEN FIBERS than cells dense regular Ct ( tendons, ligaments, cornea) dense irregular CT( reticular fibers and elastic fibers)
Metachromasia
change in color of staining shift in color of a dye from blue to purple DENSE CONNECTIVE
Types of Fibers and cells in Loose Connective Tissue
Fibers: abundant elastic fibers and collagen bundles embedded in ECM Cells: fibroblast-active cell (fibrocyte-not so active cell), mast cells, machrophages and blood capillaries
Where is Dense irregular CT found?
dermis (stratified squamous epithelium) submucosa of digestive tube more COLLAGEN FIBERS than cells
What are the cells present in Dense irregular CT?
Sparse fibroblast (separated by collagen bundles), mast cells, and marcphages
how to tell if dense irregular CT is making collagen?
if the nucleus is big cell is making collagen from the fibroblast when the nuclus is smaller then usual the cell is not making collagen (fibrocytes)
Describe dense regular connective tissue
regularly arranged collagen bundles compressed oval nucleus of the fibrocyte
What are the four major cell components of CT?
fibroblast (resident cells) macrophages mast cell plasma cell
What type of tissue is arygophilic
Reticular Tissue (can be identified ins torma of lymphatic nodule after being saturated with silver salts)
What type of tissue is RETICULAR CT?
adult dense irregular CT which reticular fibers predominate thing and branching strucutures
What is reticular tissue characteristic of?
lymphatic tissues
Reticular fibers are synthesized by?
fibroblast (reticular cells)
Reticular fibers form meshwork in which
lymphoid cells are embbeddded
Argrophilia
affinity for silver
Reticular tissue is what type of collagen?
type III
Reticular tissue is seen in….
lymphatic tissue and in bone marrow
Elastic Fibers are produced by
fibroblast and smooth muscle fibers
What type of CT is elastic?
adult dense irregular CT elastic fibers predominate and there is NO COLLAGEN!
Elastic tissue is characteristic of?
large blood vessels and ligaments
DEscribe the elastic fibers found in the wall of a blood vessel?
They are synthesized by smooth muscle cells and form discontinuous and concentric arrangements
What appear as wavy bands?
elastic tissue
Fibroblast synthesize and secrete
(ECM+COLLAGEN) BASIC SPECIFIC proteoglycans glycoproteins collagens (5 types) elastin fibronectin (glycoprotein) heparan sulfate proteoglycan
What do fibroblast synthesize that are part of the basement membrane?
fibronectin heparan sulfate
Collagen is a compondent of
collagen and the reticular fibers
What type of collagen is seen in the basal lamina?
type IV
What are the types of fibroblast?
reticular cells osteoblast (bone) chondroblast (cartilage) odontoblast (teeth)
Are reticular fibers PAS Positive?
reticular fibers and collagens in general are glycoproteins and therefore pas positive
Type I collagen
Fibrocartilage fibrillar Tendon, bone,dentin and dermis
Type II collagen
fibrillar ( thinner than type 1) Cartilage: hyaline and elastic
Type III
fibrillar lymphoid tissue Reticular collagen-> precollagen reticular lamina wound healing (replaced by type I) argyrophillic
Type IV
layers basal lamina binds to laminin does not form bundles
Type V
fibrillar amnion and chorion (in fetus) muscle and tendon sheaths doesnt form banded fibrils
Name the fibrillar collagen(s)?
Types: I, II, III, V
Name the non-fibrillar collagen(s)?
Type IV
Synthesis of Collagen Steps
In the RER 1. synthesis of precollagen and procollagen (triple helical arrangement of procollagen) 2. hydroxylation of lysine and proline by lysyl hydroxylase occurs in procollagen (requires vitamin c_scurvy) 3. glycosylation and disulfide bond formation Golgi apparatus 5packing and secretion of hydroxylated pro collagen Outside the cell 6.procollagen peptidase removes non helical end of procollagen and it becomes tropocollagen 7. Self-aggregation of tropocollagen molecule leads to formation of collagen fibrils (staggered array) 8. cross linking of collagen fibrils to form collagen fibers (FACIT COLLAGEN) 9. collagen bundle formation by proteoglycans and other glycoproteins
FACIT
fibril associated collagens with interrupted helices
lysl oxidase
cross links tropocollagen molecules stabilize staggered arangment of collagen fibrils to form fibers
Ethers Danlos Syndrome
hyperelasticty of skin and hypermobility of joints (dislocation) -defects in synthesis of procollagen collagen -type 1 collagen defect -mutations in procollagen peptidase or lysyl hydroxylase -cant form collagen fibers -defects in blood vessels and internal organs
procollagen peptidase
forms tropocollagen
lysyl hydroxylase
hydroxylation of lysine and proline needs vitamin c
Elastic Fibers is made in
RER and Golgi apparatus
Assembly of Elastin Fibers
RER 1. synthesis of 3 components of elastic fibers (fibulin 1, fibrillins 1 &2, tropoelastin) becomes proelastin Golgi proelastin is packaged and secreted into the extracellular space where it turns into tropoelastin ( with desmosine attached) Extracellular Space Assembly of fibulin 1, fibrillins and tropoelastin to produce elastic fibers
Elastic Fibers are made by
fibroblast and smooth muscle cells
Fibrillin 1
forcing bearing structural support
fibrillin 2
regulates the assembly of the elastic fiber
fibulin 1
required for co-assembly of fibrillins and elastin subunits
what type of fibroblast produce elastic fibers?
embryonic and juvenile fibroblast
Many tissues become ____elastic with age?
less elastic wrinkles
Marfans Syndrome
Issue with fibrillin 1 (chromosome 15) Increase in proteoglycans (they replace elastic lamallae) dilation of aorta mitral valve prolapse aortic dissection
Describe the periosteum in Marfans syndrome
abnormally elastic and does not provide oppositional force during development
Functions of Macrophage
- turn over senescent (old) fibers and ECM material 2. present antigens to lymphocytes as part of inflammatory and immunologic responses ** ANTIGEN PRESENTING CELLS 3. Produces cytokines
where do macrophages derive from?
monocytes (cells formed in bone marrow)
what is a kupffer cell?
macrophage of the liver capture particles in liver blood cirulation
what is a osteoclast
macrophage of the bone dissolve bone during remodeling or when calcium in blood decreases
what is a microglial cell
macrophage of CNS removal of debris when there is destruction of cells in CNS
Where do monocytes ciruclate?
in the blood and migrate into the CT where they differentiate into macrophages
Macrophages have MHC
major histo compatibility complex 1. contain abundant lysosomes for breakdown of phagocytic materials have numerous phagocytic vesicles (phagosomes) for storage of ingest materials 3. nucleus has irregular outline
Macrophages as antigen presenting cells
put desktop picture on it
Mast Cells
source of vasoactive mediator (contained in cytoplasmic granules) metachromasia
What do the cytoplasmic granules of mast cells contain?
histamine heparin chemotatic mediators
What are vasoactive products of mast cells?
leukotrines
leukotrines
-are NOT present in granules -are leased from the cell membranes of mast cells -full of granules that form once the cell reaches the connective tissue
Name the types of Mast Cells
Mucosal MC Connective Tissue MC
Mucosal MC
predominantly in the intestines and lungs
Connective Tissue MC
granules more abundant in CT mast cells
what is a vasoactive mediator
mediates constriction and dilation of blood vessels
Origin of Mast Cells
bone marrow progenitor/precursor (lack cytoplasmic granules) when they migrate into the CT/lamina propria they proliferate and accumulate cytoplasmic granules
The migration of mast cells from bone marrow to tissue is regulated by
c-kit receptor (tyrosine kinase) and its ligand *(stem cell factor)
Clinical Significance of Mast Cells (antigen)
- Antigen(allergen) binds to two adjacent IgE receptors and mast cell becomes IgE-sensitized 2. IgE-sensitized mast cell releases intracellular calcium 3. contents of cytoplasmic granules is rapidly discharged by degranulation 4. the degranulation will release histamine protease, and proteoglycans 5. synthesize inflammatory mediators derived from arachidonic acid (not present in granules ): cychoxygenase pathway-prostagladin d2 lipoxygenase-leukotrine c4
what occurs with excessive mast cell degranulation
allergic hypersensitivity reaction leads to shock (rapid drop inb lood, asthma hay fever eczema
Mast cell releases
-granule mediators (histamine, heparin, tryptase, chymase) -lipid mediators ( leukotrine) -cytokines (signaling molecules produced by specific cells of immune system)
Explain Asthma
release of histamine causes dyspnea (difficulty breathing) do to contraction of smooth muscle surrounding bronchioles and hyper-secretion of goblet cells and mucosal glands of bronchi
explain hay fever
histamine increases vascular permeability leading to edema (accumulation of fluid) -leukotrines induce increased vascular permeability associated with urticaria (swelling in dermis of skin) (vascular permeability is the permeability of blood vessels)
Plasma cells produce
all immunoglobins (single type per each plasma cell)
Plasma cells
well developed RER well developed golgi apparatus (gives light staining over nucleus & packages proteins) cartwheel nucleus (because of heterochromatin)
What are plasma cells derived from?
B lymphocytes (B cells)
Is the cytoplasm of plasma cells acidophilic or basophilic?
basophillic
The area around the nucleus of plasma cell becomes
slightly acidophilic
Cartwheel nucleus
plasma cell
How plasma cells are created
put desktop pic #2 1. antigen is taken up by a macrophage 2. the antigetn is stored in phagocytic vesicle which then fuses with a lysosome to become a phagosome 3. the phagosome has an acidic pH therefore it breaks up the antigen into small peptides 4. the small peptides attach to the MHC which is then exposed to TCELLS 5. the TCELLS then secrete cytokines or interleukins that bind to nearby B cells which are then induced into mitosis 6. the increased number of B cells now undergo differention into Ig secreting plasma cells
Adipose Cells
have MORE CELLS then collagen fibers and ground substance -most significant energy storage site in the bodyq
Cartilage and Bone
Both are dense CT with specialized cells
what type of ECM does cartilage have? Calcified or non calcified?
has non calcified ECM
what type of ECM does bone have? Calcified or non calcified?
calcified
What are the types of adipose cells?
Brown White
Brown adipose Cells
Multiocular store MANY lipid droplets and mitocondria thermogenic -dissipates energy instead of storing energy -heat generated by uncoupling production of ATP (UCP-1) -surrounded by alot of blood vessels
White adipose cells
Unicocular store SINGLE lipid inclusion provides a cushion and storage of energy (major reserve of long term energy)
Fat cells derive from
preadipocyte cells which derive from mesenchymal cell precursor
What is the effect of insulin on fat
insuling binding to insulin like growth factor 1 (IGF-1) causes preadipocytes to synthesize lipoprotein lipase (blood to fat cell transfer) this leads to primary fat cell formation in fetus
Obesity
disorder of energy balence accumulation of fat in liver insulin resistence dyslipidemia (alterations in blood fat levels) cardiovascular disease
Leptin
secreted by adipocytes regulates body weight
what occurs if one is leptin deficient
infertile and obese
leptin receptors share the same sequence as
cytokines receptors therefore it influences responses to infection and inflammatory responses
White fat nucleus
pushed to eccentric side position
_______fat lipids are in direct contact with cytosol
white
________fats do not contain a cytomembrane
white
Which has a more extensive blood supply? white or brown fat?
brown
What are the two requirements for thermogenisis?
- mitochondrial biogenesis (production of new mitocondria) 2. uncoupling protein-1
Fat stains
xylene-dissolves fat/ only nucleus and plasma membrane left osimium tetroxide-stains fat brown (lipid rich myelin in nerves) SudanIII-alchoholic solution used for detection of fat in frozen sections
Where do chondroblast derive from?
mesenchymal cells
What are the three major types of cartilage?
hyaline elastic fibrocartilage
is cartilage vascular or avascular?
avascular nutrients are received by diffusion
Cartilage is made by?
chrondoblast/chrondcytes
Cartilage is surrounded by______
Perichondrium
Perichondrium
layer of undifferentiated cells that differentiate into chondroblast
chrondrocytes rarely
divide
Interstitial growth versus appositional growth
Interstitial growth-chondrocytes within the cartilage appositional growth-undifferentiated cells at the surface of the cartilage or perichondrium
Interstitial growth
mesenchymal cells turn into chondroblast 2. which form centers of chondrogenisis ( chondroblast surrounded by ECM) 3. the chondroblast divide by mitosis produce type II collagen, hyaluronic A, GAGS and form isogenous cell groups (daughter cells aka chondrocytes remaining in the same space lacunae) 4. isogenous cell group is surrounded by territorial matrix 5. wider interterritorial matrix surrounds the territorial matrix ACTIVE DURING ENDOCHONDRIAL OSSIFICATION
What do chondroblast deposit during mitosis?
type II collagen fibers hyaluronic acid GAGS
Appositional Growth
- outermost cells of perichondrium (transitional zone between cartilage and surrounding CT) fibrous layer 2. inner cells of perichondrium (chondrogenic layer) differentiate into chondroblast and release type II collagen 3. new layer of carilage added and increases size of intial (anlagen/outline) 4. collagen grows
Chondroblast are a type of
fibroblast
Compomelic dysplasia
-mutation of sox 9 TF -encodes expression of type II collagen and proteoglycan ggrecan -with mutation null cells remain in perichondrium do not diff into chondrocytes
When chondroblast are trpped within spaces in the matrix called lacunae the cells are called
chondrocytes
What type of collagen does hyaline have?
type II
what type of collagen does elastic cartilage have?
type II
what type of collagen does fibrocartilage have?
type I
What type of cartilage has type II collagen?
hyaline and elastic
What are the special functions of hyaline cartilage?
shock absorber lubricated surface for joints
What type of cartilage lacks a perichondrium?
Fibrocartilage
where is hyaline cartilage found?
articular cartilage (area of body not lined by epithelium) temporary skeleton of fetus HIGH WATER CONTENT
where is elastic cartilage found?
external ear epiglottis auditory tube EVERY FLEXIBLE ECM CONTAINS ABUNDANT ELASTIC FIBERS
where is fibrocartilage found?
intervertebral disk, pubic symphysis articular disk of the knee ECM HAS LOW CONCENTRATION OF PROTEOGLYCANS AND WATER
how to distinguish between fibrocartilage and dense connective tissue?
pictures
Fibrocartilage is consisdered an intermediate between
hyaline cartilage and dense regular connectivetissue
What type of adipose tissue is this?
What is the top line ?
What is the bottom line?
brown adipose tissue
blood vessels
mutliocular adipocyte
What type of adipocyte is this?
What is the top line
what is the bottom line
White
eccentric nucleusuniolcular adipocyte
What type of CT is this?
Line 1 (top)
LIne 2
embroyonic (whartons jelly)
nuclus of mesenchymal cell embedded in ECM
amnion
What type of CT is this?
Line 1
Line 2
Line 3
adult connective
Loose (areolar)
Line 1-oval nuclus of fibroblast
elastic fibers (thin straight and branching
collagen bundles (thick and wavy)
What type of CT is this?
Line 1
LIne 2
LIne 3
adult CT
dense irregular
oval nuclus of fibroblast
collagen bundles (thick wavy and irregularly arranged)
What type of CT is this?
Line 1
LIne 2
LIne 3
Adult CT
dense regular
1-skeletal muscle
- regulary arranged collaen bundles
oval nucleus of birobcyte compressed by the regulary aligned collagen bundles
What type of CT is this?
Reticular tissue
what type of Ct is this?
line 1
bottom line
elastic tissue
elastic fibers
smoth muscle cells
What are these special types of CT?
adipose
cartilage
bone
hematopoeietic
(left to right)
Identify left to right
macrophages
fibroblast
collagen
What is this?
mast cell
What are these?
plasma cells
what type of carilage is this?
what is top line pointing to
hyaline
chondrocyte
hyaline cartilage identify top to bottom
line 1
line 2
line 3
line 4
line 5
cline 6
line 7
isogenous groups
nucleus
territorial matrix
lacunar rim
type Ii collagen
RER
interterriortiral matrix
What type of cartilage is this?
what is line 1
line 2
line 3
elastic
perichondrium
chondrocytes
elastic fibers
What type of cartilage is this?
Fibrocartilage
All cartilage is
avscular
