Connective Tissue - PowerPoint

							WHERE AM I?      Online Anatomy Module 1
    INTRO & TERMS
    CELL
    EPITHELIUM
    CONNECTIVE TISSUE

    MUSCLE

    NERVOUS SYSTEM

    AXIAL SKELETON

    APPENDICULAR SKELETON

    MUSCLES

    EMBRYOLOGY
            SOFT CONNECTIVE TISSUES
The „soft‟ distinction being made here is between cartilage and bone
as firm connective tissues and the softer ones, such as fatty tissue,
ligament, dermis of skin, etc.
              Articular cartilage           Dermis

            Marrow
                                                      Hypodermis

       Bone




                                      Joint capsule
         Ligament &
                                                        Periosteum
           Tendon                      Muscle


Text reading in Marieb is pp. 79-82
SMALL-GUT CONNECTIVE TISSUE ROLES

                 VILLI covered with simple
                 columnar epithelium on a core
                 of very loose-textured CT


                 Extensive area of fairly loose-
                 textured CT holding the lining
                 to the muscle of the wall



               Another layer of connective tissue
               outside and assisting the muscle
               by carrying vessels, nerves, and
               just holding things together
                   GUT VILLUS
transport
                Simple Columnar Epithelium

                absorbing ENTEROCYTES


                 mucus-secreting
                 GOBLET CELLS

                 BASAL LAMINA

                   VILLUS CORE of:
                   loose connective tissue
            {
                   C T cells
                   lymphatic capillary
                   capillaries
     CONNECTIVE TISSUE ROLES I
Connect/Support
Transport/Nourish
                                  EPITHELIUM



                                 }   Connective tissue


                             VESSEL

The connective tissue under an epithelium is termed the
LAMINA PROPRIA (adjacent layer). Where it is more
intermingled with epithelial cells, as in a gland, it
becomes the STROMA.
            THE CELL: Some basics IV
Cells do not operate in isolation. They have surroundings
and attachments - to other cells and materials outside them
               Surface specializations of the plasmalemma
               to interact with tube content

                                    Cell-cell attachments -
                                    more specializations of
                                    the plasmalemma or
                                    ‘cell membrane’

                                       Attachments to
                                       materials outside the
                                       cell in the EXTRA-
                                       CELLULAR MATRIX
                THE CELL: Some basics V
The cells shown here form a single layer. It holds this form in part
by the cells’ fastening at the base to a sticky porous membrane
named a BASAL LAMINA or a BASEMENT MEMBRANE




                                          Basement membrane



                                             Basement membrane
                                             itself attaches to
                                             connective tssue
                                             below it
            THE CELL: Some basics VI
Cell are soft and squishy. Think jellyfish - it needs water to
support it. To holds us together & for life on land and the
ability to move and manipulate things, we need a strong , in
place rigid, extracellular matrix.
                                       Cells of the soft
                                       connective tissues ,
                                       cartilage, and bone
                                       make materials that
                                       interact outside the
                                       cells to provide
                                       strength and support
                                              via
                                        EXTRA-CELLULAR
                                        MATRIX (ECM)
           CONNECTIVE TISSUE MATERIALS

Cells of the soft connective tissues make materials that
interact outside the cells to provide strength and support
                                   One very special product is the
                                   basement membrane to
                                   support epithelial cells




The bulk of the connective-tissue matrix comprises:
bound water, meaning that it does not slosh as you move
molecules to bind the water and hold other components together
long fibers to give strength and elasticity to the tissue
other sticky molecules - glycoproteins - to hold the fibers in place
        CONNECTIVE TISSUE MATERIALS: Details




bound water

molecules to bind the water - PROTEOGLYCANS

long fibers - COLLAGEN (strength) & ELASTIC

other sticky molecules - GLYCOPROTEINS
  MORE CONNECTIVE TISSUE ROLES
While the matrix properties allow the tissue to support
& connect , other things are going on.
The matrix offers an ideal place for microorganisms
to grow, so that connective tissues have a range of
defensive cells and are a battle-ground of great
medical significance
The matrix stores a number of useful materials,
including ones to help control defensive reactions and
adjacent tissues. And a special cell - the fat cell/
adipocyte - stores fats/lipids for energy & growth

Connective tissue readily repair themselves &
react to damage to other tissues
     CONNECTIVE TISSUE ROLES


Connect/Support
Transport/Nourish
Defend                 EPITHELIUM

Storage
Control
                      }  Connective tissue


                    VESSEL
Repair
  CONNECTIVE TISSUE COMPONENTS

                           Synthetic cells
                           for structural
                           macromolecules, e.g.
signals                    for building

                           fibers
                                    collagen
                                    elastic
            Defensive cells

          Cells lie in, attach to, & are supported
          by the EXTRACELLULAR MATRIX
          (ECM) of fibers & „ground substances‟
DEFENSIVE CONNECTIVE TISSUE CELLS

The matrix offers an ideal place for microorganisms
to grow (food, warmth) so connective tissues have a
range of defensive cells, and are a battle-ground of
great medical significance

  MACROPHAGE (MF) eats dead & bad stuff;
         coordinates defense
   PLASMA CELL (from B Lymphocyte)
       makes & secretes antibodies (Igs)

   MAST CELL triggers defensive reaction/
           inflammation (degranulates)
 MACROPHAGE (MF)

                                lysosomes




 PLASMA CELL
                                  MAST CELL

              Golgi



                 much GER
Cartwheel
nucleus [Peripheral clumps of
         heterochromatin]        Big
                                 granules
             MACROPHAGE Mf

             -
             POD



Macrophage can:
attach to fibers;
release & crawl around;
extend projections - podia;
recognize bad things;
wrap its podia around them;
eat the stuff (phagocytosis);
digest it with lysosomes
                           MACROPHAGE MF
Collagen
           FOCAL ADHESION - attachment
fiber




                lysosome


                                                  -POD




                    Actin monomers & filaments
                    in controlled flux for crawling,
                    podia-extension, & phagocytosis
MACROPHAGE /MF receptors
  Pathway for phagocytosis & lysosomal digestion




          lysosome


                                          -
                                          POD




              Membrane scavenger
              receptors to recognize targets
       CONTEXT FOR MAST CELL ACTIONS

                    Invader
EPITHELIUM




VESSEL
                               }
                               CT


                                      MAST CELL
                               Triggered by invader
Defensive white blood cells    Releases granules
& chemicals in vessel need     Granule agents act on
to get out to counteract the   vessels & white blood
invader                        cells to encourage exit
 MAST CELL
                   MAST-CELL ACTIVATION
                                 IgE antibody molecules



                          Fce Receptor for a region of
                          the Ig molecule




Invader
          IgE binding triggers
          degranulation
IgE binding triggers   MAST-CELL ACTIONS I
degranulation
                           Granules contain many agents (&
                           proteoglycans), e.g.

                                 HISTAMINE to increase
                                 permeability & loosen wall

      MAST CELL                                 of Vessel




             CHEMOKINES to attract
             leukocytes out into CT
        MAST-CELL ACTIONS II

                      Heparin & proteoglycans
                      influence signaling


                                Chemokine receptors
                                           White
MAST CELL                                  blood cell
                               Vessel



  Defensive blood chemicals,
  e.g., Complement
CONNECTIVE-TISSUE CELLS: TWO MORE TYPES
MACROPHAGE (MF)
         lysosomes




 PLASMA CELL                 MAST CELL               FIBROBLAST
                                              Fibroblast is an elongated cell
              Golgi                           amidst the fibers etc it has made


                 much GER
Cartwheel
                                 Big
nucleus [Peripheral clumps of
         heterochromatin]
                                 granules


  ADIPOCYTE                 Adipocyte/ fat cell grows to be very large, with a
                            thin shell of cytoplasm around a huge fat droplet


                             fat droplet
                     COLLAGEN - Molecule to Fiber
 Collagen I trimer
                       Last of the spinning.
Three intertwined      Hereafter, strength comes
helices                from cross-linking &
                               glueing




“Glueing” & control of fibril &    Assembly of trimers end-to-end,
fiber width are done by high-#     side-by-side, but staggered to
collagens, glycoproteins, and      build a cross-banded fibril
proteoglycans


                      Further glueing of
                      fibrils to make a FIBER
CONNECTIVE TISSUES   ROLES


                     CELLS


                     EC MATRIX


                     WORKING
                     CONTEXTS


                     TYPES
CONNECTIVE-TISSUE CELLS
                                        FIBROBLAST
MACROPHAGE (MF)

                                      lysosomes


 PLASMA CELL
                                         MAST CELL

              Golgi



                 much GER
Cartwheel
nucleus [Peripheral clumps of
         heterochromatin]               Big
                                        granules
 ADIPOCYTE
               One huge fat droplet
  ROLES OF CONNECTIVE-TISSUE CELLS

FIBROBLAST makes ECM; destroys ECM

MACROPHAGE (MF) eats dead & bad stuff;
       coordinates defense
PLASMA CELL (from B Lymphocyte)
    makes & secretes antibodies (Igs)

MAST CELL triggers defensive reaction/
        inflammation (degranulates)

ADIPOCYTE stores & releases „energy‟ (&
    brown adipocytes can make heat)
 ROLES OF CONNECTIVE-TISSUE CELLS

FIBROBLAST

MACROPHAGE (MF)


PLASMA CELL)


MAST CELL


ADIPOCYTE
CONNECTIVE TISSUE COMPONENTS: Cells & ECM

  Fibroblast
                 Structural &
  Osteoblast     other ECM      What are these?
  Chondroblast   molecules
  synthetic

  Macrophage
  Plasma cell
  Lymphocyte
  Mast cell
  defensive
  Fat cell or
  Adipocyte
  storage
CONNECTIVE TISSUE COMPONENTS: Cells & ECM

                                             Collagen
                                    FIBERS Reticular
 Fibroblast         Structural &
 synthetic          other ECM                 Elastic
                    molecules
                                    BINDERS &
                                    CONTROLLERS:
                                    Sticky glycoproteins
Fibroblasts rework the matrix       Water-binding
that they have formed by                  proteoglycans
carefully breaking it down, while   Destructive enzymes
synthesizing new materials to       Enzyme inhibitors
adapt to greater or otherwise       Signaling Molecules
changed loads
CONNECTIVE TISSUE „GROUND SUBSTANCE‟

                                      Collagen
                             FIBERS Reticular
 Fibroblast   Structural &
              other ECM                Elastic
              molecules
                             BINDERS &
                             CONTROLLERS:
„Ground substance‟ is        Sticky glycoproteins
the old-fashioned name       Water-binding
for the non-fiber                  proteoglycans
extracellular part of        Destructive enzymes
                             Enzyme inhibitors
connective tissue
                             Signaling Molecules
CONNECTIVE T. COMPONENTS: Reticular fibers
                                               Collagen
 Fibroblast         Structural &
                    other ECM       FIBERS Reticular
 synthetic
                    molecules                   Elastic

    Reticular fibers are a delicate version of collagen
    fibers, used so as to support cells, but not
    interfere with blood-cell interactions, e.g., in liver
                                             Reticular fibers


    HEPATOCYTES
                                              blood
                            blood vessel
Endothelial cells
lining vessel
       TYPES OF CONNECTIVE TISSUE
Around the body different combinations of these
cells, fibers, and other ECM materials are needed
The starting embryonic tissue is mesenchyme - jelly-
like, with a few thin fibers and unspecialized
mesenchymal cells
As the mesenchymal cells become fibroblasts, these
can make the tissue, by fiber packing, loose or dense
The fibroblasts may align the fibers parallel to make a
regular tissue ,or arrange them in different
orientations - an irregular tissue
Elsewhere, mesenchymal cells may become fat cells
making an adipose tissue
The tissue requirements also vary when the tissue is
somatic (in body wall or limb) rather than visceral
      TYPES OF CONNECTIVE TISSUE

   SOMATIC                VISCERAL

Loose irregular           Loose irregular
Dense irregular           Dense irregular
Reticular                 Reticular
Adipose                   Adipose
Elastic                   Elastic
Dense regular


      In the beginning was Mesenchyme
                MESENCHYME

                                 Mesenchymal cells,
                                 mostly synthetic for
 signals                         structural
                                 macromolecules, e.g. for
                                 building
                                 fibers immature
                                        collagen
             Much ground substance
             e.g., hyaluronan (a GAG)
Mesenchymal cells - precursors/ progenitors of
some differentiated CT cells, e.g., fibroblasts
Mesenchyme takes up & commits space to be a
future connective tissue, and has modest jelly-
like mechanical properties of its own
            CONNECTIVE TISSUES: Contexts

Tube Man
Head -                                  Worm Woman
modification of
body wall +                   re
brain & special
senses + start                     cvl
of two tubes             Al
  Soma - body
  wall & the limbs - - - -    - -        -   diaphragm

 Viscera                            u
 tubes, modified     o
 tubes, &
 accessory
 organs
                   SOMATIC STRUCTURES
        Articular cartilage          Dermis

       Marrow
                                               Hypodermis

Bone




                               Joint capsule
 Ligament &
                                                 Periosteum
   Tendon                       Muscle
  SOMATIC CONNECTIVE TISSUES: Dense regular




Ligament &
 Tendon dense regular     Muscle
       DENSE REGULAR CONNECTIVE TISSUE




Bundles of    {
thick collagen I
fibers
              {
                                   Looser vascular CT
           Elongated fibroblasts
                                   between the bundles
DENSE REGULAR CONNECTIVE TISSUE: Tendon




Bundles of    {
thick collagen I
fibers
              {
                                       Looser vascular CT
Elongated fibroblasts - tenocytes      between the bundles -
                                       endotendinuem

     If the tissue is in a tendon, some special names
     (not to be learned) are used
SOMATIC CONNECTIVE TISSUES: Reticular & Adipose



   Marrow reticular                   Hypodermis
                                      adipose




                            Muscle
       WHITE ADIPOSE TISSUE


Capillary
                 Adipocyte

                              Reticular
                              fibers




      Fat cell
   CONNECTIVE TISSUE - Mechanical functions
 The stringy strength of collagen allows a
 variety of mechanical actions
   Supporting - ligament
     Binding - ligament
      Restraining - ligament
       Directing - tendon
         Separating - fascia
For firmer support something has to be added to the
collagen to make cartilage or bone

The large soft cells of adipose tissue can be confined in
sheets of collagenous tissue for
                                   Padding - fat pad
 SOMATIC CONNECTIVE TISSUES: Dense irregular
The collagen fibers are arranged         Dermis dense irregular
in various directions for different
pulls on the tissue




                                               Periosteum
                                               dense irregular
Joint capsule dense irregular         Muscle
SOMATIC CONNECTIVE TISSUES: Loose irregular

   marks loose irregular filling in between more solid
structures & allowing them              freedom of movement




                                 Muscle
TYPES OF CONNECTIVE TISSUE               SOMATIC
  Loose irregular (Areolar)
  between more solid structures

        Dense irregular
        joint capsule, periosteum, dermis

              Dense regular
              tendon, ligament

                    Adipose
                    hypodermis

                          Elastic
                          elastic ligament
                        (inconspicuous in man)
SOMATIC CONNECTIVE TISSUES                   loose irregular
        Articular cartilage (hyaline)      Dermis dense irregular

       Marrow reticular                           Hypodermis
                                                  adipose
Bone




                                  Joint capsule dense irregular
 Ligament &
                                                    Periosteum
  Tendon dense regular                  Muscle      dense irregular
TYPES OF CONNECTIVE TISSUE

VISCERAL

     Loose irregular
     Dense irregular
     Reticular
     Adipose
     Elastic




In the beginning was Mesenchyme
 Tube Man
                                        Worm Woman

                              re

                         Al        cvl


                   - - - -    - -        -   diaphragm
      Liver                         u
processes blood
drained from the
GI tract
                                                  Visceral Connective Tissue 1 -
                           re
                                                  Reticular
                      Al        cvl
                                                  e.g., in liver, spleen, kidney
                - - - -    - - -      diaphragm
    Liver
                              u
processes
blood drained
from the GI
tract                                                                Reticular fibers


         HEPATOCYTES
                                                                         Macrophage
                                                    blood vessel

     Endothelial
     cells lining
     vessel
                Reticular fibers + Macrophages = Reticular
                                                     tissue
  TYPICAL TUBULAR ORGAN
              Visceral Connective Tissue 2 - Loose irregular

main working tissue -               inner service tissue -
Epithelium                          Connective tissue


                                      loose irregular ct with
                         lumen        vessels & nerves



motility tissue -                   outer service tissue -
Muscle                              Connective tissue
VISCERAL CONNECTIVE TISSUE                      AORTA
TYPES
                                                     Elastic
       ESOPHAGUS                           re
           Lamina propria
                                      Al        cvl
   lumen   Loose irregular
            Adventitia
                                - - - -    - -        -   diaphragm
                    LIVER                        u
                    Reticular                             Kidney
                                                          CAPSULE
                                                          Dense
                                                          irregular
                         MESENTERY

                         Adipose
TYPES OF CONNECTIVE TISSUE                    VISCERAL
Loose irregular
lamina propria, tunica adventitia
     Dense irregular
     organ capsules
           Reticular
           liver, spleen
                 Adipose
                 mesentery, pericardium
                       Elastic
                       lung, elastic arteries
                       have collagen fibers for strength, but
                       need much elasticity
CONNECTIVE TISSUE COMPONENTS: Cells & ECM
                                          Collagen
  Fibroblast
  Osteoblast      Structural &   FIBERS Reticular
                  other
  Chondroblast                            Elastic
                  molecules
  synthetic
                                 BINDERS &
    Macrophage                   CONTROLLERS:
    Plasma cell                  Sticky
    Lymphocyte                   glycoproteins
    Mast cell                    Water-binding
    defensive                    proteoglycans
                                 Destructive
       Fat cell or               enzymes      Enzyme
                                 inhibitors Signaling
       Adipocyte                 Molecules
       storage
     CONNECTIVE TISSUE ROLES
Connect/Support
                                   COMPARTMENTS

Transport/Nourish        LUMINAL

                                    }   (EPITHELIAL)
Defend
Storage                              }   INTERSTITIAL
                                         connective tissue


                               VASCULAR
Control
    nervous,
    paracrine (local),
    biochemical
Repair
             EXTRACELLULAR MATRIX ECM

    What cells produce and organize outside theselves
    allows them to construct huge organisms, with complex
    repertoires of movements & behaviors, and multiple
    physiologies based on separate compartments
Tight junctions
                      }   LUMINAL

                                      } (EPITHELIAL)

                                       }  INTERSTITIAL
                                          connective tissue


                                   VASCULAR
            EXTRACELLULAR MATRIX ECM 2
Cells create and achieve control over their environment by
synthesizing combinations of types of macromolecule which
interact outside the cells
  Learn the requirement, not the particular molecules meeting it
                                                Hyaluronan
Over water (why you don’t slosh as you          Large
walk)                                           proteoglycans
Why you can swallow, wink, spit, etc          Mucin glycoproteins
                                              (epithelial products)
Creation of barriers   - Basal laminae Laminin, Collagen IV
                                       Perlecan (a heparan
                                       sulfate proteoglycan)
- Connective tissue ground substance Fibronectin Tenascin

 Attachment & support                 Collagen fibrils & fibers (I &
                                      III) + associated molecules
BASAL LAMINA CONSTRUCTION a sticky hedge
Learn the requirement, not the particular molecules meeting it
              Epithelial-cell attachments to laminin




Interwoven networks of LAMININ & COLLAGEN IV
attached by Nidogen/Entactin
         Basal-lamina Proteoglycan molecules attached to
         the lattice , e.g., Perlecan
Generally

LAMININ        „IN‟ ending - glycoprotein


PERLECAN        „AN‟ ending - proteoglycan




Heparin - a glycosaminoglycan - is an exception
            EXTRACELLULAR MATRIX ECM 3
Cells create and achieve control over their environment by
synthesizing combinations of types of macromolecule which
interact outside the cells
                                                Elastic fibers &
  Elastic recovery of shape & elastic
  storage of the work of the heart &            laminae
                                                Elastin & fibrillin
  respiratory muscles
                                           Cartilage collagens II & IX
Resilient firmness in joint, airway,       aggregated proteoglycans
& fetal-skeletal cartilages                link proteins & hyaluronan
                                           cartilage glycoproteins

                                           Collagens I & XII
 Resilient hardness of bone                bone proteoglycans
                                           bone glycoproteins
                                           mineral crystals
 Again, learn the requirement, not the particular molecules meeting it
  EXTRACELLULAR MOLECULAR INTERACTIONS 1

Further assembly of the molecules to make larger &
eventually ‘visible’ structures, such as fibrils


Modification of the molecules, e.g., cross-linking, to make
them resistant to digestion

Deliberate breakdown of the molecules by the forming cells
for turnover and renewal, by proteases & other enzymes
Controlled breakdown, with more synthesis & assembly,
provides for remodeling & adaptation of ECM, e.g., to a
heavier load in tendon or cartilage

Some of these enzymes, e.g. collagenase, include a zinc atom
& require Ca2+ to work - hence Matrix Metalloproteinases, e.g.
MMP-3
 Some of these enzymes, e.g. collagenase, include a zinc
 atom & require Ca2+ to work - hence Matrix
 Metalloproteinases, e.g. MMP-3
The inhibitors of these enzymes go under the abbreviation
TIMPs - Tissue Inhibitors of MMPs; & are also made by
fibroblasts & other matrix-influencing cells

  ECM MOLECULAR INTERACTIONS - Pathology 1

Unintended degradation by enzymes released from cells,
e.g., leukocytes, engaged in defensive reactions.
ECM is the battleground for defenses initially targeted at
microorganisms.
“--itises” occur throughout the body, & are real hazards to
comfort & life, e.g., endocarditis weakens & distorts heart
valves & thus can kill
     ECM MOLECULAR INTERACTIONS - Pathology 2

Unwanted degradation by bystander inclusion in cytokine
signaling pathways of defensive cells
           IL-1
MF                         Lymphocytes of inner joint synovium


 IL-1
                              Joint cartilage cells also
           Articular          respond to the signal:
           chondrocytes       enzymes       enzyme inhibitors
                              proteoglycans



 = an inappropriate response causing cartilage matrix
 destruction - ARTHRITIS
                              IL-1 Interleukin-1 a typical cytokine
    ECM MOLECULAR INTERACTIONS - Pathology 3
 Unwanted degradation by:
 microbes trying to colonize, e.g., using bacterial hyaluronidase
 to liquify ground substance
 metastasizing cancer cells breaking through basal laminae
 & connective tissues to get into the blood or lymph streams

Unwanted synthesis - the formation of excess collagen,
clogging organs with delicate blood-cell relations.
Cytokines released by activated macrophages trigger
synthesis in fibroblasts, causing cirrhosis in the liver and
fibrosis in kidney, lung, marrow, etc

Bad assembly - genetically defective fibrillin makes an
inadequate scaffold for elastin deposition      weak aorta,
slack connective tissues, etc, of Marfan’s syndrome
This balance is
significant

                      matrix


     cells



     Thus, loose connective tissues have less matrix
     materials (except for water) and more cells than
     dense ones, because the looser textured matrix
     is more favorable to the growth of
     microorganisms, and hence needs more
     defensive cells: dense tendon needs far fewer.
     Adipose tissue is mostly the very large fat cells.
WHERE AM I?      Online Anatomy Module 1
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