Connective Tissue
Holding it all together!
Connective tissue is found
everywhere!
Main classes/types:
1. Connective tissue proper
2. Cartilage
3. Bone
4. Blood
Properties
1. common origin Mesenchyme
2. degrees of vascularity
3. great degree of “non-living” extracellular
matrix
Connective Tissue
Binds structures
Provides support and protection
Serve as frameworks, fill spaces, store fat,
produce blood cells, protect against
infection, repair damaged tissue
Abundance of matrix btw cells
Blood supply varies.
Structural elements:
Ground substance (matrix)
Fibers
Cells
Wide range of varying tissue!
Different structuresdifferent functions!
Ground Substance
Unstructured material
Fills spaces/contains fibers
Composed of:
interstitial fluid
cell adhesion proteins glue like function
Proteoglycansprotein core (point of
attachment) “GAGs” (interlock trapping
water)
Major Cell Types: Blasts vs. Cytes
 1. Blast Cells
 Fibroblasts- large star shaped cells that produce
fibers by secreting proteins into the matrix of CT
tissue.
 Chondroblast – build cartilage tissue
 Osteoblast – build osseous (bone tissue)
 Blasts build!!!!!
More Cells
Fat Cells/Adipocytes – store energy/nutrients
White Blood Cells – respond to injury and
infection to protect and heal the tissue
Mast Cells – stick around blood vessels,
detect foreign microorganisms and start the
inflammatory response against them.
Macrophages – “big eaters” phagocytize lots
of foreign material, from bacteria, to old cells,
proteins, and dust.
Fibroblast—laying matrix
CONNECTIVE TISSUE-FIBER
TYPES
A. Collagenous fibers- Thick threads of
protein (collagen)
Grouped in long parallel bundles, they are
flexible, but only slightly elastic.
Great tensile strength (ligaments and
tendons)
B. Elastic fibersComposed of protein elastin
These fibers branch, forming complex
networks.
(weaker than collagenous fiber, however
they stretch and can return back to there
shape.)
Elastic Fibers
C. Reticular Fibers
Very thin collagenous fibers
Highly branched, form supporting
networks
(LIKE A NET)
Reticular Fibers
When it comes to CT you can have a
variety of types….
Loose CT
Areolar tissue
Reticular tissue
Adipose tissue
Dense CT  regular and irregular
Cartilage types: Hyaline, Elastic,
Fibrocartilage
I.
Loose Connective Tissue
Forms delicate thin membranes
throughout the body
Main cellFibroblasts separated by a gellike matrix
Binds skin to underlying organs and fills
spaces between muscles
Lies beneath epithelium
1. Areolar = “packaging material of the
body” Prototype for CT Having all types
of fibers, cells, etc.
Function
1. support and binds other tissue
2. holds body fluids; job of matrix/ground
substance
3. Defend against infection
4. storing nutrients as fat
2 Loose Connective: Reticular
Has a network of reticular fibers.
Typically loose ground substance
Function is to typically support other cell
types such as white blood cells and mast
cells.
Thus it is found in lymphoid organs, such
as lymph nodes, bone marrow, and
spleen.
3
Adipose Tissue (considered loose
connective)
FATspecialized form of CT, develop
when certain cells store fat in droplets
within their cytoplasm.
Beneath the skin, stored in many other
locations as well.
Cushions, insulates, stores energy.
4 and 5
 Dense Connective Tissueregular or irregular
 Closely packed, thick, collagenous fibers and a
close network of elastic fibers. Relatively few
cellsmost of which are fibroblasts. Poorly
vascularized
 4. Regular = Parallel Organized fibers Tendons
and ligaments. Note some ligaments have more
elastic fibers in them and in fact these tissue are
sometimes called elastic connective tissue.
 5. Irregular = Dermis of skin and Fibrous
Coverings around some organs
 VERY STRONG TISSUE
Cartilage
 Rigid CTprovides support, frameworks, and
attachments, protects underlying tissue and
forms structural models for developing bone.
 Cartilage matrixabundant, largely composed
of colagenous fibers embedded in a gel-like
ground substance . A large percentage of water
up to 80%. Lots of GAGs (proteoglycans)
 Avascular, receives nourishment from
membranes surrounding it. (Perichondrium)
Cartilagea special case
SPECIAL CARTILAGE CELLS
CHONDROBLASTS, form
developing/growing cartilage
CHONDROCYTES, occupy small
chambers called lacunae
Cartilage structures are enclosed in a
covering of CTperichondrium (contains
the blood vessels that deliver nutrients)
THE INTERCELLULAR MATRIX
DISTINGUISHES THE TYPE OF
CARTILAGE! 
6 Hyaline Cartilage
*most common type
*very fine collagenous fibers
(looks like white glass)
Location: end of bones, joints, soft part of
nose, trachea
7 Elastic Cartilage
Dense network of elastic fibers
Much more flexible than hyaline cartilage
Location: framework of ear, parts of larynx
8 Fibrocartilage
Tough tissue, contains many collagenous
fibers
-shock absorber for structures subjected to
pressure.
Location: vertebrae (discs), knees, pelvic
girdle.