May 7, 2012
Types of Connective Tissue
Connective Tissue Proper ( Loose and Dense)
Bone -(see other chapter)
Blood-(see other chapter)
Development of Connective Tissue
Mesenchyme is embryological connective tissue that is the first type of connective tissue that
forms the other four.
Endothelium and Mesothelium are also derived from this same source.
Functions of Connective Tissue
Physical protection: The bones of the cranium, sternum, and thoracic cage protect delicate organs, such
as the brain, heart, and lungs; fat packed around the kidneys (perirenal fat)
Support and Structural framework: Bones provide the framework for the adult body and support the
soft tissues; cartilage supports such body structures as the trachea, bronchi, ears, and nose; connective
tissue sheets form capsules to support body organs such as the spleen and kidneys.
Transport: Blood carries nutrients, gases, hormones, wastes, and blood cells between different regions
of the body.
Binding of structures: Ligaments bind bone to bone; tendons bind muscle to bone; dense irregular
connective tissue binds skin to underlying muscle and bone. Storage: Fat is the energy reserve in the body; bone is a large reservoir for calcium and phosphorus.
Immune protection: Many connective tissue types contain white blood cells (leukocytes), which protect
the body against disease and mount an immune response when the body is exposed to something foreign.
A derivative of one type of leukocyte, called a macrophage, phagocytizes (“eats up”) foreign materials.
Additionally, the extracellular matrix is a viscous material that interferes with the movement and spread
of disease-causing organisms.
Connective Tissue Proper LOOSE: Areolar, Adipose, Reticular
This tissue occupies the spaces between and around organs. Loose connective tissues support the
overlying epithelia and provide cushioning around organs, support and surround blood vessels and nerves,
store lipids, and provide a medium for the diffusion of materials.
highly variable in appearance and the least specialized connective tissue in the body.
loosely organized array of collagen and elastic fibers and an abundant distribution of blood vessels.
contains all of the cell types of connective tissue proper; thought to be prototype for L.C.T.
Areolar connective tissue is found nearly everywhere in the body.
It surrounds nerves, blood vessels, and individual muscle
Cells in Areolar Tissue
Fibroblasts are cells in the Areola tissue that produce
protein fibres and ground substance. 3 types of fibres
produced are COLLAGEN, ELASIC, and RETICULAR.
Ground Substance: Fibroblast is responsible for
producing a colourless, viscous (rubbery) solution
termed Extra Cellular Matrix.
1. Collagen (White) Fibres:
fibres of collagen protein;
strong, flexible and resistant to stretch
2. Elastic (Yellow) Fibres:
fibres of elastin protein;
allows for stretch and recoil. 3. Reticular Fibres:
Made up of collagen protein (different than
collagen white fibres).
Tough but flexible.
Form branching/lattice like network in organs
like Spleen and Lymph nodes.
Many different type of cells, each responsible in
different ways for breaking down pathogens (virus,
bacteria, fungus) that enter into the body.
Second line of defence after epithelial cells.
cells that contain mainly lipids
pad and protect the body
source of regulatory hormones such as leptin
Other Types of Connective Tissue Proper Loose
Adipose Tissue (diagram above):
Connective tissue in which the primary type of cells are fat cells
Found in female breast, around some organs for protection and
Connective tissue with predominantly reticular type fibres.
Found in hollow organs like the liver, spleen and lymph nodes
Organs that act like a sponge to trap fluids Connective Tissue Proper DENSE (collagenous tissue)
Composed primarily of protein fibres and has proportionately less ground substance than does loose
Collagen fibres are the dominant fibre type.
There are three categories of dense connective tissue: (1) dense regular connective tissue, (2) dense
irregular connective tissue, and (3) elastic
Regular Connective Tissue
Collagen fibres running parallel to each other and
densely packed together
Found in ligaments (bone to bone) and tendons
(muscle to bone)
Usually poor blood supply making them slow to heal
Irregular Connective Tissue
individual bundles of collagen fibres extend in all directions
in a scattered meshwork in clumps, rather than parallel
provides support and resistance to stress in multiple
directions. i.e. deep portion of the dermis, which lends
strength to the skin and permits it to withstand applied
forces from any direction.
Dense irregular connective tissue also forms a supporting
layer around cartilage (perichondrium) and around bone
(periosteum), except at joints.
Forms a thick, fibrous capsule that supports and houses
internal organs, such as the liver, kidneys, and spleen. Elastic Connective Tissue
Branching elastic fibres and packed collagen fibres
More fibroblasts than loose connective tissue
The elastic fibres provide resilience and the ability to
deform and then return to normal shape.
Found in elastic ligaments like the Liga