Lecture 2 - Connective Tissue Flashcards
Connective Tissue Function
Provide Structural Support
Medium for nutrient exchange
Aid in Defense and protection of body
Form site for storage of fat
Connective tissue is made up of…
extracellular matrix and cells
extracellular matrix function
resists both compressive and tensile forces
extracellular matrix is made up of…
Ground substance
Fibers
ground substance is made up of…
Glycosaminoglycans
proteoglycans
adhesive glycoproteins
3 Types of Fibers in the ECM
Collagen, Elastic Fibers, and Reticular
Glycosaminoglyans (GAG)
long, inflexible, unbranched polysaccharides whose function is to attract water, resist compression and slow the movement of cells (ex. hyaluronic acid)
Proteoglycans
proteins + GAGs whose function is to attract water, resist compression and slow the movement of cells (ex. aggrecan)
Adhesive glycoproteins
large macromolecules with cell surface proteins called integrins whose function is to fasten tissue components together (ex. fibronectin
Most prevalent protein in the body
collagen
Type I collagen
Function: resists tension and pull
Location: dermis of skin, bone, capsules of organs, fibrocartilage, dentin, cementum, and tendons
Type II collagen
function: resistance to pressure
location: hyaline and elastic cartilage
Type III collagen
Also known as reticular cartilage
Function: structural support
Location: reticular fibers of the spleen, liver, lungs, and skin
Type IV collagen
Function: support and filtration
Location: basal lamina
Type V collagen
Function: associated with type I collagen
Location: fetal tissues, placenta, dermis, bone, and most interstitial tissues
Type VII collagen
Function: anchors the epidermal basal layer to the underlying dermis
Location: skin
Types of Collagen forming the basement membrane
Type IV and VII
Where is the Connective Tissue Derived From
Mesenchyme
Fibrilar Collagens
Type I, II, III, form large fibrils
Sheet-forming Collagens
Type IV, major tructural proteins of external laminae and the basal lamina
Linking Anchoring Collagens
Short Collagens that link fibrillar collagens together Type VII is one. they are an anchor
Property of Elastin Aggregates
They are cross-linked together and are able to be stretched or distended and then return to original shape
Elastic Fibers Compared to Collagen Fibers (size density)
They are thinner than type I collagen and are more sparse in networks (thinner on picture)
Reticular Fibers (composition, size, function)
Composed of Type III collagen
Have narrow diameters, are shorter and more branched than elastin
Provide supporting framework (scaffolding) for cellular constituents of tissues and organs
Types of Cells in Connective Tissue
Fixed Cells - Only located in the Connective tissue
Transient Cells - cells of immune system that come in and out
What are the Three Fixed Cells
Fibroblast
Adipose Cells
Pericytes
Fibroblast Function
Produce ECM (most abundant Cell Type) Originates in Mesenchyme
Types of Fibroblast
Active Fibroblast
Inactive Fibroblast AKA quiescent
Myofibroblasts
Myofibroblasts (Function, When seen, Dental Correlation)
Specialized Fibroblast that contracts in wound to heal it
has some contractibility and is seen in wound healing
found in periodontal ligament and nicotine inhibits it
Active Fibroblasts
Type of Fibroblast cell in the Connective Tissue
close to collagen, produce ECM
has a football shape
Inactive Fibroblast AKA quiescent fibroblast
Type of Fibroblast cell in the Connective Tissue
differentiates in to
active, smallrer then active, can become adipose,
cartilage, or osteoblasts under extreme situations
Adipocytes Function and where seen
Synthesize and store and release fat,
either unilocular or multilocular
may also form adipose tissue
seen around blood vessels
Types of Adipocytes (and structure)
White Fat - unilocular single drop large fat cells, most common for energy
Brown Fat - multilocular, several small drops
stains darker, dense blood supply lots of mitochondria, thermogenic, and found post natal
Pericytes (Where they are seen)
Associated with Blood Vessels, have long processes that wrap around the vessels and act as smooth muscle
Five Categories in Classification of Connective Tissue
Mesenchyme Connective Tissue Proper Reticular Tissue Adipose tissue Specialized Connective Tissue
Mesenchyme (What if forms in to, and consists of)
Loosely packed unspecialized cells, in ECM
Precursor for blood and blood vessels, and connective, supportive and muscle tissue
What are the types of Connective tissue proper
Loose and Dense
Loose Connective Tissue ( composition and location)
lots of ground substance, very flexible
fills in places that are just under the skin
Dense Connective Tissue types
Dense Irregular and Dense Regular
Dense Irregular Connective Tissue (composition and location)
tightly packed not organized cant make out arrangement,
and found in dermis of skin and lymph nodes
Dense Regular CT Types (two of them, location, and composition)
Collagenous - seen in tendons, organizes in parallel to resist tensile
Elastic -some organization, found in large blood vessels, organized fibers of elastic
Reticular Fiber
A connective Tissue Type
found with Collagen III that creates archetectural framework
Adipose Tissue
A category of Connective tissue
abundant in adipocytes
The Specialized Connective Tissues
Cartilage, Bone, Blood
Ehlers Danlos Syndrome
Connective Tissue Disorder Resulting in defects in fibrillar collagen. (seen as really stretchy skin) defects in collagen I as result
Marfan Syndrome
Mutation in Fibrillin I gene
Cannot maintain elastic fibers
have long bones and weird connective tissue
