Connective Tissue Flashcards
Elements of connective tissues
Extracellular matrix
- ground substance
- protein fibers (collagen, elastic, reticular)
Resident cells
- mesenchymal
- macrophages
- adipocytes
- fibroblast
Connective tissue functions
- Matrix to support and physically connect tissues to form or
- Metabolic support
- Diffusion of nutrients and waste
- Defense
- Protect
- repair
What does connective tissue drive from?
Mesenchyme
Types of connective tissue
Proper: loose/dense and regular/irregular
Special properties: adipose, elastic, mucous, hematopoietic
Supporting: cartilage and bone
Loose connective tissue
Low collagen
High cells
High ground substance
Dense connective tissue
High collagen
Low cells
Low ground substance
What is the most abundant type of connective tissue
Loose connective tissue
- Most cell types present
Where is loose connective tissue located
Under epithelia
- forms storma (non essential)
Fills space between tissue and organs
Sheaths lymphatics and blood vessels
Dense regular vs dense irregular CT
Dense regular ct:
- collagen bundles are aligned in parallel
- tendons and ligaments
Dense irregular ct:
- collagen bundles are randomly arranged
- skin and stomach
dense regular CT locations
tendons and ligaments
Extracellular matrix composition
Fibers
Proteoglycans
Multi-adhesive glycoproteins
Three main types of fibers
Collagen fibers — collagen 1
Reticular fibers — collagen 3
Elastic fibers — elastin
What is the most abundant protein in the body?
Collagen
30% of dry weight
20+ types produced (mostly by fibroblasts)
General role of collagen
Resist tension and shear forces
Assembly of collagen
Peptide chains
Pro collagen
Tropocollagen
Collagen fibrils
Collagen fibers
Osteogenesis imperfecta
A genetic disorder that causes collagen formation to be incorrect or not enough (collagen I)
Collagen I fiber
Most abundant
Resist stretch
Provide tensile strength
Found in dermis, organ capsules, bone, tendons, fibrocartilage, scar tissue
Keloid scar
Excess collagen in wound healing
Collagen I fibers
Causes large scars
collagen types (locations/synthesis/function)
Elastic fibers
ELASTIN core surrounded by fibrilin
Add resiliency to CT
Maintain extensible organs (expand)
Glycosaminoglycans
GAGs
Keratin sulfate & heparin sulfate
Linear chain of repeating disaccharides
Negatively charged (hydrophilic)
Proteoglycans
GAGs + protein backbone
“Bottle brush”
Hydration
Viscous, resists compression
Proteoglycans aggregate
Aggrecan : Proteoglycans attached to a hyaluronic acid polymer
Holds water
Lubricates joints and organs
Permanent/resident cells
Fibroblasts
Macrophages
Mast cells
Adipocytes
Fibroblasts
Permanent/resident cell
Most abundant
Secret ground substance and fibers
Macrophages
Permanent/resident cells
Wound repair
Sensing damage (histocytes)
Phagocytosis
Secrete cytokines/enzymes
Phagocytic cell derived from monocytes and yolk sac progenitors
CT resident macrophages: histocytes
Mast cells
Permanent/resident cells
Inflammatory response
HISTAMINE/HEPRIN/LEUKOTRIENES
Found in dermis, respiratory tract, digestive tract
Long lived
Derived from precursor in bone marrow
Adipocytes
Permanent/resident cells
Whole body metabolism
Store lipids
Insulate
Make hormones
Single lipid droplet, flattened nucleus
Transient cells
Lymphocytes
Plasma cells
Neutrophils
Eosinophils
Lymphocytes
Transient cells
T lymphocytes: produce plasma cells
B lymphocytes: helper and cytotoxic cells
Few in CT
Plasma cells
Transient cells
Short-lived
“clock-face”
derived from B-lymphocytes
Produce ANTIBODIES
Neutrophils
Transient cells
Respond to tissue damage and infection
Lobed nucleus and granules
Eosinophils
Transient cells
Inflammatory/infection
Reddish orange granules
anterior cruciate ligament
*parallel collagen fibers and few fibroblasts
