SM50_ConnectiveTissue Flashcards
Defining physical feature and functional features of connective tissue
Physical: cells separated from one another and surrounded by an extracellular matrix Functional: support, medium for nutrient/gas exchanged, fat storage, protection, healing and remodeling
What embryologic cell layer is connective tissue derived from? What is the name for embryologic connective tissue?
Mesoderm, mesenchyme
Composition of basal lamina (basement membrane)
collagen, laminin, other glycoproteins
Function (3 things) of basement membrane
Separated epithelial cells from underlying connective tissue, surrounds some types of cells, separates layers of cells
Types of connective tissue proper (support tissue)
Loose connective tissue, dense connective tissue, reticular connective tissue, adipose tissue
Ground substance
protein and polysaccharide matrix forming the extracellular matrix of connective tissue
Properties of loose connective tissue
- Many diff cell types with relatively fewer fibers 2. Often has high fat content (superficial fascia under skin) 3. “Packing material” 4. High amount of ground substance (appearance of empty space under microscope)
Properties of dense connective tissue
- Densely packed fibers (matrix of woven collagen fibers + elastin OR parallel collagen fibers 2. Two types: irregular - elastin; regular - parallel collagen fibers 3. Resistant to tension forces
Reticular connective tissue properties
- Branched, interconnecting meshwork in the loose connective tissue stroma 2. Location: lymphatic tissues and hematopoietic tissue 3. Reticular fibers are very fine collagen (type III fibers)
Adipose tissue properties
- Collection of adipocytes 2. Function: store energy and provide insulation and protection
Types of specialized connective tissue
Cartilage, Bone, Blood
Cells of connective tissue
Fibroblasts/myofibroblasts Macrophages Mast cells Plasma cells/lymphocytes/eosinophils Adipocytes
Recognized pathogens and releases immune mediators
Mast cells
Present antigens from ingested material to lymphocytes to help initiate immune responses
Macrophages
Produce most of fiber and matrix component molecules
Fibroblasts
Has secretory properties of fibroblasts and contractile properties of smooth muscle cells. Active in wound healing
Myofibroblasts
Derived from fibroblasts. Contain large lipid droplet
Adipocytes
Components of extracellular matrix
Fibers: -collagen -elastic fibers Ground substance: - -
Properties of collagen
-most common fibrous protein in ECM. most abundant protein in humans -released from fibroblasts are procollagen -Consists of three protein chains wrapped in helical arrangement -acidophilic -stains pink in H&E-stains -requires vitamin C for proper formation of fibers
Types of collagen
Type 1: 90% of collagens - in bone, skin, tendons, ligaments, cornea Types 1,2,3,5,9: fibrillar (protein chains assemble into fibrils) Types 5,6: form networks in basement membrane
Mutations that affect type 1 collagen cause _____ ______
osteogenesis imperfecta
Properties of elastic fibers
- Made up of elastin and microfibrils (fibrillin) and provides elasticity 2. Without fibrillin, elastin assembles into sheets, not fibers 3. Found in skin, lung, blood vessels, elastic cartilage, fetal tissues 4. Bc of random coiling, can be stretched and will return to original position
Properties of elastin
- Amorphous protein 2. Secreted from fibroblasts as a monomer, tropoelastin 3. Cross linked extracellularly and assembled as a scaffold of microfibrils
Marfan’s syndrome is characterized by
a dysfunctional form of fibrillin
Three major groups of ground substance molecules
- glycosaminoglycans (GAGs) - give connective tissue gel like quality 2. Proteoglycans 3. Multiadhesive glycoproteins
Name of the longest GAG (thousands of sugar molecules)
hyaluronan
How does GAG hydrate connective tissue?
Its negative charges bind water!
Type of connective tissue
loose
Type of connective tissue
Dense irregular
Type of Connective Tissue
Dense regular
Type of connective tissue
reticular
