What are the main functions of Connective Tissue?
- -provide and maintain form in the body
- -provide a matrix that connects and binds cells and tissues together
- -serve as a reservoir for hormones controlling cell growth and differentiation
- -Medium through which nutrients and metabolic waste are exchanged between cells and their blood supply
What are the 3 components of CT?
- -ground substance
What are the two components of the extracellular matrix (ECM)?
What are the 3 types of CT cells?
Name some types of Mesenchymal cells...
- -endothelial cells
- -smooth muscle cells
Name some types of Hematopoietic cells...
- -mast cells
- -lymphocytes (T&B)
Name some types of Macrophage-like cells...
- -monocytes (blood)
- -macrophage (tissue)
- -multinuclear giant cell (CT)
- -Kupffer cell (liver)
- -microglia (CNS)
- -osteoclasts (bone)
- -Langerhans cell (skin)
- -dentritic cell (lymph nodes)
What are the 3 CT fiber types?
What are examples of some important CT in the body?
- Organ capsules
- Stroma of organs
- Covering muscles and nerves and membranes (meninges) surrounding the CNS
What is the function of collagen?
Provides resistance to tensile forces (something being pulled apart)
What is tropocollagen?
a single molecule of collagen fiber
- a collagen molecule that leaves cell membrane (starts as procollagen)
- have 3 strands of AA – polypeptide chain similar to what will see in basal lamina
What are the layers of a collagenous fiber, starting with the inner most layer?
- Fibril (a number of collagen molecules)
- Fiber (series of fibrils)
Describe Type I collagen and give some examples.
- Strongest, largest of collagen fibers
- The most abundant collagen
EX: dense CT, muscles, ligaments, tendons
Describe Type II collagen and give some examples.
Resist compressive/shearing forces
EX: Found in articular cartilage and fibrocartilage (bones)
Describe Type III collagen and give some examples.
synonymous with reticular fibers, provides framework
EX: found in skin, artery wall, scar tissue
Describe Type IV collagen and give some examples.
major filament providing connection points for cells to bind
EX: desmosomes of basement membranes (basal lamina)
Explain what a reticular fiber is.
- Composed of type III collagen fibers
- Small diameter and "loosely" arranged -> creates a flexible network for organs that incur volume changes (arteries, spleen, liver, uterus)
- Abundant in smooth muscle, endoneurium (neurons), and the framework for hemotopoietic organs (spleen, lymph nodes, bone marrow)
- Also located in the papillary layer of the dermis
Describe the 3 fiber types of Elastic tissue.
- Oxytalan: small fibers that do not actually contain elastic protein but are resistant to tensile forces
- Elaunin: Mixture of elastin protein and oxytalan fibers
- Elastin: Polymers of elastin aggregate in the center of elastic fibers and are surrounded by network of oxytalan and elaunin fibers
What is ground substance?
a viscus, hydrophilic substance with many macromolecules (glycosaminoglycans [GAGs], proteoglycans [PGs], glycoproteins)
- occurs "between" cells
- binds cell surface receptors to fiber components of ECM
- Anchor cells within ECM; provides tissue strength and rigidity
What are some CT Proper types?
- Loose CT
- Dense CT (regular and irregular)
What are some specialized CT?
- Hematopoietic (blood)
- Mucus tissue (umbilical cord)
What are 2 supporting CT types?
Cartilage and bone
Describe loose CT and give some examples of where you may find some.
- Supports structures that are normally under low pressure and low friction forces
- Flexible tissue, well vascularized, not very resistant to tensile forces
- Contains mainly fibroblasts and collagen, with lesser amounts of elastic and reticular fibers
- Very common and found in many tissues
EX: epithelium, endomysium, endoneurium, dermis, lining of peritoneal and pleural cavities, surrounding glands, blood vessels, and mucous membranes
Describe dense CT.
- Main fxn: to offer resistance to tensile force and protection of tissues
- Have fewer cells and predominance of collagen fibers compared to loose CT
- Minimally flexible
- High resistant to stress (esp. tension)
- 2 different types: irregular and regular
Describe dense regular CT and give are some examples.
- Collagen bundles arranged into definitive, linear pattern
- Linear orientation of fibers is designed to withstand prolonged stressed exerted n the direction of fiber alignment
EX: Tendons and Ligaments
Describe dense irregular CT and give an example.
- Collagen fibers arranged in bundles without and definite orientation
- Provides resistance to stress in all directions
EX: Dermis (reticular layer)
Describe elastic tissue
- Composed of thick, parallel elastic fiber bundles, and fibroblasts
- Thin collagen gibers are scattered among the elastic fiber bundles
- Abundant elastic content confers color
- FXN: designed to provide elasticity to tissues, and recoil from extended position to flexed position
EX: mainly in ligaments of vertebral column (ligamentum flavum)