Function of connective tissue (x3)
- Structural Support
What makes up connective tissue?
Extracellular Matrix (Fibers/Ground substance)
Blood or lymph vessel
Main function of fibroblast?
Where would you expect to see a lot of active fibroblasts?
3 Types of fiber in connective tissue
Fibroblast + Vitamin C = procollagen –> collagen –> fibril –> fiber
Type I collagen function
What contains lots of type I collagen?
Skin, ligaments, tendons
Where is type IV collagen found?
Basal Lamina –> lamina densa
What attaches the cell to type IV collagen?
Where can you find type VII collagen?
BM –> anchoring fibril
Where do you find type III collagen?
Reticular Lamina w/ in BM
Fibers are in spleen, lymph nodes, liver, endocrine glands
What is the main function of fibroblasts?
Where do fibers and ground substance come from?
What types of cells are found in connective tissue? (x8)
- Mast Cells
- Plasma Cells
Where are adipocytes found?
CT of many organs
Where are chondrocytes found?
Where are osteocytes found?
What is the most common cell in CT
In general, what is the roll of mast cells?
Release mediators that contribute to the allergic response
In general, what are macrophages involved with?
Shape of plasma cells?
Nucleolus in the middle, spokes around the side
Why does cytoplasm stain purple?
Active cells produce protein (pink, acidophilic) and RNA (RER, blue, basophilic). When these colors mix, they produce purple.
What is the function of plasma cells?
Produce antibodies to an antigen that will trigger an immune response.
What is the most common type of collagen?
What is the process of forming a collagen fiber?
- Collagen fiber + Vitamin C
- Procollagen plus processing
- Fibril formation which is striped
- Bundle to form fiber
Where is Type I collagen most commonly found?
Ligaments, Skin, and Tendons
What is the major function of Type I collagen?
Where is Type IV Collagen found?
What attaches to type IV collagen?
Laminin which connects to the transmembrane protein integrin. Forms the hemidesmosome
Where can you find Type VII collagen fibers?
Basement membrane- anchors Type IV collagen to Type III collagen (reticular fibers)
The diameter of a collagen fibril ranges from 20-90 nm. How can you see type VII collagen fibrils using a light microscope?
Immunohistochemistry to type VII collagen- use fluorescent tagged antibody
Where do you find Type III collagen?
Reticular fibers in the reticular lamina of the basement membrane. They are most abundant in the spleen, lymph nodes, liver, and endocrine glands.
Reticular fibers are heavily glycosylated. Will they stain with H&E?
No, H&E does not stain glycogen.
What is the major function of reticular fibers?
Support individual cells.
What makes up elastic fibers?
What do fibroblasts secrete?
Fibrilin and Elastin to form elastin bound microfibrils
How do elastic fibers differ from collagen?
They are not as uniformly shaped as collagen fibers.
What is the ground substance made of?
- Glycoaminoglycans (GAGs)
- makes up a semifluid gel linking cells and ECM (Laminin)
How does loose CT differ from dense CT?
- Loose CT has lower fiber to cell/ground substance ratio than dense CT
- Loose CT is well vascularized, dense regular CT is not
- Loose CT is more flexible than dense CT
- Loose CT is less resistant to stress than dense CT
Where do you find dense regular CT?
Tendons and Ligaments
Where do you find dense irregular CT?
Where would you find elastic tissue?
Elastic ligaments of spine and Aorta
What is adipose tissue?
Loose connective tissue dominated by fat cells or adipocytes
What are the functions of white adipose tissue?
- Cushion other organs
- Endocrine Organ
- Shock Absorption
- Store triglycerides
What would be the most common type of fiber in adipose tissue?
Reticular fibers (adipocytes are surrounded by Type III collagen)
What is the main function of brown adipose tissue?