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What is the origin of connective tissue?
What is the origin of connective tissue?
What is the function of connective tissue?
What is the function of connective tissue?
What is the component of connective tissue that allows diffusion of tissue fluids, nutrients, and waste products?
What is the component of connective tissue that allows diffusion of tissue fluids, nutrients, and waste products?
What is the type of collagen fiber found in cartilage?
What is the type of collagen fiber found in cartilage?
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What is the characteristic of elastic fibers?
What is the characteristic of elastic fibers?
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What is the type of collagen fiber formed by epithelial cells?
What is the type of collagen fiber formed by epithelial cells?
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What is the function of reticular fibers?
What is the function of reticular fibers?
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What is the characteristic of reticular fibers under a microscope?
What is the characteristic of reticular fibers under a microscope?
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What is the main function of fibroblasts?
What is the main function of fibroblasts?
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Which type of cells can differentiate into other types of connective tissue cells?
Which type of cells can differentiate into other types of connective tissue cells?
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What is the function of reticular cells?
What is the function of reticular cells?
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What is the characteristic feature of old non-active fibroblasts?
What is the characteristic feature of old non-active fibroblasts?
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Where are pericytes present?
Where are pericytes present?
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What is the function of histocytes?
What is the function of histocytes?
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What is the characteristic feature of reticular cells?
What is the characteristic feature of reticular cells?
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What can pericytes change into?
What can pericytes change into?
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Study Notes
General Characters of Connective Tissue
- Originates from mesoderm
- Supports, binds, and connects various tissues and organs
- Composed of connective tissue cells, fibers, and ground substance (matrix)
- Rich in blood vessels and nerves
Structure of Connective Tissue
- Consists of matrix, fibers, and cells
Connective Tissue Ground Substance
- Jelly-like substance formed of acid mucopolysaccharides
- Produced by fibroblast cells
- Present between connective tissue cells and fibers, binding them together
- Allows diffusion of tissue fluids, nutrients, and waste products between components and body tissues
Connective Tissue Fibers
White Collagen Fibers
- Appear white in fresh state
- Formed of bundles, each consisting of a group of fibers
- Each fiber formed of a group of fibrils, composed of tropocollagen molecules
- Appear pink in H&E stain
- Types:
- Collagen type I: found in tendons of muscle and bone, formed by fibroblast cells and bone
- Collagen type II: found in cartilage, formed by chondroblasts
- Collagen type III: forms reticular fibers
- Collagen type IV: present in basement membranes, formed by epithelial cells
- Collagen type V: found in fetal membranes, blood vessels, and around muscles, formed by fibroblasts
Yellow Elastic Fibers
- Thin, branching, slender, and long fibers
- Appear yellow in great amounts
- Resistant to boiling and hydrolysis by acids or alkalies
- Formed of protein called elastin
- Formed by fibroblast and smooth muscle cells
- Stained yellow by Van Gieson stain and brown with orcein stain
Reticular Fibers
- Very fine, delicate fibers forming the stroma of glands like liver and salivary glands
- Not visible by H&E stain
- Appear black with silver stain and red with PAS
- Formed of collagen type III, proteoglycan, and glycoproteins
- Formed by fibroblasts and smooth muscle cells
- Function: forms reticular meshwork of stroma of organs
Connective Tissue Cells
Fixed Cells
- Long-lived cells like fibroblasts, histocytes, fat cells (adipocytes), mesenchymal cells, pericytes, and reticular cells
Free Cells
- Short-lived motile cells that enter connective tissue from blood, like free macrophages, plasma cells, mast cells, and leucocytes
Fixed Cells of Connective Tissue
Fibroblasts
- Irregular or fusiform in shape
- Basophilic cytoplasm rich in RER, Golgi complex, mitochondria, and secretory granules
- Pale oval nucleus
- Old, non-active fibroblasts are called fibrocytes, with acidophilic cytoplasm and dark nuclei
- Function: forms connective tissue fibers and ground substance; helps in wound healing
Reticular Cells
- Star-shaped cells with long processes and central rounded nuclei
- Functions: form reticular stroma of organs like spleen, lymph node, and thymus
- Can change into phagocytic cells when stimulated by antigens
Mesenchymal Cells
- Embryonic undifferentiated cells
- Pale basophilic cytoplasm with central oval nucleus and multiple cytoplasmic processes
- Function: can differentiate into other types of connective tissue cells
Pericytes
- Irregular cell membrane with multiple cell processes and oval central nuclei
- Present in the wall of blood capillaries between the basement membrane and endothelial lining
- Functions: can change into fibroblasts, smooth muscle cells, and endothelial cells; change diameter of capillaries
Histocytes (Fixed Macrophages)
- Irregular cell surface with protrusions and indentation and oval eccentric nucleus
- Cytoplasm rich in lysosomes and residual bodies
- Stained with vital stain like trypan blue
- Functions: phagocytosis of foreign bodies; antigen presentation; can fuse to form...
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Description
This quiz covers the general characters and structure of connective tissue, including its origin, function, and components. Test your understanding of connective tissue cells, fibers, and ground substance.
