FTM 46 - Connective Tissue 1 Flashcards
What are the primary components of ECM and what are the ECM’s primary functions?
How does connective tissue acquire its nutrients and clear away its waste? How do the cells of the connective tissue communitcate with the brain?
Connective tissue is directly supplied by blood, lymphatic vessels, and nerves
What is a stroma?
The supportive tissue of an epithelial organ, tumor, gonad, etc., consisting of connective tissues and blood vessels.
What is a parenchyma?
The functional tissue of an organ as distinguished from the connective and supporting tissue.
What are the common cell types found in connective tissues? Which cell types are permanently in the connective tissues and which ones only pass through connective tissues?
What are the 4 basic things to know about fibroblasts?
Fibroblasts found in an embryo
Fibroblasts found in an adult.
Firbocytes
Describe how fibroblasts in an embryo and adult appear on a microscope slide.
Describe how fibrocytes appear on a microscope slide?
Shrunken nucleus and a lose basophilic cytoplasm
What are some notable features of connective tissue that can be seen in a TEM?
Cells with extensive rER
Cells with extensive golgi
Cells with a euchromatic nucleus
An abundance of collagen fibrils outside of the cells
What are the two types of adipocytes? What are their informal names?
Unilocular (white fat)
Multilocular (brown fat)
What are some key features of unilocular adipocytes?
Why do adipocytes appear empty in H & E stains? How can this be corrected?
The lipids get washed out during the processing. However, lipids can be visualized with the use of fixatives like osmium and fat soluble stains like oil red O.
What are some key characteristics of multilocular adipocytes?
What type of cell do macrophages arise from?
Monocytes that have migrated into connective tissue
What are the names macrophages have when in liver, brain, and bone tissues?
Liver - Kupffer cells
Brain - microglia
Bone - osteoclasts
Describe some of the distinguishing features of a macrophage.
The posses an irregular cell membrane with cytoplasmic extensions (pseudopodia)
They are multinuclear and very large
Prominent golgi
Abundant lysosomes
Numerous phagocytic vesicles
What are cytokines?
Any of a number of substances, such as interferon, interleukin, and growth factors, that are secreted by certain cells of the immune system and have an effect on other cells.
Describe the cell type that mast cells arise from and their location. Describe what occurs before this cell becomes a mast cell. What other cell also arives from this precursor?
Mast cells originate in the bone marrow from precursor cells lacking cytoplasmic granules. When they migrate to connective tissue they proliferate into mast cells and accumulate cytoplasmic granules.
Mast cells and basophils circulating in the blood are derived from the same progenitor in the bone marrow
What do the cytoplasmic granules of mast cells contain? What other important compound is released from mast cells but not found in the cytoplasmic granules?
Vasoactive mediators - primarily histamine and heparin
Chemotactic mediators - to attract monocytes, neutrophils, and eosinophils circulating in blood to the site of mast cell activation
Leukotrienes are not present in the cytoplasmic granules but are released from the mast cell membrane as metabolites of arachidonic acid
What is a metachromatic dye and what is metachromasia? What causes it?
Metachromatic Dye - a stain that changes color when it binds to a specific, called a chromotrope, in a cell.
Metachromasia is the name given to the color change phenomenon
It is caused by a change in the electronic structure of the dye molecule after binding to a chromotrope
What connective tissue cell type can cause metachromasia and with what dye does this occur? Where in the cell does this occur? What other nonmetachromatic dye is useful for staining this region of the cell and why?
Toluidine blue turns a purple red color when bound to the cytoplasmic granules of a mast cell
Mast cell granules are also PAS positive because of their glycoprotein nature
Descrbie the ligh microscopic appearance of lymphocytes.
Small and spherical with very little cytoplasm and a large condensed basophilic nucleus
What are the types of lymphocytes and what can these cell mature into?
B-cells can develop into plasma cells
T-cells just stay as T-cells
What is a negative golgi image?
The golgi apparatus is too small to be visualized with H & E staining. However, its whereabouts may be detected in cells with intensely basophilic cytoplasm. This is because the golgi appartus lacks ribosomes causing it to appear relatively pale in the surrounding basophilic cytoplasm. This is called a negative image of the golgi.
What is the primary function of a plasma cell?
Synthesize and secrete a single class of immunoglobulin
What type of protein is an immunoglobulin?
Glycoprotein
Describe the light microscopic features of a plasma cell and what causes those features.
Clockface nucleus - caused by peculiar distribution of chromatin
Basophilic cytoplasm - caused by abundant rER
Negative golgi image - caused by basophilic cytoplasm
Describe the TEM features of a plasma cell.
Well developed rER
Extensive golgi apparatus
Prominent nucleolus
What are some of the key light microscopic features of an eosinophil?
Eosinophilic (red) granules in the cytoplasm
Condensed bilobed nucleus
What are the primary functions of an eosinophil?
Phagocytose antibody-antigen complexes
Kill parasitic worms
What are the 3 main types of ECM fibers and their alternate names?
Collagen Fibers
Reticular Fibers (Type-III collagen)
Elastic Fibers
What are the three primary types of ground substances?
GAGs (glycosaminoglycans)
Glycoproteins
Proteoglycans
What is the most abundant protein found in the body?
Collagen
Does hematoxylin or eosin stain collagen?
Eosin
What are the most abundant AAs found in collagen?
Glycine (30%)
Proline
Hydroxyproline
Hydroxylysine
Write out all the steps to collagen synthesis.
How many types of collagen are there? Where is each type most commonly found?
What type of collagen are reticular fibers primarily composed of?
Type-III
Describe the general appearance of reticular fibers and where they are commonly found.
They are short, thin, and branching. Normally found in organs that undergo large volume changes (spleen, arteries, intestines, testes, etc)
Which stains are best used to dye reticular fibers?
Silver and PAS (due to carbohydrate content)
What does the term argyrophilic mean?
An argyrophilic molecule binds to silver stain
What is the first type of collagen synthesized during wound healing?
Reticular Fibers (type-III collagen)
Briefly discuss the development and composition of elastic fibers.
Elastic fibers are also often yellow colored
What is the most notable feature of elastic fibers and where are these fibers typically found?
What are the best stains to use for elastic fibers?
Orcein, resorcin, or Verhoeff’s
What celly type are these?
Multilocular adipocytes
What cell types are these?
Macrophages
What type of cell is this?
Mast cell
What type of cell is this?
Lymphocyte
What types of cells are these?
Plasma Cells
What type of cell is this?
Eosinophil
Those are fibroblasts
