Connective Tissue(CT)/Cell Matrix Lecture Flashcards
What does connective tissues connect to?
What does connective tissue provide for other tissues? Give an example.
How does connective tissue help in the defense and protection of other tissues?
where is conective tissue found?
What does connective tissue support?
Connective tissue connects other types of tissue, including epithelium, muscle and nerve tissues.
Connective tissue provides various types of support for these other tissues. For example, connective tissue provides structural and metabolic support (connective tissue is highly vascularized).
Connective tissue also helps in defense and protection of other tissues from pathogens, and serves as a location for exchange of nutrients between blood and other tissues.
Connective tissue is found in many places in the body. Connective tissue is located underlying the epidermis of the skin where it mechanically supports the epithelium, provides nutrients to the overlying epithelium, and is a locus for defense against foreign invaders. Connective tissue is also found in the bones and cartilage of the body
what are the 2 main components of connective tissue?
What does the extracellular matrix provide and have?
what does the ground substance contain?
What does GAG stand for and what is it?
what do GAGs attract?Why do GAGs need to be hydraded?
What are specific types of GAGs?
What are proteoglycans?
What is a name of a specific proteoglycans?
What are the types of adhesive glycoproteins found in the matrix?explain where each component is found?
What do integrins do ?And what are they?
Connective tissue has two main components- extracellular matrix and cells.
The extracellular matrix of connective tissue provides mechanical integrity and strength to connective tissue. Connective tissue matrix is comprised of ground substance- a large amorphous gel-like substance, and fibers.
Ground substance contains several classes of molecules, including glycosaminoglycans, proteoglycans and adhesive glycoproteins. Glycosaminoglycans (GAGs) are long unbranched polymers of repeating disaccharides.
GAGs attract water and tend to be highly hydrated. The hydration of GAGs (and proteoglycans) gives the matrix its gel-like consistency and its resistance to compression (similar to a water balloon).
Specific GAGs include Hyaluronic Acid, and Chondroitin Sulfate. Proteoglycans are conglomerates of GAGs covalently attached to a central protein core. Proteoglycans are large aggregates of GAGs. One major proteoglycan is called Aggrecan.
Adhesive glycoproteins found in the extracellular matrix include laminin, which is localized to the basal lamina, and fibronectin which is dispersed throughout the extracellular matrix. Some types of integrins (the transmembrane proteins found in hemidesomosomes of epithelial cells) can directly interact with laminin and fibronectin.
What are the fibers found in the matrix?
what are collagen fibers?and what are they composed of? And what about collagens composition does it make it unique?
What are the different kinds of collagen that exist and where are they found?
What are elastic fibers made of?
How far can elastic fibers be stretched?
How are elastin molecules arranged?
what are desmosine residues?
Fibers found in the matrix of connective tissue include Collagen and Elastin. Collagen fibers are inelastic and resist tensile forces (similar to a rope). Collagen fibers are composed of subunits called tropocollagen that assemble in a staggered array containing gap regions. This staggered array imparts to collagen a periodicity (in electron microscope pictures, they look banded). There are many types of collagen including Type I- found in bones, Type II found in some types of cartilage, and Type III- fine reticular fibers found in lymph nodes and other organs of the lymphatic system. Elastic fibers are composed of Elastin and Microfibrils, and are highly elastic. Elastic fibers can be stretched up to 150% of their length and then return to their original length.
Elastin molecules are cross-linked by highly deformable cross-links called desmosine residues, and are associated with microfibrils such as fibrillin which give stability and prevents overstretching of the elastic fibers.
What are the types of cells that are found in connective tissue?where do each of these cells reside?
What do fixed cells include
(types)?
What are fibroblasts?
In light micrographs where can you see fibroblasts?
How can fibroblasts be identified?
Where can fibroblasts be found on cytoplasmic processes?
Cellular components of Connective Tissue
Several types of cells are found in connective tissue, including fixed cells (that permanently reside in the connective tissue), and transient cells (that move from the blood stream to the connective tissue during inflammation). We will focus on the fixed cells of connective tissue. The fixed cells include Fibroblasts, Adipocytes, Mast cells and Macrophages (Macrophages actually can be both fixed and transient). Fibroblasts are long, spindle shaped cells that are responsible for the synthesis of tropocollagen, and all other components of the extracellular matrix. In light micrographs, fibroblasts are often found lying along collagen fibers that they synthesized. Fibroblasts can be identified by their dark purple staining nuclei that are elongated between collagen fiber bundles.
Their cytoplasmic processes extend outwards from the nuclei but are often too pale to be seen in light micrographs.
What are adipose cells?and where are they found?
What shape are adipose cells?and what is their composition?
What is the lipid droplet like in adipose cells?
Are adipocytes found alone or in groups?
where do adipose cells tend to be located?
Adipose cells are cells that store fat, that are found in connective tissue. They are round shaped cells with a large lipid droplet that encompasses most of the cell body. The lipid droplet is so large that it pushes the cytoplasm and nucleus to a thin rim in the periphery of the cell. Adipocytes tend to be located in groups or colonies. In the dermis of the skin, adipocytes are located at the deep side and provide an insulating layer.
what system are mast cells a part of?
what do mast cells express and what do they bind to?
What happens after they bind to antigens?
What do mast cells look like morphologically?
Where can mast cells be found?Why are they found there?
Mast cells are part of the immune response. Mast cells express antibodies on their cell surfaces that bind antigens that come into the body. Upon binding antigens, Mast cells release their granules or undergo degranulation. Their granules contain molecules such as Heparin and Histamine that exert diverse effects throughout the body, including bronchial constriction, and vasodilation. In some cases, mast cell degranulation can induce anaphylactic shock.
Morphologically, mast cells are oval shaped cells that have a purple stained cytoplasm that upon closer look appears grainy (although individual granules cannot be resolved). Mast cells tend to line up along blood vessels so they can exert effects on distant tissues, by diffusion of granular components through the bloodstream.
What are macrophages?
where do macrophages originate from?
What are the 2 categories that macrophages are a part of?
What is the morphology of macrophages that gives it its fucntion? what about macrophages general shape?
Macrophages are scavengers that digest cellular and noncellular debris. Macrophages originate from Monocytes in the blood, and are considered to be both fixed and transient in connective tissue. Macrophages have extensive lysosomes to facilitate their digestion of foreign substances. These lysosomes are usually stained blue and can be individually resolved. Macrophages are motile cells, with irregular cell outlines, and a variety of morphologies.
What are the 2 main organizations and classifications of connective tissue?
Is there a high or low density of connective density in loose connective tissue, but is in high concentration?
Where can loose connective tissue be found?
What is the mesentery? what is its composition like?
If you could spread mesentery in a slide what would you find?
The two main organizations and classifications of connective tissue are loose and dense. In loose connective tissue, the density of connective tissue fibers (i.e. collagen) is low but the cellular density may be high.
Loose connective tissue is found in the mesentery throughout the body, a thin connective tissue sheath covering many organs including the stomach. Mesentery is very thin and can simply be stretched and mounted onto slides without sectioning.
In a mesentry spread you can make out collagen and elastin fibers as well as cells dispersed between the fibers. Again, the fibers in loose connective tissues are relatively sparse- which is why it is called loose.
what are the 2 types of dense connective tissues?
What is in high concentration and low in concentration in dense connective tissue?
Where is dense irregular connective tissue found?
what can you find in dense irregular connective tissue?
where is dense regular connective tissue found?How is this organized in the tendon?What else is found organized parallel to it and where else are fibroblasts muclei found??
Dense connective tissue can be of two types-irregular and regular.
In dense connective tissue the fiber density is high and the cellular density is lower.
Dense irregular connective tissue is found in most of the dermis underlying the epidermis.
In this tissue you can see thick collagen fiber bundles in a higher density than in mesentery, and also at higher magnification can make out some cells and possibly even distinguish fibroblasts.
Dense regular connective tissue is found in the tendon.
Specifically, the tendon contains bundles of collagen fibers arranged in an ordered parallel array. Fibroblast nuclei are aligned parallel to and between the collagen bundles of dense regular connective tissue.
Sample Questions:
- Which of the following classes of proteins is responsible for the ability of connective tissue matrix to resist compressive force?
A. GAGs
B. Histones
C. Glycoproteins
D. Fibers
E. Microfibrils
1A
Which of the following has collagenous connective tissue that resists forces only in one orientation?
A. Dermis
B. Mesentery
C. Tendon
D. Aorta
E. Vena cava
2C
