Chapter 2- Connective Tissue Flashcards
unlike epithelium, CT consists mostly of what two things?
- intercellular components
2. limited number of cells
what are the 4 general functions of CT?
- structural support (bone)
- medium for exchange (loose irregular)
- defense/protection (loose areolar)
- storage of adipose (perinephric fat)
what are the 4 characteristics of CT?
- derived from mesenchyme
- support cells separated by matrix
- support cells produce matrix
- cells adhere to matrix
extracellular matrix is composed of what two things?
- ground substance
2. fibers
what makes up the ground substance?
- GAGs
- proteoglycans
- adhesive glycoproteins
- other stuff
what is an important general trait about GAGs?
hydrophilic
T/F. GAGs do not support inflammation.
false; they do support inflammation
what are the two types of GAGs?
sulfated and non-sulfated
what are examples of sulfated GAGs?
- keratan sulfate
- chondroitin sulfate
- heparin sulfate
- dermatin sulfate
are sulfated GAGs smaller or larger molecules?
smaller
sulfated GAGs are covalently bonded to ______.
proteins
what is an example of non-sulfated GAG?
Hyaluronic Acid
are non-sulfated GAGs smaller or larger?
larger
what do non-sulfated GAGs form?
dense molecular network
non-sulfated GAGs hold a lot of water which is important for _______ in some tissues.
diffusion
what are some positive aspects of inflammation?
- increased fluidity aiding in cell movment
2. increase numbers of defensive cells
where does the extra fluid and defensive cells come from?
leaky capillaries and venules
what is a negative aspect of inflammation?
excessive swelling can damage blood vessels, nerves, and cells
define proteoglycan.
protein core with many sulfated GAGs attached
what are examples of adhesive glycoproteins?
laminin and fibronectin
what are the three fibers that are found in the extracellular matrix?
- collagen
- elastic
- reticular
what is the most common CT protein?
collagen
what type of collagen accounts for about 90% of the total body collagen?
type 1
type 1 collagen is known for its great ______ ______ but does not _____
tensile strength
stretch
what pathology can be associated with defective or reduced collagen?
Ehlers-Danlos Syndrome
T/F. in Ehlers-Danlos syndrome, only the skin will be affected, the blood vessels will be spared.
false; skin and blood vessels are affected
T/F. as we age, collagen fiber production is slowed but the tensile strength remains the same.
false; production slows and fibers produced are weaker
what is necessary for proper cross-linking within collagen type 1 fibers?
vitamin C
if you do not have enough vitamin C, you will have weaker collagen and a more rapid fiber break down leading to what pathology?
scurvy
what are elastic fibers composed of?
elastin and microfilaments
elastic fibers can stretch ____% of its resting length.
150%
elastic fibers are important in what two structures in the body?
- blood vessels
2. lungs
elastic fibers are commonly produced by ______ and ________.
fibroblasts
smooth muscle cells
T/F. as we age, the number of elastic fibers will decrease.
true
T/F. more pathologies are associated with elastic fibers than collagen.
false; fewer pathologies with elastic fibers
what hereditary pathology is associated with underdeveloped elastic fibers?
Marfan’s Syndrome
underdeveloped elastic fibers in Marfan’s Syndrome result in what 4 things?
- irregular and unsteady gait
- tall lean body with long extremities
- abnormal joint flexibility, flat feet, stooped shoulders and dislocation of optic lens
- aorta usually dilated and may become weakened= aneurysm
T/F. reticular fibers are almost the same as collagen type 1.
false; collage type 2
reticular fibers are common in what three structures in the body?
- liver
- bone marrow
- lymph nodes
T/F. there are no known serious pathologies associated with reticular fibers.
true
does age affect reticular fibers?
no
what fiber in the ECM is the first fiber produced during wound healing?
reticular fibers
what are the 7 different types of cells in CT?
- fibroblast
- fibrocyte
- myofibroblast
- adipocyte
- plasma cell
- macrophages
- mast cells
fibroblasts are usually derived from ______ cells.
mesenchyme
T/F. fibroblasts are very important in ordinary CT and are generally fixed.
true
when will a fibroblast divide?
would healing and when stimulated by local growth factors
T/F. fibroblasts can change into other cell types under special circumstances.
true; to chondrocytes during fibrocartilage formation & to osteocytes during certain pathologies
what are the two main functions of fibroblasts?
- structure
2. defense
what are the two structural functions of fibroblasts?
- produce and maintain matrix
2. healing
how do fibroblasts function in healing?
- produce growth factors
- scar formation (dense irregular CT, common in tendons, ligaments, epithelium, cartilage, capsules of organs, cardiac ms)
what are the two defensive functions of fibroblasts?
- produce cytokines and enzymes
2. phagocytize
T/F. a fibrocyte is a less active, mature fibroblast, so it will appear rounded.
false; appear flat
does a fibrocyte have lower or higher energy and oxygen requirements?
lower
what is the general function of fibrocytes?
maintain matrix
what can a fibrocyte produce? cannot produce?
can- HA, ground substance, reticular fibers
cannot- new collagen type 1, elastic fibers
a myofibroblast posses features of _____ and ________.
fibroblasts and smooth muscle cells
when do myofibroblasts primarily function?
- wound healing
2. tooth eruption
what are the two types of adipocytes?
unilocular and multilocular
T/F. adipocytes can divide and change into other cell types like fibroblasts.
false
adipocytes are derived from ______ cells producing _______.
mesenchyme
preadipocytes
what are the 2 general functions of adipocytes?
- lipid storage
2. regulate energy metabolism (e.g. produce leptin)
T/F. plasma cells do not divide.
true
where will you find plasma cells?
CT and lymphatic tissues/organs (not typically in blood)
what are plasma cells derived from?
b lymphocytes (type of B cells)
what is the general function of plasma cells?
produce immunoglobulins
what are macrophages?
large cells with an indented or kidney bean shaped nucleus; often containing residual bodies in cytoplasm
can macrophages divide?
yes
what are macrophages derived from?
monocytes
macrophages are a very important defensive cell and are part of the _____ ______ _______.
Mononuclear Phagocyte System
what are the member examples of the Mononuclear Phagocyte System?
- Kupffer cells
- alveolar macrphages
- monocytes
- microglia
- Langerhans cells
- osteoclasts
what are the 4 functions of macrophages?
- phagocytosis of debris and microbes
- act as an APC
- create foreign body giant cells
- release cytokines and other products
foreign body giant cells, permanent fusion of many macrohages, form in response to what two things?
- sizeable foreign substances
2. some pathogen (e.g. TB, leprosy, syphilis, granulomas, yaws)
mast cells are large cells containing granules found where?
CT proper, by blood vessels (perivascular mast cells) and under epithelium (mucosal mast cells)
how long do mast cells live?
days to few months
what are mast cells derived from?
bone marrow precursor
once thought to be derived from basophils
what are the functions of mast cells?
- mediate inflammation, immediate hypersensitivity response, anaphylaxis, asthma
- release primary mediators such as histamine, heparin, ECF, NCF, and other products
- produce and release secondary mediators such as leukotrienes and cytokines
what effects does histamine have on the body?
- increase permeability of capillaries and venules
- vasodilation of arterioles and small arteries and will therefore increase blood to area
- contraction of visceral smooth muscle
is histamine considered the “on” or “off” switch causing a flash reaction?
on switch
if histamine is considered the on switch, what is the off switch?
heparin
what effects will heparin have on the body?
binds to and inactivates histamine
what does ECF stand for?
eosinophil chemotactic factor
what effects will ECF have on the body?
attract eosinophils
what are the functions of eosinophils?
- inhibit leukotrienes
- produce a factor that inhibits mast cell degranulation
- phagocytize IgE-allergen complexes and mast cell granules
- secretes histaminase
T/F. eosinophils will help limit histamine effects, leukotrienes, and destroy parasitic worm larvae.
true
what does NCF stand for?
neutrophil chemotactic factor
what effects on the body does NCF have?
attract neutrophils
what effects do leukotrienes have on the body?
- same as histamine but 1000x stronger
2. extend and amplify the effects of histamine
what stimuli will activate mast cells?
- direct mast cell trauma
- phagocytosis
- IgE allergen complex
- complement process/molecules
T/F. first exposure binds to sensitized mast cells and mast cells degranulate while second exposure elicits IgE formation which binds to mast cells.
false; first exposure elicits IgE formation which binds to mast cells, while second exposure binds to sensitized mast cells and mast cells degranulate
memory cells are produced in _______ exposure.
first exposure
