biochem 7B pt3 Flashcards
bones are constantly dissolved by what and remineralized by what in response to mechnical stress
dissolved by osteoclasts
remineralized by osteoblasts
stress induced bony microcracks attract circulate what that differentiate into what
WBCs (monocytes)
differentiate into osteoclasts possessing an acidic compartment in contact w bone
what is remodeling
when all the bone around a microcrack is removed, osteoclasts disappear and osteoblasts lay down new bone in resposne to the stresses
why can enamel not be remolded but cementum and dentin can
new ameloblasts cannot be generated in enamel bc ameloblasts are present only during tooth development
what is the most abundant mineral in the human body
calcium
what is saliva secreted by
the parotid, submandibular and sublingunal major grind, and also minor glands scattered throughout the oral epithelium
what is the submandibular and sublingual glands composed of
acinar cells
tubular cells
(epithelial-like cells)
what does acinar cells secrete
serous (watery) fluid
what does tubular cells secrete
mucous (viscous) fluid
parotid is composed of only what type of cells
acinar cells
what is saliva composed of
water
sodium chloride - electrolyte
sodium bicarbonte - stabilize tooth surface
mucin proteins (proteoglycans that mediates viscosity)
a-amylase - digest starch
proline rich proteins
salivary glands also secrete ammonida which does what
helps buffer acids and provides better protection from caries
xerostomia
when the oral cavity becomes dry
mucins function
lubricates oral mucosa and food particles and inhibit bacterial colonization
water (dilute secretinon) function
facilitates clearance and inhibits bacterial colonization
amaylase
digests starch in food particles, promoting bolus cohesion
sodium bicarbonate, carbonic anhydrase, and statherin
stabilize tooth surfaces
protein functions
form acquired enamel pellicle
peroxidases, histatins, lysoyzme, and lactoferrin
innate immunity that inihibits bacterial growth
salivary agglutinin and mucin
innate immunity that enhances bacterial clearance
secretory immunoglobulin (sIgA)
aquired immunity that enhances bacterial clearance
where does chronic periodontis first appear
at the gingival sulcus (the tooth-soft tissue interface)
what are mouthwashes made out of
voltile aromatic compounds from plants (essential oil mixtures)
need 15-20% alcohol to maintain essential oil solubility - bene linked to increased risk of oral cancer in longtime daily human users
less popular alcohol free mouthwas made of
antiseptic [chlorhexidine (peridex)]
what are types of proinflammatory molecules
prostaglandins and thromboxanes
what enzyme catalzyes the formation of prostaglandins and thromboxanes
COX enzyme
what inhibitors might control chronic periodontitis
COX inhibitors
inhibits of COX enzymes called what and prescribed for what and how do they work
(aspirin and ibuprofen)
NSAID, prescribed to relieve pain and fever
they stop prostaglandin and thromboxane production
calcium hydroxide function
-calcified barrier formed, used as a pulp-capping agent or placed in the root canal in contact w healthy pulpal or periodontal tissue
-pH ~12.5
-hydroxyl group important as it provides an alkaline environment which encourages repair and active calcification
-calcium ions that form the barrier are derived entirely from the bloodstream and not from the calcium hydroxide
how does tooth whitening work
-oxidation reaction that breaks staining compounds
-releases free oxygen that penetrates the tooth to reach deep stains
-either uses carbamide peroxide or hydrogen peroxide
-hydrogen peroxide is the active whitening ingredient
-can cause tooth sensitivity to temp change
-oxidizes the peripheral keratin layer of gingiva which produces a temporary dead white color and burning sensation
what is hemostasis caused by
series of zymogen activations
ferric subsulfate solution (monsel’s solution) [hemostatic agent]
the astringent quality on open wound results in agglutination of surface proteins
aluminum chlordie (hemostatic agent)
-commonly in gingival retraction bc of its ability to cause contraction and shrinkage of tissue
-aluminum chloride results from its ability to precipitate protein, constrict blood cells, and extract fluid from tissues
what are the best astringents in dentistry
zinc, iron, aluminum salts
how do astrigents work
shrink or constrict body tissues
hemophilia
genetic mutations of coagulation proteins cause life-long excessive bleeding
how do excessive bleeding problems occur
diseases or drugs that affect the production of platelets or plasma proteins responsible for clotting
what inhibits adequate triple helix formation and what does it result in
mutations of glycine rsidues in collagen gene
results in fragile bones (osteogenesis imperfect), sometimes accompanied by opalescent (blue/grey, yellow brown) or completely missing teeth (dentinogenesis imperfecta)
why can humans not synthesize ascorbate/vitamin C
bc they lack L-gulconolactone oxidase
ascote/vitamin C is essential for what aa hydroxylase (2)
proline and lysine
(hydroxoloation)
cells posses large amounts of catalase, peroxidase and SOD enzymes that rapidly netraulize ROS within where
the cytosol
the antioxidant property of ascorbate is extracellularly or intercellularly
extracellularly
early symptom of ascorbate deficiency is what
loss of gingival and periodontal membrane fibers accompanied by loosening of teeth
how does scurvy occur
bc of no ascorbate, there is a prevention of collagen re-synthesis in response to stress in tissues such as the gingiva, blood vessels, and bone
w/o ascorbate, fibers are removed but no replaced, fresh collagen cannot be secreted
as a result, collagen in bone turns over more slowly, but if scurvy becomes more advanced, cessation of this turnover causes deep, intense bone pain
what is keratin made of
alpha-helical polypeptides
where is keratin found
hair, wool, skin, horns, fingernails
what parts are parakeratinized (not fully keratinized) like the skin (hard)
cells of the outer surface of the hard palate and gingival mucosa
what are the nonkeratinized (soft) regions of the oral mucosa and are they permeable to fluids and small molecules
cheeks, lips, ventral surface of tongue, soft palate
they are permeable to fluids and small molecules
