Term
| What are the 4 normal components of the tooth? |
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Definition
Crown, Neck and Root
1) Enamel
- calcium phosphate, hydroxyapatite (but without collagen, unlike bone) coverin crown.
2) Dentin
- Flexible, less-mineralized collagen connective tissue
3) Cementum
- Bone-like substance that protects dentin where it projects into the root of the tooth
4) Pulp
- Soft connective tissue with vessels and nerves |
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Term
| What are the 3 major components of the Periodontium and what are their functions? |
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Definition
Periodontium= tooth-supporting structures
1) Gingiva
- Stratified squamous epithelium and lamina propria attached to teeth at gumline by hemidesmosomes and basal lamina.
2) Periodontal ligament
- Attaches to cemuntum (covering dentin in root), anchoring the tooth in the jaw and acting as a source of new bone cells as tooth moves in bone (osteoblasts, fibroblasts)
3) Alveolar bone
- Form alveolar sockets around tooth. |
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Term
| How does Periodontitis differ from Gingivitis? |
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Definition
1) Gingivitis is
- bacterial plaque induced inflammation of gums
- without loss of epithelial attachment.
2) Periodontitis is
- Inflammation of gingiva
- Loss of epithelial attachment
- Irreversible damage to cementum, alveolar bone and/or periodontal ligament |
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Term
A patient presents with gingival redness and swelling, and complains that his gums are bleeding every time he brushes his teeth.
There is no evidence of halitosis or increased tooth mobility on exam.
What is the pathogenesis of this disease? |
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Definition
Probably Periodontitis (sounds less severe, since halitosis and tooth mobility are absent).
To distinguish from gingivitis, you would have to demonstrate that there is loss of epithelial attachment.
1) Dental plaque of gram (+) cocci bacterial biofilm adheres to gingival crevices builds up in patients with risk factors
2) Gingival inflammation leads to shift of flora to gram-negative, anaerobes
3) Immune cells react locally to produce pro-inflammatory cytokines and MMPs
4) Epithelial barrier is ulcerated and bacteria can spread systemically.
5) Damage to supporting structures occur and systemic diseases can be exacerbated
**Molecular mimicry against hsp60 can occur in SLE and CHD** |
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Term
| How would you treat a patient with peridontal disease? |
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Definition
Remember, this is gingival inflammation with epithelial barrier breakdown and damage to periodontal structures (cementum, periodontal ligaments, alveolar bone, ect).
1) Brush and Floss
2) Dental cleaning
3) Antibiotics
- Doxi is only "host-modulating" option that decreases MMP reaction.
4) Surgery if severe |
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Term
| What important systemic diseases have been associated with periodontitis? |
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Definition
1) Atherosclerosis/CVD
- Porphyromonas gingivalis found in atherosclerotic plaques up-regulates TLR expression on macrophages and endothelial cells and leading to innate immune production of inflammatory cytokines (smooth muscle loss in media and intimal connective tissue thickening)
2) DM
- Treating peridontal disease in Pima indians improved glycemic control
3) Pregnancy complications
- P. gingivalis found in amniotic fluid
- TRL-mediated IL-1 release and inflammation
- PGE2 production, which may lead to inappropriate contractions of the myometrium and lead to premature delivery.
-
ALSO
4) Respiratory disease
5) Osteoporosis
6) HTN
7) Arthritis
8) IBD
9) Psoriasis |
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Term
| How can Periodontal disease cause complications with CVD, Diabetes and Pregnancy? |
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Definition
1) Atherosclerosis/CVD
- Porphyromonas gingivalis found in atherosclerotic plaques up-regulates TLR expression on macrophages and endothelial cells and leading to innate immune production of inflammatory cytokines (smooth muscle loss in media and intimal connective tissue thickening)
2) DM
- Treating peridontal disease in Pima indians improved glycemic control
3) Pregnancy complications
- P. gingivalis found in amniotic fluid
- TRL-mediated IL-1 release and inflammation
- PGE2 production, which may lead to inappropriate contractions of the myometrium and lead to premature delivery. |
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Term
| Describe the basic histological characteristics of the Tung. |
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Definition
1) Surfaces
Dorsal
- Rough with papillae and taste buds; stratified squamous epithelium with thin keratin.
Ventral
- Stratified squamous non-keritanized epithelium.
2) Musculature
- Skeletal muscle bundles
3) Dorsal papillae
- Filiform (keratinized peaks, aid in mastication)
- Fungiform ("mushroom" keratinized papillae with taste buds laterally)
- Circumvallate (Large, smooth, keratinized papillae at rear of tung that release watery secretions)
4) Taste buds
- Neuroepithelial cells with taste hairs (darker nuclei)
- Sustentacular cells (euchromatic nuclei and glycosaminoglycan secretions)
- Basal cells |
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Term
| What are the 3 types of papillae found on the dorsal surface of the tung? |
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Definition
1) Filiform (keratinized peaks, aid in mastication)
2) Fungiform ("mushroom" keratinized papillae with taste buds laterally)
3) Circumvallate (Large, smooth, keratinized papillae at rear of toung that release watery secretions) |
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Term
| What are the 5 major "taste molecules"? |
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Definition
1) Sweet (CHO; gustducin)
2) Sour (H+)
3) Bitter
4) Salty (Na+)
5) Umami (glutamic acid)
**Sweet, bitter and umami use Gq
** Salt and sour work on ion channels |
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Term
What is innervation pattern of the following oral cavity structures?
1) Anterior tongue
2) Posterior tongue and pharynx
3) Larynx
4) Palate |
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Definition
1) Chorda tympany of CN VII
2) CN IX
3) CN X (superior laryngeal branch)
4) CN V, VII and IX |
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Term
| What is the general/structure function of the 3 major salivary glands? |
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Definition
1) Parotid (25% of oral cavity secretions)
- Located between ear and ramus of mandible
- Secretions are serous
2) Submandibular gland (60-65% of secretions)
- Found in floor of mouth just inside mandible
- Secretions are 80% serous and 20% mucous with serious demilunes
3) Sublingual gland (10%)
- Base of tongue
- 20% serous, 80% mucous with serous demilunes |
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Term
| What are the 4 general layers of the tubular portion of the GI tract? |
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Definition
1) Mucosa (folds to produce rugae (stomach) and plicae cirulares (small intestine)
- Epithelium (Pseudostratified cells, goblet cells, absorption villi)
- Lamina propria (fenestrated capillaries and lymphatics, as well as lymphocytes)
- Muscularis mucosa (aids folding-digestion and absorption)
2) Submucosa
- Blood vessels and elastin fibers
- Esophagus and duodenum have mucous glands that penetrate into submucosa
- Meissner's plexus of enteric nervous system
3) Muscularis externa
- 2 layers of perpendicular smooth muscle innervated by Aurbach's myenteric plexus lying within the junction.
- Interstitial cells of Cajal are "pacemaker cells"
4) Serosa
- Lines mesentary that suspends GI tract. |
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Term
| What are the Meissner's and Aurbach's plexuses? |
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Definition
1) Meissner's plexus is found in submucosa of tubular portion of GI tract and serves to regulate muscularis mucosa and digestive gland secretions.
2) Aurbach's plexus is found in Muscularis externa, at the junction of the 2 perpendicular layers of smooth muscle, and serves to regulate constriction and secretion (interstitial cells of Cajal are actual "pacemaker cells") |
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Term
| What are the key features of the 4 histological layers of the Esophagus? |
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Definition
Located between epiglottis and cardiac orifice of stomach; not involved in storage or digestion.
1) Mucosa
- Stratified, non-keritanized, squamous epithelium that projects down into lamina propria as "rete pegs"
- "Cardiac" mucous glands found in upper and lower 1/3 in lamina propria.
- Muscularis mucosa oriented longitudinally
2) Submucosa
- Loose connective tissue network with tubuloacinar mucous glands (also secrete lysozyme) and blood vessels
3) Muscularis Externa
- 2 layers (top 1/3 is voluntary skeltal muscle, middle 1/3 is mix and distal 1/3 is smooth)
4) Adventitia
- Esophagus descends into thorax in central mediastinum and its outmost layer is therefore adventitia. |
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Term
| What are the major functions of the stomach? |
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Definition
1) Storage of ingested food
2) Proteolytic digestion
- Pepsin (protein), rennin (milk), lipases (fats) and acidic environment
3) Mixes contents using thick smooth muscle
4) Absorption of water, salts, alcohol and drugs
5) Secretion of vitamin B12 intrinsic factor (binds B12 for later absorption in ileum) |
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Term
| What are the unique characteristics of the 4 histological layers of stomach? |
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Definition
1) Mucosa
- Surface mucous cells
- Pits drained by glands
2) Submucosa
- Ruggae
3) Muscularis externa
- 3 layers of smooth muscle
4) Serosa
- indistinguishable |
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Term
| What are the 5 anatomical regions of the stomach? |
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Definition
Cardiac, Fondus, Body, Antrum, Pylyoris
1) Cardiac- Mucous and Mucoparietal glands
- small, pale staining mucus producing cells.
2) Fondus/Body- Gastric glands
- Fondus glands, gastric glands, oxyntic glands, zymogen glands
3) Antrum- Modified gastric glands
- no parietal cells, but many G cells (gastrin)
- Produces "chyme"
4) Pyloris- Mucous glands
- Dep pits and short, coiled glands
- Enteroendocrine and mucous cells, but no chief/parietal cells
- Thickening of muscularis externa forms Pyloric Sphincter (constriction prevents leakage of chyme) |
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Term
| What is the function of "surface mucous cells" in the stomach? |
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Definition
Buffer to protect mucosa (rapid turnover, vs. glandular cells)
Simple columnar epithelium, the apical ends of which contain secretory vesicles filled with ALKALINE, carbohydrate rich glycoprotein that is released in response to friction or ethanol.
- Secreted HCO3- increased by Ca2+, PGE/F, cholinergic agents, cGMP
- Secreted HCO3- decreased by NSAIDs and aspirin (COX inhibitors) |
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Term
| What types of gastric glands cells are found in the fundus and body regions of the stomach? |
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Definition
Gastric gland is composed of Pit and Gland (isthmus, neck and base).
Isthmus has mucous neck cells, Neck has parietal cells and Base has chief cells
1) Isthmus
- Mucous neck cells secrete acid glycoprotein (cytoplasmic basophilia)
2) Neck
- Mucous neck cells
- Parietal/Oxyntic cells (HCL and B12-IF)
3) Base
- Chief cells (apical secretory granules)
- Enteroendocrine cells (basal secretory granules on EM)
- Few parietal cells |
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Term
| What are the histological/functional characteristics of gastric parietal cells? |
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Definition
Parietal/Oxyntic cells are found mostly in Neck of gland and secrete 0.1N HCl and B12-IF in response to histamine, gastrin and ACh.
1) Plump, round cells with central nucleus and homogeneous eosinophillic cytoplasm
2) Apical intracellular canalliculi (microvilli) and tubulovesicular system augment SA for H+K+ ATPAse pumps (80% of protein in cell)
3) Basolateral histamine, gastrin and ACh receptors. |
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Term
| What are the histological/functional characteristics of gastric Chief cells? |
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Definition
Regulated secretory cells (e.g. zymogen) in base of gastric glands that secrete pepsinogen, rennin and lipase in response to ACh and are inhibited by somatostatin.
**Seldom found in cardiac and pyloric glands**
- Apical cytoplasm packed with basophilic granules
- Basal cytoplasm backed with basophilic RER |
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Term
| What are the 5 major types, secretions and actions of enteroendocrine cells in the stomach? |
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Definition
1) Gastrin (G cell)
- Stimulates HCl secretion from parietal cells in neck
- Proliferation of gastric and intestinal mucosa
- Peristalsis
- Gq, IP3, DAG & Ca2+ second messengers
2) Histamine (ECL cell)
- Binds H2-receptors on basal surface of parietal cells, promoting cAMP-mediated HCl secretion.
3) Somatostatin (D cell)
- Inhibits gastrin (G cells) and Acid (parietal cels) release after stomach luminal pH drops below 3.0
- Inhibits chief cell secretion
4) Vasoactive intestinal peptide (VIP- D1 cells)
- Increases pancreatic bicarbonate and water secretion
- Decrease gastric acid secretion
- Relax lower esophageal sphincter, fundus and gall bladder
5) Grelin (Fundic cells)
- Secreted during fasting, binding hypothalamic receptors to secrete growth hormone.
- Stimulates hunger in brain and inhibits mobilization of fats in adipose tissue (paradoxically) |
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Term
| How can you tell, histologically, that the esophagus has become the cardiac region of the stomach? |
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Definition
| Epithelial transition from Stratified Squamous to Folded simple columnar. |
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Term
| What are the 3 major types of ducts found in salivary glands? |
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Definition
1) Excretory (large diameter with columnar to stratified columnar/cuboidal epithelium).
- connective tissue septa
- empty into oral cavity
2) Striated/secretory (medium diameter-1-2X acinus, with simple cuboidal to columnar epithelial and basal striations due to mitochondria)
- Acinar septa
- Change ionic composition of secretions with transport
3) Intercalated ducts (Simple cuboidal and smaller diameter than an acinus)
- Fusiform myoepithelial cells within basal lamina of serious cell membrane. |
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Term
| What unique feature of the middle 1/3 of the esophagus distinguishes it histologically from the upper and lower 1/3? |
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Definition
| Blend of smooth and skeletal muscle fiber bundles in muscularis externa |
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