| Flap 1 |
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| Flap 2 |
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| deciduous teeth |
milk or baby teeth |
| The outer surface of the tooth root is covered by __. |
cementum - calcified CT |
| What anchors tooth in bony alveolus of jaw? |
Peridontal ligament |
| Bonelike material underlying enamel cap & makes up bulk of tooth. |
Dentin |
| Dental caries |
cavities |
| Calculus |
tartar |
| Histology of pharyngeal wall |
Stratified squamous w/mucus-producing glands |
| There are 2 __ layers in pharyngeal wall. |
skeletal muscle |
| How long is esophagus? |
25 cm (10 inches) long |
| How does epithelium change abruptly at esophagus-stomach junction. |
Esophageal mucosa change from nonkeratinized stratified squamous to simple columnar epithelum which is specialized for secretion. |
| Submucosa's esophageal glands secrete? |
Mucus to grease the esophageal walls to aid food passage. |
| The outermost layer of esophagus. |
Adventitia (Fibrous CT) |
| Name 2 digestive system structures whose only role is food propulsion. |
Pharynx & esophagus |
| deglutition |
Swallowing - involves 22 separate muscle groups - buccal phase & pharyngeal-esophageal phase. |
| Which phase of deglutition is voluntary? |
buccal phase |
| The pharyngeal-esophageal phase of deflutition is controlled by __. |
Swallowing center in brainstem - medulla & lower pons - transmitted through vagus nerves. |
| What structural modification of stomach tunic allows mechanical digestion? |
Muscularis externa has 3rd layer of smooth muscle to churn food - runs obliquely. |
| Size of adult stomach |
15-25 cm (6-10 inches) 50 ml empty - 1 gallon full |
| What part of stomach is continuous with duodenum. |
Pylerus |
| Lining of stomach |
Simple columnar epithelium w/goblet cells that produce alkaline mucus - makes a bicarbonate-rich fluid layer. |
| Mucous neck cells of stomach |
Produce thin mucus - acidic |
| Parietal cells of stomach |
Secrete HCl & intrinsic factor - have microvilli |
| Intrinsic factor is? |
Glycoprotein for B12 absorption in small intestine, but produced in stomach. |
| Ph of stomach |
1.5 - 3.5 |
| Chief cells of stomach |
Produce pepsinogen (inactive) - activated by HCl & becomes pepsin - positive feedback process. |
| Enteroendocrine cells of stomach |
Release chemical messengers - histamine, gastrin, serotonin, somatostatin |
| What barrier protects stomach from self-digestion? |
Gel-like mucosal barrier - (1) bicarbonate-rich mucus, (2) tight junctions, (3) stem cells that divide & replace quickly. |
| gastritis |
inflammation of stomach wall due to anything that breaches mucosal barrier |
| Name some H2-receptor blocker drugs |
Tagmet & Zantac |
| Vagus nerve does what what with stomach. |
Stimulates secretory activity of virtually all of its glands. |
| Which hormone controls gastric secretion? |
Gastrin - enzymes, HCL |
| 3 phases of gastric secretion |
Cephalic (reflex), gastric, & intestinal - all may be occuring at same time. |
| Cephalic reflex (Phase 1) |
Conditioned reflex - occurs before food enters stomach - triggered by senses, prepares stomach - suppressed when emotinally depressed. |
| Gastric Phase (Phase 2) |
In stomach - 3-4 hours long - distension & gastrin are stimulus. |
| G cells |
Gastrin - secreting enteroendocrine cells. |
| Highly acidic gastric contents __ gastrin secretion. |
Inhibit |
| Protein __ pH in stomach |
raises - stimulates gastrin & HCl release |
| HCl secretion is stimulated by which 3 chemicals? |
ACh, gastrin, & histamine (by enterochromaffin-like cells) - all 3 combined causes HCl to pour forth. |
| Blood draining from stomach is more __ than blood serving it. |
alkaline - phenomenon called alkaline tide. |
| Intestinal Phase (3) |
2 components - excitatory & inhibitory - excitatory - gastric gland in duodendum produce intestinal gastrin: inhibitory - enterogastric reflex that puts on "breaks" to protect small intestine from acidity. |
| Enterogastric reflex |
release is inhibited. |
| Plasticity |
Smooth muscle's ability to stretch without greatly increasing tension & contracts expulsively. |
| What sets rate of stomach's peristalic waves? |
Pacemaker cells in longitudinal small muscle layers called interstitial cells of Cajal - don't initiate beat, neural does. |
| Basic electrical rhythm (BER) |
Cyclic slow waves of stomach due to pacemaker interstitial cells of Cajal. |
| Stomach usually empties completely within __ hours. |
4 |
| emesis |
vomiting |
| Where is emetic center located? |
Controls vomiting - in medulla |
