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143 Cards in this Set
- Front
- Back
Anabolism |
Uses raw material to synthesize essential compounds (building up) |
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Catabolism |
Decomposes substances to provide energy cells need to function (breaking down) |
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The digestive system acquires nutrients from the |
environment |
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Two essential ingredients required for catabolic reactions |
1. Oxygen 2. Organic molecules broken down by intracellular enzymes (carb, protein, fat) |
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Other names for the digestive tract |
Gastrointestinal tract or Alimentary canal |
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Digestive tract extends from |
Oral cavity to anus |
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Digestive tract passes through |
Pharynx, esophagus, stomach, small and large intestines |
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Oral cavity (mouth) functions |
Ingestion, mechanical processing with accessory organs (teeth and tongue), moistening, mixing with salivary secretions |
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Pharynx function |
Muscular propulsion of materials into esophagus |
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Esophagus function |
Transport of materials into stomach |
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Stomach functions |
Chemical breakdown of materials by acid and enzymes; mechanical processing through muscular contractions |
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Small intestine functions |
Enzymatic digestion and absorption of water, organic substrates, vitamins, and ions |
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Large intestine functions |
Dehydration and compaction of indigestible materials in preparation for elimination |
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Teeth function |
Mechanical processing by chewing (mastication) |
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Another word for chewing |
Mastication |
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Tongue functions |
Assists mechanical processing with teeth, sensory analysis |
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Salivary glands function |
Secretion of lubricating fluid containing enzymes that break down carbohydrates |
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Liver functions |
Secretion of bile, storage of nutrients, many other vital functions |
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Gallbladder function |
Storage and concentration of bile |
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Pancreas functions |
Exocrine cells secrete buffers and digestive enzymes; Endocrine cells secrete hormones |
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6 functions of the digestive system |
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Ingestion |
Occurs when materials enter digestive tract via the mouth (eating) |
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Mechanical processing |
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Digestion |
The chemical breakdown of food into small organic fragments for absorption by digestive epithelium |
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Secretion |
Is the release of water, acids, enzymes, buffers, and salts by epithelium of digestive tract and glandular organs |
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Absorption |
Movement of organic substrates, electrolytes, vitamins, and water across digestive epithelium into interstitial fluid of digestive tract |
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Excretion |
Removal of waste products from body fluids |
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Lining of digestive tract safeguards surrounding tissues against |
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Digestive organs and peritoneum are lined with serous membrane consisting of |
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Serosa (visceral peritoneum) |
Covers organs with peritoneal cavity |
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Parietal peritoneum |
Lines inner surfaces of body wall |
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Mesenteries |
Double sheets of peritoneal membrane
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Mesenteries function |
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Areolar tissue between mesothelial surfaces |
Provides an access route to and from the digestive tract for passage of blood vessels, nerves, and lymphatic vessels |
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During embryonic development digestive tract and accessory organs are suspended in peritoneal cavity by |
Dorsal mesentery Ventral mesentery |
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What happens to the ventral mesentery |
It disappears along most of the digestive tract |
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Where is the ventral mesentery remain in adults |
lesser omentum and falciform ligament |
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The Lesser Omentum |
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The Falciform Ligament |
Helps stabilize portion of liver relative to diaphragm and abdominal wall |
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The Dorsal Mesentery |
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Greater omentum |
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Adipose tissue in greater omentum |
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The Mesentery Proper |
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The Mesocolon |
A mesentery associated with a portion of the large intestine |
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Major organs of digestive tract |
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Accessory organs of digestive tract |
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Peritoneal fluid is produced by |
Serous membrane lining
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Peritoneal fluid functions |
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How much peritoneal fluid is absorbed daily |
~ 7 liters |
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Ascites |
Excess peritoneal fluid causing abdominal swelling
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During development, mesocolon of ascending colon, descending colon, and the rectum: |
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4 major layers of digestive tract |
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The Mucosa |
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Mucosal epithelium |
Simple or stratified depending on location, function, and stresses |
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Oral cavity, pharynx, and esophagus histology |
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Stomach, small intestine, and most of large intestine histology |
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Where are enteroendocrine cells |
Scattered among columnar cells of digestive epithelium |
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What do enteroendocrine cells do? |
Secrete hormones that coordinate activities of the digestive tract and accessory glands |
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What does folding do for the digestive tract? |
Increases surface area for absorption |
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What types of folds are in the digestive tract? |
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Lamina Propria |
A layer of areolar tissue that contains:
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Muscularis mucosae |
Narrow band of smooth muscle and elastic fibers in lamina propria |
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Smooth muscle cells of muscularis mucosae arranged in two concentric layers |
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Submucosa |
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Submucosa surrounds |
Muscularis mucosae |
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Submucosal Plexus also called |
Meissner's plexus |
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Submucosal plexus |
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Muscularis externa |
Dominated by smooth muscle cells arranged in inner circular layer and outer longitudinal layer
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Muscularis externa is involved in |
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Muscularis externa movements are coordinated by |
Enteric nervous system (ENS) |
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Enteric nervous system (ENS) |
Automatic - works on its own Primarily innervated by parasympathetic division of ANS |
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Serosa |
Serous membrane that covers the muscularis externa (except in oral cavity, pharynx, esophagus, and rectum) |
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Adventitia |
Fibrous sheath that firmly attaches the digestive tract to adjacent structures |
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The muscular layers of the digestive tract consist of |
visceral smooth muscle tissue |
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Pacesetter cells function |
Control rhythmic cycles along digestive tract |
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Smooth muscle cells in digestive tract undergo |
spontaneous depolarization, triggering a wave of contraction through entire muscular sheet |
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How is a wave of contraction triggered through the muscular sheet |
spontaneous depolarization by pacesetter cells along digestive tract
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Where are pacesetter cells located |
In muscularis mucosae and muscularis externa, surrounding the lumen of the digestive tract |
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Peristalsis |
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Steps of peristaltic motion |
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Segmentation |
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Control of digestive functions |
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Local factors |
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Neural mechanisms |
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Neural mechanisms - short reflexes |
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Neural mechanisms - long reflexes |
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Hormonal mechanisms |
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Functions of the oral cavity |
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Oral mucosa epithelium |
stratified squamous epithelium |
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Oral mucosa |
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Epithelial lining of cheeks, lips, and inferior surface of tongue |
Is relatively thin, nonkeratinized, and delicate |
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Labia |
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Vestibule |
Space between the cheeks (or lips) and the teeth |
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Gingivae |
Gums
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Functions of the tongue |
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3 pairs of salivary glands secrete into oral cavity |
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Each pair of salivary glands has |
distinctive cellular organization and produces saliva with different properties |
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Parotid salivary glands |
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Sublingual salivary glands |
"sub" = under
"lingual" = tongue
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Submandibular salivary glands |
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Saliva |
Glands produce 1.0-1.5 liters of saliva each day 99.4% water |
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Saliva functions |
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Control of salivary secretions |
Autonomic nervous system Parasympathetic - increases Sympathetic - decreases |
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Dentin |
A mineralized matrix similar to that of bone, does not contain cells |
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Pulp cavity |
Receives blood vessels and nerves through the root canal |
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Root |
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Crown |
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Alveolar processes of the maxillae |
Form maxillary arcade (upper dental arch) |
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Alveolar processes of the mandible |
Form mandibular arcade (lower dental arch) |
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Primary dentition (deciduous teeth) |
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Secondary dentition |
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Pharynx (throat) |
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Regions of the pharynx |
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Esophagus |
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Resting muscle tone |
Esophagus prevents air from entering |
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3 layers of wall of esophagus |
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Mucosa histology |
Nonkeratinized and stratified squamous epithelium |
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Mucosa and submucosa form |
Large folds that extend the length of the esophagus |
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Another word for swallowing |
Deglutition |
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Swallowing |
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3 phases of swallowing |
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Buccal phase of swallowing |
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Pharyngeal phase of swallowing |
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Esophageal phase of swallowing |
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The approach of the bolus to the stomach triggers the |
Opening of the lower esophageal sphincter |
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Major functions of the stomach |
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Intrinsic factor |
Glycoprotein required for absorption of vitamin B12 in small intestine |
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Stomach shape |
Like an expanded J |
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Regions of the stomach |
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Histology of the stomach |
Simple columnar epithelium lines all portions of stomach
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Gastric pits |
Shallow depressions in stomach that open onto gastric surface |
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Gastric glands |
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Parietal cells |
Secrete intrinsic factor and hydrochloric acid (HCl) |
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Chief cells |
Are most abundant near base of gastric gland that secrete pepsinogen |
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Pepsinogen |
Is converted by HCl in the gastric lumen to pepsin |
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Pyloric glands |
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Mucous secretions of pyloric glands |
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Somatostatin |
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Regulation of gastric activity |
Production of acid and enzymes by the gastric mucosa can be
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3 phases of gastric control |
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Cephalic phase of gastric control |
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Gastric phase of gastric control |
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Intestinal phase of gastric control |
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