digestion Flashcards
What are the 5 stages of digestion and where does each one take place?
Ingestion: mouth. Digestion: mechanical and chemical breakdown, chewing and movement in stomach. Absorption: uptake nutrients mainly in small intestine. Compaction: absorbing water and consolidating residue into feces, large intestine. Defecation.
What is the difference between mechanical and chemical digestion?
Mechanical digestion: movement, physically breakdown food, chewing, increase surface area and exposure area for chemical digestion. Chemical digestion: Hydrolysis reactions that breakdown macromolecules into monomers. Enzymes (usually end in ‘ase’).
Which organs belong to the digestive tract? Which are accessory organs?
Digestive tract: mouth, pharynx, esophagus, stomach, small intestines, large intestines, rectum. Accessory organs: teeth, tongue, salivary glands, liver, gallbladder, pancreas.
What is the nervous network that controls the digestive system?
Enteric system.
What are the two networks of the enteric nervous system?
Submucosal plexus: controls secretion of mucousa and movement of muscularis mucosae. Myenteric plexus: controls peristalsis and contractions of muscularis externa.
What are the three ways that the digestive tract is regulated?
Neural control: Short (myenteric) reflex- stretch or chemical stimulation. Long (Vagovagal) reflex- parasympathetic stimulation (increase) of digestive motility and secretion. Hormone control: (Gastrin, secretin) stimulate digestive tract. Paracrines: secretions stimulate nearby cells.
What are the functions of the mouth?
Food intake, taste, sensory response to food.
What are the functions of the cheeks and lips?
Retain food, speech, sucking/blowing, suckling.
What is the function of the tongue?
Taste, texture, manipulate food.
What is the function of the palate?
Separate oral cavity from nasal cavity.
How are the hard and soft palate different?
Hard palate made of bone and has palatine rugae. Soft palate made of skeletal and glandular tissue.
What is the uvula and what is its function?
Conical medial projection at rear of mouth. Retains food in mouth until swallowing.
What is mastication?
Chewing.
How many adult teeth? Baby teeth?
32 adult: 2 incisors, 1 canine, 2 premolars, 3 molars, top and bottom. 20 kids.
How are cavities formed?
Bacteria metabolize sugars and release acids that dissolve enamel.
What are the components/functions of saliva?
Starch digestion: salivary amylase, lingual lipase: fat digestion, IgA cleans teeth, lysozymes inhibit bacterial growth, create bolus, dissolve molecules to stimulate taste.
What is the difference between intrinsic and extrinsic salivary glands? Where are the extrinsic glands located?
Intrinsic salivary glands: small and found amid other oral tissue (lingual, labial, palatine, buccal). Extrinsic salivary glands: larger, located at parotid (anterior to earlobe), submandibular (under and along mandible), sublingual (floor of mouth).
What causes heartburn?
Acid reflux into the esophagus.
What is deglutition?
Swallowing. Controlled by swallowing center (pair nuclei in medulla oblongata).
What is the difference between parasympathetic and sympathetic stimulation of salivary glands?
Parasympathetic: glands produce thin, enzyme-rich saliva. Sympathetic: glands produce thicker, more mucous saliva.
What are the phases of swallowing?
Oral phase: voluntary, tongue collects food and pushes it posteriorly, food collects at epiglottis then slides down into laryngopharynx. Pharyngeal phase: involuntary, breathing suspended, pharyngeal constrictors push bolus down esophagus. Esophageal phase: peristalsis moves bolus into stomach.
What is the main function of the stomach?
Food storage, mechanically breakdown food, chemical digestion of proteins and fat, form chyme.
Know what each cell produces in the gastric glands.
Mucous: secrete mucous, found in cardiac and pyloric glands. Regenerative: divide rapidly and produce new cells. Parietal: secrete HCl, intrinsic factor, ghrelin. Chief: secrete gastric lipase and pepsinogen. Enteroendocrine: secrete hormones and paracrine messengers that regulate digestion.
What are the functions of HCl?
Provide immunity, liquify food into chyme, convert any iron (Fe) into usable form to create hemoglobin. Secreted by parietal cells of gastric glands.
