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191 Cards in this Set
- Front
- Back
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What are the components of the alimentary canal?
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mouth, pharynx,
esophagus, stomach, small intenstine, large intestine |
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What are the accessory digestive organs?
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teeth, tongue
salivary glands, liver, gallbladder, pancreas |
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What is the primary function of the GI tract?
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transfer nutrients, water, and electrolytes from ingested food into the blood or lymph
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What are the two types of digestive motility?
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peristalsis - propulsive movements
segmentation - mix food with digestive juice & facilitate absorption by exposing more surfaces of the digestive tract to the food |
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What are the layers of the muscularis externa, from innermost to outermost?
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circular smooth muscle
longitudinal smooth muscle |
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What type of motility involves the smooth muscle of the GI tract contracting behind a bolus of food?
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peristalsis
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What type of motility involves the smooth muscle of the GI tract contracting on a bolus of food?
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segmentation
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What are the two types of motility that occur in the stomach?
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peristalsis and receptive relaxation
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What stimulates peristalsis starting in the pyloric region of the stomach?
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pacemaker cells
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True or False: Almost all of the secretions of the GI tract get reabsorbed?
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True
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Where does the fluid component of GI secretions come from?
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blood plasma
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What is the third muscle layer of the GI tract that's only found in the stomach?
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oblique smooth muscle
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Is digestion a form a anabolism or catabolism?
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catabolism
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If you intake 2 cups of food & liquid, how many cups will you have by the time this food reaches your small intestine?
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About 9 cups (about 7 cups of secretions are added)
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What kind of epithelium lines the small intestine and is important for absorption?
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simple columnar epithelium
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What is the function of the uvula?
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prevents food from entering the nasal cavity during swallowing
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What is the function of the epiglottis?
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prevents food from entering the trachea during swallowing?
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What prevents food from entering the nasal cavity during swallowing?
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uvula
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What prevents food from entering the trachea during swallowing?
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epiglottis
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What is a sphincter?
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tightening of smooth muscle that prevents backflow
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What are the sphincters of the GI tract?
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pharngoesophageal sphincter
gastroesophageal sphincter pyloric sphincter ileocecal sphincter internal anal sphincter external anal sphincter |
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What are the three parts of the stomach?
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fundus (upper part)
body pyloric antrum |
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Do bacteria normally grow in the large intestine or the small intestine?
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large intestine
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What are the layers of the mucosa of the GI tract, from innermost to outermost?
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mucous membrane/epithelium
lamina propria muscularis mucosa |
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What are the layers of the GI tract, from innermost to outermost?
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mucosa
submucosa muscularis externa serosa |
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Which layer of the GI tract contains nerves, glands, and large blood vessels?
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submucosa
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Is the serosa layer of the GI tract parietal or visceral peritoneum?
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visceral peritoneum
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Which layer of the GI tract is known as the blood side?
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serosa
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Which layer of the GI tract is known as the food side?
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mucosa
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What makes up the enteric nervous system?
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submucosa plexus
myenteric plexus |
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What does the submucosa plexus regulate?
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secretions
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What does the myenteric plexus regulate?
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contractions and motility
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In which layer of the GI tract is the submucosa plexus located?
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submucosa
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In which layer of the GI tract is the myenteric plexus located?
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muscularis externa, between the circular and longitudinal smooth muscle layers
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What does the mucous membrane layer of the mucosa contain?
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- epithelial cells specialized for absorbing digestive nutrients
- exocrine gland cells that secrete digestive juices - endocrine gland cells that secrete blood-borne GI hormones |
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What is important about the lamina propria layer of the mucosa?
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contains gut-associated lymphoid tissue that is important in defense against disease-causing intestinal bacteria
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In which layer of the GI tract is the gut-associated lymphoid tissue located?
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lamina propria of the mucosa
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Which layer of the GI tract provides it with distensibility and elasticity?
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submucosa
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What is the function of the serous fluid that is secreted by the serosa of the GI tract?
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lubricates and prevents friction between digestive organs and surrounding viscera
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What regulates digestive motility and secretion?
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autonomous smooth muscle function
mechanical and chemical stimuli extrinsic nerves by CNS centers intrinsic plexus by local centers gastrointestinal hormones |
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What do the mechanoreceptors and chemoreceptors of the GI tract respond to?
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stretch, osmolarity, and pH
presence of substrate and end products of digestion |
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What do the mechanoreceptors and chemoreceptors of the GI tract initiate?
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reflexes to activate or inhibit digestive glands
reflexes to mix lumen contents and move them along |
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Is the enteric nervous system responsible for extrinsic or intrinsic control of the GI tract?
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intrinsic
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Is the parasympathetic part of the autonomic nervous system responsible for extrinsic or intrinsic control of the GI tract?
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extrinsic
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Are the extrinsic controls of the GI tract responsible for long or short reflexes?
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long reflexes
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Are the intrinsic controls of the GI tract responsible for long or short reflexes?
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short reflexes
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Are long reflexes of the GI tract controlled by extrinsic or intrinsic controls?
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extrinsic
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Are short reflexes of the GI tract controlled by extrinsic or intrinsic controls?
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intrinsic
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What kind of food is broken down in the mouth?
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starch is broken down by salivary amylase
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What tonsils in the oral cavity are part of the immune system?
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lingual
palatine pharyngeal |
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What kind of epithelium lines the inside of the oral cavity?
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stratified squamous epithelium
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Why are the gingiva, hard palate, and dorsum of the tongue slightly keratinized?
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to help withstand abrasion
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What helps the mouth withstrand abrasion?
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lined with stratified squamous epithelium
gingiva, hard palate, and dorsum of tongue are slightly keratinized |
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True or False: The lips have well-developed tactile sensation.
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True
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What bones make up the hard palate?
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palatine bone
palatine process of maxilla |
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Does the soft palate contain mostly skeletal muscle or smooth muscle?
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skeletal muscle
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Why is the palate slightly corrugated on either side of the midline raphe?
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provides friction to help with grinding food
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What are the four types of papillae and where are they found on the tongue?
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circumvallate on the back
filiform on the front foliate on the sides fungiform all over |
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What tastes can be sensed by the taste buds?
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bitter
salt savory/umami (monosodium glutamate - MSG) sour (acid) sweet (sugar) [fat] |
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Do extrinsic or intrinsic muscles change the shape of the tongue?
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intrinsic
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Do extrinsic or intrinsic muscles alter the tongue's position?
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extrinsic
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Do the extrinsic tongue muscles change the shape of the tongue or alter its position?
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alter its position
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Do the intrinsic tongue muscles change the shape of the tongue or alter its position?
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change its shape
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What are the functions of the tongue?
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grip and reposition food during chewing
mix food with saliva and form the bolus initiate swallowing initiate speech |
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What is the function of the filiform papillae?
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give tongue roughness and provide friction
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Which papillae give the tongue roughness and provide friction?
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filiform papillae
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Which papillae give the tongue its reddish hue?
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fungiform papillae
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How much force can the teeth produce when chewing?
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up to 200 N
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What are the three extrinsic salivary glands that secrete into the oral cavity?
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parotid
sublingual submandibular |
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What is a bolus?
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food + saliva
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Is parotid gland secretion more fluidy or mucusy?
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fluidy
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Is sublingual gland secretion more fluidy or mucusy?
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mucusy
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True or False: Saliva is required for taste.
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True
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How does saliva have antibacterial action?
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lysozyme destroys bacteria
it rinses away material that could serve as food for bacteria |
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True or False: Saliva is rich in bicarbonate buffers.
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True
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What are the intrinsic salivary glands that secrete into the oral cavity?
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buccal glands
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Are the buccal glands extrinsic or intrinsic?
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intrinsic
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Are the parotid, sublingual, and submandibular glands extrinsic or intrinsic?
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extrinsic
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Which salivary gland has a duct that opens into the vestibule next to the second upper molar?
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parotid gland
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Which salivary gland has ducts that open at the base of the lingual frenulum?
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submandibular gland
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Which salivary gland has 10-12 ducts that open into the floor of the mouth?
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sublingual gland
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Where does the parotid duct open into?
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vestibule next to the second upper molar
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Where does the submandibular ducts open into?
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base of the lingual frenulum
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Where do the sublingual ducts open into?
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floor of the mouth
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What is the composition of saliva?
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99.5% water
0.5% electrolytes and proteins |
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Is saliva slightly basic or slightly acidic?
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slightly acidic
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What electrolytes does saliva contain?
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sodium
potassium chloride phosphate bicarbonate |
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What proteins does saliva contain?
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defensins
IgA lysozyme mucin |
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How much salt does saliva contain compared to blood plasma?
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1/7
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True or False: Saliva contains metabolic wastes like urea and uric acid.
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True
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What causes extrinsic salivary glands to secrete serous, enzyme-rich saliva?
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ingested food stimulating chemoreceptors and pressoreceptors
thoughts of food |
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Does parasympathetic stimulation produce mucusy or watery saliva?
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watery
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Does sympathetic stimulation produce mucusy or watery saliva?
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mucusy
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What part of the brain contains the salivary center?
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medulla
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What are the three regions of the pharynx?
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nasopharynx
oropharynx laryngopharynx |
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True or False: Air does not pass through the pharynx.
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False
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What are the two skeletal muscle layers of the pharynx?
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inner longitudinal muslce
outer pharyngeal constrictors |
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What lines the pharynx?
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stratified squamous epithelium
mucus glands |
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What is the most complex reflex in the body?
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swallowing
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What are the two stages of swallowing?
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oropharyngeal/buccal stage
esophageal stage |
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True or False: The oropharyngeal/buccal stage of swallowing is voluntary.
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True
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True or False: The oropharyngeal/buccal stage of swallowing is involuntary.
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False
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True or False: The esophageal stage of swallowing is voluntary.
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False
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True or False: The esophageal stage of swallowing is involuntary.
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True
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Swallowing is a coordinated activity of what structures?
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tongue
soft palate pharynx esophagus 22 separate muscle groups |
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True or False: It is possible to inhale and swallow at the same time.
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False
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What controls the esophageal phase of swallowing?
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medulla and lower pons
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What is the maximum time that food spends traveling through the esophagus?
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10 seconds
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What is the function of the pharyngoesophageal sphincter?
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prevents large volumes of air from entering the esophagus and stomach during breathing
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Which sphincter prevents large volumes of air from entering the esophagus and stomach during breathing?
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pharyngoesophageal sphincter
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What is the function of the gastroesophageal sphincter?
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prevents reflux of gastric contents
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Which sphincter becomes stronger around 1 year after birth?
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pharyngoesophageal sphincter
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What can cause damage to the gastroesophageal sphincter?
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too much food in the stomach
pregnancy irritants such as certain spices |
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What results from damage to the gastroesophageal sphincter?
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heart burn
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True or False: A person who is eating while upside down will still have the food reach the stomach.
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True
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What kind of food is broken down in the stomach?
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protein
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What are the two distinct areas of gastic mucosa?
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oxyntic mucosa
pyloric gland area (PGA) |
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What are the folds in the inner wall of the stomach called?
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rugae
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What are the main functions of the stomach?
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- store ingested food until it can be emptied into the small intestine
- secrete HCl and enzymes that begin protein digestion - mixing movements convert pulverized food to chyme - secretes intrinsic factor for vitamin B12 absorption |
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What part of the stomach contains oxyntic mucosa?
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body and fundus
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What part of the stomach contains the pyloric gland area?
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pyloric antrum
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What kind of mucosa lines the body and fundus of the stomach?
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oxyntic mucosa
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What kind of mucosa lines the antrum of the stomach?
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pyloric gland area (PGA)
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What is the turnover rate for the mucosal epithelium in the stomach?
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3 days
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What do the enterochomaffin-like (ECL) cells of the stomach secrete?
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histamine
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What kind of cells are found in the stomach?
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chief cells
enteroendocrine cells mucous neck cells parietal cells |
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What do the mucous cells of the stomach secrete?
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thin, watery mucus
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What do the chief cells of the stomach secrete?
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pepsinogen
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What do the parietal cells of the stomach secrete?
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HCl and intrinsic factor
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What is the function of the HCl secreted by the parietal cells of the stomach?
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activates pepsinogen into pepsin
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True or False: Pepsinogen can be activated to pepsin by the presence of pepsin.
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True
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What are inactive precursor forms of enzymes called?
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zymogens
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What kind of cells are found in high amounts in the oxyntic mucosa of the stomach?
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mucous cells
chief cells parietal cells |
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What kind of cells are found in high amounts in the pyloric gland area of the stomach?
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D cells & G cells
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What do the G cells of the stomach secrete?
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gastrin
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What do the D cells of the stomach secrete?
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somatostatin
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Which cells secrete gastrin?
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G cells
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Which cells secrete somatostatin?
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D cells
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What is the effect of gastrin?
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stimulates acid secretion from parietal cells
stimulates pepsinogen secretion from chief cells |
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What is the effect of somatostatin?
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inhibits acid secretion from parietal cells
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After a high protein meal, will there be more D cells or G cells active in the stomach?
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G cells (to increase acid secretion)
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What is the effect of histamine?
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stimulates acid secretion from parietal cells
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What is the effect of pepsin?
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begins protein digestion
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What is the effect of intrinsic factor?
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vitamin B12 absorption
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What is the approximate pH in the stomach?
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2
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What is the only protease that can function in the presence of acid?
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pepsin
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Why is pepsin able to function in the presence of acid?
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it is small and has few H-bonds, so acid, which destroys H-bonds in proteins, is not very effective
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True or False: Carbohydrate digestion continues in the stomach.
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False - salivary amylase is degraded by stomach acid
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What three ligands stimulate HCl secretion through second-messenger systems?
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acetylcholine
histamine gastin |
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True or False: HCl denatures proteins.
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True
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How do parietal cells form and secrete HCl?
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1. CO2 from plasma enters parietal cell
2. CO2 and water form carbonic acid (catalyzed by carbonic anhydrase) 3. H2CO3 is broken down into H+ and bicarbonate 4a. HCO3- exits into plasma and Cl- enters parietal cell via exchanger 4b. H+ exits into gastic lumen and K+ enters parietal cell via H+/K+ ATPase 5. Cl- exits into gastric lumen 6. H+ and Cl- join in gastric lumen to form HCl |
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How does TUMS treat hyperacidity?
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neutralizes HCl in gastric lumen
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How do H2 receptor inhibitors like Zantac & Tagamet treat hyperacidity?
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block HCl production by inhibiting ACh
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How do proton pump inhibitors like Nexium & Prevacid treat hyperacidity?
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prevent H+ from being released into gastric lumen via H+/K+ ATPase
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What does Alkaline Tide refer to?
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blood becomes alkaline when bicarbonate exits the parietal cell and Cl- enters from plasma via the exchanger
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True or False: Proteins are broken down into amino acids in the stomach.
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False - only broken down into peptide fragments (pancreas breaks the fragments into amino acids)
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What are the three phases of regulation of gastric secretion?
|
cephalic phase - food is in mouth
gastric phase - food is in stomach intestinal phase - food is in small intestine |
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What is the effect of secretin?
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inhibits HCl secretion from the stomach
stimulates bicarbonate secretion from pancreas |
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Where is secretin produced?
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duodenum and jejunum
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What can cause stimulation in the cephalic phase of the regulation of gastric secretion?
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sight or thought of food
stimulation of taste or smell receptors |
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What can cause inhibition in the cephalic phase of the regulation of gastric secretion?
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loss or appetite or depression
decrease in parasympathetic stimulation |
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What can cause stimulation in the gastric phase of the regulation of gastric secretion?
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stomach distension
activation of chemoreceptors by peptides, caffeine, and rising pH release of gastrin into blood |
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What can cause inhibition in the gastric phase of the regulation of gastric secretion?
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pH lower than 2
emotional upset that overrides the parasympathetic division |
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What can cause stimulation in the intestinal phase of the regulation of gastric secretion?
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high pH
partially digested food entering duodenum |
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What can cause inhibition in the intestinal phase of the regulation of gastric secretion?
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distension of duodenum
fatty, acidic, or hypertonic chyme |
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What are the inhibitory effects of the intestinal phase of the regulation of gastric secretion?
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closing of pyloric sphincter
inhibition of local reflexes (ENS) and vagal nuclei release of enterogastrones |
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What helps protect the stomach being digested by its acidic secretions?
|
thick coat of bicarbonate-rich mucus on stomach wall
epithelial cells are joined by tight junctions gastric glands have cells that are impermeable to HCl damaged epithelial cells are quickly replaced |
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What are the four aspects of gastric motility?
|
filling - receptive relaxation is triggered by eating
storage - in the body of the stomach mixing - in the antrum of the stomach emptying - controlled by factors in the duodenum |
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True or False: When food enters the stomach, stomach pressure increases.
|
False - receptive relaxation allows the stomach to accomodate more volume without an increase in pressure
|
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What are the two types of stomach relaxation?
|
receptive relaxation triggered by chewing
adaptive relaxation where stomach dilates in response to gastric filling |
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What is plasticity?
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intrinsic ability of stomach muscle to relax in response to stress
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What is the intrinsic ability of stomach muscle to relax in response to stress?
|
plasticity
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How many peristaltic waves occur in the stomach in one minute?
|
3
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What is the normal capacity of the stomach?
|
about 4 cups
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What can the capacity of the stomach be expanded to?
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about 10 cups
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What is the function of the cells of Cajal?
|
initiate basal electrical rhythm (BER) for peristalsis
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True or False: Large amounts of chyme are delivered into the duodenum by a single perstaltic wave.
|
False - most is forced back toward the stomach for further mixing
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In which part of the stomach does the most vigorous peristalsis take place?
|
pylorus
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What cells initiate basal electrical rhythm (BER) for peristalsis?
|
cells of Cajal in the fundus of the stomach
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Which hormones are known as enterogastrones?
|
cholecystokinin (CCK)
secretin |
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Which feelings tend to decrease gastric motility?
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sadness
fear intense pain |
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Which feelings tend to increase gastric motility?
|
anger
aggression |
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Do feelings like sadness, fear, and intense pain tend to decrease of increase gastric motility?
|
decrease
|
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Do feelings like anger and aggression tend to decrease or increase gastric motility?
|
increase
|
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Which hormone regulates gastric emptying by regulating secretions from the pancreas and gall bladder?
|
cholecystokinin (CCK)
|
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What does cholecystokinin (CCK) regulate?
|
secretions from the pancreas and gall bladder
|
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True or False: Carbohydrate-rich chyme moves quickly through the duodenum.
|
True
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True or False: Carbohydrate-rich chyme remains in the stomach for a relatively long time.
|
False
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True or False: Fat-laden chyme moves quickly through the duodenum.
|
False
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True or False: Fat-laden chyme remains in the stomach for a relatively long time.
|
True
|
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What factors in the duodenum prevent gastric emptying?
|
fat
unneutralized acid high osmolarity high level of chyme |
