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21 Cards in this Set
- Front
- Back
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The digestive system, whats a breif overview? What muscle is the GI tract and in what structure , what is it function? What are the accesory digestive organs? assisting oragans? what do they work together to acheive, and main locations?
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Form a continuous, 9-10m tube from the mouth to the anus
Smooth muscle in the GI tract wall pushes materials from one end to the other Accessory digestive organs (liver, gallbladder, pancreas) Assisting organs (teeth, tongue, salivary glands) Accessory and assisting digestive organs work with the GI tract in the digestion of food; often originate as outgrowths from GI |
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what are the 6 functions of the digestive system and describe these functions?
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Ingestion
Acquisition of nutrients Digestion Mechanical and chemical breakdown of ingested food Propulsion Movement of food through GI tract (peristalsis and segmentation) Secretion Release of water, acid, and enzymes into the lumen of the digestive system Absorption Transport of nutrients from the digestive system to the circulatory system Elimination |
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the GI tract is a tube of what 4 concentric layers, and what do they surround, what are the names of the layers and describe them and tissue type?
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GI tract is a tube composed of four concentric layers, called tunics around the lumen
Mucosa: inner lining of epithelium (simple columnar), connective tissue (lamina propria), smooth muscle (muscularis mucosae), and MALT Submucosa: layer of loose areolar CT with blood/lymph vessels, submucosal plexus, and some glands Muscularis: inner circular and outer longitudinal layers of smooth muscle; myenteric plexus between muscle layers Serosa (or adventitia): areolar CT and simple squamous epithelium (part of visceral peritoneum); outermost covering |
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what are the 3 different nerve plexuses? what do they do?
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Nerve Plexuses (Enteric Division)
Complex interconnections of neurons between the tunics that coordinate the activities of the SM and glands of the gut wall Submucosal (Meissner’s) plexus Located within the submucosa, regulates secretion Myenteric (Auerbach’s) plexus Located in the muscularis externa, regulates motility, also called myenteric plexus |
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what is the peritoneum? what does it line? what does it contain? what are the two different types of peritoneum? what do they do?
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Large, continuous serous membrane formed of simple squamous epithelium
Lines all surfaces of the peritoneal (abdominal) cavity Contains large folds that bind the organs to one another and to the cavity walls. Parietal peritoneum Lines inner surface of body wall; secretes serous fluid and stores fat Visceral peritoneum Lines outer layer of gut tube below the diaphragm |
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what are the other two types of peritoneal and what do they do?
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Intraperitoneal
Describes organs that are suspended from the body wall by a peritoneal fold Stomach, transverse colon, small intestines, sigmoid colon Retroperitoneal Describes organs that do not have a mesentery in the adult form and are held against the posterior body wall and are partially covered by the peritoneum Kidneys, duodenum, cenasding and descending colons, rectum, uterus, pancreas |
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what is the oral cavity? and what 4 structures does it contain?
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Entrance to GI tract and site of mechanical and chemical digestion
Teeth anterior; fauces and uvula posterior Superior border formed by hard and soft palates Floor contains the tongue Vestibule: space between the cheeks or lips (labia) and gums (gingivae) |
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in the oral cavity what does saliva do? what starts digestion of carbs? fats? what else does it contain for bacterial growth? what else does saliva do?
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Moistens food; turns it into an easily swallowed semisolid bolus
Moistens and cleanses the oral cavity structures Amylase starts chemical digestion of CARBOHYDRATES (STARCH) in the mouth but is inactivated by stomach acid. Lipase chemically digests LIPIDS (FATS) in the stomach. Contains lysozyme, an antibacterial enzyme that inhibits bacterial growth Saliva also a medium for food molecules to dissolve into to stimulate taste receptors |
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what is the parotid gland? and where is located?
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Parotid Glands
Located anterior and inferior to the ear, partially overlying the masseter muscle. Saliva is conducted through the parotid duct to the oral cavity |
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submandibular glands? location?
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Submandibular Glands
Located inferior to the body of the mandible A duct opens from each gland in the floor of the mouth on the lateral sides of the lingual frenulum |
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sublingual glands? location? function?
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Inferior to the tongue and internal to the oral cavity mucosa
Each gland extends multiple tiny sublingual ducts that open onto the inferior surface of the oral cavity |
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how many adult teeth? how do they break down? what do they reside with? (location) function?
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32 adult teeth, on each side:
2 incisors 1 cuspid 2 premolars 3 molars Reside within alveoli of the maxilla and mandible Responsible for mastication |
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5 different parts of teeth? function?
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Crown: visible portion covered with enamel
Roots: portion within alveolus covered with cementum, held in place via periodontal ligaments, form a gomphosis Dentin: soft matrix in the tooth core Pulp cavity: vascular central region of tooth Root canal: narrow tunnel in roots that houses nerves and blood vessels |
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how many sets of teeth develop in lifetime? how many teeth erupt and how long after birth? lost and replaced in what direction? jaw lacks space for what?
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Two sets of teeth develop and erupt during a normal lifetime
20 deciduous teeth erupt 6 to 30 months after birth Lost and replaced by 32 permanent teeth; generally starting anteriorly and moving posteriorly Often jaw lacks space to accommodate 3rd molars, and may emerge only partially or become impacted |
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what is the tongue? formed from what 3 muscles? covered in what tissue? function? attacthed to what?
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An accessory digestive organ that is formed from hyoglossus, genioglossus, and styloglossus muscles and covered with keratinized stratified squamous epithelium
Manipulates, mixes, compresses ingested materials during chewing Inferior surface attached to floor of the oral cavity by lingual frenulum |
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what are the two pharnxy in digestive systems, structures and function, and tissure?
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oropharynx- Wall/tube of skeletal muscle connecting oral cavity to esophagus
laryngopharnyx- Lined with stratified squamous epithelium |
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what is the esophagus? stuture what does it attach to? what two splhincters does it contain? what else does it posses?
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Muscular tube connecting pharynx to the stomach
Site of peristalsis Begins inferior to the laryngopharynx, and runs posterior to trachea. Anatomy: Upper esophageal sphincter of skeletal muscle at entrance Lower esophageal (cardiac) sphincter of smooth muscle at entrance to stomach Possesses adventitia |
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what are the 2 muscle movements of GI tract?
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Peristalsis
Rippled, muscular contraction that occurs throughout the GI tract, propels mass forward Segmentation Back-and-forth churning that occurs in the small intestine |
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what are 3 functions of stomach? 3 things stomach secretes, what are 6 things stomach absorbs
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Functions:
Mixes saliva, food, and gastric “juice” to form chyme Serve as a holding reservoir for food before entering small intestine; performs chemical and mechanical digestion. Secretes gastric “juice”: HCL (kills bacteria, denatures protein), pepsin (digests protein), intrinsic factor (absorption of B-12), gastric lipase (digests fats). Stomach absorbs water, ions, fatty acids, drugs, alcohol |
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anatomy of stomach?
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Greater and lesser curvatures
Divided into cardia, fundus, body and pylorus Has large circular folds called rugae along internal wall 3 layers of smooth muscle in muscularis externa Pyloric sphincter (regulates passage of chyme to duodenum) |
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stomach: mucosa? whats it lined with? to secrete what? secretory cells extend down into what?
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Simple columnar epithelial cells (surface mucous cells) line the mucosal surface and secrete a protective mucus.
Columns of secretory cells extend down into the lamina propria forming gastric glands. Several gastric glands open into the bottom of narrow channels called gastric pits. |
