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62 Cards in this Set
- Front
- Back
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Name the 4 major functions of the GI system
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Motility
Secretion Digestion Absorption |
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How is motility regulated?
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Feedback signals control smooth muscle, which allow the mixing of material
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What is the "tube within a tube" called, what is its function, and how is it formed in utero? Due to this formation, what is a distinctive property of it?
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The alimentary canal - tube through which food passes through the digestive system and is removed. Embryo: mast cells form circle and join on midline; inner layer becomes alimentary canal, outer becomes body wall; inner grows faster than outer so it coils and convolutes into intestines.
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Secretion - what substance is secreted from what medium into what structure?
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Water from plasma secreted into alimentary canal
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What are the 2 types of digestion?
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Mechanical
Enzymatic |
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What is the purpose of absorption?
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A lot of liquid is put into the alimentary canal that can't be lost through defecation, so it must be absorbed back into circulation.
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How many types of salivary glands does the buccal cavity have?
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4
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How is a bolus formed in the mouth?
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Food softened by saliva from salivary glands; teeth grind food into smaller pieces; tongue and palate form soft ball that can be swallowed
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Besides forming the bolus, what is the major function of the palate and what are its characteristics contributing to it?
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Plays role in preventing bolus from going up into nasopharynx; soft palate does this while the bony palate contributes to bolus formation.
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Name the 4 types of tonsils
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Lingual
Pharyngeal Adenoid Palatine |
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Name the 3 portions of the pharynx
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Nasopharynx
Oropharynx Laryngopharynx |
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What is the average length of the esophagus?
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25 cm
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What types of muscle make up the esophagus and in what parts?
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Top third - all skeletal muscle
Middle third - sleketal and smooth Bottom third - all smooth muscle |
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How is the smooth muscle in the middle and lower esophagus controlled?
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By the autonomic NS
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Give both names and the location of the first GI sphincter
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Pharyngoesophageal sphincter
UES - upper esophageal sphincter Located at the top of the esophagus |
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Give the 3 names and the location of the second GI sphincter
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Gastroesophageal sphincter
Cardiac sphincter LES - lower esophageal sphincter Located at the bottom of the esophagus |
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Name the hole in the diaphragm that the esophagus passes through
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Esophageal hiatus
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What nerve plexus is associated with the esophageal surface? Where does it originate and innervate? Why is it important in pathology?
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Vagal nerve plexus. From 10th cranial nerve to diaphragm and visceral organs in abdominal cavity. Pathological conditions of esophagus can affect vagus nerve and disrupt innervation of ALL of the viscera.
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Name the 4 regions of the stomach
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Cardia
Fundus Body Pyloric region |
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Describe the cardia
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Where the esophagus joins the stomach
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Describe the fundus
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Where gas is trapped as digestion releases CO2 and other gases. Gas is released through the LES as an eruptation. Sits at a level superior to the LES.
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Describe the body of the stomach
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Thinner smooth muscle in wall, very glandular. Some contraction and high control of tone when not eating.
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Name the three regions of the pyloric region (one has 2 names)
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Antrum
Pylorus canal Pyloric sphincter (Pylorus) |
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Describe the antrum
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Start of the mixing, grinding, and churning. Thick smooth muscle wall
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Describe the pylorus canal
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Forces material out of the stomach into the small intestine
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Describe the pylorus
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Sphincter through which food is moved from the stomach to the intestine by the contraction of the pylorus canal. 3rd sphincter of the GI system. Accumulation of very strong smooth muscle
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What does 'antrum' mean in Latin?
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Cave
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What does 'pylorus' mean in Latin?
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Gate guard
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Describe the lesser omentum and give its main purpose
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Two parts: hepatoduodenal ligament, hepatogastric ligament. Made of thick connective tissue. Purpose is to hold up the stomach when it is full and heavy.
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Where is the agular notch located?
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On the superior side of the stomach in the lesser curvature, at the dividing point between the body of the stomach and the antrum.
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Describe the greater omentum and its purposes.
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An apron inside abdominal cavity attached to the greater curvature of the stomach on the inferior side. Made of fat deposits (the major fat-storing organ). Saturated with arteries and veins, which allows quick inflammatory response to injured or infected intestinal area, also acts like a plug when intestines are perforated to prevent spilling of intestinal contents into the body cavity.
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Name and describe the 4 stomach conditions relating to tone from neurologtical conditions of the ANS.
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Hypertonic stomach: too much tone, doesn't relax when food is put into it
Orthotonic stomach: sags with own weight when stand up, not enough tone Hypotonic stomach: even less tone, sags below level of iliac crest Atonic stomach: flaccid back with no stimulation to contract. |
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Define mesenteries
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Double sheets of serous membranes tt suspend parts of the GI tract; routes for NN, AA, VV, and lymphatic vessels. Sometimes called ligaments - connect one ORGAN to another in the abdomen.
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Name the two serous membranes lining the surfaces in the abdominal cavity
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Parietal peritoneum - lines inner surface of abdominal cavity
visceral peritoneums - line outer surfaces of individual organs in abdominal cavity |
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How many serous membrane layers make up the greater omentum?
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4
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Name the three parts of the small intestine and give their dimensions
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Duodenum - 25 cm long, 2.5 cm wide
Jejunum - 2 m long Ileum - 2.75 m long |
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Give the backgrounds for the names of the small intestine components.
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Duodenum - "twelve fingers"
Jejunum - "empty" Ileum - "twisted" |
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Name the 4th GI sphincter
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Ileocecal sphincter
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Describe the cecum
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Blind pouch at the base of the ascending colon, where the ileocecal sphincter connects the ileum and cecum. Vermiform appendix is a blind tube projecting off the cecum.
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Name the 3 parts of the large intestine
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Cecum
Vermiform appendix Colon |
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Name the 4 parts of the colon
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Ascending
Transverse Descending Sigmoid |
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Through what vessel does the entire venous network of the GI tract drain, into what organ, and into what vessel does it drain from there?
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Hepatic portal vein, into the liver, then empties into IVC
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What is an alternative oral drug delivery mechanism to avoid hepatic first pass metabolism? Where does the drug go instead?
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Package drug in lipid-soluble chylomicrons, absorbed into lymphatic system tt travels to L shoulder and drains into R heart, lungs, L heart and finally into all body cells before traveling to the liver.
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What is the beginning of the lymphatic system in the intestines called? Describe.
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Lacteal - 1-cell-thick vessel similar to capilary, located in intestinal villi. Material can only enter and flow in 1 direction - into thoracic lymphatic duct, the major lymphatic vessel of the body.
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Name the 3 parts of the end of the large intestine
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Rectum - 20 cm, continues from sigmoid colon to anal canal
Anal canal Anus |
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Name the 5th and 6th GI sphincters
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Internal sphincter - involuntary in the anus
External sphincter - voluntary in the anus, outermost |
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Name the general junction of the hepatic portal vein and the IVC
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Portocaval anastomoses
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Name the 4 portocaval anastomoses
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Esophageal
Paraumbilical Rectal Retroperitoneal |
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The three hemorrhoidal veins drain into which vessels?
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Superior and middle hemorrhoidal veins - into hepatic portal vein
Inferior hemorrhoidal vein - into IVC |
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Name the 4 layers of the GI tract wall, from innermost to outermost
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Mucosa
Submucosa Muscularis externa Adventitia |
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Name the 3 layers of the mucosa, from innermost to outermost.
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Epithelium
Lamina propria Muscularis mucosae |
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Describe the lamina propria
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Connective tissue with blood and lymphatic vessels, nerves, ducts of glands, and lymph nodes
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Describe the muscularis mucosae
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Very narrow band of smooth muscle
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Describe the epithelium
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Varies in each part of GI tract. Constantly replaced. Stratified squamous epithelium in esophagus keeps lamina propria from being exposed to material in esophagus
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Define rugae
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The folds in the epithelium of the intestines due to contraction of the muscularis mucosae.
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Describe the submucosa
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Connective tissue containing nerve plexus on the outer aspect, also contains blood & lymphatic vessels, lymph nodes, and glands
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What is another name for the nerve plexus of the submucosa?
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Meissners plexus
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Describe the muscularis externa
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2 layers of smooth muscle: circular and longitudinal. Both coordinated by neuronal control and communication through myenteric plexus
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What is another name for the myenteric plexus?
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Auerbachs plexus
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Describe the adventitia
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Connective tissue on surface of muscularis externa. May or may not also have serous membrane (mesentery) covering it.
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What are the 2 types of innervation of the GI tract
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Extrinsic - ANS
Intrinsic - Enteric NS |
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Describe the extrinsic innervation of the GI tract (& the 2 types of extrinsic innervation)
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Sympathetic innervation: mainly postganglionic adrenergic neuronal fibers
Parasympathetic innervation: via vagus & pelvic NN, mainly preganglionic cholinergic fibers |
