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50 terms

chapter 25 DIGESTIVE SYSTEM

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____is the physiological process that moves a nutrient from the outside to the inside of the body
absorption
the serous membranes that suspend the stomach and intestines from the abdominal wall are called
mesenteries
this image shows tissue layers of the digestive tract. what does 3 represent
muscularis externa
this image shows tissue layers of the digestive tract. what does 2 represent
serosa (mesentery)
these nutrients are all absorbed without being digested except
proteins
these are all accessory organs of the digestive system except
spleen
each of the following lists some of the tissue layers of the digestive tract. which one has them in correct order from lumen to external surface
lamina propria, muscularis mucosae, submucosa, muscularis externa, serosa
the small intestine in suspended from the abdominal wall by
the mesentery
chemical digestion breaks down ____ into ____
nucleic acids; nucleotides
the ____ regulates digestive tract motility, secretion, and blood flow and its neurons are found in the ____
enteric nervous system; submucosa and muscularis externa
the surface of the tongue is covered with ____ stratified squamous epithelium, and has bumps called ____, site of taste buds.
nonkeratinized; lingual papillae
infants have ____ deciduous teeth, whereas adults have ____ permanent teeth.
20;32
from superficial to deep, these are the structures found in a typical tooth
enamel, dentin, pulp
these are normally found in saliva except
protease
the ____ gland is an extrinsic salivary gland; whereas the ____ gland is an intrinsic salivary gland
submandibular; lingual
the swallowing center is located in
the medulla oblongata
the buccal phase of swallowing is under ____ control and the pharayngoesophageal phase is ____
central nervous system; controlled by autonomic reflexes
acid reflux into the esophagus ("heartburn") is normally prevented by
the lower esophageal sphincter (LES)
this image shows the stomach. what does 3 represent
gastric rugae
hydrochloric acid (HC1) is secreted by ____ cells
parietal
____ , which is secreted by ____ cells, is necessary for Vitamin B12 absorption
intrinsic factor; parietal
pepsinogen is produced by ____ and is activated by ____
chief cells; hydrochloric acid (HC1) secreted by parietal cells
why are several digestive enzymes secreted as zymogens
so they act only in the stomach lumen and do not digest intracelluar proteins
the enterogastric reflex serves to
inhibit gastric motility when there is chyme in the small intestine
____ is a hormone, whereas ____ is an enzyme
secretin; pepsin
____ is associated with food stretching the stomach and activating myenteric and vagovagal reflexes, which in turn stimulate gastric secretions
the gastric phase
the organ that stores excess glucose and releases it later into the blood is
the liver
a hepatic triad consists of
bile ductule, branch of hepatic artery, and branch of hepatic portal vein
of the following components of bile, only ____ has/have a digestive function.
bile salts
the ____ synthesizes bile acids by metabolizing _____
liver; cholesterol
pancreatic enzymes are secreted in response to the hormone
cholecystokinin (CCK)
which of these is not a component of the pancreatic juice
enterokinase
which of these nutrients is absorbed by the lacteals of the small intestine
triglycerides
which of the following enzymes functions at the lowest pH
pepsin
which of these is the site of contact digestion
brush border of the small intestine
the small intestine has a very large absorptive surface associated with all these structures except
rugae
the migrating motor complex
milks the chyme toward the colon
the ____ of the small intestine is/are similar to the ____ of the stomach
intestinal crypts; gastric pits
carbohydrate digestion begins in the ____ whereas protein digestion begins in the ____
mouth; stomach
_____ break(s) down ____
peptidases; proteins
the sodium-glucose transport protein (SGLP)
transports glucose and sodium from the intestinal lumen into the epithelial cells
amino acids and monosaccharides are absorbed in the ____, and fatty acids are absorbed in the ____
small intestine; small intestine too
lecithin prepares fats for hydrolysis by forming
emulsification droplets
proteins are digested by different enzymes acting in the following sequence
pepsin, trypsin, carboxypeptidase, dipeptidase
____ transport lipids to the surface of the intestinal absorptive cells, which process them into ____
micelles; fat globules
the three most abundant classes of nutrients are
fats, proteins, and carbohydrates
the muscle tone of the ____ along the colon contracts it lengthwise, causing its walls to bulge and form pouches called _____
taeniae coli; haustra
bacterial flora carry out all of the following except
digest most of the proteins we get in the diet
bacteria constitute about ______% of the dry weight of the feces
30
defecation is stimulated by
stretching of the rectum