____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