bio 171t exam 3 material (respiratory and digestive)

digestive system consists of

GI tract and accessory organs

digestive tract begins at

mouth and continues through pharynx, esophagus,

stomach, small intestine and large intestine

Accessory digestive organs include

teeth, tongue, gallbladder, salivary glands, liver, and pancreas

mesenteries

double sheets of peritoneal membrane

The digestive system processes food, extracts nutrients, and eliminates the residue

true

The outermost layer of the digestive tract, which is composed of a thin layer of areolar tissue andsimple squamous epithelium, is called the ________

serosa (mesentery)

Hydrochloric acid (HCl) is secreted by __________ cells.

parietal

Most of the fat in the body is stored in what form?

triglycerides

Which of the following is not an accessory organ of digestion

spleen

Which of the following is the accessory organ of digestion responsible for producing bile?

liver

The small intestine is suspended from the abdominal wall by the ________

mesentery

The ________ regulates digestive tract motility, secretion, and blood flow. Its neurons are found in the ________

enteric nervous system; submucosa and muscularis externa

The layer that is responsible for the motility that propels food and residue through the digestive tract is called the

mucosa externa

Which of the following nutrients must be digested in order to be absorbed

proteins

Which of the following is not normally found in saliva

protease

The swallowing center is located in the ___

medulla oblongata

The oral phase of swallowing is under control and the pharyngoesophageal phase is ___

Central nervous system; controlled by the autonomic nervous system

The ___ regulates the flow of contents from the stomach to the duodenum

Pyloric sphincter

Pepsinogen is produced by ________ and is activated by ________, which is secreted by________.

chief cells; hydrochloric acid (HCl); parietal cells

________ is a hormone, whereas ________ is an enzyme

Secretin; pepsin

The ________ phase is associated with food stretching the stomach and activating myenteric andvagovagal reflexes, which in turn stimulate gastric secretions

gastric

The ___ stores excess glucose and releases it into the blood when needed

liver

The ___ synthesizes bile acids by metabolizing ___

liver; cholesterol

The ____ of the small intestine is/are similar to the __ of the stomach

Intestinal crypts; gastric pits

Which of the following bile components contributes to digestion

bile salts

Which of the following enzymes functions at the lowest pH

pepsin

Lipids are transported to the surface of the intestinal absorptive cells via ___ and are then processed into __

Micelles; chylomicrons

Carbohydrate digestion begins in the ___ whereas protein digestion begins in the ___

mouth; stomach

The three most abundant classes of nutrients are

fats, proteins, and carbohydrates

Which of the following is not a function of gastric hydrochloric acid (HCl)?

emulsify lipids

An example of chemical digestion is the break down of __________ into __________.

nucleic acids; nucleotides

Acid reflux into the esophagus ("heartburn") is normally prevented by __________.

the lower esophageal sphincter (LES)

Defecation is stimulated by __________.

stretching of the rectum

Which of the following nutrients is absorbed by the lacteals of the small intestine?

triglycerides

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 enzyme(s) called __________ break(s) down the substrate called __________.

peptidases; proteins

mucosa

mucous membrane consisting of an epithelium, which is moistened by glandular secretions, and a lamina propria of areolar tissue

submucosa

layer of dense irregular connective tissue

that surrounds the mucosa

serosa does not cover

muscular layer of the oral cavity, pharynx, esophagus, and rectum

villi

small mucosal projections into the lumen of the small intestine

multi-unit smooth muscle cells innervated by

motor units

The esophagus enters the abdominopelvic cavity by passing through the ________________ of the diaphragm.

esophageal hiatus

Which of the following major layers of the digestive tract is described as a layer of dense, irregular connective tissue filled with blood vessels and the plexus of Meissner?

submucosa

An error in swallowing is most likely detected by the __________.

larynx

Which of the following is not a step in the overall digestive process?

excretion

The active process that occurs when food enters the digestive tract via the mouth is __________.

ingestion

Which macromolecules begin being digested in the oral cavity?

carbohydrates and lipids

What is the order of the layers of the gastrointestinal tract, starting with the layer in contact with the food?

Mucosa; submucosa; muscularis externa; serosa

Which oral structure(s) is/are responsible for manipulating food to assist in chewing and in the production of the enzyme lipase?

tongue

What type of epithelium makes up the oral mucosa?

Stratified squamous

What cells in the digestive epithelium produce hormones that help regulate the digestive tract?

enteroendocrine cells

Which of the following is the term for swallowing?

deglutition

Which of the following is not found in the lamina propria?

epithelial tissue

Many visceral smooth muscle networks have rhythmic cycles of activity in the absence of neural stimulation because of __________.

pacesetter cells that spontaneously depolarize and trigger the contraction of entire muscular sheets

What is the importance of the mesenteries?

Stabilizing the attached organs

Preventing the intestines from becoming entangled

A route for blood vessels to and from the digestive tract

Which of the following digestive regions is responsible for the propulsion of materials into the esophagus?

pharynx

The digestive tract motility and secretions are controlled by a complex set of mechanisms. Which of the following is NOT a normal way the digestive tract functioning is controlled?

Somatic motor neurons

Why would you NOT be able to swallow a completely dry food bolus?

The dry food would stimulate sympathetic activity, inhibiting peristalsis.

The dry food would inhibit parasympathetic activity in the esophagus.

Friction with the walls of the esophagus would make peristalsis ineffective.

What is the benefit of the large folds of the lining of the esophagus?

Expansion for swallowing

Which of the following is NOT a function of hydrochloric acid in the stomach?

Breaking down disaccharides into monosaccharides

The primary effect of secretin is to __________.

increase the secretion of bile and buffers by the liver and the pancreas

Which two factors play important parts in moving the chyme from the stomach into the small intestine?

Stomach distension and gastrin release

The numerous transverse folds in the small intestine that serve to increase the surface area for absorption are the __________.

circular folds (plicae cicrulares)

What is the correct sequence of events in moving a bolus of food to the stomach?

Bolus is moved to oropharynx; epiglottis folds over glottis; esophageal peristalsis; opening of lower esophageal sphincter

The enteroendocrine cells of the intestinal glands are responsible for producing which intestinal hormones?

Cholecystokinin and secretin

What is the hormone secreted by the small intestine that dilates capillaries in the small intestine area?

VIP

The hormone gastrin __________.

increases the activity of the parietal and chief cells

Which cells secrete intrinsic factor?

Parietal cells

The primary functions of intestinal juices include which of the following?

To dissolve digestive enzymes and the products of digestion

To moisten the chyme

To assist in buffering acids

Fatty acids and lipids are absorbed into the ____________ found in each villus of the small intestine.

lacteal

Triglycerides coated with proteins create complexes known as  __________.

chylomicrons

Which of the following is NOT produced by the gastric glands in the stomach of an adult?

rennin

Chief cells in the gastric glands secrete ________________.

pepsinogen

Which peptide hormone causes the secretion of insulin from the pancreatic islets?

GIP

The muscular sphincter that guards the opening between the ileum and the cecum is the __________.

ileocecal valve

The absorption of which vitamin would be impaired if the stomach were removed?

B12

Which process is NOT involved in the secretion of hydrochloric acid by the parietal cells of the stomach?

Movement of Cl^- from the intestinal lumen to the interstitial fluid.

What is the benefit of the stomach having rugae?

Allowing the expansion of the lumen

What component of the food would increase the number of chylomicrons in the lacteals?

fats

Put the regions of the stomach in the order through which food and chyme would pass.

Cardia, fundus, body, pyloric part

dorsal and ventral mesenteries suspend

peritoneal cavity

peritoneal cavity

serous membrane that lines the abdominopelvic cavity,

covering most of its organs

visceral peritoneum covers

organs

parietal peritoneum lines

abdominal walls

ventral mesentery remains in adults between

the stomach and the liver

greater omentum

dorsal mesentery of the stomach

Esophagus function

Actively moves food and liquids to the
stomach

esophagus enters the abdominopelvic cavity through

esophageal hiatus

Lower esophageal sphincter at ___ and is normally ___

inferior end; contracted

Deglutition

act of swallowing

deglutition facilitated by

secretions of saliva and mucus

stages of deglutition

• Voluntary

• Pharyngeal

• Esophageal

voluntary stage of deglutition

bolus passed to oropharynx

Pharyngeal stage of deglutition

involuntary passage through pharynx into
esophagus

Esophageal stage of deglutition

involuntary passage through esophagus to
stomach. peristalsis pushes bolus

Pharynx passes from

nasal cavity to esophagus

Salivary amylase secreted by

salivary glands

Salivary amylase acts on

starches

Only ___ can be absorbed

monosaccharides

Lingual Lipase secreted by

lingual glands of tongue