Chapter 24

How does the mucosa of the rectum compare with that of the colon and the cecum?

The colon and the cecum are lined with a simple columnar epithelium for absorption, whereas the rectum is lined with a stratified squamous epithelium because the rectum is next to the opening to the exterior of the body.

Gastric glands, which produce most of the gastric juices, are abundant in which of the following regions of the stomach?

The fundus and the body

What is the function of bile?

To emulsify lipids

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

Tongue

The small, slender structure that is attached to the large intestine and is suffused with lymphoid nodules is the __________.

appendix

The reflex that occurs in the large intestine and promotes the movement of feces toward the anus is the __________.

defecation reflex

The chemical breakdown of food into small organic fragments that can be absorbed by the digestive epithelium is __________.

digestion

When two fluids are separated by a selectively permeable membrane, water tends to flow into the fluid that has the __________.

higher concentration of solutes

The primary effect of secretin is to __________.

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

The plicae of the intestinal mucosa, which bears the intestinal villi, are structural features that __________.

increase the total surface area for absorption

Functions of saliva:

- moistening food - helping clean oral surfaces - dissolving food

The "doorway to the liver" (porta hepatis) includes the __________.

bile duct, hepatic portal vein, and hepatic artery

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

larynx

What type of tooth can have two or three roots and is best suited for helping in mastication by grinding and crushing food?

molars

Regions of the small intestine

- Duodenum - Ileum - Jejunum

The following digest proteins:

- Enteropeptidase - Pepsin - Trypsin

Hydrochloric acid functions include:

- Facilitating protein digestion - Activating pepsin - killing microorganisms

Effects of advancing age on the digestive system

- Increase in dental caries and gingivitis, resulting in loss of teeth - Increase in peptic ulcers - Increase in the rate of digestive system cancers

statements about peritonitis:

- It could result in a burst appendix. - It can be caused by bacteria entering the abdominal cavity during a surgical procedure. - It is an inflammation of the peritoneal membrane.

Substances thats are absorbed in the large intestine:

- Organic Wastes such as Urobilinogens - water - vitamins such as vitamin K

Systems adversely affected by inadequate calcium absorption

- Skeletal - Muscular - Cardiovascular

What is the importance of the mesenteries?

- Stabilizing the attached organs - a route for blood vessels to and from the digestive tract - preventing the intestines from becoming entangled

The following digest carbohydrates:

- Sucrase - Pancreatic alpha-amylase - lactase

The primary functions of intestinal juices include:

- assisting buffering acids - dissolving digestive enzymes and the products of digestion - moistening chyme

Digestive tract functioning is controlled by

- pH changes - hormones - Myenteric reflexes

Reasons you are not able to swallow a completely dry food bolus

- the dry food would inhibit parasympathetic activity in the esophagus - Friction with the walls of the esophagus would make peristalsis ineffective - dry food would stimulate sympathetic activity, inhibiting peristalsis

In the oral cavity, the digestive enzyme __________ is found in saliva and begins the digestion of __________.

amylase; startch

The pancreas produces enzymes that digest __________.

carbohydrates, lipids, proteins, and nucleic acids

Triglycerides coated with proteins create complexes known as __________.

chylomicrons

Why are older people sometimes subjected to recurring episodes of constipation?

decreased smooth muscle tone

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

expansion for swallowing

The intestinal epithelium absorbs monosaccharides via __________.

facilitated diffusion and cotransport mechanisms

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

fats

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

ileocecal valve

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

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

plicae circularis

Which of the following causes an immediate increase in the rates of glandular secretion and peristaltic activity in all segments of the small intestine?

Gastroenteric Reflex

What are the pouches that give the colon its typical appearance?

Haustra

Which type of tooth is responsible for clipping and cutting?

Incisor

The hormone gastrin __________.

Increases the activity of the parietal and chief cells

Which of the following produces, on a daily basis, the least number of the peristaltic contractions that force food through the digestive tract?

Large intestine

Which layer of the digestive tract is responsible for peristalsis and segmentation?

Muscularis externa

What is the cell type that secretes intrinsic factor?

Parietal Cells

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

Pharynx

The lowest portion of the stomach, which forms the sharp curve of the J-shaped stomach, is the __________.

Pylorus

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

Rennin

Villikinin, motilin, and somatostatin are produced in the __________.

Small intestine

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

Stomach distension and gastrin release

What type of epithelium makes up the oral mucosa?

Stratified squamous

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

The two positive-feedback loops involved in the defecation reflex are __________.

the stretch receptors in the rectal walls and the sacral parasympathetic system

Why is diarrhea potentially life threatening?

Loss of water and electrolytes

These processes are involved in the secretion of hydrochloric acid by the parietal cells of the stomach

- Active transport of H+ and diffusion of Cl- - Countertransport of Cl- and HCO3- - CO2 reacts with H2O

Which mineral requires calcitriol and PTH for its absorption by the digestive tract?

Ca2+

What is the correct sequence of parts in the colon moving from the small intestine to the anus?

Cecum; ascending colon; transverse colon; descending colon; sigmoid colon; rectum

There are some obvious bends in the colon that you don't see in the small intestine. What are the names of these bends?

Flexures

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

GIP

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

What is the average composition of fecal waste material?

75% water, 5% bacteria, 20% indigestible material, inorganic matter, & epithelial remains

What is the benefit of the stomach having rugae?

Allowing the expansion of the lumen

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

B12

Which of the following phases of gastric activity is brought on by the sight, smell, or thought of food?

Cephalic Phase

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

Cholecystokinin and secretin

If you put marbles in your mouth, which cranial nerve monitors receptors that detect their presence and causes the salivary reflex?

Cranial Nerve V

Which of the following is the term for swallowing?

Deglutition

What is the main stimulus that triggers the defecation reflex?

Distension of the rectum

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

Enteroendocrine cells

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

VIP

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

ingestion

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

Sympathetic stimulation of the muscularis externa promotes __________.

muscular inhibition and relaxation

Which regions of the pharynx serve as passageways for food on its way to the esophagus?

oropharynx and laryngopharynx

The enzyme lactase, which breaks down lactose into glucose and galactose, is secreted by __________.

the brush border of the small intestine

What is perhaps the most important function of the large intestine?

water reabsorption

The nutrients that can be absorbed without preliminary preparation but that may require special transport mechanisms are __________.

water, electrolytes, and vitamins