Chapter 23: Digestion

Before the blood carrying products protein digestion reaches the heart, it first passes through capillary networks in

Bacteria constitute about 30% of the dry weight of the feces.

An hepatic triad consists of

a bile ductule and branches of the hepatic artery and the hepatic portal vein.

Which of these best describes a lacteal?

a lymphatic vessel designed to help introduce fats to the blood

Tooth structure includes:

a thin periodontal ligament that holds the tooth in place.

What control mechanism opens the gastroesophageal sphincter?

peristalsis in the esophagus

Dextrinase carries out one of the very final stages in the digestion of

polysaccharides.

The function of the goblet cells is to:

produce mucus that protects parts of the digestive organs from the effects of powerful enzymes needed for food digestion.

All of the following enzymes digest proteins except

ribonuclease which digests RNA.

All of the following except ______ contribute to the large surface area available for nutrient absorption in the small intestine.

rugae

Which digestive process does NOT occur in the mouth?

segmentation

In addition to active transport, glucose can be absorbed from the chyme by means of

solvent drag.

The falciform ligament

suspends the liver from the diaphragm and the anterior abdominal wall.

The swallowing center is located in

the brainstem

Bacteria-destroying macrophages are found in sinusoids of

the liver

The entry of bile and pancreatic juice into the duodenum is controlled by:

the sphincter of Oddi.

Which of the following is the primary physiological function of the large intestine?

water absorption and feces elimination

T/F Ingested food raises the pH of the stomach contents.

True

T/F The bulk of a tooth is composed of a bonelike material called dentin.

True

T/F The first teeth to appear are the deciduous teeth.

True

T/F The gastroileal reflex relaxes the ileocecal valve when the stomach is full of food.

True

T/F The stomach secretes gastrin when its internal pH rises.

True

T/F Another term for swallowing is deglutition

True

Under normal conditions, the gastric mucosa pours out as much as:

2 to 3 liters of gastric juice per day.

A fluid secreted into the small intestine during digestion that contains cholesterol, emulsification agents, and phospholipids is:

Bile

Digestion of which of the following would be affected the most if the liver were severely damaged?

Digestion of lipids

Which of the following enzymes do not digest any nutrients?

Enterokinase

T/F Food that is stored in the fundus of the stomach often remains in storage for up to 7 hours before being mixed with the powerful gastric juices secreted by the cells of the stomach.

False. A typical meal is emptied from the stomach in about four hours.

T/F Due to postmortem shrinkage, the small intestine is shorter in a cadaver than it is in a living person.

False. Due to muscle tone, the small intestine is shorter in a living person than it is in a cadaver.

T/F The stomach lining is so well protected by mucus and tight junctions that its epithelial cells die at a very slow rate.

False. The epithelial cells of the stomach only live three to six days.

T/F The soft palate rises reflexively to open the nasopharynx when we swallow food.

False. The soft palate rises reflexively to close off the nasopharynx when we swallow food

T/F The layer of muscle in the intestine directly in contact with the serosa is the circular layer.

False. outer longitudinal layer.

T/F The function of the enzyme salivary amylase is to begin digesting proteins.

False. starch

What type of blood capillary located in this sublayer is uniquely suited for absorption of nutrient material?

Fenestrated

T/F At the junction of the main pancreatic duct and the common bile duct is an enlarged area called the hepatopancreatic ampulla.

True

T/F Digestive enzymes digest each other, allowing the amino acids to be absorbed and reused.

True

Which of the following cells are not found in the gastric glands?

Goblet cells

The enterogastric reflex regulates the _______________ phase of gastric activity.

Intestinal

Short-chain triglycerides found in foods such as butterfat molecules in milk are split by a specific enzyme in preparation for absorption. Which of the following enzymes is responsible?

Lipase splits short-chain triglycerides

The ________ contains lobules with sinusoids (lined with macrophages) that lead to a central venous structure.

Liver

SGLT, an active transport pump of the small intestine, can only absorb glucose by simultaneously transporting

Na+

Which of the following produce intrinsic factor?

Parietal cells

Which of the following enzymes functions at the lowest pH?

Pepsin

Pepsin digests _____________ to _____________.

Proteins to peptides

Hormones that inhibit gastric secretion include:

Secretin

If an incision has to be made in the small intestine to remove an obstruction, the first layer of tissue to be cut is the:

Serosa

The site of production of secretin and cholecystokinin is the:

Small intestine

The layer of the digestive tube that contains blood vessels, lymphatic nodes, and a rich supply of elastic fibers is the:

Submucosa

This tissue layer consists of a thick layer of loose connective tissue containing blood vessels, lymphatic vessels, a nerve plexus, and in some places, glands that secrete lubricating mucus into the lumen.

Submucosa

The dental formula for an adult is 2-1-2-3. What does the 1 stand for?

The canine tooth

Which of the following best describes the capillary wall structure found in the liver lobules?

The capillary walls have openings that allow large proteins and small cells to pass through.

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?

The correct order of some of the tissue layers of the digestive tract from lumen to external surface is lamina propria, muscularis mucosae, submucosa, muscularis externa, serosa.

Which of the following is not a phase of gastric secretion?

The enterogastric phase

The esophagus pierces through the diaphragm at the ___________, and its submucosa contains _______________ glands that secrete mucus.

The esophagus pierces through the diaphragm at the hiatus, and its submucosa contains esophageal glands that secrete mucus.

All of the following glands secrete mainly mucus, except for

The gastric glands

The hepatic portal vein leads to what?

The liver

T/F The stomach's contractile rhythm is set by pacemaker cells found in the spinal cord.

The stomach's contractile rhythm is set by pacemaker cells found in the longitudinal layer of the muscularis externa of the greater curvature.

Which layer of the alimentary canal contains not only glands and blood vessels but also a nerve plexus that helps regulate digestive activity?

The submucosa layer

Surgical cutting of the lingual frenulum would occur most near to which part of the body?

Tongue

Which of these nutrients are absorbed by the lacteals of the small intestine?

Triglyceride

Secretin is a hormone that is liberated by the small intestinal mucosa in response to:

acidic chyme entering the small intestine.

Which of the following constitute a portal triad?

bile duct along with a portal venule and arteriole

Of the following components of bile, only __________________ has/have a digestive function.

bile salts

The ingestion of a meal high in fat content would cause which of the following to occur?

bile to be released from the gallbladder to emulsify the fat in the duodenum.

All of the following nutrients are absorbed by blood capillaries of the villus except

cholesterol.

Pancreatic amylase cannot get to the small intestine via the:

cystic duct.

Which of the following apply to the small intestine?

most of the water absorption from the digestive tract occurs here.

Unitary smooth muscle is found in all hollow organs except for the heart. What structure do both heart muscle and unitary smooth muscle share that allows them to contract as a functional group?

gap junctions

Secreted by G cells of the gastric glands

gastrin.

Most of the water entering the digestive tract each day comes from

gastrointestinal secretions.

Which cells in the small intestine's mucosa secrete mucus?

goblet cells

The __________ circulation drains all of the organs of the digestive system.

hepatic portal

The mechanical process of digestion does not include:

hydrolysis.

The terminal portion of the small intestine is known as the:

ileum.

The enterogastric reflex serves to

inhibit gastric motility when there is chyme in the small intestine.

Which of the following is not characteristic of the large intestine?

it is longer than the small intestine.

Each of the following lists contains some of the tissue layers of the digestive tract. Which list has them in the correct order from lumen to external surface?

lamina propria-muscularis mucosae-submucosa-muscularis externa-serosa.

Bile is secreted by the __________ under hormonal influence of __________.

liver; secretin

Which of the following propels food residue over large areas of the colon three to four times a day?

mass movement