Digestive System: Anatomy and Function

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Questions and Answers

Which of the following characteristics accurately describe the epithelium found in the stomach?

Stratified squamous epithelium with goblet cells.
Pseudostratified ciliated columnar epithelium.
Simple columnar epithelium specialized for absorption.
Simple columnar epithelium with mucous-secreting cells. (correct)

Brunner's glands are a distinctive feature of which gastrointestinal structure, and in which layer are they primarily located?

Duodenum; submucosa (correct)
Appendix; muscularis externa
Esophagus; adventitia
Stomach; mucosa

What is the primary function of the gastric pits found in the stomach's mucosa?

To house glands that secrete gastric juices. (correct)
To increase the surface area for nutrient absorption.
To produce bile for fat emulsification.
To facilitate peristaltic movements.

Villi and intestinal crypts are prominent mucosal structures in the duodenum. What is the main purpose of villi?

Increase surface area for absorption. (A) Signup and view all the answers

Pyloric glands are found within the mucosa of a specific gastrointestinal organ. Which of the following organs contains pyloric glands?

Stomach (B) Signup and view all the answers

Which of the following characteristics correctly differentiate serosa from adventitia in the GI tract?

Serosa is covered by mesothelium, whereas adventitia lacks a mesothelium layer. (C) Signup and view all the answers

A pathologist is examining a tissue sample from the tongue and notes numerous projections on the dorsal epithelium. These projections are small, cone-shaped, and heavily keratinized. Which type of papillae are they MOST likely observing?

Filiform papillae (C) Signup and view all the answers

During a physical examination, a doctor observes a patient's tongue and notices several mushroom-shaped structures, primarily on the anterior region. These structures appear reddish due to underlying blood vessels. Which specific structures are MOST likely being observed?

Fungiform papillae (A) Signup and view all the answers

A surgeon is operating on a section of the GI tract that is freely floating within the peritoneal cavity. Which type of tissue covering is MOST likely present on the outer surface of this section?

Serosa, covered by mesothelium (B) Signup and view all the answers

Which of the following best describes the PRIMARY function of saliva within the oral cavity regarding the initial stages of digestion?

To provide lubrication for swallowing and begin carbohydrate digestion (D) Signup and view all the answers

A tissue sample taken from the outer layer of a GI tract segment shows no distinct mesothelium and appears directly connected to the abdominal wall. This sample MOST likely came from a region covered by which structure?

Adventitia (C) Signup and view all the answers

What is a key structural difference between filiform and fungiform papillae that relates to their function?

Filiform papillae are heavily keratinized, providing texture, while fungiform papillae have a thinner epithelial covering, often containing taste buds. (D) Signup and view all the answers

If a surgeon needs to mobilize a segment of the small intestine during a procedure, which tissue layer MUST be carefully handled to minimize friction and potential damage to surrounding structures?

The serosal layer, responsible for secreting fluid to reduce friction (D) Signup and view all the answers

Which gastric cell type is primarily responsible for the production of hydrochloric acid (HCl) in the stomach?

Parietal/Oxyntic Cells (B) Signup and view all the answers

Why is intrinsic factor, secreted by parietal cells, essential for normal physiological function?

It facilitates the absorption of Vitamin B12 in the terminal ileum. (B) Signup and view all the answers

How do surface mucous cells protect the stomach lining from damage?

By producing a thick layer of mucus and secreting bicarbonate ions. (B) Signup and view all the answers

If a patient undergoes a total gastrectomy (removal of the stomach), which of the following nutritional deficiencies is most likely to develop long-term?

Vitamin B12 Deficiency (B) Signup and view all the answers

What is the primary function of the pyloric sphincter, formed by the thickening of the middle circular layer of the muscularis externa?

To regulate the release of chyme into the duodenum. (D) Signup and view all the answers

Which layer of the gastric wall contains dense connective tissue, lymph vessels, and a network of blood vessels essential for nutrient absorption?

Submucosa (C) Signup and view all the answers

The myenteric (Auerbach's) plexus, found between the muscle layers of the muscularis externa, is primarily responsible for what function?

Propelling food through the digestive tract. (B) Signup and view all the answers

Pepsinogen is secreted by chief cells and is converted into pepsin in the stomach. What is the importance of secreting pepsinogen in an inactive form?

To prevent auto-digestion of the stomach lining by pepsin. (C) Signup and view all the answers

What is the role of soluble mucus, manufactured by neck mucous cells, in the stomach?

Lubricating the alimentary canal and becoming part of chyme. (C) Signup and view all the answers

Which hormone is produced by the 'I' cell and what is its primary function?

Cholecystokinin; stimulates release of pancreatic enzymes (C) Signup and view all the answers

Which layer of the muscularis externa is NOT present in all areas of the stomach?

Inner Oblique (D) Signup and view all the answers

If a patient's gastric motility is significantly reduced, which of the following hormones might be deficient?

Gastrin (B) Signup and view all the answers

Which cell type, when stimulated, leads to an increase in stomach acid production?

ECL cell (A) Signup and view all the answers

A drug that inhibits the action of which hormone would likely be prescribed to alleviate symptoms of excessive intestinal peristalsis?

Motilin (C) Signup and view all the answers

A patient is experiencing difficulty with fat digestion due to impaired gallbladder contraction. Which hormone level is most likely affected?

Cholecystokinin (B) Signup and view all the answers

If a researcher aims to study a substance that decreases intestinal peristalsis, which hormone should they focus on?

Neurotensin (B) Signup and view all the answers

Which hormone directly inhibits the secretion of hydrochloric acid (HCl)?

Gastric inhibitory peptide (D) Signup and view all the answers

Which hormone stimulates the release of pancreatic buffer?

Secretin (A) Signup and view all the answers

Which of the following pairs correctly matches a hormone to its primary effect on blood glucose levels?

Glucagon and increase blood glucose (C) Signup and view all the answers

If chief cells aren't releasing enzymes effectively, supplementing which hormone might help?

Pancreatic polypeptide (D) Signup and view all the answers

Which structural feature is responsible for the characteristic sacculated appearance (haustra) of the colon?

The presence of the taeniae coli, which are three longitudinal bands of muscle. (C) Signup and view all the answers

In the large intestine, what is the primary function of the abundant goblet cells found within the epithelium?

Producing mucus to lubricate the passage of feces. (A) Signup and view all the answers

If a patient has damage to the Auerbach/Myenteric nerve plexus in their large intestine, which function would be most directly affected?

Contractions of the muscularis externa for peristalsis. (B) Signup and view all the answers

How does the absorptive function of the large intestine differ from that of the small intestine?

The large intestine primarily absorbs water, whereas the small intestine primarily absorbs nutrients. (A) Signup and view all the answers

Which histological feature is characteristic of the appendix?

Numerous lymphoid nodules in the mucosa and submucosa. (A) Signup and view all the answers

What is the significance of germinal centers within the lymphoid nodules of the appendix?

They are active sites of B-lymphocyte production. (A) Signup and view all the answers

How do primary and secondary follicles differ within the lymphoid tissue of the appendix?

Primary follicles are homogenous, while secondary follicles have pale, active germinal centers. (C) Signup and view all the answers

A surgeon is operating on a patient and needs to identify the transverse colon. Which characteristic of the transverse colon would assist in its identification?

It is covered by serosa and is intraperitoneal. (D) Signup and view all the answers

What is a key feature that distinguishes the large intestine from the small intestine at the macroscopic level?

The presence of taeniae coli and haustra in the large intestine. (D) Signup and view all the answers

Which of the following best describes the muscularis externa of the large intestine?

Two complete layers (inner circular and outer longitudinal) plus the taeniae coli. (A) Signup and view all the answers

What is the primary function of lacteals found within the lamina propria of the small intestine?

Absorbing lipids and transporting them to the cisterna chyli via the thoracic ducts. (A) Signup and view all the answers

The plicae circulares, villi, and microvilli collectively function to:

Increase the surface area available for nutrient absorption in the small intestine. (C) Signup and view all the answers

The muscularis mucosae, composed of smooth muscle fibers, extends into the core of individual villi. What is its primary role?

To facilitate movement of the villi, increasing contact with digested food products. (C) Signup and view all the answers

In cases of acute gastroenteritis caused by a virus attacking microvilli, which of the following is the most likely consequence?

Severe malabsorption due to the reduced surface area for nutrient uptake. (B) Signup and view all the answers

If the flow of nutrients from the enterocytes to the liver is blocked, what would happen?

Nutrient absorption is impaired as the nutrients cannot reach the circulation for distribution. (D) Signup and view all the answers

Which component of the lamina propria is specifically responsible for absorbing lipids?

Lacteals (D) Signup and view all the answers

What is the primary function of the Crypts of Lieberkuhn?

Openings for tubular glands (D) Signup and view all the answers

Why does lactose intolerance often result in diarrhea and flatulence?

Unabsorbed lactose attracts water into the large intestine, promoting bacterial fermentation and gas production. (D) Signup and view all the answers

What is the function of Plicae circulares?

Enhance nutrient absorption (B) Signup and view all the answers

What is the role of lymphoid follicles in the lamina propria?

Initiating immune responses. (D) Signup and view all the answers

Flashcards

Filiform papillae

Projections on the tongue's dorsal epithelium, primarily for texture.

Fungiform papillae

Mushroom-shaped papillae, involved in taste sensation.