In which region of the GI tract is the longitudinal muscle of the muscularis arranged into distinct longitudinal bundles?
- A. Duodenum
- B. Jejunum
- C. Ileum
- D. Colon
Correct Answer: D
Rationale: The correct answer is D: Colon. The colon has the longitudinal muscle of the muscularis arranged into distinct longitudinal bundles called taeniae coli. This unique structure helps in the formation of haustra, the pouches seen in the colon. In contrast, the duodenum, jejunum, and ileum do not have this specific arrangement of longitudinal muscle bundles. The duodenum has a smooth muscle layer, while the jejunum and ileum have a continuous layer of smooth muscle without distinct longitudinal bundles. Therefore, the colon is the region of the GI tract where the longitudinal muscle is organized into distinct bundles.
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Which of the following enzymes is involved in the breakdown of proteins?
- A. amylase
- B. lipase
- C. pepsin
- D. maltase
Correct Answer: C
Rationale: The correct answer is C: pepsin. Pepsin is an enzyme produced in the stomach that helps break down proteins into peptides. It works in a highly acidic environment, denaturing proteins. Amylase (A) breaks down carbohydrates, lipase (B) breaks down fats, and maltase (D) breaks down maltose into glucose. Pepsin is specifically designed to target proteins, making it the correct choice.
Donald is a 61 y.o. man with diverticulitis. Diverticulitis is characterized by:
- A. Periodic rectal hemorrhage.
- B. Hypertension and tachycardia.
- C. Vomiting and elevated temperature.
- D. Crampy and lower left quadrant pain and low-grade fever.
Correct Answer: D
Rationale: The correct answer is D because diverticulitis typically presents with crampy pain in the lower left quadrant of the abdomen and a low-grade fever. This is due to inflammation or infection of the diverticula.
A: Periodic rectal hemorrhage is more characteristic of diverticular bleeding, not diverticulitis.
B: Hypertension and tachycardia are not typically associated with diverticulitis but may occur in severe cases or with complications.
C: Vomiting and elevated temperature can occur but are not as specific to diverticulitis as the combination of symptoms described in option D.
Secretin hormone:
- A. Released in response to acidic gastric juice.
- B. Stimulates stomach mobility.
- C. Stimulates HCL secretion.
- D. All of the above are correct.
Correct Answer: A
Rationale: The correct answer is A because secretin hormone is released in response to acidic gastric juice, acting to neutralize the acidity by stimulating pancreatic bicarbonate secretion. Choice B and C are incorrect as secretin does not stimulate stomach mobility or HCL secretion. Therefore, the correct answer is A as it aligns with the function of secretin in regulating pH balance in the digestive system.
Which two regions of a tooth contain living cells?
- A. dentin and enamel
- B. anatomical crown and cementum
- C. enamel and cementum
- D. dentin and cementum
Correct Answer: D
Rationale: The correct answer is D. Dentin and cementum are the two regions of a tooth that contain living cells. Dentin is the hard tissue beneath the enamel and cementum that forms the bulk of the tooth structure. It contains living cells called odontoblasts responsible for dentin formation. Cementum is the hard tissue covering the tooth root and is essential for anchoring the tooth in the jawbone. Cementum contains living cells called cementoblasts responsible for cementum formation. Therefore, both dentin and cementum are vital regions of a tooth that house living cells involved in tooth development and maintenance.
A: Dentin and enamel - Enamel is the outermost layer of the tooth and does not contain living cells.
B: Anatomical crown and cementum - Anatomical crown is not a region of the tooth containing living cells.
C: Enamel and cementum - Enamel does not contain living cells, only mineralized structures.
The portion of a tooth which lies within the mandible socket is called the _____.
- A. dentin
- B. crown
- C. root
- D. cementum
Correct Answer: C
Rationale: The correct answer is C: root. The root of a tooth is the portion that lies within the mandible socket, anchoring the tooth in place. The root helps support the tooth and allows for the transfer of nutrients. Dentin (A) is the hard tissue beneath the enamel, crown (B) is the visible part of the tooth above the gumline, and cementum (D) covers the root surface but is not the portion within the mandible socket.