During the process of absorption, nutrients from food go from:

Answer Explanation

d. smooth muscles

- Correct: Smooth muscles are responsible for moving food through the digestive system via a process called peristalsis. Peristalsis involves rhythmic contractions and relaxations of the smooth muscle layers in the walls of the digestive organs, such as the esophagus, stomach, and intestines. These coordinated muscle movements propel food forward along the digestive tract, allowing for mechanical digestion, mixing with digestive fluids, and absorption of nutrients.

a. digestive fluids

- Incorrect: Digestive fluids, such as saliva, gastric juice, bile, and pancreatic enzymes, play crucial roles in the digestion and breakdown of food into smaller molecules. However, they do not directly move food through the digestive system.

b. enzymes

- Incorrect: Enzymes are biological catalysts that facilitate chemical reactions involved in the breakdown of food molecules into smaller, absorbable components. While enzymes aid in digestion, they do not themselves move food through the digestive system.

c. mucous membranes

- Incorrect: Mucous membranes line the inner surfaces of the digestive tract and secrete mucus, which lubricates and protects the epithelial cells from mechanical damage and chemical irritation. While mucous membranes are important for maintaining the health of the digestive tract, they do not actively move food through the digestive system.

Answer Explanation

c) pyloric sphincter

- Correct: During gastric emptying, chyme (partially digested food) is released from the stomach into the duodenum through the pyloric sphincter. The pyloric sphincter is a muscular valve located at the junction between the stomach and the duodenum. It regulates the passage of chyme from the stomach into the small intestine, allowing for controlled release and preventing backflow of intestinal contents into the stomach.

a) pyloric antrum

- Incorrect: The pyloric antrum is the lower portion of the stomach that leads into the pyloric canal. It is involved in mixing and churning food, but it does not regulate the release of chyme into the duodenum.

b) pyloric canal

- Incorrect: The pyloric canal is the narrow portion of the stomach that connects the pyloric antrum to the pyloric sphincter. It is involved in directing chyme toward the pyloric sphincter for release into the duodenum, but it is not the site of chyme release itself.

The esophageal hiatus is an opening in the diaphragm through which the esophagus passes as it descends from the thoracic cavity into the abdominal cavity. It is not directly involved in gastric emptying.

Answer Explanation

a) esophagus

- Correct: The esophagus is supported by a layer of adventitia rather than serosa. The adventitia is a connective tissue layer that covers organs and structures that are not located within the peritoneal cavity. In the case of the esophagus, it lies behind the trachea and heart and passes through the diaphragm before connecting to the stomach. Since it is located outside the peritoneal cavity, it is covered by adventitia instead of serosa, which is the visceral peritoneum that covers organs within the abdominal cavity.

b) stomach

- Incorrect: The stomach is supported by a layer of serosa, which is the visceral peritoneum covering organs within the abdominal cavity.

c) small intestine

- Incorrect: The small intestine is supported by a layer of serosa, which is the visceral peritoneum covering organs within the abdominal cavity.

d) large intestine

- Incorrect: The large intestine is supported by a layer of serosa, which is the visceral peritoneum covering organs within the abdominal cavity.