Which of the following substances triggers a hypersensitivity reaction?

a. The volume of the cell decreases: When a red blood cell is placed in a hypertonic solution (solution with a higher concentration of solutes outside the cell compared to inside), water will move out of the cell through osmosis to equalize the concentration on both sides of the cell membrane. This movement of water causes the red blood cell to shrink (crenate).

b. The permeability of the cell membrane decreases: Incorrect. The permeability of the cell membrane to water remains relatively constant.

c. The permeability of the cell membrane increases: Incorrect. Osmosis is a passive process that doesn't require increased permeability.

d. The volume of the cell increases: Incorrect. A hypertonic solution will cause the cell to lose water and shrink.

a. Pyloric sphincter: This sphincter regulates the passage of chyme from the stomach into the duodenum.

b. Lower esophageal sphincter: This sphincter prevents the backflow of stomach contents into the esophagus.

c. Ileocecal sphincter: This controls the flow of material from the ileum of the small intestine into the cecum of the large intestine.

d. Internal anal sphincter: This sphincter controls the release of feces from the rectum but is not involved in the release of chyme