which of the following describes the primary function of the pyloric sphincter

ATI TEAS 7

TEAS 7 Science Practice Test

1. What is the primary function of the pyloric sphincter?

A. to regulate the movement of food material from the stomach to the duodenum
B. to neutralize stomach acid
C. to prevent digested food materials and stomach acid from entering the esophagus
D. to begin the process of chemical digestion

Correct answer: A

Rationale: The primary function of the pyloric sphincter is to regulate the flow of partially digested food material (chyme) from the stomach into the small intestine, specifically the duodenum. This control is essential for proper digestion and absorption of nutrients in the small intestine. Choices B, C, and D are incorrect. Choice B is incorrect because neutralizing stomach acid is primarily the function of the stomach lining and antacid mechanisms. Choice C is incorrect because preventing the backflow of digested food materials and stomach acid into the esophagus is mainly the role of the lower esophageal sphincter. Choice D is incorrect because the chemical digestion process primarily starts in the stomach through the action of gastric juices, not the pyloric sphincter.

2. What is the primary function of the endocrine system?

A. Heartbeat
B. Respiration
C. Electrolyte and water balance
D. Homeostasis

Correct answer: D

Rationale: The correct answer is D. The primary function of the endocrine system is to maintain homeostasis. Homeostasis refers to the stable internal conditions of the body, including body temperature, blood pH, and glucose levels. The endocrine system achieves this by releasing hormones that regulate various physiological processes and help keep the body's internal environment in balance. Choices A, B, and C are incorrect because while the endocrine system does influence heart rate, electrolyte and water balance, and respiration to some extent, its primary role is to regulate homeostasis by releasing hormones.

3. What is the difference between emphysema and chronic bronchitis, both chronic obstructive pulmonary diseases (COPD)?

A. Emphysema damages alveoli, while chronic bronchitis inflames airways.
B. Emphysema causes coughing, while chronic bronchitis leads to shortness of breath.
C. Emphysema is more reversible than chronic bronchitis.
D. Emphysema affects only smokers, while chronic bronchitis can occur in non-smokers.

Correct answer: A

Rationale: Emphysema is characterized by the destruction of alveoli in the lungs, leading to decreased surface area for gas exchange. Chronic bronchitis, on the other hand, involves inflammation and narrowing of the airways, leading to excessive mucus production and coughing. Therefore, the correct difference between emphysema and chronic bronchitis is that emphysema damages the alveoli, while chronic bronchitis inflames the airways. Choice B is incorrect because chronic bronchitis is associated with coughing, not emphysema. Choice C is incorrect as chronic bronchitis is typically less reversible compared to emphysema. Choice D is incorrect as both emphysema and chronic bronchitis are commonly seen in smokers, but chronic bronchitis can also occur in non-smokers due to other factors such as air pollution or genetic predisposition.

4. Which of the following is NOT a type of antibody?

A. IgA
B. IgM
C. Interferon
D. IgG

Correct answer: C

Rationale: A) IgA: This is a type of antibody found in mucosal areas such as the gut, respiratory tract, and genitourinary tract. It plays a role in mucosal immunity. B) IgM: This is a type of antibody produced during the primary immune response and is the first antibody to be produced in response to an infection. C) Interferon: Interferons are signaling proteins produced by cells in response to viral infections. They play a role in the immune response by interfering with viral replication, but they are not antibodies. D) IgG: This is the most abundant type of antibody in the bloodstream and is involved in long-term immunity. Therefore, the correct answer is C) Interferon, as it is not a type of antibody.

5. What is the product of the reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH)?

A. NaCl + H2O
B. NaOH + HCl
C. Na2Cl + H2O
D. NaClO3 + H2

Correct answer: A

Rationale: When hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH), it forms sodium chloride (NaCl) and water (H2O) according to the following chemical equation: HCl + NaOH -> NaCl + H2O. Therefore, the correct answer is NaCl + H2O (Choice A). This reaction is a classic acid-base neutralization reaction where the acid (HCl) reacts with the base (NaOH) to form a salt (NaCl) and water (H2O). Choice B (NaOH + HCl) is incorrect because the order of the reactants matters in a chemical reaction, and in this case, HCl is the acid reacting with NaOH. Choices C (Na2Cl + H2O) and D (NaClO3 + H2) are incorrect because they do not represent the products of the reaction between HCl and NaOH as per the balanced chemical equation.