what is the function of the stomach in digestion

HESI A2

Anatomy and Physiology Hesi A2 Practice Test

1. What is the function of the stomach in digestion?

A. To absorb nutrients
B. To break down food
C. To secrete digestive enzymes
D. To store glucose

Correct answer: B

Rationale: The correct answer is B: 'To break down food.' The stomach's primary function in digestion is to break down food mechanically and chemically. It accomplishes this by mixing food with gastric acid and digestive enzymes, resulting in the formation of chyme, a semi-liquid mixture that moves on to further digestion in the small intestine. Choice A is incorrect because the absorption of nutrients occurs mainly in the small intestine, not in the stomach. Choice C is incorrect because while the stomach does secrete digestive enzymes like pepsin, its primary role is not just limited to enzyme secretion. Choice D is incorrect because the storage of glucose primarily occurs in the liver and muscles, not in the stomach.

2. Which of the following epithelial types is correctly matched with its major function?

A. Simple squamous epithelium – diffusion
B. Stratified squamous epithelium – protection
C. Stratified squamous epithelium – diffusion
D. Simple columnar epithelium – secretion or absorption

Correct answer: D

Rationale: The correct answer is D. Simple columnar epithelium is indeed primarily responsible for secretion and absorption due to its tall shape and presence of microvilli, which increase surface area for these functions. Simple squamous epithelium is mainly involved in diffusion, allowing for the exchange of gases or nutrients. Stratified squamous epithelium functions more for protection against mechanical stress and pathogens, as it forms a tough, protective barrier due to its many layers.

3. What is the primary role of the small intestine in nutrient absorption?

A. To break down food
B. To absorb nutrients
C. To secrete digestive enzymes
D. To store glucose

Correct answer: B

Rationale: The correct answer is B: 'To absorb nutrients.' The small intestine is the primary site for nutrient absorption in the digestive system. It plays a crucial role in absorbing nutrients from digested food into the bloodstream, facilitating the delivery of essential nutrients to the body for various functions and processes. Choices A, C, and D are incorrect because while the small intestine does contribute to the breakdown of food and does secrete digestive enzymes, its primary function is to absorb nutrients, not to store glucose.

4. What is the first step in pulmonary circulation?

A. Blood moves toward the heart through the pulmonary veins.
B. The pulmonary artery carries blood from the heart to the lungs.
C. Carbon dioxide is exchanged for oxygen.
D. Oxygenated blood moves through the aorta.

Correct answer: B

Rationale: The correct answer is B: The pulmonary artery carries blood from the heart to the lungs. The first step in pulmonary circulation involves the right ventricle of the heart pumping deoxygenated blood into the pulmonary artery. The pulmonary artery then carries this deoxygenated blood from the heart to the lungs for oxygenation. This step is crucial for the exchange of carbon dioxide for oxygen to occur in the lungs, facilitating the oxygenation of blood. Choices A, C, and D are incorrect because they do not represent the initial step in pulmonary circulation. Option A refers to blood moving away from the heart, option C describes the gas exchange process that occurs in the lungs but not as the first step, and option D mentions oxygenated blood moving through the aorta, which happens after oxygenation in the lungs.

5. Which of the following is known as the production of red blood cells?

A. Thrombopoiesis
B. Erythropoiesis
C. Hematopoiesis
D. Phagocytosis

Correct answer: B

Rationale: Erythropoiesis specifically refers to the process of producing red blood cells (erythrocytes) in the bone marrow. Hematopoiesis is the broader term that encompasses the production of all types of blood cells, including red blood cells, white blood cells, and platelets. Phagocytosis is the process by which cells engulf and digest particles, while thrombopoiesis is the production of platelets. Therefore, the correct answer is B as it directly relates to the production of red blood cells.