which part of the brain is responsible for regulating breathing and heart rate

HESI A2

Anatomy HESI A2 Practice Test

1. Which part of the brain is responsible for regulating breathing and heart rate?

A. Cerebrum
B. Medulla oblongata
C. Cerebellum
D. Hypothalamus

Correct answer: B

Rationale: The correct answer is the Medulla oblongata. This structure, located in the brainstem, plays a crucial role in regulating essential functions such as breathing, heart rate, and blood pressure. It serves as a control center for autonomic functions necessary for maintaining life. The Cerebrum (Choice A) is mainly responsible for higher brain functions such as thinking and voluntary movements, not for regulating basic physiological processes like breathing and heart rate. The Cerebellum (Choice C) is involved in coordination, balance, and muscle control, but not in regulating breathing and heart rate. The Hypothalamus (Choice D) plays a role in regulating body temperature, hunger, and thirst, but it is not primarily responsible for controlling breathing and heart rate.

2. Which parts of the heart are separated by the mitral valve?

A. Left atrium and right atrium
B. Right atrium and right ventricle
C. Left ventricle and right ventricle
D. Left atrium and left ventricle

Correct answer: D

Rationale: The mitral valve, also known as the bicuspid valve, separates the left atrium and the left ventricle of the heart. Its primary function is to prevent the backflow of blood from the left ventricle to the left atrium during the heart's contraction. Therefore, option D, 'Left atrium and left ventricle,' is the correct answer. Choices A, B, and C are incorrect because they do not represent the parts separated by the mitral valve.

3. What is the primary function of the kidneys in the urinary system?

A. To filter waste from the blood
B. To produce urine
C. To regulate blood pressure
D. To maintain fluid balance

Correct answer: A

Rationale: The correct answer is A: 'To filter waste from the blood.' The primary function of the kidneys in the urinary system is to filter waste products and excess substances from the blood, forming urine, which is then excreted from the body. This process helps maintain the body's internal environment by regulating the balance of electrolytes, fluid levels, and eliminating metabolic waste products. Choices B, C, and D are incorrect because while the kidneys do produce urine, regulate blood pressure, and maintain fluid balance, their primary function within the urinary system is the filtration of waste from the blood.

4. Which of the following is not part of the body’s secondary defense system?

A. Macrophages
B. Leukocytes
C. T cells
D. Cilia

Correct answer: D

Rationale: Cilia are not part of the body's secondary defense system. They are hair-like structures primarily involved in movement and transporting substances across cell surfaces, such as in the respiratory tract for debris and pathogen removal. However, cilia do not play a direct role in the immune response mechanisms characteristic of the body's secondary defense system. Macrophages, leukocytes, and T cells are immune cells that actively participate in the secondary defense system by targeting and eliminating pathogens.

5. What is the role of the gallbladder in digestion?

A. To produce bile
B. To store and concentrate bile
C. To break down fats
D. To secrete digestive enzymes

Correct answer: B

Rationale: The gallbladder's primary function in digestion is to store and concentrate bile produced by the liver. Bile is essential for the digestion and absorption of fats in the small intestine. While the gallbladder does not produce bile (Choice A) or secrete digestive enzymes (Choice D), it plays a crucial role in storing and releasing bile when needed. Therefore, the correct answer is B.