HESI A2
HESI A2 Anatomy and Physiology 2023
1. Which of the heart's four chambers is the largest and the strongest?
- A. Left ventricle
- B. Left atrium
- C. Right ventricle
- D. Right atrium
Correct answer: A
Rationale: The correct answer is the left ventricle. The left ventricle is the largest and strongest chamber of the heart. It pumps oxygenated blood to the entire body, making it a vital component of the circulatory system. The left atrium receives oxygen-rich blood from the lungs, the right ventricle pumps deoxygenated blood to the lungs for oxygenation, and the right atrium receives deoxygenated blood from the body.
2. What is the function of the medulla oblongata in the brain?
- A. To control breathing and heart rate
- B. To regulate body temperature
- C. To coordinate voluntary movements
- D. To process sensory information
Correct answer: A
Rationale: The correct answer is A: To control breathing and heart rate. The medulla oblongata is a vital part of the brainstem responsible for regulating essential functions such as breathing, heart rate, and blood pressure. These functions are crucial for maintaining life, and the medulla oblongata plays a key role in ensuring the body's survival. Choices B, C, and D are incorrect because regulating body temperature is primarily controlled by the hypothalamus, coordinating voluntary movements is associated with the cerebellum and motor cortex, and processing sensory information is related to the thalamus and sensory cortex, not the medulla oblongata.
3. Which hormone is responsible for regulating blood sugar levels?
- A. Insulin
- B. Glucagon
- C. Thyroxine
- D. Melatonin
Correct answer: A
Rationale: Insulin, produced by the pancreas, is the hormone responsible for regulating blood sugar levels. It works by facilitating the uptake of glucose into cells, helping to lower blood sugar levels. Glucagon, on the other hand, works to increase blood sugar levels by promoting the release of glucose from the liver. Thyroxine is a hormone produced by the thyroid gland that regulates metabolism. Melatonin, a hormone that helps regulate sleep-wake cycles, is not responsible for regulating blood sugar levels. Therefore, the correct answer is insulin.
4. Which muscle is responsible for breathing?
- A. Diaphragm
- B. Intercostal muscles
- C. Rectus abdominis
- D. Pectoralis major
Correct answer: A
Rationale: The diaphragm is the primary muscle responsible for breathing. It is a large, dome-shaped muscle located at the base of the chest cavity. When it contracts, it flattens, increasing the volume of the chest cavity and causing inhalation. When it relaxes, it returns to its dome shape, decreasing the volume of the chest cavity and causing exhalation. The intercostal muscles, located between the ribs, assist the diaphragm in breathing by expanding and contracting the chest cavity. The rectus abdominis and pectoralis major are not directly involved in the process of breathing.
5. Nerve tissue is composed of neurons and connective tissue cells that are referred to as which of the following?
- A. Osteoblasts
- B. Neuroglia
- C. Osteocytes
- D. Arterioles
Correct answer: B
Rationale: Neuroglia are specialized connective tissue cells that provide support and protection to neurons in the nervous system. They assist in the proper functioning of neurons and are essential for maintaining the overall health of nerve tissue. Therefore, in the context of nerve tissue composition, neuroglia are the connective tissue cells associated with neurons. The other choices, osteoblasts, osteocytes, and arterioles, are not the correct types of connective tissue cells found in nerve tissue. Osteoblasts are involved in bone formation, osteocytes are mature bone cells, and arterioles are small blood vessels that supply blood to tissues.
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