Kaplan Nursing Entrance Practice Exam

Which of the following describes the nephron?

1. Structural component of the heart

2. Functional unit of the kidneys

3. Muscle tissue in the lungs

4. Part of the nervous system

The correct answer is: Functional unit of the kidneys

The nephron is correctly identified as the functional unit of the kidneys. Each kidney contains approximately one million nephrons, which play a crucial role in the body's urinary system. They are responsible for filtering blood and producing urine, thereby regulating water, electrolyte balance, and waste elimination. The nephron consists of several key components, including the glomerulus, which filters the blood, and the renal tubules, where reabsorption and secretion processes occur. This intricate structure and function make the nephron essential for maintaining homeostasis within the body, as it filters out toxins and excess substances while retaining what the body needs. The other options refer to different anatomical components or systems entirely. The heart is composed of various types of tissues but does not include nephrons. Muscle tissue is primarily associated with movement and is found in the lungs primarily as smooth muscle around the airways, which has no relation to nephron function. The nervous system consists of neurons and glial cells, and while it interacts with the kidneys, it does not include any structures known as nephrons. Thus, recognizing the nephron as the functional unit of the kidneys is critical for understanding renal physiology and the overall functioning of the urinary system.