what is the primary function of the alveoli in the lungs

HESI A2

Anatomy HESI A2 Practice Test

1. What is the primary function of the alveoli in the lungs?

A. Removing carbon dioxide from the blood
B. Exchanging oxygen and carbon dioxide
C. Transporting oxygen to the bloodstream
D. Filtering blood

Correct answer: B

Rationale: The primary function of the alveoli in the lungs is to exchange oxygen and carbon dioxide. The alveoli are tiny air sacs in the lungs responsible for this gas exchange during breathing. Oxygen diffuses from the inhaled air into the blood in the capillaries surrounding the alveoli, while carbon dioxide diffuses from the blood into the alveoli to be exhaled out of the body. Choice A is incorrect because the alveoli primarily facilitate the exchange of gases, not just the removal of carbon dioxide. Choice C is incorrect as the alveoli do not transport oxygen to the bloodstream but rather facilitate the exchange of gases. Choice D is incorrect as the alveoli are not involved in filtering blood but in gas exchange to ensure proper oxygenation and removal of carbon dioxide in the respiratory process.

2. Which of the following statements best describes endocrine glands?

A. They secrete chemicals into the blood
B. They secrete enzymes into ducts
C. They produce sweat
D. They produce saliva

Correct answer: A

Rationale: Endocrine glands are ductless glands that release hormones directly into the bloodstream. These hormones are then carried to target organs and tissues throughout the body, where they regulate various physiological functions. The statement 'They secrete chemicals into the blood' accurately describes the function of endocrine glands. Choices B, C, and D are incorrect because endocrine glands do not secrete enzymes into ducts, produce sweat, or produce saliva. These functions are typically associated with exocrine glands, sweat glands, and salivary glands, respectively.

3. 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.

4. What is the primary function of white blood cells?

A. To carry oxygen
B. To fight infections
C. To transport nutrients
D. To clot blood

Correct answer: B

Rationale: White blood cells, also known as leukocytes, play a crucial role in the immune system by primarily fighting off infections caused by pathogens like bacteria, viruses, and other invaders. They help the body recognize and destroy these harmful agents, contributing to the body's defense mechanisms against diseases. Choice A is incorrect because the primary function of red blood cells, not white blood cells, is to carry oxygen. Choice C is incorrect as the transportation of nutrients is mainly carried out by the bloodstream as a whole, not specifically by white blood cells. Choice D is incorrect as the process of blood clotting is primarily managed by platelets in the blood, not white blood cells.

5. Which hormone is involved in the regulation of water balance in the body?

A. ADH
B. Insulin
C. Cortisol
D. Thyroxine

Correct answer: A

Rationale: The correct answer is ADH (antidiuretic hormone), also known as vasopressin. ADH helps regulate water balance in the body by controlling the amount of water reabsorbed by the kidneys. When there is a need to conserve water, ADH levels increase, leading to more water reabsorption and concentration of urine. Insulin is involved in regulating blood sugar levels, not water balance. Cortisol is a stress hormone that helps regulate metabolism and immune response, not water balance. Thyroxine is a thyroid hormone that regulates metabolism, growth, and development, not water balance.