which statement about white blood cells is true

ATI TEAS 7

ATI TEAS Science Questions

1. Which statement about white blood cells is true?

A. B cells are responsible for antibody production.
B. White blood cells are produced in the bone marrow before entering the bloodstream.
C. Platelets, a specialized class of blood cells, function to clot blood and stop bleeding.
D. The majority of white blood cells are active throughout life, providing immunity across all age groups.

Correct answer: A

Rationale: The correct answer is A: B cells, a type of white blood cell, are responsible for producing antibodies in response to pathogens. Antibodies play a crucial role in identifying and neutralizing foreign substances like bacteria and viruses in the body, aiding in the immune response and protecting against infections. This function is essential for maintaining a healthy immune system. White blood cells, including B cells, are produced in the bone marrow before entering the bloodstream. Platelets, not white blood cells, are a specialized class of blood cells that function to clot blood and stop bleeding. While white blood cells provide immunity, not all of them are active throughout life as some have specific lifespans and functions.

2. Which type of tissue protects the respiratory system's trachea?

A. Bone
B. Cartilage
C. Collagen
D. Keratin

Correct answer: B

Rationale: Cartilage is the correct answer as it provides flexible support and protection in the trachea. Cartilage is specifically designed to maintain the trachea's shape and prevent it from collapsing during breathing. Bone is a rigid tissue, not found in the trachea, and would not provide the necessary flexibility for breathing. Collagen is a structural protein but does not offer the same support and flexibility as cartilage in this context. Keratin is a protein that forms structures like hair and nails, and it is not present in the trachea to provide protection.

3. Which of the following constituents of blood is a biconcave disc that is round and flat without a nucleus?

A. Plasma
B. Platelet
C. RBC
D. WBC

Correct answer: C

Rationale: The correct answer is C, RBC (Red Blood Cell). Red blood cells are biconcave discs that lack a nucleus, allowing them to carry oxygen efficiently. Plasma (A) is the liquid component of blood that carries various substances. Platelets (B) are cell fragments important for blood clotting. White blood cells (WBCs) (D) are part of the immune system and have a nucleus.

4. What happens during expiration?

A. The diaphragm contracts and the thoracic cavity expands.
B. The diaphragm relaxes and the thoracic cavity contracts.
C. The thoracic cavity expands, increasing pressure.
D. The diaphragm relaxes and moves upward.

Correct answer: B

Rationale: The correct answer is B. During expiration, the diaphragm relaxes, causing the thoracic cavity to contract. As the thoracic cavity decreases in size, the pressure inside the lungs increases, leading to air flowing out of the lungs. This process helps to expel carbon dioxide-rich air from the body. Choices A, C, and D are incorrect. In choice A, the diaphragm contracting and the thoracic cavity expanding describes inspiration, not expiration. Choice C is incorrect because during expiration, the thoracic cavity actually decreases in size. Choice D is incorrect as the diaphragm moving upward is not a typical movement associated with expiration.

5. Which of the following is NOT a function of the muscular system?

A. Movement
B. Maintaining posture
C. Generating heat
D. Regulating blood sugar levels

Correct answer: D

Rationale: The muscular system is responsible for movement, maintaining posture, and generating heat. Regulating blood sugar levels is not a function of the muscular system. This function is primarily carried out by the endocrine system, specifically the pancreas and its production of insulin and glucagon. Choices A, B, and C are all correct functions of the muscular system as they involve the contraction and relaxation of muscles to produce movement, support the body's structure, and generate heat as a byproduct of muscle activity.