Nokea
Which of the following structures in the body is responsible for protecting the lungs and heart?
- A. Rib cage
- B. Pelvis
- C. Femur
- D. Vertebral column
Correct Answer: A
Rationale: The rib cage is the correct answer. It plays a crucial role in protecting vital organs like the lungs and heart. The rib cage forms a protective barrier around these organs, shielding them from external trauma or injuries. It acts as a sturdy cage, offering structural support and safeguarding the delicate tissues and structures of the lungs and heart. The pelvis, femur, and vertebral column do not directly protect the lungs and heart; instead, they have other important functions in the body, such as supporting the body's weight, enabling movement, and protecting the spinal cord.
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Which structure of the respiratory system bifurcates into the primary bronchi?
- A. Trachea
- B. Alveoli
- C. Bronchioles
- D. Larynx
Correct Answer: A
Rationale: The trachea is the structure that bifurcates into the primary bronchi. The trachea is a tube that carries air to and from the lungs. It divides into the left and right primary bronchi at a specific point called the carina, which then further divide into secondary and tertiary bronchi, leading to the bronchioles. The alveoli are the tiny air sacs at the end of the bronchioles where gas exchange occurs, not the structure that bifurcates into the primary bronchi. Bronchioles are smaller airway branches that come after the bronchi but do not bifurcate into them. The larynx, also known as the voice box, is located above the trachea and is responsible for sound production, not the bifurcation into primary bronchi. Therefore, the correct answer is the trachea.
What is the structure and function of elastic arteries?
- A. They are the smallest arteries and constrict and dilate frequently.
- B. They are medium-sized arteries that distribute blood to various organs.
- C. They are the largest arteries and stretch and recoil to accommodate blood pressure changes.
- D. They are thin-walled arteries that supply blood to the capillaries.
Correct Answer: C
Rationale: The corrected answer is C. Elastic arteries, like the aorta, are the largest arteries in the body. They possess elastic fibers in their walls, allowing them to stretch and recoil in response to the pulsatile nature of blood flow from the heart. This elasticity helps to maintain blood pressure by absorbing the pressure waves generated by the heart's contractions and ensuring continuous blood flow to the organs. Choices A, B, and D are incorrect because elastic arteries are not the smallest arteries, do not constrict and dilate frequently, are not medium-sized arteries for distributing blood to various organs, and are not thin-walled arteries supplying blood to capillaries. Elastic arteries have a specific structure and function related to their ability to accommodate blood pressure changes due to their elastic properties, which is essential for the cardiovascular system's proper functioning.
What are the three regions of the small intestine?
- A. Duodenum, ileum, jejunum
- B. Cecum, ileum, jejunum
- C. Duodenum, jejunum, ileum
- D. Duodenum, jejunum, colon
Correct Answer: C
Rationale: The correct answer is C: Duodenum, jejunum, ileum. The small intestine is divided into three regions: the duodenum, jejunum, and ileum. The duodenum is the initial segment where most chemical digestion takes place. The jejunum and ileum follow the duodenum and are primarily responsible for nutrient absorption. Choice A is incorrect because the order is incorrect. Choice B is incorrect because the cecum is part of the large intestine, not the small intestine. Choice D is incorrect because the colon is part of the large intestine, not the small intestine.
What do ligaments connect?
- A. Muscle to muscle
- B. Bone to bone
- C. Bone to muscle
- D. Muscle to tendon
Correct Answer: B
Rationale: Ligaments are fibrous connective tissues that connect bone to bone, providing stability and support to joints. They help prevent excessive movement in the joints and maintain proper alignment between bones during movement. Ligaments are not directly involved in connecting muscle to muscle, bone to muscle, or muscle to tendon. Choice A is incorrect because ligaments do not connect muscle to muscle. Choice C is incorrect as ligaments do not connect bone to muscle. Choice D is incorrect as ligaments do not connect muscle to tendon.
What is the electrical charge of the nucleus?
- A. A nucleus always has a positive charge.
- B. A stable nucleus has a positive charge, but a radioactive nucleus may have no charge and instead be neutral.
- C. A nucleus always has no charge and is instead neutral.
- D. A stable nucleus has no charge and is instead neutral, but a radioactive nucleus may have a charge.
Correct Answer: A
Rationale: A nucleus always has a positive charge. This is because the nucleus is composed of positively charged protons, along with neutral neutrons. The positive charge of the protons is balanced by the negative charge of the surrounding electrons in an atom, resulting in an overall neutral charge for the atom as a whole. Therefore, choice A is correct as it accurately reflects the positive charge of the nucleus due to the presence of protons. Choices B, C, and D are incorrect because they do not accurately represent the fundamental composition and charge distribution within an atom's nucleus. A stable nucleus consists of positively charged protons and neutral neutrons, leading to an overall positive charge, and not a neutral charge as suggested in the incorrect choices.