Nursing Elites

1. The muscular diaphragm plays a vital role in respiration. When it contracts, it:

• A. Increases lung volume for inhalation
• B. Decreases lung volume for exhalation
• C. Filters dust and particles from inhaled air
• D. Produces mucus to lubricate the airways

Correct answer: A

Rationale: The muscular diaphragm plays a crucial role in respiration by contracting and flattening during inhalation. This action increases the volume of the thoracic cavity, which leads to a decrease in pressure within the lungs, allowing air to rush in and fill the expanded space. Choice B is incorrect because the diaphragm contracting increases the lung volume for inhalation, not decreases it for exhalation. Choice C is incorrect as the role of filtering dust and particles is primarily performed by the respiratory system's other structures like the nasal passages and the mucous membranes. Choice D is incorrect as mucus production is mainly carried out by specialized cells in the respiratory system and not by the diaphragm.

2. Where does the nerve impulses send neurotransmitters across a synapse to a muscle cell to stimulate muscle contraction?

• A. sarcomere
• B. tendon
• C. myelin sheath
• D. neuromuscular junction

Correct answer: D

Rationale: The neuromuscular junction is the specific area where nerve impulses trigger the release of neurotransmitters that cross the synaptic gap to bind to receptors on the muscle cell membrane. This binding initiates muscle contraction by stimulating the muscle cell. The sarcomere is the basic contractile unit in a muscle fiber, not the location where nerve impulses communicate with muscle cells. Tendons are connective tissues that attach muscles to bones and are not involved in transmitting nerve impulses. The myelin sheath is a protective covering around nerve fibers but is not directly involved in transmitting neurotransmitters to muscle cells for muscle contraction.

3. Which of the following is the primary physical barrier the body uses to prevent infection?

• A. mucus membranes
• B. stomach acid
• C. skin
• D. urine

Correct answer: C

Rationale: The correct answer is 'C: skin.' The skin is the primary physical barrier the body uses to prevent infection. It acts as a protective shield that prevents harmful microorganisms from entering the body. The outer layer of the skin, known as the epidermis, acts as a tough physical barrier that blocks the entry of pathogens. Additionally, the skin has special immune cells that can help fight off invaders that manage to breach the physical barrier. Choices A, B, and D are incorrect. While mucous membranes, stomach acid, and urine play important roles in the body's defense against pathogens, the primary physical barrier is the skin, which covers the entire body and provides a robust protective barrier.

4. Which of the following is a characteristic of an interneuron?

• A. Forms neural circuits
• B. Interacts with effectors
• C. Sends impulses to the CNS
• D. Functions as an efferent nerve cell

Correct answer: A

Rationale: The correct characteristic of an interneuron is that it forms neural circuits, connecting sensory and motor neurons within the central nervous system. Interneurons facilitate communication between different neurons in the central nervous system, helping in the processing and integration of signals. Choice B is incorrect as interneurons primarily interact with other neurons, not effectors. Choice C is incorrect as interneurons typically do not send impulses to the CNS; they operate within the CNS. Choice D is incorrect as interneurons are not efferent nerve cells; they are mainly involved in processing signals within the CNS rather than transmitting signals to effectors.

5. To which of the following bone types do the spine and hips belong?

• A. Curved bones
• B. Irregular bones
• C. Flat bones
• D. Long bones

Correct answer: B

Rationale: The correct answer is B: Irregular bones. The spine and hips belong to the category of irregular bones. Irregular bones have complex shapes that do not fit into other bone type categories. These bones serve functions such as support and protection, and their shapes vary depending on their specific roles in the body. Choice A, curved bones, is incorrect because bones like ribs are typically described as curved, not the spine and hips. Choice C, flat bones, is incorrect as flat bones include the skull and ribs, but not the spine and hips. Choice D, long bones, is also incorrect because long bones include bones like the femur and humerus, which are elongated with a shaft and distinct ends, unlike the spine and hips.

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