Nursing Elites

1. Which valve prevents the return of blood into the right ventricle?

• A. Pulmonary semilunar valve
• B. Aortic semilunar valve
• C. Tricuspid valve
• D. Mitral valve

Correct answer: A

Rationale: The correct answer is A: Pulmonary semilunar valve. The pulmonary semilunar valve is located between the right ventricle and the pulmonary artery. It opens to allow blood to be pumped into the pulmonary artery but closes to prevent blood from returning back into the right ventricle. The aortic semilunar valve is located between the left ventricle and the aorta. The tricuspid valve is located between the right atrium and right ventricle, and the mitral valve is located between the left atrium and left ventricle. Therefore, the pulmonary semilunar valve is the specific valve responsible for preventing the backflow of blood into the right ventricle during the cardiac cycle.

2. Where does visual processing begin in the eye?

• A. Cornea
• B. Optic nerve
• C. Retina
• D. Eyelid

Correct answer: C

Rationale: Visual processing begins in the retina, not the cornea, optic nerve, or eyelid. The retina is a layer of tissue at the back of the eye that contains photoreceptor cells responsible for converting light into neural signals that are then sent to the brain for processing. The cornea is the transparent outer layer of the eye that helps focus light, but it does not process visual information. The optic nerve transmits visual information from the retina to the brain, it does not initiate visual processing. The eyelid is a protective covering for the eye and is not involved in visual processing.

3. Which of the following statements regarding the working of the heart is not correct?

• A. The atria contract, and the valves open to allow blood into the ventricles.
• B. The heartbeat begins when the heart muscles relax, and blood flows into the atria.
• C. The valves close to stop blood from flowing backward.
• D. The ventricles contract, forcing blood to leave the heart.

Correct answer: B

Rationale: The correct answer is B because the heartbeat actually begins when the heart muscles relax, allowing the chambers to fill with blood. The contraction phase follows, which propels blood out of the heart. The other statements are accurate in describing the normal sequence of events in the heart's functioning: the atria contract to push blood into the ventricles, the valves close to prevent backflow of blood, and the ventricles contract to pump blood out of the heart.

4. Which structure helps regulate body temperature by constricting or dilating in response to temperature changes?

• A. Sebaceous glands
• B. Hair follicles
• C. Sweat glands
• D. Langerhans cells

Correct answer: C

Rationale: Sweat glands play a crucial role in regulating body temperature by producing sweat that evaporates from the skin surface. This evaporation cools the body when it is hot and helps to maintain a stable internal temperature. Sebaceous glands produce oil to lubricate the skin, hair follicles are responsible for hair growth, and Langerhans cells are a type of immune cell in the skin. Therefore, the correct answer is 'Sweat glands' as they are specifically designed to respond to temperature changes by constricting or dilating to help regulate body temperature.

5. What is the term for a genetic disorder caused by a mutation on the X chromosome?

• A. Autosomal dominant disorder
• B. Autosomal recessive disorder
• C. Sex-linked recessive disorder
• D. Sex-linked dominant disorder

Correct answer: C

Rationale: A genetic disorder caused by a mutation on the X chromosome is termed a sex-linked recessive disorder (Option C). This type of disorder is more commonly seen in males due to their single X chromosome, making them more vulnerable to X-linked mutations. Females have two X chromosomes, providing a protective effect against X-linked disorders.\n- Autosomal dominant disorders (Option A) result from a mutation in one copy of a gene on non-sex chromosomes (autosomes) and are not specifically related to the X chromosome.\n- Autosomal recessive disorders (Option B) occur due to mutations in both copies of a gene on autosomes, not on the X chromosome.\n- Sex-linked dominant disorders (Option D) are rare and lead to more severe symptoms in males as they only require one copy of the mutated gene on the X chromosome to express the disorder. However, this is not the term for a genetic disorder caused by an X chromosome mutation.

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