Nursing Elites

1. During exercise, heart rate increases to deliver more oxygen to the body's tissues. What other cardiovascular response also increases?

• A. Blood pressure decreases
• B. Blood vessel diameter narrows
• C. Blood flow to muscles increases
• D. Blood viscosity thickens

Correct answer: C

Rationale: During exercise, the cardiovascular response includes an increase in blood flow to the muscles to deliver more oxygen and nutrients needed for energy production. This helps to support the increased demand for oxygen and nutrients by the working muscles. Blood pressure typically increases during exercise to help facilitate this increased blood flow to the muscles. Additionally, blood vessel diameter may widen (vasodilation) to allow for more blood flow, rather than narrow. Blood viscosity does not typically thicken during exercise.

2. Molecular clocks utilize the accumulation of mutations in DNA sequences to estimate the evolutionary divergence time between species. This method relies on the assumption that:

• A. The rate of mutation is constant across all genes and all species.
• B. Species with more morphological similarities diverged more recently.
• C. Mutations are always beneficial and contribute to increased fitness.
• D. The fossil record provides the most accurate estimates of evolutionary relationships.

Correct answer: A

Rationale: A molecular clock is a method used to estimate the time of divergence between species by measuring the accumulation of mutations in DNA sequences. This method relies on the assumption that mutations occur at a relatively constant rate over time. If the rate of mutation were not constant, it would be challenging to accurately estimate the evolutionary divergence time between species. Therefore, option A is the most appropriate choice as it aligns with the fundamental principle underlying the molecular clock hypothesis. Option B is incorrect because the assumption that species with more morphological similarities diverged more recently does not directly relate to the concept of molecular clocks and the accumulation of mutations in DNA sequences. Option C is incorrect because mutations are not always beneficial and do not always contribute to increased fitness. Mutations can be neutral or deleterious as well, and their accumulation is what is used to estimate evolutionary di

3. Which of the following structures is responsible for preventing the backflow of blood from the left ventricle into the left atrium?

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

Correct answer: D

Rationale: The correct answer is D, the Mitral valve. The mitral valve, also known as the bicuspid valve, is situated between the left atrium and the left ventricle. Its primary function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The other choices are incorrect because: A) The aortic valve prevents backflow from the aorta into the left ventricle. B) The pulmonary valve prevents backflow from the pulmonary artery into the right ventricle. C) The tricuspid valve prevents backflow from the right ventricle into the right atrium.

4. What is the name of the long bone found in the upper arm?

• A. Femur
• B. Tibia
• C. Humerus
• D. Radius

Correct answer: C

Rationale: The correct answer is the humerus. The humerus is the long bone located in the upper arm, between the shoulder and elbow. Option A, Femur, is incorrect as it is the long bone found in the thigh. Option B, Tibia, is incorrect as it is a long bone found in the lower leg. Option D, Radius, is incorrect as it is a bone located in the forearm, not the upper arm.

5. What is the Doppler effect, and how does it explain the shift in frequency of sound waves perceived by an observer?

• A. It affects light waves, not sound waves.
• B. It's the change in wave speed due to medium density.
• C. It's the perceived change in frequency due to relative motion.
• D. It's the bending of waves due to different mediums.

Correct answer: C

Rationale: The Doppler effect is the perceived change in frequency of a wave due to relative motion between the source of the wave and the observer. This phenomenon is commonly observed with sound waves, where the pitch of a sound appears higher as the source moves towards the observer and lower as the source moves away. Option A is incorrect as the Doppler effect primarily applies to sound waves, not light waves. Option B is incorrect because the Doppler effect is not about the change in wave speed due to medium density but rather a change in perceived frequency. Option D is incorrect as it describes wave bending due to different mediums, which is not the primary concept behind the Doppler effect. Therefore, option C accurately describes the Doppler effect and its application to the shift in frequency of sound waves perceived by an observer.

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