Nursing Elites

1. Which neurotransmitter is responsible for stimulating muscle contraction?

• A. Dopamine
• B. Acetylcholine
• C. Serotonin
• D. Norepinephrine

Correct answer: B

Rationale: Acetylcholine is the neurotransmitter responsible for stimulating muscle contraction at the neuromuscular junction. When an action potential reaches the end of a motor neuron, acetylcholine is released into the synaptic cleft and binds to receptors on the muscle cell membrane, leading to muscle contraction. Dopamine, serotonin, and norepinephrine are neurotransmitters that have different functions in the nervous system and are not directly involved in stimulating muscle contraction. Dopamine is involved in reward and pleasure pathways, serotonin regulates mood and behavior, and norepinephrine is involved in the 'fight or flight' response.

2. When a person pushes a box across the floor, which of the following forces is NOT doing work?

• A. The person's pushing force
• B. The normal force from the floor
• C. The gravitational force on the box
• D. The frictional force between the box and the floor

Correct answer: B

Rationale: The normal force from the floor is perpendicular to the direction of motion of the box, so it does not contribute to the work being done. Work is only done by forces acting in the direction of motion of an object. In this case, the normal force is acting at a right angle to the motion, hence it does not perform any work on the box. The person's pushing force, the gravitational force, and the frictional force are all acting in the direction of motion of the box, so they contribute to the work being done in moving the box across the floor.

3. An object is thrown upwards and reaches a maximum height. Which of the following statements is TRUE about its velocity and acceleration at the peak?

• A. Velocity is zero and acceleration is maximum upwards.
• B. Velocity is maximum and acceleration is zero.
• C. Velocity is maximum and acceleration is maximum upwards.
• D. Velocity is zero and acceleration is maximum downwards.

Correct answer: A

Rationale: At the peak of the object's motion, its velocity is zero because it momentarily stops before changing direction and starts to fall back down. The acceleration at the peak is maximum upwards as gravity is acting against the object's motion, slowing it down until it stops momentarily. Choice A is correct because at the peak, the object's velocity is zero, and the acceleration is maximum upwards. Choice B is incorrect because the velocity is not maximum but zero at the peak. Choice C is incorrect as both velocity and acceleration are not maximum at the peak. Choice D is incorrect as the acceleration at the peak is upwards, opposing the object's motion, not downwards.

4. Which element is essential for the formation of hemoglobin?

• A. Calcium
• B. Iron
• C. Potassium
• D. Sodium

Correct answer: B

Rationale: The correct answer is Iron. Iron is essential for the formation of hemoglobin, the protein in red blood cells that binds and transports oxygen throughout the body. Calcium (Choice A), Potassium (Choice C), and Sodium (Choice D) are not directly involved in the formation of hemoglobin and its oxygen-carrying function.

5. Which part of the brain is responsible for coordinating voluntary muscle movements?

• A. Medulla oblongata
• B. Cerebellum
• C. Thalamus
• D. Hypothalamus

Correct answer: B

Rationale: The cerebellum is responsible for coordinating voluntary muscle movements. It plays a crucial role in motor control, helping to maintain balance, posture, and coordination of voluntary movements. The medulla oblongata is involved in regulating basic life functions such as breathing and heart rate. The thalamus serves as a relay center for sensory information, while the hypothalamus is primarily involved in regulating various physiological processes like body temperature, hunger, and thirst. Hence, the correct answer is the cerebellum as it is specifically associated with voluntary muscle coordination, unlike the other brain regions listed.

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