Nokea
A patient goes to the doctor with a cold and sore throat and asks for antibiotics. The doctor refuses to prescribe antibiotics because the illness is caused by which of the following pathogens?
- A. Protist
- B. Fungus
- C. Virus
- D. Bacteria
Correct Answer: C
Rationale: The correct answer is C: Virus. Antibiotics are ineffective against viral infections, such as colds and sore throats caused by viruses. They are only effective against bacterial infections. In this case, the doctor refuses to prescribe antibiotics because the patient's illness is viral, not bacterial. It is important to differentiate between viral and bacterial infections to ensure appropriate treatment and avoid unnecessary use of antibiotics, which can contribute to antibiotic resistance.
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Which of the following blood vessels is affected by a myocardial infarction?
- A. coronary
- B. vena cava
- C. pulmonary
- D. aorta
Correct Answer: A
Rationale: A myocardial infarction affects the coronary arteries, not the vena cava, pulmonary, or aorta. The coronary arteries supply blood to the heart muscle, and blockages in these arteries can result in a heart attack. The vena cava is a large vein that carries deoxygenated blood back to the heart, the pulmonary arteries carry deoxygenated blood from the heart to the lungs for oxygenation, and the aorta is the main artery that carries oxygenated blood from the heart to the rest of the body. These vessels are not typically associated with myocardial infarctions as they perform different functions within the circulatory system.
Where are the tibia and fibula located in the body?
- A. Coxal
- B. Antecubital
- C. Crural
- D. Tarsal
Correct Answer: C
Rationale: The tibia and fibula are located in the crural region of the body. The crural region, also known as the lower leg, is situated between the knee and the ankle. The tibia and fibula are the two bones found in this region and play a crucial role in the skeletal structure of the lower limb. The coxal region refers to the hip, the antecubital region is located at the front of the elbow, and the tarsal region pertains to the ankle area. Therefore, the correct answer is C, crural, as it specifically refers to the location of the tibia and fibula in the lower leg.
What is the approximate threshold value for mammalian neurons?
- A. -80 mV
- B. -55 mV
- C. 0 mV
- D. +35 mV
Correct Answer: B
Rationale: The approximate threshold value for mammalian neurons is around -55 mV. At this membrane potential, the neuron becomes more excitable and is more likely to generate an action potential. If the membrane potential reaches this level or depolarizes beyond it, it triggers the opening of voltage-gated ion channels, leading to the initiation of an action potential. Values below this threshold are considered subthreshold and do not usually result in action potential generation. Understanding the threshold potential is crucial in assessing the excitability and firing properties of neurons, as it represents the critical point at which the neuron transitions from a resting state to an active state, enabling the transmission of electrical signals.
Emphysema caused by damage to alveoli from toxins and pollutants is likely to result in the body having difficulty performing which of the following actions?
- A. Exchanging oxygen and carbon dioxide
- B. Absorbing food
- C. Releasing histamine and acetylcholine
- D. Producing enzymes
Correct Answer: A
Rationale: Emphysema is a condition that damages the alveoli in the lungs, leading to the loss of elasticity and reduced surface area for gas exchange. As a result, individuals with emphysema have difficulty in exchanging oxygen and carbon dioxide efficiently. The damage impairs the lung's ability to transfer oxygen from the air into the bloodstream and remove carbon dioxide from the body. Absorbing food (B), releasing histamine and acetylcholine (C), and producing enzymes (D) are not directly affected by emphysema.
How does soap's property as an emulsifier make it useful for washing dirt off one's hands with water?
- A. Soap's dual polar and nonpolar nature helps bond oil and water.
- B. Soap's rough texture physically scours grime off surfaces.
- C. Soap's enzymatic action helps to dissolve grime into smaller particles.
- D. Soap's acidity causes grime to precipitate into the water.
Correct Answer: A
Rationale: The correct answer is A. Soap acts as an emulsifier due to its dual polar and nonpolar nature. This unique feature allows soap molecules to interact with both oil and water, facilitating their bonding. When washing hands with soap and water, the soap molecules attract oil and dirt on the skin because of their dual nature. Consequently, the dirt and oil become suspended in the water, making it easier to wash them away. Therefore, soap's dual polar and nonpolar nature enables it to effectively remove dirt and oil from the skin when combined with water.