1. Which hormone is responsible for regulating sleep-wake cycles and is influenced by light exposure?

A. Melatonin
B. Cortisol
C. Estrogen
D. Glucagon

Correct answer: A

Rationale: The correct answer is A: Melatonin. Melatonin is a hormone produced by the pineal gland in the brain and plays a crucial role in regulating the sleep-wake cycle, also known as the circadian rhythm. Melatonin levels typically rise in the evening in response to darkness and help signal to the body that it's time to sleep. Exposure to light, especially blue light, can inhibit the production of melatonin, making us more alert and awake. Cortisol (option B) is a stress hormone that helps regulate metabolism and immune response. Estrogen (option C) is a female sex hormone, and glucagon (option D) is a hormone that increases blood sugar levels. Therefore, the hormone responsible for regulating sleep-wake cycles and influenced by light exposure is melatonin.

2. What is a contraceptive method that uses hormones to prevent ovulation?

A. Spermicide
B. Barrier method (condom, diaphragm)
C. Combined oral contraceptive pill
D. Intrauterine device (IUD)

Correct answer: C

Rationale: The correct answer is C: Combined oral contraceptive pill. This method uses hormones, such as estrogen and progestin, to prevent ovulation, thicken cervical mucus to block sperm, and thin the uterine lining to prevent implantation of a fertilized egg. Spermicide (A) is a chemical that kills sperm but does not prevent ovulation. Barrier methods (B) like condoms and diaphragms physically block sperm from reaching the egg. Intrauterine devices (IUDs) (D) are inserted into the uterus and work by either releasing hormones or creating a barrier to prevent fertilization, but they do not specifically target ovulation.

3. A medication order is for 250 micrograms of a drug to be administered subcutaneously. The available syringe measures in milliliters. How many milliliters should the nurse draw up?

A. 0.00025 milliliters
B. 0.0025 milliliters
C. 0.025 milliliters
D. 0.25 milliliters

Correct answer: B

Rationale: First convert micrograms to milliliters, knowing 1000 micrograms equal 1 milliliter. Divide the desired dosage (250 micrograms) by the conversion factor (1000 micrograms/milliliter) to find the volume needed: 250 micrograms / 1000 micrograms/milliliter = 0.00025 milliliters. However, drawing such a small volume might be inaccurate, so round to the nearest practical measurement, which is 0.0025 milliliters.

4. A solution is considered saturated when...

A. More solute can be dissolved
B. The solvent starts to evaporate
C. The solution becomes cloudy
D. It reaches a specific temperature

Correct answer: B

Rationale: The correct answer is B: 'The solvent starts to evaporate.' A solution is considered saturated when the solvent can no longer dissolve any more solute at a given temperature. When the solvent starts to evaporate, it means that the solution is becoming more concentrated and reaching its saturation point. This is a key indicator of a saturated solution. The other options do not accurately describe the concept of a saturated solution, making them incorrect choices.

5. Inhalation

A. Expiration
B. Respiration
C. Aspiration
D. Aspiration

Correct answer: B

Rationale: The correct answer is B: 'Respiration.' Inhalation refers to the process of breathing in air, while respiration is the overall process of gas exchange in the body, including both inhalation and exhalation. Expiration refers specifically to the process of breathing out air. Aspiration, on the other hand, refers to the act of inhaling foreign objects into the lungs, which can be harmful. Therefore, 'Respiration' is the most appropriate term related to 'Inhalation' as it encompasses the entire process of breathing and gas exchange in the body.

6. What is the term for a hydrocarbon chain with no double or triple bonds between carbon atoms?

A. Saturated
B. Unsaturated
C. Aromatic
D. Alkene

Correct answer: A

Rationale: A saturated hydrocarbon chain has only single bonds between carbon atoms. The other choices are associated with unsaturation or aromaticity.