Answer: Heroin (diacetylmorphine) is a highly lipid-soluble opioid that rapidly crosses the blood-brain barrier, causing intense euphoria; highly addictive; overdose causes respiratory depression and death.
- A Heroin is understood pharmacologically to function merely as a relatively weak and mild over-the-counter painkiller for headaches, comparable in strength to common aspirin or paracetamol tablets sold without prescription
- B Heroin (diacetylmorphine) is a highly lipid-soluble opioid that rapidly crosses the blood-brain barrier, causing intense euphoria; highly addictive; overdose causes respiratory depression and death
- C Heroin is understood to possess essentially no meaningful addictive potential whatsoever, even among regular habitual users, allowing patients to stop using it at any time without withdrawal symptoms occurring
- D Heroin is classified pharmacologically as a powerful central nervous system stimulant rather than as a depressant drug, producing alertness and increased heart rate rather than sedation and slowed breathing
Correct answer: B. Heroin (diacetylmorphine) is a highly lipid-soluble opioid that rapidly crosses the blood-brain barrier, causing intense euphoria; highly addictive; overdose causes respiratory depression and death
Explanation: Heroin: semi-synthetic opioid from morphine, diacetylated for higher lipophilicity (crosses BBB 100x faster than morphine). Acts on mu-opioid receptors in brain. Causes: euphoria, analgesia, respiratory depression (overdose mechanism). Withdrawal: intense cravings, pain, vomiting, insomnia. Treatment: methadone/buprenorphine maintenance, naloxone (overdose reversal).
The Plasmodium parasite needs both hosts: the female Anopheles mosquito injects sporozoites while biting (infecting the human liver and RBCs, causing the malaria fever cycle), then picks up gametocytes from an infected person's blood, completing the parasite's sexual stage inside the mosquito.
Concept context
Pathogens, infectious diseases, non-infectious diseases, drugs, cancer, and public health. High NEET importance.