Final answer:
Enkephalins, dynorphins, endorphins, and endomorphins are all types of opioid peptides that function as the body's natural painkillers by binding to opioid receptors in the brain. They are naturally occurring substances with a variety of physiological roles, including pain regulation, mood control, and stress response.The Options 'c' and 'd' are the correct answer while option 'a' and 'b' are incorrect.
Step-by-step explanation:
The substances mentioned: enkephalins, dynorphins, endorphins, and endomorphins, are all indeed related; they are types of opioid peptides. Opioid peptides are small chains of amino acids that function as neurotransmitters in the brain and are involved in pain regulation, among other physiological activities. They bind to opioid receptors in the brain to produce analgesic effects, essentially acting as the body's natural painkillers.
Enkephalins and dynorphins, along with endorphins and endomorphins, are all different types of opioid peptides, but they slightly differ in their structure and function. The statement c. 'All these substances are opioid peptides' is the correct answer to the student's question. While they are all distinct substances within their own right -- endomorphins are indeed distinct from enkephalins, as indicated by option d, and enkephalins are a form of endorphins, contrary to option a. Option b is incorrect because dynorphins are indeed related to opioid peptides.
Opioid peptides and their receptors are targets for synthetic opioids used in pain management, and they are subject to research due to their role in addiction, mood regulation, and stress response. These peptides are produced naturally in the body and include well-known substances such as the neurotransmitter substance P and hormones like oxytocin and vasopressin, both of which have multiple roles beyond pain management.