Final answer:
The inability to smell, termed anosmia, is typically associated with a dysfunctional olfactory nerve, which is the first cranial nerve responsible for the sense of smell. This may be caused by factors including head trauma or aging, but there is potential for recovery if the nerve is not completely severed.
Step-by-step explanation:
If a client is unable to smell morning coffee, the olfactory nerve, which is the first cranial nerve, is likely dysfunctional. This condition is known as anosmia.Anosmia may occur due to various reasons, including blunt trauma to the head or aging. The sensory neurons in the olfactory epithelium normally have a short lifespan, and new neurons regularly replace the old ones.
These new neurons send out axons that grow along the existing neural pathways into the central nervous system (CNS). However, if the olfactory nerve is severed, such as in a motor vehicle accident, it can cause a permanent loss of smell if all the nerve fibers are sheared and unable to regrow. In situations where the axons are not completely destroyed, there is potential for the sense of smell to be restored as neurons can regenerate and eventually reconnect.