Certified Neuroscience Registered Nurse (CNRN) Practice Exam

Which tissue in the head/brain is non-pain sensitive?

1. Meninges

2. Brain parenchyma

3. Cerebrospinal fluid

4. Gray matter

The correct answer is: Brain parenchyma

The brain parenchyma is indeed non-pain sensitive due to the absence of pain receptors (nociceptors) in this tissue. This characteristic is significant in clinical contexts, particularly during neurosurgical procedures or conditions affecting the brain. While the surrounding structures, such as the meninges, have pain-sensitive fibers that can lead to pain sensations, the brain parenchyma itself does not register pain. This lack of pain sensitivity allows for certain interventions in the brain to be performed with less discomfort for the patient, as you can manipulate or biopsy brain tissue without the immediate sensation of pain. The meninges, on the other hand, are sensitive to pain and can contribute to headaches and other pain syndromes when inflamed. Cerebrospinal fluid also does not have pain receptors but plays a protective role and is not the tissue in question. Gray matter, which contains nerve cell bodies and is located within the brain, is also not pain-sensitive like the parenchyma because it has no exposure to nociceptive function. Recognizing which tissues are pain-sensitive and which are not is crucial in understanding patient experiences and responses to various neurological conditions and treatments.