Answer
Pain signals from different regions of the head and body are transmitted to the brain via various cranial and spinal nerves. Here are the cranial nerves involved in each of the situations you mentioned:
(a) When sand blows into your eye, causing pain:
- The cranial nerve involved is the trigeminal nerve, specifically its ophthalmic branch (V1).
- The ophthalmic branch of the trigeminal nerve carries sensory information, including pain, from the eye and its surrounding structures.
(b) When you bite the back of your tongue, causing pain:
- The cranial nerve involved is still the trigeminal nerve, but in this case, it's the lingual branch of the mandibular division (V3).
- The mandibular division of the trigeminal nerve supplies sensory innervation to the tongue, including the sensation of pain when the tongue is bitten.
(c) When your stomach hurts from eating too much:
- The cranial nerves are not directly involved in conveying pain signals from the stomach. Instead, pain signals from the digestive organs, like the stomach, are primarily transmitted through spinal nerves.
- Specifically, pain signals from the stomach would travel through spinal nerves that correspond to the thoracic and upper abdominal regions of the spinal cord, such as the thoracoabdominal nerves.
- These spinal nerves relay the pain signals to the brain, allowing you to perceive abdominal discomfort or pain.
In summary, cranial nerves play a role in transmitting pain signals from specific regions of the head, but for pain originating from the stomach or other internal organs, spinal nerves are primarily responsible for conveying these signals to the brain.
Work Step by Step
Pain signals from different regions of the head and body are transmitted to the brain via various cranial and spinal nerves. Here are the cranial nerves involved in each of the situations you mentioned:
(a) When sand blows into your eye, causing pain:
- The cranial nerve involved is the trigeminal nerve, specifically its ophthalmic branch (V1).
- The ophthalmic branch of the trigeminal nerve carries sensory information, including pain, from the eye and its surrounding structures.
(b) When you bite the back of your tongue, causing pain:
- The cranial nerve involved is still the trigeminal nerve, but in this case, it's the lingual branch of the mandibular division (V3).
- The mandibular division of the trigeminal nerve supplies sensory innervation to the tongue, including the sensation of pain when the tongue is bitten.
(c) When your stomach hurts from eating too much:
- The cranial nerves are not directly involved in conveying pain signals from the stomach. Instead, pain signals from the digestive organs, like the stomach, are primarily transmitted through spinal nerves.
- Specifically, pain signals from the stomach would travel through spinal nerves that correspond to the thoracic and upper abdominal regions of the spinal cord, such as the thoracoabdominal nerves.
- These spinal nerves relay the pain signals to the brain, allowing you to perceive abdominal discomfort or pain.
In summary, cranial nerves play a role in transmitting pain signals from specific regions of the head, but for pain originating from the stomach or other internal organs, spinal nerves are primarily responsible for conveying these signals to the brain.
