Central Nervous System
20. Hot water bag use in intestine colic works by inhibiting- AIPG 2010
|C||Cold receptor in skin|
|D||Due to increased temp of peritoneal membr|
a. Afferent fibers from visceral structures reach the CNS via sympathetic and parasympathetic nerves. Their cell bodies are located in the dorsal roots and the homologous cranial nerve ganglia.
b. Specifically, there are visceral afferents in the facial, glossopharyngeal, and vagus nerves; in the thoracic and upper lumbar dorsal roots; and in the sacral roots .
c. Vagal connections provide a massive sensory link for "physiological information", while sympathetic unmyelinated C fibres provide sensations of visceral pain.
Pain innervation of the viscera. Pain afferents from structures between the pain lines reach the CNS via sympathetic pathways, whereas, they traverse parasympathetic pathways from structures above the thoracic pain line and below the pelvic pain line.
Gate Control Theory & Lateral inhibition
a. Stimulation of skin at the site of pain also gives some pain relief. The relief may result from inhibition of pain pathways in the dorsal horn gate by stimulation of large-diameter touch-pressure afferents.
b. Collaterals from these myelinated afferent fibers synapse in the dorsal horn. These collaterals inhibit the input from nociceptive afferent fibres that also synapse in the dorsal horn. This is called the gate-control hypothesis.
c. The same mechanism is probably responsible for the efficacy of counterirritants, Hot water bags etc . Stimulation of the skin over an area of visceral inflammation produces some relief of the pain due to the visceral disease by inhibiting C unmyelinatedAdrenergicfibres from GIT carrying visceral pain.