NURS 2320U Lecture Notes - Afferent Nerve Fiber, Reflex Arc, Cranial Nerves
Document Summary
A dermatome is an area of skin supplied with afferent nerve fibres by a single posterior spinal root. The areas supplied by each nerve are illustrated on page 660 of the textbook. There are 31 pairs of spinal nerves (8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal). The spinal nerves are mixed nerves because they contain both sensory and motor fibres. The assessment of dermatomes, which are specific skin surfaces and specific skeletal muscles, provides information on pns function and its integrity with the cns (jarvis, 1999). Stroke patients or patients with spinal anesthesia (c- section) may be at risk. Reflexes control and permit quick reactions to potentially painful or damaging situations. Reflexes also help the body maintain balance and appropriate muscle tone. There are four types of reflexes: (1) deep tendon (myotatic), (2) superficial, (3) visceral (organic), and (4) pathological (abnormal).
