somatic

Examples of somatic in the following topics:

• Comparing the Somatic and Autonomic Nervous Systems

  • The peripheral nervous system includes both a voluntary, somatic branch and an involuntary branch that regulates visceral functions.
  • The peripheral nervous system (PNS) is divided into the somatic nervous system and the autonomic nervous system.
  • The somatic nervous system (SoNS) is the part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles.
  • The somatic nervous system controls all voluntary muscular systems within the body, and also mediates involuntary reflex arcs.
  • The somatic nervous system consists of three parts:

• Localization of Pain

  • Localization of pain is determined by whether the pain is superficial somatic, visceral, or deep somatic.
  • Nociceptive pain may also be divided into visceral, deep somatic, and superficial somatic pain.
  • Deep somatic pain is initiated by the stimulation of nociceptors in ligaments, tendons, bones, blood vessels, fasciae, and muscles, and is a dull, aching, poorly localized pain.
  • Examples of injuries that produce superficial somatic pain include minor wounds and minor (first degree) burns.

• Autonomic Reflexes

  • In these cases, the body will interpret the afferent pain stimulus as somatic.
  • If the peritoneal cavity becomes inflamed or if the bowel is suddenly distended, the body will interpret the afferent pain stimulus as somatic in origin.
  • This schematic (but not anatomically correct) depiction of a typical spinal nerve indicates (1) somatic efferent fibers, (2) somatic afferent fibers, (3 to 5) sympathetic efferent fibers, and (6 and 7) sympathetic afferent fibers.

• Somatic Sensory Pathways to the Cerebellum

  • Commonly recognized sensory systems are those for vision, hearing, somatic sensation (touch), taste, and olfaction (smell).

• Branches of Spinal Nerves

  • The dorsal ramus: Contains nerves that serve the dorsal portions of the trunk carrying visceral motor, somatic motor, and sensory information to and from the skin and muscles of the back.
  • The ventral ramus: Contains nerves that serve the remaining ventral parts of the trunk and the upper and lower limbs carrying visceral motor, somatic motor, and sensory information to and from the ventrolateral body surface, structures in the body wall, and the limbs.

• Micturition and the Micturition Reflex

  • Physiologically, micturition involves coordination between the central, autonomic, and somatic nervous systems.
  • The muscles controlling micturition are controlled by the autonomic and somatic nervous systems, which open the two sphincters during the voiding phase of micturition.
  • The external urethral sphincter (sphincter urethrae) is under somatic control and is consciously relaxed (and thus opened) during micturition.

• Pons

  • The alar plate produces sensory neuroblasts, which will give rise to the solitary nucleus and its special visceral afferent column, the cochlear and vestibular nuclei (which form the special somatic afferent fibers of the vestibulocochlear nerve), the spinal and principal trigeminal nerve nuclei (which form the general somatic afferent column of the trigeminal nerve), and the pontine nuclei, which is involved in motor activity.
  • Basal plate neuroblasts give rise to the abducens nucleus (forms the general somatic efferent fibers), the facial and motor trigeminal nuclei (form the special visceral efferent column), and the superior salivatory nucleus, which forms the general visceral efferent fibers of the facial nerve.

• Antibodies: Classes and Affinity Maturation

  • Antibodies undergo class switching, somatic hypermutation, and affinity maturation to improve their effectiveness to specific pathogens.
  • In these rapidly dividing cells, the genes encoding the variable domains of the heavy and light chains undergo a high rate of point mutation by a process called somatic hypermutation (SHM).

• Pain Sensation

  • Nociceptive pain can be divided into visceral, deep somatic and superficial somatic pain.
  • Deep somatic pain is initiated by stimulation of nociceptors in ligaments, tendons, bones, blood vessels, fasciae and muscles, and is a dull, aching, poorly localized pain.
  • Examples of injuries that produce superficial somatic pain include minor wounds and minor (first degree) burns.

• Function and Physiology of the Spinal Nerves

  • The peripheral nervous system is divided into the somatic nervous system and the autonomic nervous system.
  • The somatic nervous system consists of afferent and efferent nerves and is associated with the voluntary control of skeletal muscle movements.
  • Numbers indicate the types of nerve fibers: 1 somatic efferent, 2 somatic afferent, 3–5 sympathetic efferent, 6–7 sympathetic afferent.