General Functions of the Autonomic Nervous System

• ANS regulates organs/processes not under conscious control including:

  1. circulation

  2. digestion

  3. respiration

  4. temperature

  5. sweating

  6. metabolism

  7. some endocrine gland secretions

• Sympathetic system is most active when the body needs to react to changes in the internal or external environment: The requirement for sympathetic activity is most critical for:

  1. temperature regulation

  2. regulation of glucose levels

  3. rapid vascular response to hemorrhage

  4. reacting to oxygen deficiency

• During rage or fright the sympathetic system can discharge as a unit--affecting multiorgan systems.

• Sympathetic fibers show greater ramification.

• Sympathetic preganglionic fibers may traverse through many ganglia before terminiating at its post-ganglionic cell. Synaptic terminal arborization results in a single preganglionic fiber terminating on many post-ganglionic cells.

• This anatomical characteristic is the basis for the diffuse nature of sympathic response in the human and other species.

• Sympathetic Responses

• Increases heart rate & blood pressure

• Blood flow to skeletal muscles is increased

• Increases blood glucose

• Dilates bronchioles & pupils

• Parasympathetic responses

• Slows heart rate

• Constricts the pupil

• Lowers blood pressure

• Increases gastrointestinal motility

• Helps in empting bowel and bladder

Category: Pharmacology Notes