Autonomic Nervous System (A.N.S) Structure and Function

Autonomic Nervous System (A.N.S)

• A.N.S is divided into sympathetic and parasympathetic nervous systems.
• Sympathetic outflow comes from all thoracic and upper three lumber segments of the spinal cord.
• Parasympathetic outflow comes from:
• Cranial division: III, VI, and X cranial nerves.
• Sacral division: 2nd and 3rd sacral segments of the spinal cord.

Organs Under A.N.S Control

• Organs under parasympathetic tone: Heart, G.I.T., urinary tract, and tracheobronchial tree.
• Organs under sympathetic tone: Blood vessels.
• Organs under both sympathetic and parasympathetic systems: Iris and urinary bladder.

Function of A.N.S

• Regulates involuntary functions of the body, such as digestion, circulation, body temperature, and sweat.
• Functions of sympathetic and parasympathetic systems are usually opposing each other.
• The effect on a certain organ is the sum of both effects.

Drugs Acting on Sympathetic N.S: Adrenaline

• Adrenaline is a potent stimulant of both α and β receptors.
• Therapeutic uses:
• Local:
  • To stop local bleeding (e.g., epistaxis).
  • Added to local anesthetics to prolong their effect.
  • Nasal decongestant in common cold.
  • On eye to treat glaucoma.
• Systemic:
  • Dilates tracheobronchial tree in cases of bronchial asthma.
  • Cardiotonic (can be given intracardiac in cases of heart arrest).
  • Treats allergy and anaphylactic shock due to its physiologic antidote effect on histamine.

Autonomic Nervous System (A.N.S)

• A.N.S is divided into sympathetic and parasympathetic nervous systems.
• Sympathetic outflow comes from all thoracic and upper three lumber segments of the spinal cord.
• Parasympathetic outflow comes from:
• Cranial division: III, VI, and X cranial nerves.
• Sacral division: 2nd and 3rd sacral segments of the spinal cord.

Organs Under A.N.S Control

• Organs under parasympathetic tone: Heart, G.I.T., urinary tract, and tracheobronchial tree.
• Organs under sympathetic tone: Blood vessels.
• Organs under both sympathetic and parasympathetic systems: Iris and urinary bladder.

Function of A.N.S

• Regulates involuntary functions of the body, such as digestion, circulation, body temperature, and sweat.
• Functions of sympathetic and parasympathetic systems are usually opposing each other.
• The effect on a certain organ is the sum of both effects.

Drugs Acting on Sympathetic N.S: Adrenaline

• Adrenaline is a potent stimulant of both α and β receptors.
• Therapeutic uses:
• Local:
  • To stop local bleeding (e.g., epistaxis).
  • Added to local anesthetics to prolong their effect.
  • Nasal decongestant in common cold.
  • On eye to treat glaucoma.
• Systemic:
  • Dilates tracheobronchial tree in cases of bronchial asthma.
  • Cardiotonic (can be given intracardiac in cases of heart arrest).
  • Treats allergy and anaphylactic shock due to its physiologic antidote effect on histamine.

This quiz covers the structure and function of the Autonomic Nervous System (A.N.S), including the sympathetic and parasympathetic nervous systems and the organs they control.