Pharmacology: Nervous System

• The nervous system functions at the ______ level(s).

  voluntary and involuntary
• Central Nervous System


  consists of the brain and spinal cord
• Central Nervous System


  receives and interprets sensory information via peripheral afferent nerves, and then, initiates appropriate motor responses via peripheral efferent nerves.
• Peripheral Nervous System


  composed of 12 pairs of cranial nerves and 31 pairs of spinal nerces
• Peripheral Nervous System


  separated into two divisions: somatic and visceral
• Somatic Division 


  somatic nerves are the branches of cranial and spinal motor nerves that innervate skeletal muscle (voluntary). these nerves are under voluntary control of the cerebral cortex.
• Visceral Division or Autonomic Nervous System


  the visceral nerves are the branches of the cranial and spinal motor nerves that innervate cardiac and smooth muscle (involuntary) of the internal organs and glands.
• Visceral Division or ANS

  the visceral nerves are regulated by the hypothalamus and medulla oblongata
• Which of the following are true regarding efferent and afferent nerves?

  • Afferent nerves interpret sensory information
  • Efferent nerves initiate motor responses
• The normal balance of the body's internal organs, maintained by the ANS, is known as

  homeostasis
• The nerves of the sympathetic division of the ANS originate from which of the following?

  lumbar and thoracic nerves
• the ANS is composed of the parasympathetic and sympathetic divsions
• parasympathetic division (“craniosacral division”): originate from the brain (cranial nerves 3, 7, 9, 10) and spinal cord (sacral nerves S2 to S4).
• parasympathetic division 


  the cranial nerves supply the internal organs and glands of the head, thoracic cavity band upper portion of the abdominal cavity. the sacral nerves supply the lower portion of the abdominal cavity and pelvic cavity.
• sympathetic nervous system (”thoracolumbar division”)

  originate from the thoracic and lumbar spinal nerves (T1 to L3).
• sympathetic nervous system (”thoracolumbar division”)

  the thoracic nerves supply the internal organs and glands of the head, thoracic cavity, and upper abdominal cavity.
• sympathetic nervous system (”thoracolumbar division”)

  the lumber nerves supply the lower portion of the abdominal cavity and the pelvic cavity.
• most blood vessels do not receive parasympathetic innervation. blood pressure is controlled by either increasing sympathetic activity to cause vasoconstriction or decreasing sympathetic activity to cause vasodilation.
• “fight or flight”


  during this reaction, the adrenal medulla releases epinephrine (“adrenaline”) and some norepinephrine into the blood. these neurotransmitters then act as hormones and travel to all sympathetic receptor sites producing intense sympathetic stimulation.
• sympathetic stimulation

  • increases heart rate and force of myocardial contraction
• sympathetic stimulation


  bronchodilation allows for more air exchange in the lungs
• sympathetic stimulation: 


  activity of GI and urinary tract is inhibited
• parasympathetic:


  increase body functions such as digestion and elimination of waste products
• Smooth muscle of the blood vessels do not receive parasympathetic innervation
• Cardiac and smooth muscle possess a special property called

  autorhythmicity
• When one division of the nervous system increases the activity of a particular organ while the other decreases the activity is referred to as ______.

  dual autonomic innervation
• What occurs when the sympathetic division is stimulated in the fight or flight reaction?

  • Vasoconstriction
  • Decreased GI motility
• Which of the following is true of blood pressure in regards to autonomic nerve function?

  • Decreased sympathetic activity causes vasodilation
  • Increased sympathetic activity causes vasoconstriction
• The nerves of the ANS innervate which of the following muscles?

  • Smooth
  • Cardiac
• When is the parasympathetic division more active?

  • During restoration of body energy stores
  • During periods of rest
• In the ANS, what do neurons that emerge from the central nervous system form?

  Preganglionic nerve fiber
• What occurs to the heart when the sympathetic division is activated?

  • Contractility is increased
  • Heart rate increases
• Which neurotransmitter is responsible for stimulation of the parasympathetic cholinergic nerves?

  Acetylcholine
• Which of the following are the two main types of cholinergic receptors?

  • Nicotinic
  • Muscarinic
• The parasympathetic nerves increase which of the following body functions?

  • Defecation
  • Urination
  • Digestion
• Neurons that travel from the ganglion to the internal organ form the _____.

  postganglionic nerve fiber
• In the sympathetic division, the postganglionic neurons release NE to stimulate the ____ receptors.

  adrenergic
• The cholinergic receptors are stimulated by

  acetylcholine
• adrenergic neuronal blocker


  drug that acts at the neuronal nerve endings to reduce the formation or release of NE
• alpha-adrenergic drug


  drug that stimulates the alpha-adrenergic receptors