ANS

• What is the autonomic nervous system (ANS) a branch of?

  The efferent division of the peripheral nervous system (PNS)

  
• What does the autonomic nervous system (ANS) control?

  The body's internal environment in a coordinated manner
• Which muscles and glands does the ANS regulate?

  Cardiac muscle, smooth muscle, and glands
• Which internal organs are controlled by the ANS?

  Heart, lungs, stomach, pancreas, eye, sweat glands, bladder, kidney, liver
• What part of the nervous system integrates autonomic reflexes?

  The spinal cord
• What autonomic reflexes are not subject to higher control?

  Urination and defecation
• Which parts of the brain regulate cardiovascular, respiratory, and digestive tracts?

  The medulla and pons
• What functions does the hypothalamus control in relation to the ANS?

  Heart rate, blood pressure, and respiration
• What are the two main divisions of the ANS?

  The sympathetic and parasympathetic nervous systems

  
• What is the primary function of the sympathetic nervous system?

  To prepare the body for "fight or flight" responses
• What is the primary function of the parasympathetic nervous system?

  To promote "rest and digest" activities
• What are the effects of the sympathetic nervous system on the body?

  • Dilates pupils
  • Increases heart rate and contractility
  • Dilates airways
  • Inhibits digestive activity
  • Closes sphincters
  • Stimulates release of glucose
  • Inhibits salivation

  
• What are the effects of the parasympathetic nervous system on the body?

  • Constricts pupils
  • Slows heart rate and contractility
  • Constricts airways
  • Stimulates digestive activity
  • Opens sphincters
  • Stimulates salivation

  
• What is the structure of every ANS pathway from the CNS to the effector organ?

  CNS → pre-ganglionic neuron → ganglion → post-ganglionic neuron → effector organ
• What is a ganglion in the context of the ANS?

  A cluster of neural cell bodies outside the CNS
• What is the role of varicosities in the ANS?

  To increase surface area targeted by neurotransmitter release
• What neurotransmitter is released by pre-ganglionic nerves in the parasympathetic system?

  Acetylcholine (ACh)
• What type of receptors does acetylcholine bind to in the ANS?

  Cholinergic receptors
• What are the two types of cholinergic receptors?

  Nicotinic and muscarinic receptors
• What type of receptors are adrenergic receptors?

  Metabotropic receptors
• What is the effect of α1 adrenergic receptors?

  Excitatory, increases contraction of arterioles
• What is the effect of β1 adrenergic receptors?

  Excitatory, increases contraction of cardiac muscle
• What is the role of the adrenal medulla in the sympathetic nervous system?

  It secretes neurotransmitters (hormones) into the blood

  
• What percentage of hormone release from the adrenal medulla is adrenaline?

  80%

  
• What is the primary function of muscarinic antagonists?

  To block muscarinic receptors
• What is the effect of adrenergic agonists on the body?

  They activate adrenergic receptors
• What neurotransmitter do most sweat glands release?

  Acetylcholine (ACh)
• How do the sympathetic and parasympathetic systems work together in the body?

  They provide dual reciprocal innervation, allowing rapid and precise control

  
• What is tonic activity in the context of the ANS?

  Partial activation of both systems under most circumstances
• What happens to the sympathetic nervous system during emergency situations?

  It dominates and promotes responses for physical activity
• What happens to the parasympathetic nervous system in quiet situations?

  It dominates and promotes body maintenance
• What are the effects of sympathetic stimulation on the heart?

  Increased rate and force of contraction
• What are the effects of parasympathetic stimulation on the heart?

  Decreased rate and force of contraction (atria only)
• What are the effects of sympathetic stimulation on the lungs?

  Bronchiole dilation
• What are the effects of parasympathetic stimulation on the lungs?

  Bronchiole constriction
• What are the effects of sympathetic stimulation on the digestive tract?

  Decreased motility and inhibition of secretions
• What are the effects of parasympathetic stimulation on the digestive tract?

  Increased motility and stimulation of secretions
• What are the effects of sympathetic stimulation on the eye?

  Pupil dilation
• What are the effects of parasympathetic stimulation on the eye?

  Pupil constriction
• What regulates heart rate and force of contraction?

  The sino-atrial (SA) node and myocytes