CHAPTER 16

• What is the autonomic nervous system also known as?

  Visceral motor system
• What does the autonomic nervous system regulate?

  Basic life support systems without conscious control
• What are the aspects of higher-order functions considered in this chapter?

  Consciousness, learning, and intelligence
• How does the autonomic nervous system contribute to survival during unconsciousness?

  It makes routine homeostatic adjustments in physiological systems
• What physiological functions does the autonomic nervous system coordinate?

  Cardiovascular, respiratory, digestive, urinary, and reproductive functions
• What triggers visceral reflexes in the autonomic nervous system?

  Somatic or visceral sensory information
• What happens to the body in response to cold weather according to the autonomic nervous system?

  The ANS stimulates arrector pili muscles causing goosebumps
• How does a sudden loud noise affect the body through the autonomic nervous system?

  It can increase heart rate and temporarily stop digestive gland secretion
• What are the major types of receptors in the autonomic nervous system?

  Plasma membrane receptors
• What is the primary structural difference between the somatic and autonomic nervous systems?

  • SNS motor neurons exert direct control over skeletal muscles
  • ANS motor neurons synapse on visceral motor neurons in autonomic ganglia
• What are the two major divisions of the autonomic nervous system?

  Sympathetic and parasympathetic divisions
• How do the sympathetic and parasympathetic divisions typically interact?

  They often have opposing effects on the same effector
• When does the sympathetic division typically activate?

  During exertion, stress, or emergency
• What are the overall responses to increased sympathetic activity?

  1. Heightened mental alertness
  2. Increased metabolic rate
  3. Decreased digestive and urinary functions
  4. Activation of energy reserves
  5. Increased respiratory rate and dilation of respiratory passageways
  6. Increased heart rate and blood pressure
  7. Activation of sweat glands
• What is the primary function of the parasympathetic division?

  To stimulate visceral activity and promote "rest and digest" functions
• What are the overall responses to increased parasympathetic activity?

  1. Decreased metabolic rate
  2. Decreased heart rate and blood pressure
  3. Increased secretion by salivary and digestive glands
  4. Increased motility and blood flow in the digestive tract
  5. Stimulation of urination and defecation
• What is the role of the hypothalamus in the autonomic nervous system?

  It contains the integrative centers for autonomic activity
• What are preganglionic neurons in the autonomic nervous system?

  Visceral motor neurons that extend to ganglia
• What are ganglionic neurons in the autonomic nervous system called?

  Postganglionic neurons
• What do postganglionic fibers do in the autonomic nervous system?

  They extend to the peripheral target organs
• What are the three locations where ganglionic neurons may synapse in the sympathetic division?

  1. Sympathetic chain ganglia
  2. Collateral ganglia
  3. Adrenal medullae
• What is the thoracolumbar division of the autonomic nervous system?

  The sympathetic division due to its preganglionic neurons' location
• What neurotransmitter do preganglionic fibers release in the sympathetic division?

  Acetylcholine (ACh)
• How does the adrenal medulla function in the sympathetic division?

  It secretes neurotransmitters directly into the bloodstream
• What is the pathway for sympathetic preganglionic fibers targeting structures in the body wall?

  • Preganglionic fibers synapse in sympathetic chain ganglia
  • Each chain contains multiple ganglia affecting various organs
• How many sympathetic chain ganglia are typically present in the body?

  3 cervical, 10–12 thoracic, 4–5 lumbar, 4–5 sacral, and 1 coccygeal ganglion
• What is the role of myelinated white ramus communicans in the sympathetic division?

  It carries myelinated preganglionic fibers into a nearby sympathetic chain ganglion
• How do preganglionic fibers in the sympathetic division diverge?

  One preganglionic fiber can synapse on two dozen or more ganglionic neurons
• What is the function of sympathetic chain ganglia?

  They control effectors in the body wall, thoracic cavity, head, neck, and limbs
• What do collateral ganglia innervate?

  Abdominopelvic tissues and viscera
• What is the adrenal medulla considered in the sympathetic division?

  A modified sympathetic ganglion
• What happens when the adrenal medullae are stimulated?

  They secrete neurotransmitters into the bloodstream
• How does the release of neurotransmitters from the adrenal medullae function as hormones?

  It allows neurotransmitters to affect target cells throughout the body
• What is the significance of the sympathetic chain ganglia in the autonomic nervous system?

  • They allow for widespread effects on multiple organs
  • They facilitate rapid responses to stress
• What is the primary role of the sympathetic division during emergencies?

  To prepare the body to deal with emergencies
• What physiological changes occur during the "fight or flight" response?

  Increased alertness, metabolic rate, heart rate, and blood flow to muscles
• How does the sympathetic division affect digestive processes during stress?

  It temporarily stops digestive processes
• What happens to breathing during sympathetic activation?

  Breathing becomes quicker and deeper
• What is the effect of sympathetic activation on sweat glands?

  It activates sweat glands
• What is the overall pattern of responses to increased parasympathetic activity?

  Decreased metabolic rate and increased digestive activity