Lecture 3

• What is the primary function of the nervous system?


  To send messages from various parts of the body to the brain and back to tell the body what to do

  
• What are the two main components of the central nervous system (CNS)?

  Brain and spinal cord
• What does the peripheral nervous system (PNS) consist of?

  Nerves and ganglia outside of the brain and spinal cord

  
• How can the peripheral nervous system be divided?

  Into motor and autonomic subdivisions
• What is the difference between the motor and autonomic subdivisions of the PNS?

  Motor subdivision deals with conscious functions, while autonomic subdivision deals with unconscious functions
• What are the functions and organs innervated by the motor and autonomic subdivisions?

  • Motor subdivision:
  • Function: Conscious sensory & motor functions
  • Organs innervated: Skin, skeletal muscle & tendons
  • Autonomic subdivision:
  • Function: Unconscious sensory & motor functions
  • Organs innervated: Smooth & cardiac muscle, glands & viscera
• Where are the nerve cell bodies located in the motor subdivision?

  Entirely within the CNS
• What are preganglionic and postganglionic neurons in the autonomic system?

  Preganglionic neurons have cell bodies in the CNS and synapse with postganglionic neurons in PNS ganglia
• What are the two divisions of the autonomic nervous system?

  • Sympathetic division
  • Parasympathetic division
• What is gray matter primarily composed of?

  Mostly neuron cell bodies
• What is white matter primarily composed of?

  Bundled axons
• What is a reflex in the context of the nervous system?

  A body's autonomic response to particular stimuli
• What does the enteric nervous system control?

  The digestive tract, pancreas, and gallbladder
• What does functional imaging allow researchers to do?


  Match specific functions with activity in certain areas of the brain
• What are the roles of the brainstem and cerebrum in arousal and sleep?

  They control arousal and sleep states
• How is arousal defined in the context of the nervous system?

  As a state of awareness of the external world
• What is sleep characterized by?

  A state in which external stimuli are received but not consciously perceived
• What is a biological clock?

  A molecular mechanism that directs periodic gene expression and cellular activity
• How are emotions processed in the brain?

  They depend on structures including the amygdala, hippocampus, and parts of the thalamus
• What is the reward system in the brain?

  A neural circuit that provides motivation for activities that enhance survival and reproduction
• How does drug addiction affect the reward system?

  It dramatically affects the reward system
• What are the functions of the cerebral cortex?

  • Language processing
  • Reasoning
  • Social understanding
  • Voluntary muscle movement
  • Learning and recalling information
• What is neuronal plasticity?

  The capacity for the nervous system to be remodeled in response to its own activity
• How is autism believed to be related to neuronal plasticity?

  A defect in neuronal plasticity may underlie autism
• What are the types of memory and their storage systems?

  • Non-verbal memories: perceptual skills & motor skills (stored in corpus striatum & cerebellum)
  • Verbal memories: left hemisphere
  • Visuospatial memories: right hemisphere
  • Fearful memories: amygdala
  • Long-term visual memories: inferior temporal lobe
  • Verbally coded numerical facts: left inferior frontal lobe
  • Declarative memory: facts and past events (located in medial brain)
• What is the difference between short-term and long-term memory?

  Short-term memory lasts seconds and is limited, while long-term memory lasts years and is more permanent
• What is the NIH brain initiative?

  A collaborative research effort to accelerate understanding of the human brain and treat brain disorders
• What is the significance of the evolution of cognition in vertebrates?

  It required the evolution of a highly convoluted cerebral cortex
• What are sensory receptors?

  Sensory cells or organs that detect stimuli
• What is transduction in sensory processing?

  The conversion of sensory stimulus from one form to another
• What is perception in the context of sensory processing?

  The detection of a stimulus by a sensory cell
• How is sensory information transmitted through the nervous system?

  As nerve impulses or action potentials
• How is the intensity of a stimulus encoded in sensory receptors?

  In the rate of action potentials produced by sensory receptors
• What are the types of sensory receptors and their functions?

  • Chemoreceptors: detect solute concentration and specific molecules
  • Pain receptors (nociceptors): detect harmful conditions
  • Thermoreceptors: detect heat and cold
  • Mechanoreceptors: sense physical deformation
  • Electromagnetic receptors: detect electromagnetic energy
• What are statocysts in invertebrates?

  Mechanoreceptors that sense gravity and maintain equilibrium
• How does hearing work in mammals?

  The ear transduces mechanical stimulus into nerve impulses perceived as sound
• What role do hair cells play in hearing?

  They detect motion and convert it into nerve impulses
• What do utricle and saccule allow us to perceive?

  Position with respect to gravity and linear movement
• What does the bending of hair cells in one direction cause?

  Depolarization of the cell and increased neurotransmitter release
• What happens when hair cells bend in the opposite direction?

  It has the opposite effect, decreasing neurotransmitter release