HA12 - Chapter 16

• What does Chapter 16 explore in relation to the nervous system?


  It explores the levels and components of sensation.
• What is the process called when incoming sensory information is combined with other information?


  Integration.
• What are the three complex integrative functions of the brain introduced in this chapter?


  Wakefulness and sleep, learning and memory, and language.
• What is the role of sensory receptors in the process of sensation?


  Sensory receptors respond to specific stimuli and initiate the sensation process.
• What are the four events that typically occur for a sensation to arise?

  Stimulation of the sensory receptor, transduction of the stimulus, generation of nerve impulses, and integration of sensory input.
• What is transduction in the context of sensory receptors?


  It is the conversion of stimulus energy into a graded potential.
• How does a graded potential differ from an action potential?


  A graded potential varies in amplitude and is not propagated, while an action potential is a fixed amplitude signal that propagates along the neuron.
• What triggers the generation of nerve impulses in sensory neurons?


  When a graded potential reaches threshold.
• Where are conscious sensations or perceptions integrated in the CNS?


  In the cerebral cortex.
• What is the definition of sensation?


  The conscious or subconscious awareness of changes in the external or internal environment.
• What is the difference between sensation and perception?


  Sensation is the awareness of stimuli, while perception is the conscious interpretation of those sensations.
• What are the two classes of sensory modalities?

  General senses and special senses.
• What do general senses include?


  Tactile sensations, thermal sensations, pain sensations, and proprioceptive sensations.
• What are special senses?


  They include the sensory modalities of smell, taste, vision, hearing, and equilibrium.
• What is the role of proprioceptors?


  They provide information about body position, muscle length and tension, and joint movement.
• How do sensory receptors respond to stimuli?


  By generating a graded potential known as a receptor potential.
• What is adaptation in sensory receptors?


  It is the decrease in receptor potential amplitude during a maintained, constant stimulus.
• What are exteroceptors?


  Receptors located at or near the external surface of the body that are sensitive to external stimuli.
• What do interoceptors monitor?


  Conditions in the internal environment, such as those in blood vessels and visceral organs.
• What do proprioceptors provide information about?


  Body position, muscle length and tension, and joint movement.
• What type of stimuli do mechanoreceptors detect?


  Mechanical stimuli such as deformation, stretching, or bending of cells.
• What do thermoreceptors detect?


  Changes in temperature.
• What do nociceptors respond to?


  Painful stimuli resulting from physical or chemical damage to tissue.
• What do photoreceptors detect?


  Light that strikes the retina of the eye.
• What do chemoreceptors detect?


  Chemicals in the mouth (taste), nose (smell), and body fluids.
• What do osmoreceptors detect?


  The osmotic pressure of body fluids.
• What are the different ways to classify sensory receptors?

  1. Microscopic structure

  • Free nerve endings
  • Encapsulated nerve endings
  • Separate cells

  1. Location of receptors and origin of stimuli

  • Exteroceptors
  • Interoceptors
  • Proprioceptors

  1. Type of stimulus detected

  • Mechanoreceptors
  • Thermoreceptors
  • Nociceptors
  • Photoreceptors
  • Chemoreceptors
  • Osmoreceptors
• What is the classification of sensory receptors based on microscopic structure?


  • Free nerve endings: bare dendrites for pain, thermal, tickle, itch, and some touch sensations.
  • Encapsulated nerve endings: dendrites enclosed in connective tissue for pressure, vibration, and some touch sensations.
  • Separate cells: receptor cells synapse with first-order sensory neurons (e.g., photoreceptors, hair cells, gustatory receptors).
• What is the classification of sensory receptors based on location and activating stimuli?


  • Exteroceptors: sensitive to external stimuli, provide information about the external environment.
  • Interoceptors: monitor internal conditions, usually not consciously perceived.
  • Proprioceptors: provide information about body position and movement.
• What is the classification of sensory receptors based on the type of stimulus detected?

  • Mechanoreceptors: detect mechanical stimuli.
  • Thermoreceptors: detect temperature changes.
  • Nociceptors: respond to painful stimuli.
  • Photoreceptors: detect light.
  • Chemoreceptors: detect chemicals.
  • Osmoreceptors: detect osmotic pressure.
• What are receptor cells that synapse with first-order sensory neurons located in?


  Retina of the eye, inner ear, and taste buds of the tongue
• What are the three types of receptors based on location and their functions?

  • Exteroceptors: Sensitive to external stimuli, provide information about the external environment.
  • Interoceptors: Provide information about the internal environment, usually not consciously perceived.
  • Proprioceptors: Provide information about body position, muscle length and tension, and equilibrium.
• Where are exteroceptors located?


  At or near the body surface
• What type of information do interoceptors provide?


  Information about the internal environment
• What do proprioceptors provide information about?


  Body position, muscle length and tension, and equilibrium
• What are the types of stimuli detected by different receptors?

  • Mechanoreceptors: Detect mechanical stimuli (touch, pressure, vibration).
  • Thermoreceptors: Detect changes in temperature.
  • Nociceptors: Respond to painful stimuli.
  • Photoreceptors: Detect light.
  • Chemoreceptors: Detect chemicals in taste and smell.
  • Osmoreceptors: Sense osmotic pressure of body fluids.
• What are corpuscles of touch also known as?


  Meissner corpuscles
• Where are corpuscles of touch located?


  In the dermal papillae of hairless skin
• What type of receptors are hair root plexuses?


  Rapidly adapting touch receptors found in hairy skin
• What do Type I cutaneous mechanoreceptors respond to?


  Continuous touch