nervous tissue

• What are the three types of nerve cells?

  Sensory, relay, and motor neurons
• What is nervous tissue primarily composed of?

  Specialized cells known as neurons
• What are the two main types of nervous tissue?

  Grey matter and white matter
• What are the two main components of the nervous system?

  Central nervous system and peripheral nervous system
• What is the function of nerve cells?

  To transmit signals around the body
• What is a bundle of nerve cells called?

  A nerve
• What is the role of dendrites in nerve cells?

  To communicate with neighboring cells
• What surrounds the axon of a nerve cell?

  Myelin sheath
• What is the function of the myelin sheath?

  To electrically insulate the axon
• What are the main components of a nerve cell?

  • Cell body/Soma: contains the nucleus
  • Axon: conducts electric impulses
  • Myelin sheath: electrically insulating layer
  • Dendrite: receives chemical signals
  • Schwann cells: produce myelin sheath
  • Node of Ranvier: gaps in myelin sheath
• What do sensory neurons do?

  Receive information from receptor cells
• What types of receptors do sensory neurons use?

  Photoreceptors, chemoreceptors, mechanoreceptors, thermoreceptors
• Where are relay neurons found?

  In the brain and spinal cord
• What do motor neurons do?

  Transmit information from CNS to effectors
• What are effectors?

  Cells or organs that carry out instructions
• What responses do effectors bring about?

  Muscle contraction or hormone release
• What is the difference between myelinated and non-myelinated nerve cells?

  Myelinated transmit impulses faster
• What are the characteristics of myelinated and non-myelinated nerve cells?

  • Myelinated:
  • Transmit impulses very fast
  • 1 - 3 ms
  • Have nodes of Ranvier
  • Non-myelinated:
  • Transmit impulses slower
  • 3 - 120 ms
  • No nodes of Ranvier
• What happens when an action potential reaches the synaptic bulb?

  Calcium channels open, allowing calcium ions in
• What do synaptic vesicles do when calcium ions enter?

  Fuse with the cell membrane to release neurotransmitters
• What is resting potential?

  Potential difference across a non-active nerve cell
• What is the approximate resting potential of a nerve cell?

  -60mV
• What happens when neurotransmitters bind to receptor sites?

  Sodium ion channels open in the membrane
• What is depolarization in nerve cells?

  Rapid influx of sodium ions into the cell
• What is the action potential value during depolarization?

  Approximately +40mV
• What occurs during repolarization?

  Potassium ions flow out, restoring negativity
• What is saltatory conduction?

  Signal jumps from one node to the next
• Why is saltatory conduction faster?

  Impulse jumps between nodes, using less ATP
• What is the structure of a single nerve?

  Contains both motor and sensory neurons
• What is the purpose of capillaries in nerves?

  To supply oxygen and glucose to cells
• What is a reflex?

  An automatic response to a stimulus
• What is the reflex arc?

  The sequence of a reflex action in the nervous system
• What disorders are associated with imbalances of brain chemicals?

  Parkinson's disease and depression
• What are the symptoms of Parkinson's disease?

  Muscle tremors, stiffness, and slowness of movement
• What causes Parkinson's disease?

  Death of dopamine-secreting neurons in the brain
• What is dopamine's role in the nervous system?

  Controls movement and emotional response
• What drug replaces lost dopamine in Parkinson's patients?

  L-dopa
• How do SSRIs affect the nervous system?

  They interfere with normal synapse functioning
• What is Prozac used for?

  To reduce depression
• How do SSRIs affect serotonin levels?

  They prevent serotonin reabsorption