Physiological / Biological Psychology

• What are the two fundamental types of cells in the nervous system?


  Neurons and glia
• What is the primary function of neurons?

  To transmit information throughout the nervous system
• What are the three main parts of a typical neuron?

  Cell body (soma), dendrites, and axon
• What is the role of dendrites in a neuron?


  Dendrites receive signals from other neurons
• How does the axon function in a neuron?

  The axon transmits signals away from the cell body to other neurons, muscles, or glands
• What is the function of the myelin sheath?

  To speed up signal transmission along the axon
• How are neurons classified?

  Based on their function (sensory, motor, interneurons) or structure (unipolar, bipolar, multipolar)
• What are the types of glial cells and their functions?

  • Astrocytes: Provide structural support, regulate the blood-brain barrier, maintain chemical environment.
  • Oligodendrocytes (CNS) and Schwann Cells (PNS): Produce myelin sheath for faster signal transmission.
  • Microglia: Act as immune cells, removing waste and protecting against pathogens.
  • Ependymal Cells: Line ventricles and help produce and circulate cerebrospinal fluid.
• Approximately how many neurons are in the adult human brain?

  About 86 billion neurons
• What significant discovery did Santiago Ramón y Cajal make about neurons?


  He demonstrated that the nervous system is made up of individual cells (neurons) connected by synapses
• What term did Waldeyer coin related to neurons?

  Neurons
• What is the role of a motor neuron?

  To receive excitation through its dendrites and conduct impulses to a muscle
• How does a sensory neuron function?

  A sensory neuron is specialized to be highly sensitive to a particular type of stimulation
• What is the significance of dendritic spines?

  Dendritic spines increase the surface area available for synapses
• What does the cell body (soma) of a neuron contain?

  The nucleus, ribosomes, and mitochondria
• What is the typical diameter range of a neuron’s cell body?

  From 0.005 mm to 0.1 mm in mammals
• What is the axon’s primary function?

  To convey an impulse toward other neurons, organs, or muscles
• What is an efferent axon?

  An efferent axon carries information away from a structure
• What is an afferent axon?

  An afferent axon brings information into a structure
• What is the blood-brain barrier (BBB)?


  The BBB is a mechanism that excludes most chemicals from the vertebrate brain
• Why is the blood-brain barrier essential?

  1. Protection from harmful substances (toxins, pathogens).
  2. Regulation of the brain's microenvironment (homeostasis).
  3. Prevention of neurotoxicity (protects against blood-borne neurotoxins).
  4. Isolation of neurotransmitter systems (prevents peripheral neurotransmitters from affecting brain function).
  5. Facilitation of brain function and cognitive processes (ensures neuronal sensitivity).
  6. Minimization of immune system interaction (reduces risk of autoimmune attacks).
• What do vertebrate neurons primarily depend on for nourishment?

  Glucose
• What is a nerve impulse?

  A nerve impulse is an electrical signal that travels along the axon of a neuron
• What is the thickness of the neuron membrane?

  About 8 nanometers (nm)
• What is the resting potential of a neuron?

  The resting potential is typically around -70 millivolts (mV)
• What ions are primarily involved in maintaining the resting membrane potential?

  Sodium (Na⁺) and potassium (K⁺) ions
• What is the role of the sodium-potassium pump?

  To actively transport 3 Na⁺ ions out and 2 K⁺ ions into the neuron
• What happens during depolarization of a neuron?

  Voltage-gated Na⁺ channels open, allowing Na⁺ ions to rush into the cell
• What is the all-or-none principle in action potentials?

  Once the threshold is reached, the action potential will occur fully and propagate along the entire length of the axon
• What is the typical threshold for triggering an action potential?

  Around -55 mV
• What occurs after the threshold is reached during an action potential?

  More Na⁺ channels open, leading to a rapid influx of Na⁺ and an increase in membrane potential
• What is the typical peak membrane potential during an action potential?

  Typically around +30 to +40 mV
• What is the significance of the resting membrane potential?

  It maintains a difference in electrical charge necessary for neuronal activity
• How does the blood-brain barrier contribute to homeostasis in the brain?

  It regulates the passage of ions, nutrients, and other substances to maintain a stable environment
• What is the role of astrocytes in the nervous system?

  Astrocytes provide structural support and regulate the blood-brain barrier
• What is the function of microglia?

  Microglia act as the brain's immune cells, removing waste and protecting against pathogens
• What is the function of ependymal cells?

  Ependymal cells line the ventricles of the brain and spinal cord, helping produce and circulate cerebrospinal fluid
• How does the blood-brain barrier protect the brain from toxins?

  It prevents potentially harmful substances in the blood from entering the brain tissue
• What is the role of the sodium-potassium pump in maintaining resting potential?

  It actively transports Na⁺ out and K⁺ into the neuron, maintaining concentration gradients
• What happens to the membrane potential during rapid depolarization?

  The membrane potential increases significantly due to the influx of Na⁺ ions